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zandrew
04-29-2013, 10:31 PM
I am curious as to what size intercooler plumbing people are running and what levels of hp they can run with it. Also what intercooler are you using.

I bought a Evo intercooler off the classifieds since it is light weight and should handle my goals. I half assed my current intercooler in since I knew it was not going to be permenant. I am currently running 2" cold and 2.5" hot. It seems like a stagger sets are "considered" more effective.

Yes I have searched but as usual I have came across many different perspectives that seem to work. I know one guy that runs 2.25" and makes more then my goals without an issue. I would like to keep the current diameter if it can hold up.

I am also sick of reattaching couplers on the side of the road. I am going to weld up 2 pieces of pipe with 2 couplers per side (hotside is done). My BOV is mounted upside down behind where the stock IC'r setup goes into the black steel frame brace on the cold side. I like this position if there is no issues with it mounted this way but have considered welding it too intercooler pipe itself. I like to eliminate every clamp possible. I have a forge 007 DV. Is this stupid?

Gumby
04-29-2013, 10:48 PM
On my 2871r I run 2.5" piping both sides, with a Teeadstone tr8, and a Forge 007 DV.

catbed
04-29-2013, 11:30 PM
2" hot side, 2.5" cold side with a precision 600.

mykeg6
04-30-2013, 12:15 AM
2.5" all the way. Comp turbo 5556

Seerlah
04-30-2013, 02:41 AM
I am under the precept that you want to run 2.25" hot side and 2.5" cold side for the GT2871R. Different applications would use different sized piping. Right now I have a custom side mount that used the stock hot side piping, then a custom 2.5" outlet to a custom 2.5" aluminum TIP to the 2.5" stock throttle body. I have a front mount not installed yet, and plan on 2.25" hot side and 2.5" cold side with that.

viceprp
04-30-2013, 02:55 AM
2.5" hot and cold side on a GT30r. Thinking of going 3" cold side in the future.

zandrew
04-30-2013, 05:19 AM
I have only blown off the hot side once and it has 4 couplers on it. I have blown the cold side of atleast 6-7 times and only has them at tb and ICr. I just have a cheap eBay ICr right now. Having the DV welded seem stupid t anyone?

c0r3y.af
04-30-2013, 05:28 AM
2" hot side, 2.5" cold side on a 3071r.

Seerlah
04-30-2013, 06:09 AM
Yeah, welding the DV is a bad idea. Mainly for convenience factors (ie servicing).

c0r3y.af
04-30-2013, 06:29 AM
Yeah, welding the DV is a bad idea. Mainly for convenience factors (ie servicing).

I agree with this. If you know how to weld you could always V-band it though.

Nateness
04-30-2013, 07:33 AM
I'm running 2.25" hot and 2.5" cold. From a fluid mechanics perspective, it stands to reason that running the largest piping diameter possible will yield the greatest flow with the least amount of power draw from the compressor. In practice, this is generally true, but with a few exceptions:

- minimize the number of transition fittings
- minimize bends
- avoid dramatic transitions in size
- avoid sudden changes in direction


With that in mind, it seems most practical to simply match the hot inlet port on the intercooler and match the diameter of the throttle body on the cold side. This logic seems to explain the typical 2.5" hot side (matches stock TB) and the 2.25" hot side (slightly larger than the discharge of the turbo).

M-Hood
04-30-2013, 01:31 PM
I am under the precept that you want to run 2.25" hot side and 2.5" cold side for the GT2871R. Different applications would use different sized piping. Right now I have a custom side mount that used the stock hot side piping, then a custom 2.5" outlet to a custom 2.5" aluminum TIP to the 2.5" stock throttle body. I have a front mount not installed yet, and plan on 2.25" hot side and 2.5" cold side with that.

Correct, 2.25" hot side and 2.5" cold side is the best setup for a 2871r size turbo.

zandrew
04-30-2013, 02:48 PM
I am going bigger. I am just running this now to get accustomed to Maestro (and use up the stock motor). I am building a 83x92.8 and shooting for 400awhp with the 5552 or GT3076 (or???). Whatever piping I run I would "like" for it to accomadate my future build.

Will 2.25" and 2.5" work for it? I really don't want to go 2.5" and 3".

Nateness
04-30-2013, 04:05 PM
Of course 2.25 and 2.5 will work.

You probably mean, will you gain noticable power by going larger. Do the math. Figure out the velocity through the pipes. That will tell you if you need to go bigger...

viceprp
04-30-2013, 06:21 PM
Depends what TB you go with.

Turbo Nerd
04-30-2013, 06:28 PM
TR1235 3" in/out

034Motorsport
04-30-2013, 06:34 PM
While it may be counter intuitive, the most efficient setup is to run a larger diameter on the hot side (pre intercooler) and a smaller size on the cold side (post intercooler). Air is denser when it is cooler. This will give you the best response, etc.

For a GT2871, I would go 2.5" pre and 2.25" or 2" post.

