Intercooler Piping size

[WidebodyWoody]

Might sound like a random question that might have lots of answers, but really there should only be 1.

My turbo outlet is 2" inside diameter. But 2.5" outside diameter. What size would best suit this?

Secondly, Magna Intake for 2.6. Whats the best size throttle body to suit with this Turbo outlet/intercooler piping size. Obviously we don't want to go up in size as it takes longer to fill the space. So would I go 2.25" or 2.5"?

[OLD FART]

IMHO everything is a compromise
Richard from ARE Cooling would be the be one of the more switched on people to contact as he has done a lot of research/testing in this area.

[fugazi]

2" (inside) would bee best and then a "diffusor" or coned pipe up to whatever the IC inlet is.

[WidebodyWoody]

Here is what I currently have directly after the turbo



As you can see, it goes from the 2" down to something like 1.5" or smaller. Whatever the std intercooler piping is. It does this currently because it goes through the crappy hose intercooler piping and the std intercooler and the TBI. I am going to change all this, so anything from 2" up will be a vast improvement I am hoping. But I would like to get the flow right. I don't mind going 2" to the Intercooler and maybe 2.5" to the TB MPI. What you guys think?

[NXTIME]

I would suggest 2" out of the turbo to cooler and then same size as t/b on inlet side. I will be using these when I eventually go MPI on mine (using XF t/b = 2.5" piping).

[WidebodyWoody]

Yeah I was considering going XF throttle body as well. I didn't know it was 2.5"

I see no need in changing the piping size honestly as it should flow better being the same size all the way through. Just need to make sure that the piping is lined up, as the outside diameter of the turbo will more than definetly be thicker than that of the 2" IC piping.

Also I was wondering, if I route the IC piping the same as the image below, as in going either side of the radiator, because its shorter, would it be more responsive and would I get much heat soak from the radiator?

[dirtygalant]

evos with factory 300ish hp make do with 2-2.25" piping and they are usually good for another 50ish hp before needing to be upgraded.

Personally myself I would upside the end tank inlet/outlet on the intercooler to 2.5" and run 2.5" for as much as you can, and just have a reducer for the turbo outlet.

[WidebodyWoody]

Because the turbo outlet is 2.5" outside diameter, I probably wouldn't need a reducer as it would help keep the piping lined up just coupling it to the turbo. It shouldn't harm it dropping from 2" to 2.5" without a smooth transition would it?

[dirtygalant]

shouldn't do. I wouldn't focus so much on the intercooler piping diameter because it's only going to flow as much as the whatever component in the system flows less - be it the intercooler itself, throttle body etc. If you are going to do custom intercooler piping you may as well do it once and do it right with 2.5" piping, that way you wont need to re-do it in years to come if/when you decide to chase more power. The stock IC flows quite well once you upside the end tank pipe diameters.

[WidebodyWoody]

Yeah well I was going to change the Intercooler to a better flowing, larger PWR one anyway.

[Bruzman]

Determining the optimal piping size is extremely hard without exact facts and figures (Turbo specs, Exhaust specs, Throttle Body specs, etc).

Keep in mind a Turbo produces 2 positive effects:

1. Boost (PSI): The amount of air condensed into each square inch. A smaller turbo will be able to produce the PSI quicker but not as much per square inch. The bigger the piping and inter-cooler area, the longer it takes to pressurise the area.

2. Flow: The amount/speed the intake uses the pressurised air at different RPM. Once the turbo pressurises the intake, the intake will use more air at higher rpm's. In saying that, the turbo is receiving more exhaust, but at some point it's gotta give, and a smaller turbo will not be able to keep up with demand. The larger the piping and inter-cooler area, the more pressurised air it can hold once pressurised, and therefore won't lose presure as quickly.

Turbo size is the easiest way to guess/judge/determine your piping requirements (Without getting exact facts and figures). Turbos size (Small or Large) is relative to the engine size and spec, so this is all theory. Lets pretend the Smaller and Larger Turbo have the same bearing for this theoretical demonstration (Journal or ball-bearing). Upgrading from Journal to Ball-bearing can change theory/outcome. What you do with the theory behind this is yours.

A Smaller Turbo (for arguments sake, factory Turbo) will gain boost quicker, but lose boost at RPM the longer you stay without change gears (In the assumption that the factory turbo was design relatively small compare to the engine size and specs).

2inch pipe on this "Smaller Turbo" is more optimal towards gaining boost quickly but will lose boost-over-time the longer you hold boost in that RPM range. If your using the car for Daily driving or light Track work, this is fine.

3inch pipe on this "Smaller Turbo" is more optimal towards Holding boost longer but will take longer to gain boost. If your using the car for Drag Racing or Dyno work, this is fine.

