Intake elbows?

[5spd GT]

Stanger007 - Your synopsis on the throttle body flowing the exact same is exactly what I have been telling people for a couple years now. Many throttle bodies are thrown on that are not needed, and it gives them the "touchier" pedal that you described. Now with forced air in front of the throttle body, it makes it even touchier.

By the way, Paul is planning on doing a fox-body swap dyno I believe. Technically, with his couple changes coming up it is possible to see gains from the fox-body swap (if any) and then change out just the throttle body and see gains just from it on his 331. Now of course that is his money and time we are talking about

Grady - I was referring to actually having to "cut" a new hole in the fenderwell closer to the firewall. This would only happen with a foxbody throttle body or foxbody TB swap. By doing that it puts the throttle body on the same line as the upper plenum intake tract. Then you just run as straight of pipe as possible across to the strut tower area and then into the fenderwell. So there is no 45 or 90* turns atleast.

That is what I wondering if it was possible and if it could be done?

It could probably done an ugly and a pretty way. I hope that clarifies my "crazy thought."

By the way, your "home set-up" is actually pretty nice! You got rid of most of the "fenderwell kit" bend.

 

[final5-0]

As I see it David

You are talking about going in for cool air behind the shock tower

I guess the main thing would be if you have the room to do it

I can say with my shorty ProM 80 and the filter they supply with it .....

The two piece unit is just so honkin huge

If you look at my pic above ...
the filter is as far in the fender as one can go and still not use a bend

Grady

 

[5spd GT]

I wonder how it was set-up on Paul's dad's ride? Maybe him and I got the set-up idea confused

I figured size would be an issue, no doubt.

 

[final5-0]

I could not say what would or would not work here David

I guess one would just need to apply some

Good Ole Hot Rod Creative Thinking Here
and
Make It Work With What Ever It Takes

That is all I did with mine
but
I never did get around to making it more pretty

Then again ... Function always has been my first priority :Word:

Grady

 

[Black95GTS]

Bends are a minor detriment compared to changing the diameter of the pipe. Obviously running the cold air intake straight from the manifold to the throttle body to the maf to the filter is ideal, however, if you are running a more conventional setup then you want to focus on maintaining a smooth, identical diameter through the whole intake tract.

Bends are called "minor losses" while changes in diameter and friction are called "major losses" in fluid mechanics text books. So you can see why that stock ribbed hose is complete trash.

Instead of focusing on bends and pipe length, design should focus on a continuous smooth pipe surface of unvarying diameter.

IE, if you have a manifold with a 75mm opening, you should run a 75mm throttle body, 75mm tubing, and a 75mm MAF for optimal flow. Affecting the turbulence of the flow should be avoided even at the cost of bending the tract.

Don't take my word for it, google head loss, minor loss, major loss, darcy-weisbach, etc.

With this in mind, when someone claims that size X throttle body can flow Y CFM, I tend to take that flow value with a grain of salt. I really don't care how much air throttle body flows on someone's flow bench. If that criteria was used, then pretty much every throttle body would flow enough for any 8.2 deck combo. The flow value that I care about would be if that throttle body were attached to the exact same intake tract that I installed on my car. In that case, I guarantee one would find that the throttle body that had the same inside diameter as the entire intake tract would flow more, and have less turbulence, then a mismatched tract despite the manufacturer's claim that the mismatched throttle body has enough flow.

Some people would then say... but the manifold necks down from 75mm to 65mm. My response is that the engineers that designed the intake manifold have a reason to reduce flow pressure and increase velocity at that point. What that is, I don't know, but engineer's in general are pretty sharp and as an engineer, I will tell you straight up I would never implement a design without a reason and math to back it up. Perhaps increasing velocity at that point aids the air to evenly distribute itself to the cylinders?

Because nobody read that, I'll summarize and say I think Paul will pick up some ponies because switching to a larger throttle body will minimize head loss, NOT because he was lacking flow from just the throttle body. Less loss, more air, more power!

Adam (got an A in Fluid Dynamics!)

 

[final5-0]

Good to see you get involved here Adam

I have always been the first to say I can't say for certain
every time we get around to discussing the issue of
air intake possibilities.

I have not had the formal training such as you so I would like to ask a Q
and see what your past knowledge tells you about something a lot of us
do.

