three inch IC piping with a 16g??

[99gst_racer]

What about 80mm tb and 3" IC pipe on a bigger turbo?

Exactly. With a large-framed turbo and a large TB, there can be benefits with a 3" intercooler pipe.

Abel Racing made more power with a larger TB and 3" upper IC pipe: http://members.cox.net/abelracing/aboutus/Flame/index.htm
(^^^ 6th dyno graph)


But, if a large TB and 3" IC piping is coupled with a small framed turbo such as the 16G, then I can't foresee any power gains. If anything, the added pre-plenum volume will just delay response and possibly cause poor low throttle driveability.

We all know that intake air velocity through the intake ports/valves is extremely important for power production. I wonder if the velocity of the air before it arrives at the intake ports has any impact on the final velocity as it travels through the intake ports?

Most definitely. That's exactly why you can yield positive performance results from removing the throttle body before the plenum, and replacing it with individual throttle bodies after the plenum. A pre-plenum restriction can greatly and negatively affect velocity (turbulence) and cause a loss of air density in the plenum, which will in turn reduce velocity through the runners/ports.

 

[wishihadatalon]

Exactly. With a large-framed turbo and a large TB, there can be benefits with a 3" intercooler pipe.

Abel Racing made more power with a larger TB and 3" upper IC pipe: http://members.cox.net/abelracing/aboutus/Flame/index.htm
(^^^ 6th dyno graph)


But, if a large TB and 3" IC piping is coupled with a small framed turbo such as the 16G, then I can't foresee any power gains. If anything, the added pre-plenum volume will just delay response and possibly cause poor low throttle driveability.


Most definitely. That's exactly why you can yield positive performance results from removing the throttle body before the plenum, and replacing it with individual throttle bodies after the plenum. A pre-plenum restriction can greatly and negatively affect velocity (turbulence) and cause a loss of air density in the plenum, which will in turn reduce velocity through the runners/ports.

I ran a 3" upper i/c pipe with my 16g with no real issues. I did it because I was going to run a PRO-M maf (like the GM but better ) and I didn't like the instant expanders that everyone uses. Up by the throttle body I used a nice cone taper pipe from Summit. It worked well but I was also building my setup for something larger. I see 2.5" piping being plenty if that is the setup that you plan to keep.

 

[1gDSM4g63]

Exactly. With a large-framed turbo and a large TB, there can be benefits with a 3" intercooler pipe.

Abel Racing made more power with a larger TB and 3" upper IC pipe: http://members.cox.net/abelracing/aboutus/Flame/index.htm
(^^^ 6th dyno graph)

Well, I guess there are more important things to consider than switching to a 3" cold side IC since it only make 15 hp +/-.

 

[DSMunknown]

We all know that intake air velocity through the intake ports/valves is extremely important for power production. I wonder if the velocity of the air before it arrives at the intake ports has any impact on the final velocity as it travels through the intake ports?

Huh, I thought that would be pretty obvious.

 

[romeen]

Huh, I thought that would be pretty obvious.

Not necessarily smartass.....

The velocity of water down the spillway of a dam is independent of the velocity of the river leading up to the dam. But our engines are a little more dynamic than that analogy.

Anyway, given that we all accept that as a true statement wouldn't that suggest that 2" piping will yield better results with a 16G than bigger piping? There are obviously other variables affecting results so it would be great if someone had before/after dyno results of several piping diameters with an otherwise identical setup.

 

[DSMunknown]

Com'on Romeen. You know it's not just about the dyno runs. Logging results are much more informative. It's definitely not about peak power and performance. It's what's under the curve that's interesting.

 

[haioku-rocket]

the time it takes to fill the extra volume at the velocity that the charge is flowing is like split tenths of a second. Its actually been tested. If people are complaining about turbo lag going from 2.5" to 3" they just have no idea what they are talking about and probably have a boost leak. Honestly there shouldn't be any noticeable difference in lag. People this is like splitting hairs. I mean who cares? 3" or 2.5" it will all perform the same. I would like to see that buschur thread would be very interested on "how" 2.5 performed better as I find that hard to believe....

I have had 50MM and 70MM piping on my car. I haven't noticed a difference. Only reason I went to 70MM is because the stock 60MM TB on the evo OD is exactly 70MM. So a same size coupler going from the piping to the TB did the trick great. No difference between 50 and 70MM from what I have noticed.

 

[Jeff99GS]

I have my car set up with 2" IC piping from the Turbo to the intercooler inlet....and then 2.5" from the IC outlet to the throttle body.

