Finally! A valid TFS-R and TFS Box R intake dyno comparison on a street stroker.

5spd GT

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Not sure why you quoted his question to me. The test he was asking about, and the one you appear to be asking about now, are of the same motor from bottom to top, with the exception of a swap from a 75mm TB to a 90mm TB on the same TFS Box-R upper manifold. The TB swap resulted in 14 extra hp below 6000 rpm.

So it was the exact same upper intake (not removed) and it was just a TB swap with a port match opening? I would enjoy reading this article.
 
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90lxcoupe

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It's also not going to want to rev out above 6k, which IMO doesn't take full advantage of the shorter runners in the Box-R. I think the Box-R would prefer to have an extended rev-range well into the mid 7k range, perhaps higher.

I dont really agree with this, mostly because of the fact that the person who spec'd out my camshaft stated that the intake and headers would be the two limiting factors concerning RPM and power. Until i see a test where a box R intake actually makes power past 7250rpm, i will take his word for it. I think the long runners are what hurt all of these EFI SBF intakes back. The runners on the Box-r are shorter than other intakes, but they are still much longer than a Victor Jr or a Super Victor.
 

95Vert383AOD

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I have a friend who was an engine builder. (Chevy Guy)

When i was building my 383 and was pondering these same questions he explained to me that the LS2 and LS7 had a 90mm Bore. my 383 is around that displacement and in intended for performance.

I too have a trickflow box r with accufab 90mm TB.

Chris
 

FastDriver

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So it was the exact same upper intake (not removed) and it was just a TB swap with a port match opening? I would enjoy reading this article.

Yes. If by "port match" you mean that the 90mm TB should be very close to the 90mm inlet, then yes. No inlet-match work was done or anything, though. It was straight of the shelf.

I dont really agree with this, mostly because of the fact that the person who spec'd out my camshaft stated that the intake and headers would be the two limiting factors concerning RPM and power. Until i see a test where a box R intake actually makes power past 7250rpm, i will take his word for it. I think the long runners are what hurt all of these EFI SBF intakes back. The runners on the Box-r are shorter than other intakes, but they are still much longer than a Victor Jr or a Super Victor.

You could be right, but honestly how would this guy know? Has he done testing that indicated a loss up high in comparison to these intakes? Or, is it just an educated guess based on the runner length? What I do know is that the TFS-R intake can flow in excess of 300cfm with a port job. So, I'm thinking it should make plenty of power into high RPM.

I have a friend who was an engine builder. (Chevy Guy)

When i was building my 383 and was pondering these same questions he explained to me that the LS2 and LS7 had a 90mm Bore. my 383 is around that displacement and in intended for performance.

I too have a trickflow box r with accufab 90mm TB.

Chris

I agree, I think you made a good decision.:nice:
 

NIKwoaC

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Nik, what took you so long? I knew you'd like the article.

I've been crazy busy with work and personal life. Have not been getting my regular amount of therapy time on StangNet, haha. Took me 3 tries before I could make the post you're reading now, I kept getting pulled away!

I would've been one of those guys telling you that about a 75mm vs. a 90mm. In fact, I think I have said that to you in the past. I wouldn't have expected that result.

Yea, but you're more open minded than some that I see on the internet, and (obviously, from this post) willing to learn and accept new ideas. There will be some that will see this test and only try to poke holes in the logic and ignore the results.

From that article, here's how I gather you could tell if it will make a difference in your motor. In the article, they recorded a vacuum of 1" at WOT. Switching to the 90mm TB resulted in a drop from 1" to .3" vacuum @ WOT. I'm assuming they were taking these measurements at high rpm. I would also assume that you'd need a combo where the heads and intake were not already the weak point in flow. Both of those assumptions should be evident if you measured your manifold vacuum, particularly if you can figure out how to datalog that info. Of course, keep in mind that a vacuum doesn't necessarily indicate that the TB is the cause - could be the MAF, filter, piping, etc...

This is what I always try to tell people when the discussion turns to TB/MAF sizing. In a high performance motor, there is no "sizing" of these parts. There's no magic formula that helps you pick a TB size. You just select one that is big enough (within reason) to minimize manifold vacuum as much as possible at WOT. (...And this pretty much comes down to the size of the intake opening, or how much you can hog it out.) ANY vacuum at WOT is an indication of flow inefficiency upstream of the intake, and it is GIVING UP POWER.

The OEM has a pretty good handle on this thinking; the Coyote has an 80mm TB and the LS junk has had "huge" TBs for years. Why 5.0 guys are still limiting themselves to 75mm, I have no idea.

On the dyno graph comparison, there was no hit to torque or power anywhere. The difference increased almost linearly as rpm increased. I would have expected the 75mm to start reaching its potential before the 90 mm actually made any difference. From this test, that does not seem to be the case.

Mo air is mo powa. :D

I can't scan it for you, because I downloaded the digital book for $25. I think we can work out something better, though. Shoot me an email to [email protected]

Was the book worth your hard earned money? I may pick it up myself. Are there paper copies out there?

I wouldn't expect drivability issues, but the tune would have to be more precise, since opening the TB blade by any given angle will result a greater difference in the amount of air that flows. To be more concise, you lose resolution regarding the TPS input at low throttle. Naturally, I'd expect a motor with a huge TB to be more sensitive to the throttle down low. So that means 1/3 throttle with the small TB might be more like 1/4 throttle with the larger one. At low RPM - cruising speeds, you might not feel a difference in acceleration between 1/3 throttle and WOT.

Now, I have *heard* that the bigger TBs (like the Accufab 90) have different geometry on the butterfly valve lever that is supposed to modulate the blade slower at lower openings to help with this issue. I do not know if that is true or not, just what I've heard. Either way, I know of guys running 90s on STREET driven 302s with no problems.