How would you say a fellow that has a large meter such as a ProM 80 or
Lightning would make out here

Using your above example ...

You would be drawing air from a larger opening and then necking down
to a smaller size the rest of the way to the upper intake.

I mean ... using a meter of 77mm or larger is a pretty common thing

Grady

 

[Killercanary]

I'll try and get some pics, but for now I'll try and descibe it:

Delete the EGR and get the thin EGR delete plate so that the TB bracket has something to bolt to. We used the UPR delete plate. Out of the TB we used a 45* elbow coupler connected to a straight piece of pipe. On the other end of the pipe is a straight coupler connected to a Pro-M 80mm MAF and filter. We had to cut the inner fender to get it to work, but it basically looks like Grady's setup above. I will be doing the exact same setup.

The problem with the 94-95 setup that has been described to me by people that make their living dealing with airflow is more of the step up in the elbow than the "bends."

 

[Black95GTS]

Good to see you get involved here Adam

I have always been the first to say I can't say for certain
every time we get around to discussing the issue of
air intake possibilities.

I have not had the formal training such as you so I would like to ask a Q
and see what your past knowledge tells you about something a lot of us
do.

How would you say a fellow that has a large meter such as a ProM 80 or
Lightning would make out here

Using your above example ...

You would be drawing air from a larger opening and then necking down
to a smaller size the rest of the way to the upper intake.

I mean ... using a meter of 77mm or larger is a pretty common thing

Grady

I think that introducing anything that disrupts the flow through the intake is a detriment. That includes going to a larger meter. One of the slickest setups I've seen is on a yellow sn95 running a 347 with vic jrs, vic5.0 intake ported to accept an 80mm throttle body, an 80mm throttle body, and a 80mm Pro-M. He's running 10s.

The intake tract feeds the vacuum created in the manifold. When you go wide open throttle, you are exposing the manifold to full atmospheric pressure, and the vacuum gets filled. Anything that disrupts the air flow into the manifold by changing intake diameter, or using pipe with a rough surface, will reduce the pressure of the incoming air, add turbulence, and in turn reduce power.

A larger throttle body WILL increase throttle response, making the car "touchier." The larger blade opening will cause the manifold vacuum to be exposed to more of the atmosphere compared to a smaller blade.

This is also why you hear a lot of people say that adding a cold air system increased their throttle response... they haven't "added" power per say, they have reduced loss. Amounts to the same thing but there is a difference. When someone deletes their air conditioner... they aren't adding horse power, they are reducing loss.

There is a point where technology limits how close we can get to the ideal, like you are saying Grady. If an MAF existed that was 75mm and could support the same HP that an 80mm could, then running a 75mm MAF, with a 75mm throttle body, and 3 inch tubing would make more sense. Perhaps MAP technology is the way to go when maximizing HP is the goal...

Adam

 

[MysteryMachine]

very good question grady i was wondering that myself. I have a 90mm LMAF that will be going on someday and 75mm everything else. I fell though with the upgrade in inj and everything else it shouldn't be as bad, Kinda liek I'm making up for it. Either way I'm sure I'll fell a difference. I will anyway if I do a build up but thats besides the point.

OT:

Hey Rick did you get my other PM?

 

[5spd GT]

Bends are a minor detriment compared to changing the diameter of the pipe. Obviously running the cold air intake straight from the manifold to the throttle body to the maf to the filter is ideal, however, if you are running a more conventional setup then you want to focus on maintaining a smooth, identical diameter through the whole intake tract.

Bends are called "minor losses" while changes in diameter and friction are called "major losses" in fluid mechanics text books. So you can see why that stock ribbed hose is complete trash.

Instead of focusing on bends and pipe length, design should focus on a continuous smooth pipe surface of unvarying diameter.

Adam, first off I want to say thanks for your feedback. I actually enjoy your "backed" evidence. You know that there are a couple out there that are bias in their suggestions. Just so everyone knows, but I am not talking about anyone that has posted in this thread.

Now, onto the topic. I apologize for talking about bends and I did not intend to portray that bends are the most important determiner in power production.

Before I speak briefly on friction and diameter, it has been a long time since I have seen a stock ribbed piece unit. Is it "ribbed" on the inside? Anyone got pictures?

