NikwoaC's "Commitment Issues" Engine Build

Discussion in '1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-' started by NIKwoaC, Mar 13, 2011.


  1. NIKwoaC

    NIKwoaC 中國製造

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    I agree, some cylinder heads are just flat out better at flowing air than others, regardless of runner volume, or more importantly, cross sectional area. Any head that flows the same or better than an equivalent head with more cross sectional area is obviously a superior design.

    I don't necessarily jive with the notion that big heads kill low end torque. That's kind of a generic slippery slope statement. Like anything, it's all about the combo. If cam and intake are selected properly, "big" heads can achieve respectable torque numbers at "low" engine speed. To what extent and how far that can go, well, I intend to find out. Once I get this together and running, I fully intend to take it to a dyno and see what happens. :D
     
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  2. stykthyn

    stykthyn Commander of the snuggie cultists

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    I wish mine still looked as decent as it did on the stand :(

    alas I am lazy and never clean it so its full of road grime now.
     
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  3. skunk21

    skunk21 Active Member

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    I don't either go totally with the notion but with all the possible combos one needs to go basic. once you toss in compression, boost, intake and cam like you stated then it takes this debate in awhole different direction. dialing down into very basics a stock bottom end sbf, with a mild cam and basic intake I don't think will benefit from large heads or the go big theory. now you take that same motor and start tossing around different cam specs and adding boost or compression and then at all changes or am I off in my thinking? The "bigger" heads benefit from the higher rpms where they can utilize the air much better or added air from boost so something has to suffer even a little which adds up somewhere down the line if you know what I mean.
     
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  4. Mr. Rustypwnz

    Mr. Rustypwnz Advanced Member

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    my buddies vic jr 210 heads, come on strong around 4k and pull past 7k with ease, nasty awesome setup this is!

    if ya ever need help with checking clearances or whatever, let me know, its only gas money lol
     
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  5. NIKwoaC

    NIKwoaC 中國製造

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    Ha, mine will end up the same way, believe me. I put a bunch of effort into cleaning and painting the Explorer intake when I installed that, and aside from the occasional wipe-down of the upper, it never got much attention once it was in the car. When I yanked the engine, the lower was all covered in road crud and dead bugs, haha. If you're gonna drive the damn thing, it's going to get dirty. :nice:

    See, I think this is where a lot of car guys get hung up. We're told our whole lives by "experts" that building an engine is a series of compromises. You give up a little bit of this for a little bit of that. To a certain extent, some of that may be true, but I really believe that if you think outside the box a little, you can do some pretty awesome stuff.

    I could ramble on about this stuff forever (my wife tells me I need to start a blog, haha), but another topic for discussion that kind of further shows how SBF guys get "stuck" in a mode of thinking is throttle body size. Look at how mainstream SBF throttle bodies from BBK, Holley, etc only go up to 75mm, and yet the Coyote comes from the factory with an 80mm TB! It is still really common to see guys build 347s and bigger with 75mm TBs. I'm not here to bash guys who have 347s with 75mm TBs, don't get me wrong. It's just another thing that kind of makes you think.

    Is that the car that had the TFS stage 2? 7K on a stock bottom end would make my butt pucker a bit, haha. Not sure that I'm that ballsy! I think I'm going to limit this thing to 6500 or so until I build a more durable bottom end.

    Funny story, but I will tell you that one of the first things that got me interested in this whole big head/small engine thing was my lame ass '06 Fusion DD. It's just an auto with a 4-popper, but when you have your foot in it, it shifts at 6500 every time. Which got me thinking, if my snoozer daily driver easily buzzes to 6500 rpm after sitting in a traffic jam for 30 minutes, why the hell do I want to build an engine for my Mustang that has a lumpy idle and still only makes power to 6000-6200? :chin:

    So that brought me to doing some research on "big" heads/intakes and how to cam them to work well on small engines and now here we are.

    Of course, all my logic could be flawed, and this car could end up being a turd on the street. If that's the case, I still have the hardware in place to make a mean stroker out of it so, it's a win-win in the end. :shrug:

    ANYWAY, thanks for the offer man. :D I'll shoot you a line if I run into any trouble. You're definitely going to see my ass at ORP this summer, though. I think I still owe you a meet-up at the dragstrip, right?
     
    #85
  6. FastDriver

    FastDriver Mod Dude

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    No worries, Nik. You're not going to have to worry about how your motor runs. You're going to make good power down low, and I imagine you'll spin the motor a bit to get some good numbers from the motor. I think there's truth to the port-velocity argument, but I doubt it's really that significant.