Until we see more testing, I'd hold on to it to verify that the Box actually does make more power on your combo.

Nik, if I head that way in the next year like we talked about (a big if) and you haven't swapped it, let's get together and do a little dyno testing, for the hell of it. I'm running a 75mm TB on my box upper, because the HP kit's piping is too small for a 90mm - that's what I was told. I have higher priorities to work through at the moment regarding both life and the car, but eventually, I'll fab up larger piping and switch over to the 90mm TB.

Chris

Sounds good. :nice:

Interesting test, but I have to agree with Tom. The camshaft is the gatekeeper to all incoming and exiting air. The particular combination switch (intake) could be tailored towards one side or the other. Atleast that test is much better than many comparisons I have seen. A 75mm TB is plenty for that combination IMO.

Joking? Here we have a legitimate test where switching to the 90mm TB proved significant gains over the 75. It doesn't get any more clear cut than this: the 75mm WAS NOT "plenty" for that combination.

The only difference between those two intakes tested is the TB opening diameter? The runner shape, length, taper, etc. is all the same?

Not sure what you're asking...? See below.

[...] same motor from bottom to top, with the exception of a swap from a 75mm TB to a 90mm TB on the same TFS Box-R upper manifold. The TB swap resulted in 14 extra hp below 6000 rpm.

It feels like that's a bit of a hand-waved answer. Why wouldn't these supposed advantages of long-runners manifest themselves in that range with any cam?

How do you take advantage of a long runner intake? Cam it to make power in that powerband. Correct me if I'm wrong, but the XE274 is pretty well documented and should be a pretty tame cam on a 331 with plenty of vacuum and pretty streetable. It should produce plenty of low-mid range tq. It's also not going to want to rev out above 6k, which IMO doesn't take full advantage of the shorter runners in the Box-R. I think the Box-R would prefer to have an extended rev-range well into the mid 7k range, perhaps higher. So to me, it seems like this cam should be advantageous to the long-runner intake in this test, if anything.

Keep in mind, Chris, that the cam does not dictate the rpm band of the engine alone. It is the combo of parts that does, and I think that is part of what Tom was getting at above.

It would be my guess that a more aggressive cam might help the long runner intake shine a bit more, but maybe at the cost of some drivability. Of course, put that more aggressive cam in the box intake engine, and it will likely rev even higher and make even more power, so I'm not sure that camming the long runner intake engine would necessarily help it outperform the box intake engine, but maybe just help it do better than it did in that test.

Of course I'm generalizing here a little bit. I know cam guys will do different things with valve events given the style of intake used. That said, if a GOOD cam guy were given the opportunity to create a cam tailored to each intake, my hunch is that the Box might still have the edge. Who knows.

It's all about the combo, hell, I've seen guys with iron GT40 junk make 350 to the tire and run 11s. There are just obviously better parts to help you make more power when put together right, and I think this article is good argument that the Box R is a serious piece.

Still, until I've seen otherwise, this article has shown me that the commonly held perception that boxes will trade low and mid-range power for high-end is a myth. Perhaps it applies to other designs, but it surely doesn't seem to apply in this test. Again, I welcome anyone to demonstrate their point with a different comparison between this box upper and a standard TFS upper.

:Word:

The runners on the Box-r are shorter than other intakes, but they are still much longer than a Victor Jr or a Super Victor.

Yea, I've thought about this before. The runners in the lower intake alone are longer than those in a single plane intake. Runners in a single plane intake are shooooort.
 

90lxcoupe

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You could be right, but honestly how would this guy know? Has he done testing that indicated a loss up high in comparison to these intakes? Or, is it just an educated guess based on the runner length? What I do know is that the TFS-R intake can flow in excess of 300cfm with a port job. So, I'm thinking it should make plenty of power into high RPM.

Flow numbers really dont mean much if the runners are just too long. He isnt just making an educated guess, i know that, I do not know if he has made back to back testing but he told me that in every combination he has used a R intake, it does not make power past around 7200 and the lower intake is the restriction, not the upper.
 

FastDriver

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Forgive me for my inquisitive nature, but I don't put a ton of faith in anything I haven't seen with my own eyes, unless it rationally follows from my own experiences...

Can you get the specifics on the combos he's run (cam, heads, intake, box or standard), dyno comparisons, or track comparisons, etc.? How does one determine that the lower intake is the restriction? Considering what they can flow, the volume is there to support some serious power. Have other boxes, like the Reichard upper, been tried with the TFS lower? That would reduce runner length, since even the box upper extends the length of the runners by about 3".
 

FastDriver

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Here's a comparison between the 2011 5.0 and the Boss 302:

comparo-chart-boss-vs-GT-1600-thumb-717x520-78999.jpg


Now, I know Ford rates the 5.0 10 lb-ft less than the Boss, but look at how the low end compares in this dyno. The Boss 302 doesn't just pull away due to the increased rpm capability, the Boss would clearly kick the 5.0's ass if shifted at the same point. And look! in this test they went all the way down to 2500 rpm where the box suddenly jumped out in front of the long-runner.

Granted, this may not be as valid a comparison because the BOSS also had some exhaust work done. Still, one thing it does show is what happens with optimized cams. If box designs were as bad as made out to be (losing 50 ft-lbs on the low end), I don't think anything else would make up for that kind of a loss. The other cool thing to consider is that this is just a 302. So it obviously doesn't take a big 400inch windsor stroker to take advantage of a box's advantages.

Chris
 

90lxcoupe

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Forgive me for my inquisitive nature, but I don't put a ton of faith in anything I haven't seen with my own eyes, unless it rationally follows from my own experiences...

