# Diffrence between 2.25 & 2.5 IC piping



## Vdubsolo (Apr 11, 2004)

Like the topic states..I would like to know the diffrence..I doing a front mount on my vrt..aand plan on running both pipes under the engine bay..none under the car..It looks like the 2.25 is going to fit better than the 2.5..Im keeping my a\c also so fittment is going to be tight on the passeger side of the engine bay( it seems like its the only spot where the 2.5 is an issue )..near the rad support and IC..Im aiming for 325-350 whp..Is the 1\4inch diffrence In piping going to make a big diffrence??


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## hel-mut (Oct 26, 2003)

*Re: Diffrence between 2.25 & 2.5 IC piping (Vdubsolo)*

one pipe is a 1/4" larger than the other use em both poo


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## Loren Wallace (Oct 15, 2005)

with the piping 2.25 and 2.50, a quarter of an inch i dont think will be a noticeable difference. since you said there were issues with fitment i wouldnt take any chances and just go with the 2.25, i would go the safe way incase problems could occur when its all done


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## Vdubsolo (Apr 11, 2004)

*Re: (J Eagan)*

Anybody else??


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## Vdubsolo (Apr 11, 2004)

*Re: Diffrence between 2.25 & 2.5 IC piping (Vdubsolo)*

Bump..


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## Vdubsolo (Apr 11, 2004)

*Re: Diffrence between 2.25 & 2.5 IC piping (Vdubsolo)*

Up


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## EdsGTI (Mar 9, 2003)

if the turbo has a T04e or b cover, use a 2.25" pipe. If its a T04S 2.5" outlet compressor housing use a 2.5" pipe. If you have plans to upgrade to something more then 350whp i would use 2.5"
My car is setup with 2.5" pipes and has an intercooler with 2.75" endtank inlet/outlets. thats planned for 400whp on pump and 500+ with race gas+nitrous.


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## Vdubsolo (Apr 11, 2004)

*Re: (EdsGTI20VT)*

The turbo I have T3\T4 TURBO...Im leaning towards 2.5inch piping but it depends on witch way I route the piping as of now..


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## Vdubsolo (Apr 11, 2004)

*Re: Diffrence between 2.25 & 2.5 IC piping (Vdubsolo)*

TTT


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## Vdubsolo (Apr 11, 2004)

*Re: Diffrence between 2.25 & 2.5 IC piping (Vdubsolo)*

TTT


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## Vdubsolo (Apr 11, 2004)

*Re: Diffrence between 2.25 & 2.5 IC piping (Vdubsolo)*

Ehh I was bored and figured why not bring this one bacck..the car is almost done and should be ready to start up with in the week..I went with the 2.25 IC piping..and just want to hear your thoughs of the diffrence in pipe size, power wise if it will effect the amount of power id make at the same boost levels..with one another.. http://****************.com/smile/emthup.gif


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## VR6-JettaIII (Jul 21, 2003)

*Re: Diffrence between 2.25 & 2.5 IC piping (Vdubsolo)*

Use a 2.25" intercooler pipe. It will increase velocity flow, whereas with a 2.5" pipe velocity will be decreased. Velocity is what will get more air in the cylinder more-so than mass will.
- Chris


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## _muppet_ (Aug 5, 2004)

http://grapevine.abe.msstate.e....html
The difference in volume is more than it seems.


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## Vdubsolo (Apr 11, 2004)

*Re: (_muppet_)*


_Quote, originally posted by *_muppet_* »_http://grapevine.abe.msstate.e....html
The difference in volume is more than it seems.

It is..but still Im thinking that its not going to be much of a diffrence..but im not to sure..i would think since the pipe is smaller that the air would flow through quicker..but quick isnt more..dose a 1\4 inch make that much of a diffrence when were talkin IC pipe..


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## _muppet_ (Aug 5, 2004)

I don't know whether it makes a big difference or not, but you would think needing to fill about 20% more volume up to whatever pressure you are running would affect lag by quite a bit.


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## leebro61 (Nov 7, 2001)

*Re: (_muppet_)*


_Quote, originally posted by *_muppet_* »_I don't know whether it makes a big difference or not, but you would think needing to fill about 20% more volume up to whatever pressure you are running would affect lag by quite a bit. 

I doubt it. Any decent sized to4e turbo is going to be flowing upwards of 40 pounds of air per minute. Many people are running turbos flowing 1.5 times that amount. I think we are talking fractions of a second here. BTW I have 2.75" hot side and 3" cold side piping. I will let you know how it works out spool wise compared to a 2.5" plumbed car running the same turbo/similar setup.