A Bigger Turbo (for arguments sake, a Larger aftermarket Turbo) will boost later, produce more boost, hold boost longer and may not lose pressure.

3inch pipe on this "Bigger Turbo" is more optimal all around. You may even consider going larger if it's a MASSIVE Turbo or a bearing upgrade (Journal upgrading to ball-bearing).

My recommendation:

Go 2.5 inch piping if a Factory Standard Turbo (or one's with close Specs).
It is a good middle ground estimation. I don't have enough knowledge of your system, but this size piping has the best theoretical chance of optimal performance. It will take longer to boost, but give the Air more area to collect.

3 inch or greater piping if a Upgraded Turbo (specs clearly greater than original).
What I said before speaks for itself.

Sadly, I could not find where I originally learned this information as a reference/proof. Hopefully I made sense and you believe my reasoning.
(NOTE/REMEMBER: Determining the optimal piping size is extremely hard without exact facts and figures. This is all THEORY)

[WidebodyWoody]

Thanks. That was some good information. The turbo is indeed much bigger than stock. I originally bought a Garrett GT35RLS turbo but they royally shafted me the company I went through. I thought I was getting the GT35RLS and a Haltech E6X but what I got was a Haltech E6K and a hybrid weird turbo. It actually looks like both were off someone elses car before I got them. The turbo I am pretty sure is a Garrett GT35 front with a smaller early Evo style exhaust housing. Its still a ball bearing turbo, and honestly, I am glad it isn't a GT35 as it would have been too big anyway.

Looks like I might need to do some more research. Worst case scenario, I get 2.5" and 3" and dummy them up with hoses holding them together and bench mark them both and keep what I like best and get them welded up.

[Sargeant_Khan]

It sounds like you're on a really tight budget. You're opting for a pwr intercooler?
:beer

[Bruzman]

I originally bought a Garrett GT35RLS turbo but they royally shafted me the company I went through. I thought I was getting the GT35RLS and a Haltech E6X but what I got was a Haltech E6K and a hybrid weird turbo. It actually looks like both were off someone elses car before I got them.

Didn't you want to complain and get it replaced with the correct gear? It did you find what you got satisfactory anyway?
GET MAD AND FUCK SHIT UP!

The turbo I am pretty sure is a Garrett GT35 front with a smaller early Evo style exhaust housing. Its still a ball bearing turbo, and honestly, I am glad it isn't a GT35 as it would have been too big anyway.

Seems like a Good match if looking for hard boost! here is why:
(I get the picture you understand woody, but I am sure their are many many more people reading this post that want to learn)

Small EVO style exhaust housing + Ball bearing:

The Exhaust housing is the optimal size for a Stock Engine. As long as your engine isn't modified to much it is "Perfect"! If your engine is modified alot, than a bigger Exhaust housing would of been more optimal.

If the Exhaust housing is smaller than optimal size, then it would restrict exhaust flow and the piston won't move as quickly because it's having difficulty pushing the fumes.
If the Exhaust housing is bigger than optimal size, then it won't create enough force/pressure to spool the turbo.

Clearly a ball-bearing turbo spools quicker than a journal turbo. Mixing this with the prefect exhaust housing, and it should start boosting alot quicker than your stock turbo.

The Turbo should spool quickly because of the ball-bearing and exhaust housing system. Possibly even around the 2k rpm mark. It might not reach full boost extremely quickly because of the size of the compressor, but it will gain PSI growth at a much quicker rate than your stock or standard GT35.

GT35 Turbo inlet/compressor

The GT35 Turbo's compressor will be able to create much higher PSI than your stock turbo. The compressor will even be able to keep up with the flow required to keep PSI at max. It will also hold this higher PSI safely (for turbo system, not engine)

Compressor, ball-bearing and exhaust housing as a TEAM:

*Quick spool
*high and stable PSI
*ENOUGH SAID! Winning Turbo! Congratz! :beer

Looks like I might need to do some more research. Worst case scenario, I get 2.5" and 3" and dummy them up with hoses holding them together and bench mark them both and keep what I like best and get them welded up.

I'd love to see your research! It's going to be hard to Beachmark tho! You'll need a quick eye! :x

Easy enough to Beachmark the spool time.
Mark the RPM that the Turbo starts to boost and gets full boost. (that's if you can read it quick enough. I think yours should be pretty quick)

To beachmark the boost hold, take it to almost MAX rpm. Then watch to see if the PSI drops any. Personally, I feel that turbo setup will probably hold boost perfect through both.

Like I said, I'd love to see the Research, but I would easily put money on the 3inch because it's it's a larger compressor with ball-bearing. I think that benchmarking will probably be a waste of time and money.

I recommend going with the 3inch and never looking back.

[NXTIME]

Woody, that is how I had my cooler piping on my JA, and also how I will be running them on my widey with a bigger cooler.