Can you get the specifics on the combos he's run (cam, heads, intake, box or standard), dyno comparisons, or track comparisons, etc.? How does one determine that the lower intake is the restriction? Considering what they can flow, the volume is there to support some serious power. Have other boxes, like the Reichard upper, been tried with the TFS lower? That would reduce runner length, since even the box upper extends the length of the runners by about 3".

Can you find any tests where a EFI, non carbed style intake makes power past 7500 rpm? Not trying to call you out or anything, i am just curious, cause ive never seen one.

I cant answer these questions, i know that he has probably forgotten more than i know, and held the EFI renegade record for a while, which i am pretty sure they run street style intakes, so i think if he could have used the R to make more power, he would have. The guy just dosent do cams, he builds motors, so if i had to guess, i would say the way he determined the lower was a restriction was by running it on the dyno. If you want to call him and ask, i can give you the number to his shop.
 

FastDriver

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Nah, I'd be an ******* to call and start questioning a guy I don't know. Matter of fact, the only thing that comes to my mind for high revving intakes is the carbed stuff that has been modified for fuel injection. However, I'm I would like to check one place to see what he was running and how high he was spinning his motor, but alas I can't get there through this gov't computer - it's blocked for me. Do me a favor, if you don't mind, and google "marc arnold," which should show the first link about his EFI '93 cobra. He's running hydraulic roller cams on his combos, too. So, I don't think he'd be going much over 7500 RPM, but please take a look and let me know. I distinctly remember that he's running EFI and hydraulic roller with andersen high-rev cams and spinning the piss out of his motors to very impressive results. However, I don't recall the intake he used or exactly how high he spun his aftermarket blocked motors. Aside from that, I've never really delved into high RPM setups that go beyond 7k or so.

BTW, you were right to call me out about the box making power into the mid 7s as that was groundless speculation on my part. Point for you, sir!
 

90lxcoupe

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Nah, I'd be an ******* to call and start questioning a guy I don't know. Matter of fact, the only thing that comes to my mind for high revving intakes is the carbed stuff that has been modified for fuel injection. However, I'm I would like to check one place to see what he was running and how high he was spinning his motor, but alas I can't get there through this gov't computer - it's blocked for me. Do me a favor, if you don't mind, and google "marc arnold," which should show the first link about his EFI '93 cobra. He's running hydraulic roller cams on his combos, too. So, I don't think he'd be going much over 7500 RPM, but please take a look and let me know. I distinctly remember that he's running EFI and hydraulic roller with andersen high-rev cams and spinning the piss out of his motors to very impressive results. However, I don't recall the intake he used or exactly how high he spun his aftermarket blocked motors. Aside from that, I've never really delved into high RPM setups that go beyond 7k or so.

BTW, you were right to call me out about the box making power into the mid 7s as that was groundless speculation on my part. Point for you, sir!

http://the-arnolds.net/Cobra/

He wouldnt take it as questioning i dont think, super cool dude, I bet if you PM'd him on yelowbullet he would be more than happy to share info. I googled Marc Arnold, and ive seen that site before i think. With his emmisions 306 it didnt say how high he was revving it. With the high compression 306/hi rev cam it peaked 402hp at 6500 rpms. That was with a Victor 5.0 intake. He also said with that combo the motor revved cleanly to 7800rpm.

Now heres where it gets interesing on that page. The 347 build twisted wedge heads and hi-rev cam. He starts out with a ported TFS R lower, with a vortch mondo box upper. It made 474hp at 7200rpm and 386 ft lb at 5700rpm. He put a super victor EFI on the car, but he also changed the headers, and cylinder heads at the same time and it made power to 7500 and ran a 9.7 at 140 vs a 9.99 at 135 with the old setup.

With the TW-r head, the super victor, and a N 113 anderson cam he made peak power at aroiund 8400 rpm on the high compression 359'' motor he is currently running.

For the record, im not trying to call anyone out, i just want to know if anyones actually done it.

Heres another high winding 347 just because
http://www.youtube.com/watch?v=8ThFWc45h5c&feature=bf_next&list=HL1319560668&lf=mh_lolz
 

FastDriver

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That's too many changes to attribute the power gain to the intake alone, obviously. However, the statement is clear: the super victor is the better high RPM stroker motor selection, though I don't think that's a surprise to anyone. 600 N/A rwhp and 8400 RPM is just tits! (am I allowed to say that as a moderator?)

Anyway, no worries bro. You're not calling anyone out. It's something I'd like to see too. If anything, I think Marc's car is evidence to support your point, though I'm not convinced yet. 7200 RPM peak ain't bad, though. That's a 7500-7700 shifted car, possibly higher.
 

90lxcoupe

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Anyway, no worries bro. You're not calling anyone out. It's something I'd like to see too. If anything, I think Marc's car is evidence to support your point, though I'm not convinced yet. 7200 RPM peak ain't bad, though. That's a 7500-7700 shifted car, possibly higher.

Yep, that guy has his stuff set up right, i wish his stuff was 12:1ish CR and pump gas though. 7200 peak definitley is nothing to be ashamed of. I think that is a happy medium between making respectable power and not really spending alot of money like you would to spin the motor up to or past 8k. I am still using stock hyd lifters in my setup

Im hoping to be at around 7000 for the peak, id be happy with 6800. I think my car peaked around 6300 with the headers killing it up top. I went from 1 5/8" at the head to a 1 7/8'' with adapter plates at the head. I will find out sunday when i hit the dyno.

If i keep this current setup for a while, I plan on putting a super vic EFI with a 4150 style, 4 hole throttle body on it and see how far i can really take this car naturally aspirated. So maybe we can have some solid results from a test on the same car, same combo, same dyno, just different days to base off of.