    Chris
     
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  7. 90lxcoupe

    90lxcoupe Mustang Master

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    That seems like a bargain, that is with the porting too? Its good your doing that BTW, i had issues with my R lower sitting way to high on the block
     
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  8. FastDriver

    FastDriver Mod Dude

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    BTW, the comment about the Coyote running an 80mm TB - it revs to 7500rpm, right? So it should be moving as much air as a 377c.i. motor at 6k rpm. I don't think an 80 is going to hurt anything!

    Still, I don't think a big TB would ever hurt performance. I could see how it would make tuning a little more challenging.

    What are you planning to rev the motor to?
     
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  9. Mr. Rustypwnz

    Mr. Rustypwnz Advanced Member

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    yeah, its the 94 gt with the tfs stg 2, he is going to a single plane intake with a 90mm tb setup, here really soon with a tfs stg 3 or larger, but it made 335rwhp on a stock OLD shortblock, now its a fully balanced and girdled and built 306, with I think 8 or 9 cc dome pistons, on the same H/c/i, and now you can feel it needs more cam, but I think as it sits It would make 360rwhp, I want it to make close to 400rwhp and be a n/a 306, I think that would be awesome.
     
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  10. NIKwoaC

    NIKwoaC 中國製造

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    Thanks man. Don't get me wrong, I do believe that port velocity is a factor in performance, I just think that it's one of the many pieces of the puzzle though. And it's kind of a vague piece, at that. Lots of stuff influences it, you know? Valve events, port shape/efficiency... So it's kind of hard to nail down, IMO.

    I actually had you in mind when I was talking to him about that, because I knew you had 205s and your R needed some milling. He actually included that on the first estimate before I even said anything about it. Like I said before, he made it sound like the 205's ports were so big that it kind of needs it (port matching), but they also make sure it sits down on there nicely.

    Edit: I don't think I did a very good job of answering your question there, haha. YES, from what I understand the $150 covers port matching and any milling, if necessary.
     
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  11. NIKwoaC

    NIKwoaC 中國製造

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    I THINK, not sure, but I thought I heard that the stock Coyote red lines at 7000.

    Again, I've HEARD that once you get into ~90mm TB on a 302, you have to mess with the throttle position tuning for it to "act" right. My understanding is that it's more a drivability thing, since the computer is expecting part-throttle TPS values from a TB 30mm smaller, haha.

    Ultimately, I'm not sure if I'll rev THIS motor much past 6500. Being that it is the stock bottom end with the stock, heavy pistons, I don't want to take any chances of throwing one of those slugs into my $2000 heads. :p I would not be surprised if the motor still wants to pull past that, though.

    It is certainly possible. With that top end, some compression, and some RPM, it'll make some serious steam. I would go with something more "personalized" than a TFS3 though. I think you're probably looking at getting into solid roller territory, too.
     
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  12. FastDriver

    FastDriver Mod Dude

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    Oh, must be the Boss 302, then. In any case, the TB thing is definitely related to part throttle/drivability stuff. It sounds like you've already got it, but I like talking so here we go: Essentially, you want as small a tb as possible to give you the most resolution at part throttle. What I mean is that say you're accelerating moderately from a red-light, you can decide to use the throttle to accelerate at 10% TPS or 50% TPS and anywhere in between. You'll note a difference in acceleration up to a point, somewhere around 2/3 throttle on a stock tune, if memory serves. That's because the air-flow allowed through the throttle body is actually having an effect on the air that makes it into the cylinder. Somewhere around that point, opening the TB more is not going to impact the amount of air that makes it to the cylinder because you're already flowing enough to completely fill the cylinder, or the head/intake if they're the limiting factor in air flow. At 2000 RPM, even on stock TB, you won't be able to use all of the TB. The bigger the throttle-body, the more quickly you'll reach that point. With a monster 90mm TB, you may get to that point at 20% Throttle. That means that the computer has less increment to work with for the tune - load vs. RPM. Even the mass-air cars take the TPS into account in the tune. So, this is going to throw off the stock tune. It also means that the pedal is going to be more touchy than the stock pedal was. It gives the illusion that the car is much stronger down-low, or "revs faster" when in actuality it's just that you're placing more load on the engine with the less throttle. It's not going to hurt anything, though it's not going to be helpful at all, either. At some point, just as with the heads, more flow is useless.