I think it helps cool the air better, Think of blowing air through a straw...now blow air through a toilet paper tube....the air being forced through the straw comes out cooler!

Its like when you Open a bottle of nitrous or spray some hairspray...thats also why Home Air Compressor tanks are Usually HOT to the touch but if you spray the air out it becomes cold?

another example would be to open your mouth WIDE and push out air....Its hot right?

Now make a whistling face and blow air out....its colder!!

I believe that's why brent Rau uses this type of setup on his car as well. Notice the 3" turbo outlet...then it gradually goes to 3.5" then 4"

Now some of you will say he did this just to make the charge pipe fit on his Intake Manifold....But he could have used that 4" pipe all the way from the turbo....or even better, why not use 9" pipe the whole way! The reason he didnt is because there is NO benifit in having an IC pipe that's much bigger than the turbo outlet....and Im sure his car is Faster like this than it would be with solid 4" pipe

And YES this is splitting hairs but EVERY little bit counts!

 

[RipperXX]

I have my car set up with 2" IC piping from the Turbo to the intercooler inlet....and then 2.5" from the IC outlet to the throttle body.

I think it helps cool the air better, Think of blowing air through a straw...now blow air through a toilet paper tube....the air being forced through the straw comes out cooler!

Its like when you Open a bottle of nitrous or spray some hairspray...thats also why Home Air Compressor tanks are Usually HOT to the touch but if you spray the air out it becomes cold?

another example would be to open your mouth WIDE and push out air....Its hot right?

Now make a whistling face and blow air out....its colder!!

I believe that's why brent Rau uses this type of setup on his car as well. Notice the 3" turbo outlet...then it gradually goes to 3.5" then 4"

Now some of you will say he did this just to make the charge pipe fit on his Intake Manifold....But he could have used that 4" pipe all the way from the turbo....or even better, why not use 9" pipe the whole way! The reason he didnt is because there is NO benifit in having an IC pipe that's much bigger than the turbo outlet....and Im sure his car is Faster like this than it would be with solid 4" pipe

And YES this is splitting hairs but EVERY little bit counts!

While your sort of on the right trail about a compressed gas getting cold when it expands quickly. Your also off in some area's and giving very poor examples. I am trying to be nice because my original reaction was more like


Simply put when you compress air which is a mixture of a lot of gas's it gets hot, when it expands it cools. The faster it expands the colder it will be. Different ID of pipe and routing can be used for max power or quicker responce although as some have already said the difference is not a night and day difference like some seem to think.

Assuming everything in the intake tract from the air filter to the TB is 3" the 3" would in theory make more power for a few reasons such as less pressure (boost) to get the same air flow, to cooler air temps mostly due to running less boost to get the desired amount of air flow.

Shorter routing with smaller pipes will promote reaching peak boost faster, so that type of setup would be more responsive. But that doesn't mean it would make more power. And again there wont be a night and day difference maybe a few hundered rpm at most.


2 1/2" ID pipe is fine for I would say 80% of people out there.

 

[Jeff99GS]

While your sort of on the right trail about a compressed gas getting cold when it expands quickly. Your also off in some area's and giving very poor examples. I am trying to be nice because my original reaction was more like


Simply put when you compress air which is a mixture of a lot of gas's it gets hot, when it expands it cools. The faster it expands the colder it will be. Different ID of pipe and routing can be used for max power or quicker responce although as some have already said the difference is not a night and day difference like some seem to think.

Assuming everything in the intake tract from the air filter to the TB is 3" the 3" would in theory make more power for a few reasons such as less pressure (boost) to get the same air flow, to cooler air temps mostly due to running less boost to get the desired amount of air flow.

Shorter routing with smaller pipes will promote reaching peak boost faster, so that type of setup would be more responsive. But that doesn't mean it would make more power. And again there wont be a night and day difference maybe a few hundered rpm at most.


2 1/2" ID pipe is fine for I would say 80% of people out there.

A 16g has a small outlet and if you use 3" pipe on a 16g I believe you will lose more Boost pressure by the time it gets to the Throttle body than if you used 2.5 or 2.25 pipe. Meaning the turbo will have to work harder to fill the bigger Pipes and take longer to get to the engine...(aka) less power. Thats just my opinion and Its seems Buschur had the same results and it also looks like brent Rau uses the Same setup...SOOOO Im gunna stick with that chief.