Indeed, bends are minor losses. This does not mean that it should not be considered, which you know. Again, as you know a change in the direction of air (aka. bend) causes the air to lose energy and inertia.

Now onto friction, a smooth pipe is not as ideal as one might believe. This all goes back to laminar vs. turbulent flow in relation to the roughness of the surface, based off of Reynold's number. Air flows over a boundary from the wall. Air does not flow against the wall so I do not see that the aftermarket wall offerings are restrictive. Air speed at the pipe wall is, in effect, zero. Air flows over this boundary...

I agree with keeping the diameter as even as possible, within reason, but this two is not the end all either.

IE, if you have a manifold with a 75mm opening, you should run a 75mm throttle body, 75mm tubing, and a 75mm MAF for optimal flow. Affecting the turbulence of the flow should be avoided even at the cost of bending the tract.

Don't take my word for it, google head loss, minor loss, major loss, darcy-weisbach, etc.

With this in mind, when someone claims that size X throttle body can flow Y CFM, I tend to take that flow value with a grain of salt. I really don't care how much air throttle body flows on someone's flow bench. If that criteria was used, then pretty much every throttle body would flow enough for any 8.2 deck combo. The flow value that I care about would be if that throttle body were attached to the exact same intake tract that I installed on my car. In that case, I guarantee one would find that the throttle body that had the same inside diameter as the entire intake tract would flow more, and have less turbulence, then a mismatched tract despite the manufacturer's claim that the mismatched throttle body has enough flow.

Here is where my problem with keeping everything exactly the same. You know that a 75mm MAF is not going to flow as good as a 75mm open pipe. The MAF sensor, like the throttle body blade and screws, obstruct this flow and piping linearness. So what is one to do?

This is the point where I believe that the flow numbers may actually have some reason behind them. Not just because the #1 throttle body company in the nation says so. Now keeping the diameter is a great place to start no doubt

I see a gain being done with a better matching of the throttle body size to the intake piping as well. I cringe when I see someone stick on a 4.00" powerpipe or home made pipe (101.6mm), and then have a 65-70-75mm TB. This is an abrupt change of air flow and I can see a gain from this, not because the throttle body could not flow enough, but because the abrupt change of size is then increased.

I see post that the throttle body cannot flow enough As you stated, this is not the case, but just mismatched parts.

On a side note, a larger pipe decreases air speed. A smaller pipe increases air speed.

Some people would then say... but the manifold necks down from 75mm to 65mm. My response is that the engineers that designed the intake manifold have a reason to reduce flow pressure and increase velocity at that point. What that is, I don't know, but engineer's in general are pretty sharp and as an engineer, I will tell you straight up I would never implement a design without a reason and math to back it up. Perhaps increasing velocity at that point aids the air to evenly distribute itself to the cylinders?

Because nobody read that, I'll summarize and say I think Paul will pick up some ponies because switching to a larger throttle body will minimize head loss, NOT because he was lacking flow from just the throttle body. Less loss, more air, more power!

Adam (got an A in Fluid Dynamics!)

Yes, the Holley Systemax has a 75mm opening where the throttle body mates up. It does neck down to roughly 65mm a couple inches in. I believe this is to increase air speed (remember, smaller pipe increases air speed), and with the large-small-large tract going into the upper plenum, I believe you are onto something. Since air flows along the boudary layer of air along the wall, it could help distribute the air more evenly to each manifold runner, therefore into the combustion chamber.

I have seen some stick 75-90 mm TB's on the Systemax and have kept the "two inches" in the intake unported. This creates an abrupt change again.

If the engine actually needs it, port INTO the intake, not just the intake opening to "match" a throttle body.

I fully respect the engineering background. I am around a few of these guys. My brother is in school now for mechanical engineering and we have spoke of topics such as this. He has been apart of fluid dynamics, static, dynamic classes as well. My father is an electrical engineer/business master's graduate, and my uncle is an industrial engineer. Anyways, enough of my ramblings. I have really begun to self-teach myself some of this air/fluid theory myself. It is quite interesting...

Now, I got an "A" in public speaking, but that does not mean I should go give a State of the Union address

Thanks for the feedback and perspective. I hope you did not take any of my comments as derogatory, because I actually agree with A LOT of what you have stated.