    Check out the following numbers off of Accufab's website for a 5.0 mustang:

    So a 75mm TB flows at 28" a massive 1045 CFM - almost enough to flow 3 of your heads ports at not even a 1 atmosphere pressure differential at the same time! That's a ridiculous amount of flow! In actuality the pressure differential is never going to be that high, even at the cylinder, but at the same time it will be even less than that at the TB. Of course, you're not going to need anything larger to meet your engine's requirements. Swapping to the 90mm TB allows another 300+CFM. All that's going to do on a 302 is reduce part-throttle resolution, if you picked up any power from the swap, I'd be surprised. Again, just as with your heads, I don't feel this is in any way a mistake, it's just a choice. Afterall, why by a TB twice? If you put this thing on a 408, you might pick up a few hp as a 408 is probably going to draw every bit of what those heads can muster, particularly a high-revver.

    6500, eh? That's a good redline. Keeps you from spending coin on the valvetrain, too. At the 7k point, you have to worry about main-cap/crank walk, valve float, push-rod flex, etc... Probably not worried about losing a piston or rod yet, but a stock crank is going to flex, and if you float a valve into the piston, the resulting impact on those purdy heads would make you cry.
     
    #92
  13. NIKwoaC

    NIKwoaC 中國製造

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    Yea, I'm going to be reusing the 70mm TB I already have on the car for the time being. I figure when I step up in cubes, I'll step up on the TB at the same time, thus why I went with the 90mm upper. I'm thinking in the meantime it's going to take some finagling because of the big mismatch, but it will be worth it in the future.

    Have you heard of Jay Allen, Chris? He's kind of lost some face recently with some of the SBF community because of some disagreements in business transactions, but that's neither here nor there. Anyway, I was reading some stuff he wrote a while back about how he was flow testing a top end he had. I don't remember all the exact numbers, but he had heads that flowed something like 350cfm, a lower intake that flowed maybe 400, an upper that flowed somewhere around the same, and one of those "bigger" TBs that flowed 1000+, I can't remember if it was the 75mm or what. Anyway, he first flowed the heads on a bench, then bolted on the lower and flowed the two together, then added the upper, etc. What was interesting was that with each consecutive addition, including that 1000CFM TB, he ultimately lost some amount of flow through the system.

    I'll have to see if I can find where he talked about that. I mean, I'm not sure that a sub 6500 rpm NA 302 could ever "need" a 90mm TB, but that kind of stuff is just really interesting to me.

    Haha yes, yes it would. Though, I'm not sure if you saw above, but they are putting upgraded dual springs and titanium retainers on the heads. Hopefully valve float won't be an issue, but I'm definitely worried about the other things you mentioned.
     
    #93
  14. 90lxcoupe

    90lxcoupe Mustang Master

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    Thats a deal, my motor just came out yesterday, im gonna give them a call and probably send it there
     
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  15. FastDriver

    FastDriver Mod Dude

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    I know Jay Allen. Have spoken with him a couple of times. I even followed their crew over to S B F tech, which he runs, and I still have an account there. I like listening to his contrarian views, and I think he's a pretty smart guy. However, I'm not his biggest fan, and either him or his cult-like followers pushed me away from the conversations in general. It seemed to me that if you have a freethinking attitude and don't fall in lock-step with their views, then you're not worthy of listening to their discussions. Disagreements get too personal. So, I've stayed away for the most part. I didn't know anything about him losing any face.

    Anyway, I'm sure he can spec a mean cam, and I know full-well that he's in the bigger is better camp as opposed to the port-velocity one. I just don't know why we play around with any of this stuff is a set of hogged out yates heads with a custom cam is always going to give the best performance.

    I'm told that the original Boss 302 race team actually decrease the port volume of the production heads when they put them on their race cars. Did you know that the original Boss 302 came with a 245cc intake port? Of course in race trim, they spun the motors 8k+ RPM. I also know that the winning team on a couple of the Engine Masters Challenges reduced the port volume of the cleveland style heads You've got me looking up magazine articles :) Check this interesting comparison of nearly identically displaced small blocks:

    Muscle Car Engine Shootout - Ford Boss 302 Vs. Chevy DZ 302 - Hot Rod Magazine

    Note the interesting phenomenon of the ford with 245cc heads and a mild cam making more power at 3k RPM, but the chevy making more mid-range from 4000-5200 RPM. After 5800, the Boss comes out on top. Still, with a shift point of 6k RPM, the Chevy build is clearly better. With your shift point at 6500, I think it'd be too close to call. We know who wins when the shift point is unrestricted.