I think the 4 hole TB also would be much better for a street driven car, and also think it would make more power in the right combo. I also believe i could get the car to drive better at part throttle because of the fact that they use a progressive linkage, so when you are just giving it a little gas, only 2 small throttle blades are opening, instead of one huge blade like the 90mm has on it.
 

5spd GT

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Yea, but you're more open minded than some that I see on the internet, and (obviously, from this post) willing to learn and accept new ideas. There will be some that will see this test and only try to poke holes in the logic and ignore the results.

I believe that questioning and testing ideas (and parts) is a way to learn and accept or no longer accept ideas. You say, poking holes in logic, but I see trying to understand why "it is, what it is." In fact, this open mindedness led me to go a bit crazy with my 306 with the "bigger is better theory". I have an AFR 185 comp with a custom camshaft that mirrors and exceeds many 347^3+ camshaft specs, with a heavily ported SMII that dwarfs the Performer that was on it, to the tune of 30-40% larger runner area dimensions (measured myself), but guess what, the runner length is near identical. Ed must have got this one wrong ;)

The problem is that we all contradict ourselves on a regular basis. We preach, "it is the combination", but then pick out the POSITIVES when we see fit, but neglect to mention that the combination probably played a large part in the results that you believe we ignore. Luckily Tom Moss reminded us of this.

This is what I always try to tell people when the discussion turns to TB/MAF sizing. In a high performance motor, there is no "sizing" of these parts. There's no magic formula that helps you pick a TB size. You just select one that is big enough (within reason) to minimize manifold vacuum as much as possible at WOT. (...And this pretty much comes down to the size of the intake opening, or how much you can hog it out.) ANY vacuum at WOT is an indication of flow inefficiency upstream of the intake, and it is GIVING UP POWER.

I agree with this completely, but it seems to be out of context of this test. I did not see anyone stating a magic formula to pick a TB size. In fact, this should show that it entirely depends on the engine combination, otherwise we would be guilty of the very thing we preach against (i.e. We see dyno results on ONE engine combination and believe it is the answer. In other words, we see a TFS-R vs. TFS-R Box comparison and assume that a shorter runner with a large box style plenum is the answer for all 331's.) This is a post hoc fallacy.

Assuming you are speaking of pressure drops behind the TB (or whatever intake piece you want), there is diminishing returns with this method of vaccum. Say you have a 331 @ 6,000 RPM sitting at 100% VE, this equals 575 cubic feet a minute. Place a TB that can flow 1000 CFM and then add 200 more potential cfm and you just get a .209 value drop in vacuum, but if you move from a 800 cfm TB and move up 200 more potential CFM, you get a .384 value drop in vacuum. So I am with you here.

The OEM has a pretty good handle on this thinking; the Coyote has an 80mm TB and the LS junk has had "huge" TBs for years. Why 5.0 guys are still limiting themselves to 75mm, I have no idea.

There are two large factors for TB sizing from the factory.

1. Packaging (Go delete your EGR plate, then start bolting up the TB - you will see where packaging comes into play on more than just a TB)

2. Modular use (using them on different engines to keep R&D, cost, etc. down)

Unfortunately, in third is power.

It is all a complete package (literally).

Speaking of LS engines, I am not sure I would consider a 71.5 mm wide circular TB is "huge." An Ls1 has a 71.5mm (75mm opening) TB from the factory, and include a throttle cam. Take the '98-'99 pulley system for opening the throttle, which has very close to the same cable pull to the angle of the blade. Now, what did GM do for the later years following 1999? They created a nautilus shell style throttle cam, where the part throttle portion of the cam requires more pull on the cable, with less degree angle actually being applied to the throttle body. As the blade gets closer to WOT, the radius of the cam shrinks and allows the blade to open up completely to WOT. So why would GM, do this?

Easy answer; it is to help with part throttle touchiness.

The minimum area I measured in my ls1 intake TB track was 73.14.

I am not sure who you are referring to on limiting their engines to 75 mm TB's. Most engines out there do not need the extra 3^inches from a 75 mm TB to a 90 mm TB.

Mo air is mo powa. :D

This is true, IF the other induction parameters (valve events + intake system + exhaust system) is matched.

Slapping on a large intake on an already good performing engine could hurt as well as help it. The volume of a larger intake (or smaller intake) may be productive (or counterproductive) to the efficiency of the engine.

Now, I have *heard* that the bigger TBs (like the Accufab 90) have different geometry on the butterfly valve lever that is supposed to modulate the blade slower at lower openings to help with this issue. I do not know if that is true or not, just what I've heard. Either way, I know of guys running 90s on STREET driven 302s with no problems.

No need to hear any longer, this is true for many aftermarket TB's. Refer back to the nautilus cam talk (which is like MOST OEM's now) + many are going to drive by wire set-ups, so touchiness or sensitive pedals are no longer an issue. The computer controls tip-in; no longer the other way around. I do not see any problems with a 90 mm TB on a 302, in fact, if we looked at just driveability (for the sake of healthy debate), I would prefer a larger style TB on a lower powered engine actually (302 vs. 427).


Joking? Here we have a legitimate test where switching to the 90mm TB proved significant gains over the 75. It doesn't get any more clear cut than this: the 75mm WAS NOT "plenty" for that combination.

Serious - do you not believe that the pressure drop from the 3"^2 area from the 75mm TB to 90mm opening could cause an issue? Bernoulli principle at work. Do you think the box style could attribute more to a larger TB? I do. After all, when does the "plenum" begin, when the throttle is WOT?



Not sure what you're asking...? See below.

Thank you, FastDriver already answered it for me, you just missed it I believe-no biggie.