 

[Black_Bullet]

A 16g has a small outlet and if you use 3" pipe on a 16g I believe you will lose more Boost pressure by the time it gets to the Throttle body than if you used 2.5 or 2.25 pipe. Meaning the turbo will have to work harder to fill the bigger Pipes and take longer to get to the engine...(aka) less power. Thats just my opinion and Its seems Buschur had the same results and it also looks like brent Rau uses the Same setup...SOOOO Im gunna stick with that chief.

Not really, the same amount of flow reaches the engine, it might just take longer to "fill" the piping to a certain pressure. The turbo isnt really working harder, I dont think the turbo cares if its 2.5 or 3in piping, its just going to spin up to whatever the set boost pressure is/ or to whatever its capable of flowing, which ever comes first....

 

[->PrOjEcTGS<-]

This is how I will explain it and how I understand it.

I like your idea on the air compressor theory. I'm gonna separate this into two extreme scenarios. The compressor motor will represent your turbo since it compresses air like a turbo does. The motor (16G) has a fixed HP and output (40lb/min). The tank is going to represent your Intercooler Piping. Take a regular 33 gallon tank like this one:

You must be logged in to view this image or video.

Now, see how long it takes to fill that tank to 150psi. This vaguely demonstrates the larger IC piping volume.

Now, assuming you use the same compressor motor (16g @ 40lb/min) take a much smaller 2 gallon tank like this one and see how long it takes to fill up:

You must be logged in to view this image or video.

It's not going to take as long to fill up the smaller tank is it?

Now hook a blow gun to your tank (Engine & Exhaust) and start blowing air (WOT). The smaller tank (2.5" IC piping) since the reserve capacity is lower, will need to be refilled sooner and more often to maintain a PSI level. The larger tank (3" IC piping) will take longer for it to need to be refilled. But at that point again it will take the larger tank longer to fill back up to maintain it's psi level. If your pump (16g) flows the same on both tanks, your larger tank will maintain a lower PSI level since the compressor motor can not fill it up fast enough to handle the larger tank yet the volume inside is more. You will get the same flow out of the larger tank (3" IC piping) at a lower PSI level than you would on the smaller tank (2.5" IC piping) at a higher PSI level. You must work the pump (turbo) harder to keep the larger tank at the same PSI level as the smaller tank? Now, which can your pump best support?

Doesn't really matter which one you choose. But, you will see your turbo max itself out at a lower boost pressure if you go with a larger IC piping especially if it's a small turbo.

 

[romeen]

I still think that the greater air velocity created by the smaller piping (2-2.5") will yield a power curve and response better suited to most types of driving, especially on the street.

Com'on Romeen. You know it's not just about the dyno runs. Logging results are much more informative. It's definitely not about peak power and performance. It's what's under the curve that's interesting.

I completely agree, but without a dyno how do you know what that curve looks like?

 

[Black_Bullet]

I still think that the greater air velocity created by the smaller piping (2-2.5") will yield a power curve and response better suited to most types of driving, especially on the street.

I agree with ^^

But just because some piping takes longer to fill up than another ( if its even negligable)
it doesnt mean the turbo is going to flow less... Flowing less would be choking it/ restrictions
but were not talking about that...

Also your looking at psi to directly to airflow.
In this scenerio, if the difference of the 2.5 piping was that pronounced over the 3in piping, ( which i doubt it is) then the only thing that would likely happen would be the 16g would still flow its 40lb/min of air, but it would just do it with a bit less boost since it would physically take more air to fill a larger pipe at X boost level... Or it could just affect the rpm were peak power/ air flow was reached... ( I.E. Later or sooner rpm)

Also consider that pressure directly translate to heat, so you actually WANT to make more power on less boost, because that way your not heating up the air charge from trying to run high psi to make x amount of airflow.
Thats why bigger turbos, or smim, or big cam setups are really efficient and make big power is because they can make the setup dish out much more air flow before the "pressure" ( psi ) goes too high... That keeps excessive heat down, were as you may need 25psi on a 16g just to flow like a 50trim at 20... ( random example, )

The only thing the smaller piping is going to do is make the air flow faster ( velocity)
but neither pipe size would be a restriction for that sized turbo so neither would alter overall airflow potiential, but the shape of the curve definitly could be affected.

Now obviously , most ppl just go with either whats available, or whats tried and true.
If 3in pipeing isnt needed and the setup doesnt call for it, then theres no reason to run it when it could
argueably affect spool time/ shape of the curve. On a much larger turbo undoubtably 2.5 may literally be a restriction past a certain level of flow. I dont think 3in is bad on a 16g setup, but i think its unnecessary.