    Anyway, as a general rule, anything you add to the intake tract is going to have a negative impact on flow. I still believe that a 75mm is not going to create anything but a negligible impact on top-end performance.
     
    #95
  16. NIKwoaC

    NIKwoaC 中國製造

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    Now, I don't want you to be disappointed, I'm not sure if that is a reduced price since I'm buying the heads and intake through them. :D But you should definitely call them, they seem like they really know what they're doing. They are a little difficult to contact though, I usually have to leave a voicemail and wait for them to call back.
     
    #96
  17. NIKwoaC

    NIKwoaC 中國製造

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    Yep, I was too late to the party over at S B F tech to ever be involved in any of those arguments, but I've read a few of them, and you're right, things would get out of control on a regular basis.

    I won't say much about the Jay Allen thing, since I was never involved in any of it, so it's not really my place to say anything. I will say that the mods over at S B F tech issued a statement and removed him and his section from the board, even though he stopped posting over there a long time ago.

    I'm pretty sure I have that issue of HRM lying around somewhere... I'll have to see if I can find it.

    The Boss is always a hot topic when discussing the big head/small engine thing, and I think what you have to keep in mind is that is an engine that was designed 40 years ago. It was also a carb motor, and from what I understand, EFI gives us a little more flexibility in the BH/SE arena.

    Something interesting about those Boss numbers, is notice how huge the intake valve and the port volume are, but HRM shows a peak flow of 274 CFM. That's AFR 185 territory, a head that's a whopping 60cc smaller. Not sure how different the port length is, so I can't say anything about cross sectional area, but that's still strong argument for port efficiency versus just sheer size. The thing about race teams reducing the volume is interesting, I haven't heard that before. It's possible they were aiming to make the port more efficient, rather than just make it smaller. I have heard about the Engine Masters guys doing that. Wasn't it the Kasse team? Those guys work absolute magic, no questioning that.

    Is there actual plotted dyno charts anywhere for that test? I'd like to see them. Something interesting to note is that the Boss gives up .5 CR to the Chevy. I don't think it's unrealistic to think that a bump from 10.5 to 11 would make up for for the 8 ft-lb difference between the two, but you never know. Also without seeing the actual plotted dyno curves, you can't say much.

    I'd also be inclined to think the Boss would be a little more manageable on the street, since it has 26 degrees less duration on the cam at .050 than the Chevy. :chin: But then again, .050 numbers don't tell the whole story.

    Yep, I see it the same way. I just take it from more of a argument for looking at it as a system, more than just focusing on individual parts. Knaw whaddI'm sayin?
     
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  18. 90lxcoupe

    90lxcoupe Mustang Master

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    The LS3/L92 GM heads are pretty big and right at home on stock LQ4/LQ9 which is 360 cubic inches

    I kinda disagree with this, people told me my 205s' would be way to big on my small motor and it was going to be a dog at low RPMS, and its exatly the opposite and made good power below 6000 rpms, that is all going to change now that i am getting more agressive with the cam and RPMS though, but im still not worried about low end grunt with the new cam

    I look forward to seeing the numbers and agree with that statement, i think its going to prove people wrong
     
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  19. HotFox

    HotFox Active Member

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    Interesting discussion... Nik What is your port size at the opening (length x Width) of the TW205's? I will measure when home tonight my AFR 205's and post up what they are I just want to see how close or far off they are. I know that I will have to port match my super victor to the AFR heads height is close but width is .1-.15 wider. I am also worried on going to bigger heads on my combo as well, especially with the intake. The Professional Products single plane is WAY smaller then my new Edel Super Victor.

    I have made decisions on heads and intake strictly recommendations of my custom cam guy ED Curtis. So will see shortly! I will also be on the dyno to see the difference between the previous 185's and the new heads and intake.

    I know I like the looks of my AFR205’s with 7mm by 1.08 intakes. Then I see a set of LSX flowing 400cfm and want find a way to put a set of those on my little Windsor. Also makes my AFR heads look like stock Ford heads:nonono:.

    Should be on the flow bench in a week to see what they flow on a 4.030” bore. Most likely will just do a little bowl work/valve job and call it good. But will flow first to baseline before any work.

    This little experiment will prove whether big heads combined with the right cam and supporting parts will provide good power at lower rpm. Obviously Nik's combo is much more extreme:nice:.

    Scott
     
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  20. 90lxcoupe

    90lxcoupe Mustang Master

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    If i remember right the TF heads are 2.200 long by 1.600 wide
     
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