Keep in mind, Chris, that the cam does not dictate the rpm band of the engine alone. It is the combo of parts that does, and I think that is part of what Tom was getting at above.

Yes, you are correct, which is why your comments seem to contradict themselves. You are speaking about the TFS-R Box as how "bigger is better" prevails, but it is the combination of engine parts/tune that make this happen.


It would be my guess that a more aggressive cam might help the long runner intake shine a bit more, but maybe at the cost of some drivability. Of course, put that more aggressive cam in the box intake engine, and it will likely rev even higher and make even more power, so I'm not sure that camming the long runner intake engine would necessarily help it outperform the box intake engine, but maybe just help it do better than it did in that test.

By more aggressive, what do you mean? Ramp rate, increase in durations @.006", .100", .200", etc.? Lift over the lobe? The intake system is not a cut and dry as many believe. Go read some Gordon Blair stuff, in particular Design and Simulation of Four Stroke Engines. He literally has a couple hundred pages of research in intake designs. I own it and have read through it a couple years ago and the more I read it, the more questions I had. :)

Your comments about adding a more aggressive camshaft to the TFS-R (non-box) seems to imply the "big head/small camshaft" theory. Well, Ed decided to go bigger on all parts of my new combo, but it works because it is matched - so I take it there are more ways to skin a cat. It is all in the combination! If you go with a large cylinder head (relative to cylinder volume), ensure that you have a matching large volume intake and tuned length with the 3rd or 4th harmonic. This is where the camshaft comes into play.

A large cylinder head + intake system may like a delayed intake opening (or at least slow beginning ramp rate) so when the piston speed increases on the intake stroke towards its peak speed, the draw on the intake runner (head + intake) is greater. This is when the curtain area should be maximized in a timely manner. The change in air pressure will increase the air speed (some call it velocity) and will bring inertia with it. You need less duration. Matched parts become crucial when you go with various parts, like small or larger intakes.

With a large port velocity profile (relative to the cylinder volume), you need to "limit" the camshaft valve activity, not try to feed the cylinder more air with longer/larger durations. Thinking about how a basic 4-stroke engine works, you also will benefit with larger exhaust parameters with a large induction system.

There is no perfect set-up (large induction + small cam or small induction + larger camshaft). They just need to be matched, as this dyno session was matched better and it had some strong results to back it up. :nice:

Anyways, back on topic. For sake of argument - let's take the aforementioned XE274HR on this 331. Given the specs of that camshaft, the TFS 185 heads, I get a optimized 3rd tuned harmonic of ~12.9". Well, low and behold, the TFS-R BOX (9.0") + TFS 185 (4.75") length equals 13.75". This is less than an inch from ideal. However, add the extra 2.00" on to create the TFS-R runner length + same cylinder head, you get 15.75" - even further from ideal. The TFS-R BOX fits much closer, compared to the previous dyno run using a tuned length an entire two inches off near optimal. I wonder why the power went up? :) Factor in the assumed increase in taper from the BOX upper to lower, and you get even closer to the needed harmonic for a 12.9" length runner.

It was not a coincidence that at those funny RPM's (3700 and 3200) that we saw variations in HP/FT LB numbers at the wheels - tuned length and other intake parameters played a big part in this.

Of course I'm generalizing here a little bit. I know cam guys will do different things with valve events given the style of intake used. That said, if a GOOD cam guy were given the opportunity to create a cam tailored to each intake, my hunch is that the Box might still have the edge. Who knows.

Yes, you are generalizing, but it makes discussion better. I am not sure I agree with your assessment by looking at the "all else equal" situation you are creating for the cam pro. It depends on the combination entirely. Of course, one could have the exact same heads, cam, and intake, but yet run entirely different times or drive completely different. I would estimate there are 100 different reasons for this that are obvious, so I believe it is incorrect to look at this dyno run that FastDriver showed us from back in late '05 (put in MM&FF in March '06, then published in the book in '08) and assume that a TFS-R Box is better for all engines "all else being equal."

In fact, here is the results of a 30 second google fest showing how a TFS-R Box did not work for some. I hope this reaffirms that the combination and goals are what matter, not just the intake:

"Well im gonna try to help clear up some of this & this is from real world testing. i have 331ci motor with a ysi on it & afrs 205s & a small hyd roller cam when i first started going to the track i was running a fully ported edlebrock peformer rpm 1 intake & my best run was 8.98 & 150. The next race season i switched to the box r intake had the car tuned & the best that i could get out of it was a 9.1 @ 151 thats after many many tries the car seemed to be down on mid range power. So i got pissed because i spent 650$$ & was running slower, so i switch back to the rpm intake & the car was leaving alot harder so i ended up running 8.96 @ 155 mph this was in 09'. Now 2010 after talking to a few other guys i decided to switch back to the box & have Kurgun tune the car, so in apirl 2010 i had Kurgun tune the car & she made 920 rwhp that same day i took the car to byron dragway & clicked off a 8.99 @ 155.70 with a 1.40 60' i was happy got a 8sec timeslip with the box. So as the race season goes on the car is running low 9.0s & 152 with 60' times from 1.29 to 1.35 i also made a few more 8 sec passes with best of 8.92 & 153 i was happy but i could tell the car had more in it. so... i switch back to the rpm & went testing & i started to run 8.80s @ 155 to 156 & then i got the car to run 8.70s @ 158 with some more testing. I think the cam has alot to do with it as i was trying to shift @ 7200 with the box @ i was shifting @ 6800 with the rpm all i can tell u is that my car is faster with the rpm. i think the rpm had a little bit more mid range power than the box, my best mph in the 1/8 with the box was 122 & with the rpm was 125. the box is a bad ass intake if ur shifting @ high rpms. i will switch back to the box whenever i change my cam to a solid roller, my cam was made to shift @ 6800 rpm"

"My buddy's 418W made 435hp/450lbft with the R intake and then made 435hp/400lbft with the Box R. Basically, he lost 50lbft and gained nothing for hp. On the same dyno, no other changes...all numbers at the wheels of course.