I had a much longer post, but it did not post

 

[5spd GT]

I think that introducing anything that disrupts the flow through the intake is a detriment. That includes going to a larger meter. One of the slickest setups I've seen is on a yellow sn95 running a 347 with vic jrs, vic5.0 intake ported to accept an 80mm throttle body, an 80mm throttle body, and a 80mm Pro-M. He's running 10s.

The intake tract feeds the vacuum created in the manifold. When you go wide open throttle, you are exposing the manifold to full atmospheric pressure, and the vacuum gets filled. Anything that disrupts the air flow into the manifold by changing intake diameter, or using pipe with a rough surface, will reduce the pressure of the incoming air, add turbulence, and in turn reduce power.

I have to make a few quick comments. If this yellow sn-95 (Drew's car) is what you are referring too, remember that the 10 second time slip have very LITTLE to do with the intake piping size. Much of that is suspension (1.4 60 ft) as you know. Trying to imply that the intake tract is a good reason why it hit the 10 second timeslip is commiting a post hac fallacy Adam.

Just because X is there does not mean Y occurs. I see this so much on the forums.

"Well, he had a 75mm throttle body and was running 117 mph with his 302."

You know as well as I that it is all in the details and overall package. Not one single valve that lets air enter the engine.

A larger throttle body WILL increase throttle response, making the car "touchier." The larger blade opening will cause the manifold vacuum to be exposed to more of the atmosphere compared to a smaller blade.

This is also why you hear a lot of people say that adding a cold air system increased their throttle response... they haven't "added" power per say, they have reduced loss. Amounts to the same thing but there is a difference. When someone deletes their air conditioner... they aren't adding horse power, they are reducing loss.

You are totally correct about the "touchier" throttle. Been there done that, like many of us. I cannot say that my cold air intake or friend's cold air intake gave them any noticeable throttle response. But hey, no need for me to get picky

There is a point where technology limits how close we can get to the ideal, like you are saying Grady. If an MAF existed that was 75mm and could support the same HP that an 80mm could, then running a 75mm MAF, with a 75mm throttle body, and 3 inch tubing would make more sense. Perhaps MAP technology is the way to go when maximizing HP is the goal...

Adam

I recall that Pro-M stated that their 80mm offering to us supports 800 horsepower.

I doubt the 75mm is far behind.

 

[Black95GTS]

I have to make a few quick comments. If this yellow sn-95 (Drew's car) is what you are referring too, remember that the 10 second time slip have very LITTLE to do with the intake piping size. Much of that is suspension (1.4 60 ft) as you know. Trying to imply that the intake tract is a good reason why it hit the 10 second timeslip is commiting a post hac fallacy Adam.

Just because X is there does not mean Y occurs. I see this so much on the forums.

"Well, he had a 75mm throttle body and was running 117 mph with his 302."

You know as well as I that it is all in the details and overall package. Not one single valve that lets air enter the engine.



You are totally correct about the "touchier" throttle. Been there done that, like many of us. I cannot say that my cold air intake or friend's cold air intake gave them any noticeable throttle response. But hey, no need for me to get picky



I recall that Pro-M stated that their 80mm offering to us supports 800 horsepower.

I doubt the 75mm is far behind.

Ahhh my old sparring partner, but here I think were are agreeing with each other yet do not quite want to admit it.

I can see where one might read what I wrote and thing the air induction piping cause Drew to run 10s... I didn't mean it to come out that way. That would be crazy to say and I agree.

In terms of the MAF meter itself and the blade of the throttle body disrupting flow... I don't really know how that affects things, I suppose it could be modeled.

But I have a question, and I'm not being a smart ass when I ask this, but how can one throttle body flow so much more then another of the same size? IE, you have three brands of throttle body, Edelbrock, Accufab, and BBK. They are all 70mm. Yet the Accufab flows more... how? Isn't it basically a 70mm hole with a blade in the middle? I believe that Accufab uses the best quality parts, but the physical properties of a throttle body are basically the same, so how can the flow be that much different??

Adam

 

[gcomfx.com]

I switched from a 65mm BBK to a 75mm Ford Racing. I obviously didn't do my research enough as I thought I would need a larger coupling for the T/B. I didn't. The EXIT hole of the T/B was the only thing larger on the 75mm T/B. They both had the same size entry in front of the blade. The 65 just had a taper at the rear of the T/B the 75 did not. Makes me wonder why I couldn't have just milled out the back of the 65 to get the same results.