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## leebro61 (Nov 7, 2001)

*Re: (leebro61)*


_Quote, originally posted by *leebro61* »_ I think we are talking fractions of a second here. 

Lol, based on the density of air, assuming 12 feet of piping, assuming a turbocharger that flows 40lbs/minute (a generic to4e 50 trim will do this), 2.5" piping will take approximately .009 seconds longer to fill than 2.25" piping.
Don't believe me? Get google to tell you the density of air. Convert it to units of lb/in^3. Then convert how the turbo flow in lbs/min to lbs/sec. Then calculate the volume of your piping in cubic inches. Cubic inches will cancel, as will pounds. This leaves you time in seconds. Obviously this doesn't account for changes in temperature and pressure, etc. etc. from compressing the air, but even worse case scenario, I can't imagine you noticing any sort of difference, until you get into 12" diameter charge piping










_Modified by leebro61 at 9:43 PM 7-12-2006_


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## Vdubsolo (Apr 11, 2004)

*Re: (leebro61)*


_Quote, originally posted by *leebro61* »_
Lol, based on the density of air, assuming 12 feet of piping, assuming a turbocharger that flows 40lbs/minute (a generic to4e 50 trim will do this), 2.5" piping will take approximately .009 seconds longer to fill than 2.25" piping.
Don't believe me? Get google to tell you the density of air. Convert it to units of lb/in^3. Then convert how the turbo flow in lbs/min to lbs/sec. Then calculate the volume of your piping in cubic inches. Cubic inches will cancel, as will pounds. This leaves you time in seconds. Obviously this doesn't account for changes in temperature and pressure, etc. etc. from compressing the air, but even worse case scenario, I can't imagine you noticing any sort of difference, until you get into 12" diameter charge piping









_Modified by leebro61 at 9:43 PM 7-12-2006_

well Im running a t3\t4 57trim turbo...im not worried about timming of boost kicking in..as much as im wondering if the size diffrence will affect my over all horsepower..say my set up running however much boost with 2.25 piping vs 2.5 piping..will the numbers be diffrent on the dyno? Im leaning towards no..and if they are it wont be much under 5whp







I could be wrong...but thats what im asuming..


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## leebro61 (Nov 7, 2001)

*Re: (Vdubsolo)*


_Quote, originally posted by *Vdubsolo* »_well Im running a t3\t4 57trim turbo...im not worried about timming of boost kicking in..as much as im wondering if the size diffrence will affect my over all horsepower..say my set up running however much boost with 2.25 piping vs 2.5 piping..will the numbers be diffrent on the dyno? Im leaning towards no..and if they are it wont be much under 5whp







I could be wrong...but thats what im asuming..

My point was really to disprove the people who swear up and down that running large intercooler piping will hurt performance. Personally, I would rather have my piping too big than too small. At least it looks cool that way








I don't know how much power/if any you will lose by running small intercooler piping, but I imagine it isn't a huge amount. You at least went 2.5" on the cold side right? I don't feel like rereading the thread


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## EuroKid83 (Jan 26, 2005)

*Re: Diffrence between 2.25 & 2.5 IC piping (Vdubsolo)*

It's not the size of the piping that matters, It's how well it flows that makes the difference. I know a few people running 2.125" pipe that have put down some pretty impressive numbers. Just go with whatever fits the best.


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## leebro61 (Nov 7, 2001)

*Re: Diffrence between 2.25 & 2.5 IC piping (EuroKid83)*


_Quote, originally posted by *EuroKid83* »_It's not the size of the piping that matters, It's how well it flows that makes the difference. I know a few people running 2.125" pipe that have put down some pretty impressive numbers. Just go with whatever fits the best.

This is true too. You can have 3" intercooler piping but if you route it like a rollercoaster, it's not going to flow any better than a well layed out smaller size.


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## THEERY2.1 (Feb 26, 2003)

*Re: Diffrence between 2.25 & 2.5 IC piping (leebro61)*

LOts of people run 2.25 making over 400 whp


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## Vdubsolo (Apr 11, 2004)

*Re: Diffrence between 2.25 & 2.5 IC piping (THEERY2.1)*

My set up is 2.25 all the way around..and I think it will flow well..Its a little bendy coming out of the IC going in to the intake but its not to bad..its also going in to a SRI ..I think i did a good job as far as flow..I have been slacking with the pictures..ill try and get some up tommorrow..just so u can see what im working with..


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## VR6OOM (Nov 8, 2002)

*Re: Diffrence between 2.25 & 2.5 IC piping (Vdubsolo)*








PICS!!!


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