He now used the Box R on a 427 and made 505hp/503lbft...with different heads and a different cam.
"

Now, did reading those two real world reviews (among others that I did not include) lead me to believe that the TFS-R Box is an ill-equipped intake? Absolutely not! It just tells me that it was not good for the particular combination, just as it can also play in a positive light, as the test that Fast Driver posted. It worked for that combo, no doubt! There is no logic I have to make-up, it just worked, but for a host of reasons (some mentioned above). Along those same lines, the dyno graph of the Boss 302 and GT above with two different intake styles are a stroke of engineering genius. Those engines have different components, goals, and design factors that allow the engine to work optimally to what it's intended goal was. The same reason why a "short runner" intake on an LT1 @ 2.875" gets out powered by a 10.375" ls1 intake (measured these myself). It is the combination - not the intake.

It's all about the combo, hell, I've seen guys with iron GT40 junk make 350 to the tire and run 11s. There are just obviously better parts to help you make more power when put together right, and I think this article is good argument that the Box R is a serious piece.

Combination plays a major role, but also the goals of the car along with weight, daily driver vs. street car vs. track car, etc.


Yea, I've thought about this before. The runners in the lower intake alone are longer than those in a single plane intake. Runners in a single plane intake are shooooort.

Tuned harmonics, packaging (think large carb/air filter sitting under a stock hood), dry vs. wet flow are major reasons for the differences. Most of the EFI lowers are like you are alluding to are in the 5.5" to 6.5" range. But, the cross sectional differences, taper, harmonic wave tuning, etc. all keep similar powerbands and potential. In fact the LT1 intake is shorter than 95% of the old school single/dual plane intakes, and it was EFI. Hmmm...

In short, one dyno or a couple test can not conclude that a 90 mm TB is needed or that a box intake is best for all engine combinations. Those famous words we hate to hear so much:

It Depends!

I just wasted 30+ minutes and just scratched the surface. :bang:
 

FastDriver

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I believe that questioning and testing ideas (and parts) is a way to learn and accept or no longer accept ideas. You say, poking holes in logic, but I see trying to understand why "it is, what it is." In fact, this open mindedness led me to go a bit crazy with my 306 with the "bigger is better theory". I have an AFR 185 comp with a custom camshaft that mirrors and exceeds many 347^3+ camshaft specs, with a heavily ported SMII that dwarfs the Performer that was on it, to the tune of 30-40% larger runner area dimensions (measured myself), but guess what, the runner length is near identical. Ed must have got this one wrong ;)

I don't understand your point here. Nik is running a TFS-R and a 205cc Head on his 302. I'll let him speak for himself, but he doesn't have a problem with using big parts. BTW, Ed didn't seem to have a problem with my setup, either.

I agree with this completely, but it seems to be out of context of this test. I did not see anyone stating a magic formula to pick a TB size. In fact, this should show that it entirely depends on the engine combination, otherwise we would be guilty of the very thing we preach against (i.e. We see dyno results on ONE engine combination and believe it is the answer. In other words, we see a TFS-R vs. TFS-R Box comparison and assume that a shorter runner with a large box style plenum is the answer for all 331's.) This is a post hoc fallacy.

No I'm not guilty of that. I'm guilty of asking for evidence to show me that the TFS standard upper is beneficial for any purpose. Start from scratch with a motor and build a 331 or 347 that will turn the best ETs in street trim (i.e. hydraulic cam, spinning to less than say 6000 RPM) and which intake ends up on top? I don't care which cam or heads you use. That's the question I want answered. Then lets take the question up a notch and say the shift points are at 6500? 7000? Does the optimal intake change? I'm not asking for any combination, but I do want to know which is a better combo to build.

Assuming you are speaking of pressure drops behind the TB (or whatever intake piece you want), there is diminishing returns with this method of vaccum. Say you have a 331 @ 6,000 RPM sitting at 100% VE, this equals 575 cubic feet a minute. Place a TB that can flow 1000 CFM and then add 200 more potential cfm and you just get a .209 value drop in vacuum, but if you move from a 800 cfm TB and move up 200 more potential CFM, you get a .384 value drop in vacuum. So I am with you here.

Cool! Then it does surprise you to learn that in fact a 75mm TB was not enough on this 331?

I am not sure who you are referring to on limiting their engines to 75 mm TB's. Most engines out there do not need the extra 3^inches from a 75 mm TB to a 90 mm TB.

When building a motor, the question is more along the lines of "why not?" rather than saying "I think this will be enough." I basically pick the throttle body first that works, and 2nd try to match it to the inlet on the upper. I would have gone with the 90mm on my own combo, but it won't work with my HP turbo kit. I'll probably modify the induction at some point to take advantage of the benefit. I might find that it reduces my exhaust pressure ratio problem a little as an added benefit.

This is true, IF the other induction parameters (valve events + intake system + exhaust system) is matched.
Isn't that always the case? So the question really becomes, are you better off, worse off, or indifferent in using either intake when building the combo from scratch?

Slapping on a large intake on an already good performing engine could hurt as well as help it. The volume of a larger intake (or smaller intake) may be productive (or counterproductive) to the efficiency of the engine.
We know this stuff. Those of us actively participating in this thread are beyond this level of knowledge.