On our Time Attack car, we run 2.5" both sides with an Evo10 intercooler due to its light weight and its fin construction (very good at shedding heat at high speeds, not so good at dyno stuff where a bar/plate can fight delta better). Supports 600whp.

3" is extremely overkill. 3" will support 850whp. I ran 2.5" on my 6262 in my S4, and my 2.0L has 2.5" both sides as well.

zandrew
04-30-2013, 06:36 PM
I was thinking about using the VR6 TB but it seems like it is not necessary for my goals.

Ultimately I want to build a car that makes an honest 400awhp with the best possible daily characteristics. My 1.8 has an absolute horrible dead spot at 1200-2400 which sucks ass around town. I am hoping adding the extra stroke and bore will erase at best; reduce at worst this annoyance.

Not that I am after larger piping at all. I just want the right size for my goals without choking the turbo and at the same time hurt intake velocity. If 2.25" and 2.5" is more then ample I will go with it.

Max I am not trying for a dyno queen LOL. I just want something that is going to work. Did you push the Evo IC'r to 600whp? I searched some Evo forums and they suggested 400whp but I never came across anyone that actually pushed it.

Thanks for the replies.

melomandn
04-30-2013, 10:21 PM
While it may be counter intuitive, the most efficient setup is to run a larger diameter on the hot side (pre intercooler) and a smaller size on the cold side (post intercooler). Air is denser when it is cooler. This will give you the best response, etc.

What am I missing here? Why would you want 2" hot side and 2.5" cold side? Since cold air is more dense why would you want the piping to be smaller on that side instead of bigger to handle the more dense flow?

catbed
04-30-2013, 11:29 PM
While it may be counter intuitive, the most efficient setup is to run a larger diameter on the hot side (pre intercooler) and a smaller size on the cold side (post intercooler). Air is denser when it is cooler. This will give you the best response, etc.

For a GT2871, I would go 2.5" pre and 2.25" or 2" post.

On our Time Attack car, we run 2.5" both sides with an Evo10 intercooler due to its light weight and its fin construction (very good at shedding heat at high speeds, not so good at dyno stuff where a bar/plate can fight delta better). Supports 600whp.

3" is extremely overkill. 3" will support 850whp. I ran 2.5" on my 6262 in my S4, and my 2.0L has 2.5" both sides as well.

I would like to hear an explanation as well. I just pulled out my fluids book, and it makes sense from a fluid mechanics standpoint to keept velocity constant through the system with Bernoulli's equation, but I have always heard bigger cold side is better. Could just be another myth that everyone hangs on to though. [>_<]

I was planning on upgrading my 2" hot side to 2.5", and throwing on my 65mm V6 throttle body as 2.5" ≈ 63 mm.

kraylon
05-01-2013, 01:30 AM
I have a intake manifold from a small port B5 that has been modded to fit a 70mm throttle body, I cant remember if its a S4 throttle body of a vr6. i bought this from the classifieds a couple of years ago with the plans on using it but life happened and I wasn't able to get the turbo that I planned on, so not to thread jack but this piece needs a home.
PM me with questions about it

Anyways good reading in this thread I too have had this same question a few times [up]

zandrew
05-01-2013, 05:45 AM
I know that manufactures also typically do smaller hotside and larger cold side. They have the money for research so it does make me wonder.

M-Hood
05-01-2013, 09:26 AM
I am going bigger. I am just running this now to get accustomed to Maestro (and use up the stock motor). I am building a 83x92.8 and shooting for 400awhp with the 5552 or GT3076 (or???). Whatever piping I run I would "like" for it to accomadate my future build.

Will 2.25" and 2.5" work for it? I really don't want to go 2.5" and 3".


You don't need 3", hell I don't even run a 3" IC pipe and I have made 650awhp. lol

You won't really need anything larger then 2.5" on either side for anything making up to 600whp. As for the hot side, you can just match up the pipe to the size of the turbo outlet. If you are aiming for 400whp then just do 2.5" pipes on both sides.



I know that manufactures also typically do smaller hotside and larger cold side. They have the money for research so it does make me wonder.

Reason for running a smaller IC pipe on the hot side is to keep velocity up which is going to help push the air thru the core, once the air is thru the core. This is why the ER uses a 2.25" hot side pipe and a 2.5" cold side pipe for their 600hp Competition FMIC kit for the A4 1.8t. Their 800hp Race series FMIC setup which is basically the custom setup they built on my car uses 2.5" pipes on both sides.

c0r3y.af
05-01-2013, 10:35 AM
You won't really need anything larger then 2.5" on either side for anything making up to 600whp. As for the hot side, you can just match up the pipe to the size of the turbo outlet. If you are aiming for 400whp then just do 2.5" pipes on both sides.

I agree with this. My compressor outlet is 2" which is why I run 2" piping on the hot side. I run 2.5" on the cold side to match my TB. I can't imagine anything larger than 2.5" improving performance.