 

[5spd GT]

Ahhh my old sparring partner, but here I think were are agreeing with each other yet do not quite want to admit it.

I can see where one might read what I wrote and thing the air induction piping cause Drew to run 10s... I didn't mean it to come out that way. That would be crazy to say and I agree.

In terms of the MAF meter itself and the blade of the throttle body disrupting flow... I don't really know how that affects things, I suppose it could be modeled.

I knew you did not mean that that is the reason, but I wanted to throw that out there, because I see bias based post like that on here and other sites from time to time.

Now about his induction, he also has a 4.00" pipe. Remember that is 101.6mm.

So we have 101.6 - 80 - 101.6 - 80 - and no telling what the intake "necks down" too.

But I have a question, and I'm not being a smart ass when I ask this, but how can one throttle body flow so much more then another of the same size? IE, you have three brands of throttle body, Edelbrock, Accufab, and BBK. They are all 70mm. Yet the Accufab flows more... how? Isn't it basically a 70mm hole with a blade in the middle? I believe that Accufab uses the best quality parts, but the physical properties of a throttle body are basically the same, so how can the flow be that much different??

Adam

I will let Accufab answer that question I actually already alluded to it earlier.

"And to further complicate the “guessing” process, all throttle bodies of the same dimension, do not have the same CFM rating. You might think that Brand A’s 75 MM throttle body would flow the same as Brand B’s 75 MM throttle body. Such is not the case, because all throttle bodies have a “major obstruction” in the middle of the air path, namely a throttle blade and shaft. How well the air flows over and under this obstruction will define the CFM a specific throttle body will flow. A big fat shaft with the attachment screws for the blade sticking up into the air stream will impact the CFM of that throttle body."

So again the valve shaft, screws, blade thickness, and then you may get into the design to make airflow more efficient.

When I spoke to a Holley rep, I got some numbers that were higher.

Accufab:

65 MM - 664 CFM
70 MM - 787 CFM
70 MM - 896 CFM (Race version)
75 MM - 924 CFM
75 MM - 1045 CFM (Race version)
80 MM - 1142 CFM
85 MM - 1322 CFM
90 MM - 1369 CFM
105 MM - 1550 CFM

Holley:

65 MM - 750 CFM*
70 MM - 790 CFM*
75 MM - 840 CFM*
80 MM - 892 CFM*

*Information given by Tech Rep.

BBK:

70 MM - 726 CFM

Something I try to keep in mind, aside from matching the diameter:

If you've got a throttle body that delivers 100% of the peak air requirements of your engine when the throttle plate is fully open, you have control of the air throughout 100% of the throttle position range. If you go to an oversized TB that delivers 100% of the air that your engine can consume while the throttle plate is only 60% open, you have given up usable throttle-control range for no advantage.

Now Adam, I REALLY like the idea of keeping the piping all as close as possible so do not get me wrong

gcomfx - Milling, or better yet porting is something the ls1 guys do all the time. They go from 71.5" (on the back) to 75mm (on the back lip).

 

[final5-0]

Of course ... I'm interested in what happens with a large meter of 80mm or larger
simply cause I got one

Since I brought up the subject of meters

Allow me to elaborate a bit if you will

We have talked about 75mm meters a lot here and the reason seems to be so
we can kinda keep things matched from one end to the other.

Here is what I gotta bring up about the meter.

I just did not in any way want to compromise with my meter and I paid
a bit extra to make that happen.

1) I picked a ProM meter for a specific reason
and
2) I picked the 80mm in their line for a specific reason

So ... I will keep my meter of choice

I saw all you said Adam
but
It still seems to me

If you draw air from a 90mm, 80mm, 77mm, or 75mm opening (the meter)
what would be the difference as long as the pipe on the outlet of the meter,
the bend to make the turn, and throttle body were done as you said
suggested in keeping the size the same all the way through.

I guess the 90mm would act like a funnel of sorts ... maybe

Also ... I wanna make it clear in my setup .....
The meter is on the end as seen in the pic above
rather than
In the middle of the intake pipe as you see on some setups

Good discussion guys

Grady