No need to hear any longer, this is true for many aftermarket TB's. Refer back to the nautilus cam talk (which is like MOST OEM's now) + many are going to drive by wire set-ups, so touchiness or sensitive pedals are no longer an issue. The computer controls tip-in; no longer the other way around. I do not see any problems with a 90 mm TB on a 302, in fact, if we looked at just driveability (for the sake of healthy debate), I would prefer a larger style TB on a lower powered engine actually (302 vs. 427).

Cool. This makes sense. As I typed up my last response, I thought it would be cool to design a throttle body to do this. Probably should have realized it was already standard in design. Clarify the reasoning on your last point. I can't imagine you'd want to put a 90mm on a 302, and a 60mm on a 427. What are you trying to say there?

Serious - do you not believe that the pressure drop from the 3"^2 area from the 75mm TB to 90mm opening could cause an issue? Bernoulli principle at work. Do you think the box style could attribute more to a larger TB? I do. After all, when does the "plenum" begin, when the throttle is WOT?

The only issue I believe it caused was a gain of some pretty decent HP. So I don't see how you can defend the statement, "A 75mm TB is plenty for that combination," which is what he's asking if you're serious about. I don't see how you can say that after seeing the results, either. 75mm was clearly not enough for that combination.

I'm not sure what that last question is getting at. The plenum begins at the inlet. Naturally everything in the intake tract is an extention of the component before it, though. What's the point there?

Yes, you are correct, which is why your comments seem to contradict themselves. You are speaking about the TFS-R Box as how "bigger is better" prevails, but it is the combination of engine parts/tune that make this happen.

Bigger appears to be better. If I were a bettin' man, I'd put my money on the fact that this box intake will come out on top (power, ETs, etc...) if the only part you restricted in the build was the intake manifold to compare TFS Box-R, and TFS-R.

Your comments about adding a more aggressive camshaft to the TFS-R (non-box) seems to imply the "big head/small camshaft" theory. Well, Ed decided to go bigger on all parts of my new combo, but it works because it is matched - so I take it there are more ways to skin a cat.
Great point.

A large cylinder head + intake system may like a delayed intake opening (or at least slow beginning ramp rate) so when the piston speed increases on the intake stroke towards its peak speed, the draw on the intake runner (head + intake) is greater. This is when the curtain area should be maximized in a timely manner. The change in air pressure will increase the air speed (some call it velocity) and will bring inertia with it. You need less duration. Matched parts become crucial when you go with various parts, like small or larger intakes.

Ok... now we're getting into a tech discussion that I've always wanted to understand, but have never devoted the time to, or had someone I felt confident in explaining it to me. So, I'm going to take this and your remaining tech comments regarding cams and open a new thread in 5.0 tech, I believe that subject diverges from the TFS-R vs. Box-R discussion. Please join.

Yes, you are generalizing, but it makes discussion better. I am not sure I agree with your assessment by looking at the "all else equal" situation you are creating for the cam pro. It depends on the combination entirely. Of course, one could have the exact same heads, cam, and intake, but yet run entirely different times or drive completely different. I would estimate there are 100 different reasons for this that are obvious, so I believe it is incorrect to look at this dyno run that FastDriver showed us from back in late '05 (put in MM&FF in March '06, then published in the book in '08) and assume that a TFS-R Box is better for all engines "all else being equal."



In fact, here is the results of a 30 second google fest showing how a TFS-R Box did not work for some. I hope this reaffirms that the combination and goals are what matter, not just the intake:

C'mon... you know me, David. We've spent plenty of time jousting here back in the day. I'm offended (not really) that you didn't think I've already done a google search or two... The problem is that those are not well documented, and certainly not as clean as a scientific test on the dyno. The first example has, at least, a little merit where it sounds like the guy legitimately put time and effort into getting the tune right and trying to make the combination work. The problem is it's anecdotal. We can't see the details, like cam specs, testing methods, resulting tunes, etc... We don't get to see what happened to the powerband. He talks about changing his shift point, which adds a variable that may not have been the right way to go, and doesn't talk about whether or not he tried shifting lower with the Box-R. If you know the guy - on Hardcore from earlier this year, right? - ask for the dynos and the tunes. I would love to see how the car combination reacted when it was changed. We don't race dynos, but in a situation where we're comparing components and finding optimum shift points, they can be extremely effective, and they produce consistent repeatable results. However, I suspect that the guy didn't dyno it based on his comment that he believes he lost some low end - probably would be something he knew and could attest to if he had a dyno in front of him.

The second example is laughably stereotypical of internet generalizations: "My buddies *insert engine, or vehicle information here* lost *insert rounded number here* with that *insert engine component here*.

In short, one dyno or a couple test can not conclude that a 90 mm TB is needed or that a box intake is best for all engine combinations. Those famous words we hate to hear so much:

Hopefully, one dyno is just the start. Show us another where the 90mm TB was no advantage or where the box intake was bested, and lets really begin the discussion.

I just wasted 30+ minutes and just scratched the surface. :bang:

It was no waste. Come dig a little deeper in the cam thread and teach me some ****.
 

NIKwoaC

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Damn, 5spd GT, I wish I had more time to formulate a good response to that post, because it was pretty good. I'll touch on what I can...

I believe that questioning and testing ideas (and parts) is a way to learn and accept or no longer accept ideas. You say, poking holes in logic, but I see trying to understand why "it is, what it is." In fact, this open mindedness led me to go a bit crazy with my 306 with the "bigger is better theory". I have an AFR 185 comp with a custom camshaft that mirrors and exceeds many 347^3+ camshaft specs, with a heavily ported SMII that dwarfs the Performer that was on it, to the tune of 30-40% larger runner area dimensions (measured myself), but guess what, the runner length is near identical. Ed must have got this one wrong ;)

Sounds like a nice combo!