Im not saying Im right, but just my opinion.

 

[->PrOjEcTGS<-]

I agree with ^^

Also your looking at psi to directly to airflow.
In this scenerio, if the difference of the 2.5 piping was that pronounced over the 3in piping, ( which i doubt it is) then the only thing that would likely happen would be the 16g would still flow its 40lb/min of air, but it would just do it with a bit less boost since it would physically take more air to fill a larger pipe at X boost level... Or it could just affect the rpm were peak power/ air flow was reached... ( I.E. Later or sooner rpm)

Exactly...

 

[haioku-rocket]

Jeff man...you got it all wrong.

Not really, the same amount of flow reaches the engine, it might just take longer to "fill" the piping to a certain pressure. The turbo isnt really working harder, I dont think the turbo cares if its 2.5 or 3in piping, its just going to spin up to whatever the set boost pressure is/ or to whatever its capable of flowing, which ever comes first....

more or less agree.

I still think that the greater air velocity created by the smaller piping (2-2.5") will yield a power curve and response better suited to most types of driving, especially on the street.



I completely agree, but without a dyno how do you know what that curve looks like?

That works in theory. But in real life its not even noticeable. Boost response???? Maybe about 50 RPM difference. Whatever you consider a few split tenths of a seconds if that, its not even worth talking about.


I went from a crossflow intercooler 31.5x8x3.5 to a vertical flow core 18x3.5x10 and removed 4 feet of 70MM (2.75" OD)piping. So basically I reduced the amount of volume to fill by 782 cubic inches. On my logs with the Power FC there was only 100-150 RPM in difference in the logs on my data-log it software... Period. Lets say you are going from 2.5" to 3" piping, and say you have approximately 7 feet of intercooler piping, so the difference in volume to fill if everything remains the same is exactly 181.43 cubic inches. So if I can only log 100-150 RPM difference on 782 cubic inches; then everyone here arguing about 181.43 cubic inches, that its going to be laggier, and perform worse is just ridiculous, stupid, and pointless....

Do we even want to calculate how long it takes a 16g to fill that extra 181 cubic inches of volume up at the velocity that it pushes air? Do we even want to go there?

Like I said it doen't make a difference. Splitting hairs over nothing.

 

[Jeff99GS]

Jeff man...you got it all wrong.

No you guys just dont get what im sayin...You are all saying EXACTLY what I was trying to say...Just In a diffrent way LMFAO If the boost gets to the cars faster thats better in my opinion??? I mean what the Fu*k?????????

You guys Bitchin can go ahead and use a 15" sewer pipe for your IC piping and see how it works for ya..

Someone said buschur had better results with 2.5 than 3" why is that?????????????? If im SOOOO wrong

Its a Proven fact that when a gas that is underpressure is released that it cools. Like NItrous, Propane, Butane, Oxygen, and the list goes on...Thats all I was saying.

 

[->PrOjEcTGS<-]

Bottom line is: You need to get the correct piping for your application.

Very abstract analogy but, what's wrong with the stock fuel feed lines (Stock IC Piping)? They are too small once you add a larger pump (larger turbo). Now would you put a 10AN feed line on the stock fuel pump? Why not? Because you still have a crappy stock pump that isn't going to be able to back that extra volume. Throw an Aeromotive A1000 pump (GT35R) on it and you wouldn't even think twice.

Another analogy. Take a garden hose. Now why don't we all have garden hoses the size of fire hoses? Because the piping in the house can't flow the amount that the hose can carry. Will you still get the same amount of water out of the hose if you were to use one? Sure. Unless your original hose was too small to begin with, restricting the flow.

I'm not saying whether or not to use 2.5" or 3.0" I just know there is a point of diminishing returns when it comes to going larger on things. Just keep it all the same. If your intercooler has 3" inlets, then go with 3". If it has 2.5" inlets, use 2.5".

 

[DSMunknown]

Wonder if anyone's split the difference and experimented with 2.75 inch piping.

 

[dsm-onster]

Bottom line is: You need to get the correct piping for your application.

Yes but what is that?

I'm going to throw a monkey wrench in this whole thing and state the obvious. Any sealed barrel of air (plenum) with a stack on it (intercooler pipe) has a resonance. What is anyone, including the top racers doing about that? Porche has been using the expansion from the "trough" of the resonance (negative resonance) to allow more timing and denser air. This assists pumping loss and BSFC on several levels.

Diameter affects this resonance significantly. Length even more. When it comes to chosing the ideal, experimenting really affords the best opportunity.