Assuming you are speaking of pressure drops behind the TB (or whatever intake piece you want), there is diminishing returns with this method of vaccum. Say you have a 331 @ 6,000 RPM sitting at 100% VE, this equals 575 cubic feet a minute. Place a TB that can flow 1000 CFM and then add 200 more potential cfm and you just get a .209 value drop in vacuum, but if you move from a 800 cfm TB and move up 200 more potential CFM, you get a .384 value drop in vacuum. So I am with you here.

...

I am not sure who you are referring to on limiting their engines to 75 mm TB's. Most engines out there do not need the extra 3^inches from a 75 mm TB to a 90 mm TB.

Lots of guys get hung up on not going any bigger than 75mm. I see it almost all the time on the internet, Mustang mags, and even cars I see on the street.

The thing is, crunching the numbers is great. Stacking up CFM requirements and figuring out manifold vacuum is a great way to at least get an idea of what is going on. But unfortunately, we don't race the data, we race the car, and I can't remember ever reading about a comprehensive test where a EFI SBF didn't benefit from moving up on TB size. I'm sure there is a point of diminishing returns, definitely. But if we're talking about choosing between a 75mm and an 80 or a 90 on a 331 or 347, I firmly believe that bigger is the way to go there, in just about any scenario. Of course, there comes a limit to what the intake will accept, as I know you can't go 90 on a lot of intakes due to the EGR passages.


Serious - do you not believe that the pressure drop from the 3"^2 area from the 75mm TB to 90mm opening could cause an issue? Bernoulli principle at work. Do you think the box style could attribute more to a larger TB? I do. After all, when does the "plenum" begin, when the throttle is WOT?

I guess I'm not sure where you're going with the Bernoulli's Principle thing there...

The problem is that we all contradict ourselves on a regular basis. We preach, "it is the combination", but then pick out the POSITIVES when we see fit, but neglect to mention that the combination probably played a large part in the results that you believe we ignore. Luckily Tom Moss reminded us of this.

Yes, you are correct, which is why your comments seem to contradict themselves. You are speaking about the TFS-R Box as how "bigger is better" prevails, but it is the combination of engine parts/tune that make this happen.

I don't see how I'm contradicting myself. Yes, properly matching the combo is what makes the difference between a decent engine and an amazing engine, but the individual parts are the building blocks of the combo. The phrase "only as strong as the weakest link" does have at least some validity here. Some parts are just going to have greater power making potential than others.

Go read some Gordon Blair stuff, in particular Design and Simulation of Four Stroke Engines. He literally has a couple hundred pages of research in intake designs. I own it and have read through it a couple years ago and the more I read it, the more questions I had. :)

Going to have to check that out, sounds like good stuff!

Anyways, back on topic. For sake of argument - let's take the aforementioned XE274HR on this 331. Given the specs of that camshaft, the TFS 185 heads, I get a optimized 3rd tuned harmonic of ~12.9". Well, low and behold, the TFS-R BOX (9.0") + TFS 185 (4.75") length equals 13.75". This is less than an inch from ideal. However, add the extra 2.00" on to create the TFS-R runner length + same cylinder head, you get 15.75" - even further from ideal. The TFS-R BOX fits much closer, compared to the previous dyno run using a tuned length an entire two inches off near optimal. I wonder why the power went up? :) Factor in the assumed increase in taper from the BOX upper to lower, and you get even closer to the needed harmonic for a 12.9" length runner.

It was not a coincidence that at those funny RPM's (3700 and 3200) that we saw variations in HP/FT LB numbers at the wheels - tuned length and other intake parameters played a big part in this.

Good stuff. :nice:
 

Grabbin' Asphalt

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Yup, rising from the ashes here, great thread btw. So i was thinking of this entire longer runner v.s. shorter one results with a smaller cam with larger heads idea, ...which is kinda where i am because my P heads have been super ported, hence my 320rwtq with an Ecam and 1.6 rollers with a ported Cobra intake. If i went to an TFS R intake how much more pop I'd really get. I mean it's way more air but do you think my 220/220 duration would like it in N/A form?? I could even add 1.7 rollers if i wanted more lift, maybe be at a .536 then, thoughts anyone??
 

NIKwoaC

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Yup, rising from the ashes here, great thread btw. So i was thinking of this entire longer runner v.s. shorter one results with a smaller cam with larger heads idea, ...which is kinda where i am because my P heads have been super ported, hence my 320rwtq with an Ecam and 1.6 rollers with a ported Cobra intake. If i went to an TFS R intake how much more pop I'd really get. I mean it's way more air but do you think my 220/220 duration would like it in N/A form?? I could even add 1.7 rollers if i wanted more lift, maybe be at a .536 then, thoughts anyone??

Like @5spd GT said above, "it depends". Switching up to better flowing parts and a more optimized cam is only ever going to help your situation, though.
 

Grabbin' Asphalt

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Like @5spd GT said above, "it depends". Switching up to better flowing parts and a more optimized cam is only ever going to help your situation, though.

Right, I know my cam & intake are doing a serious limitation to what theses heads can potentially do. I mean 320rwtq Ecam pushing "P" heads is begging for more air/lift :rlaugh:
So i read your entire build last night and loved how you thought outside the box for your build. I had limited funds on my build at the time but had a vision of a high compression/small cam build and surprised a sh!t ton of folks too :nice: My funds are limited with this DD so i cannot do any type of cam up grade but I may be able to add more air flow, maybe adding an intake. If I were to get a TFS R, I could be ready for future upgrade when building another motor. Think my Ecam could blossom even further??
 

Grabbin' Asphalt

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Ok so im off the R intake, just not spinning past 5800-6000 on the streets anyways and i know the ecam is outta breath there anyways. And i need all the rwtrq i can get with my heavy DD on the streets.