2.5 or 3 inch IC pipe question
Thread Starter
Joined: Nov 2001
Posts: 2,239
Likes: 1
From: Watertown, NY
2.5 or 3 inch IC pipe question
ok im still confuse on this because im been talking with alot of people about this and they give me different answer. i have stock 93 engine with the stock twin sequecial on my 89 FC rx7 and im looking for respond over power and i know that the stock IC pipe is 2.75 inch on the FD and i cant find anybody that have that size pipe. and i already have a FMIC from my old turbo II setup but my question is should i run 3 inch with no issues or i should get 2 1/2 inch pipe instead?
Rotary Enthusiast
Joined: Oct 2006
Posts: 1,319
Likes: 1
From: BC, Canada
I was under the impression that stock piping was 2.5"???
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/diameter-stock-intake-piping-703841/
=Ben
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/diameter-stock-intake-piping-703841/
=Ben
to answer the question you asked...if you're looking for response the 2.5 " would be more responsive then 3".
Less area to fill = faster response.
3" would have better flow characteristics and thus a higher top end power.
EDIT: that is in theory that 3" would have a higher top end power because of increased flow. i've seen dyno results (i would post them but they are on another car forum) that show no increase in power going from 2.5 to 3", and actually had an increase in intake temperature w/ 3" piping. the theory behind the higher temperature was that the higher flow wasnt allowing the intercooler to pull the heat out as effectively as the 2.5". and maybe because the turbo has to work slightly harder which generates more heat. So maybe any HP increase from the higher flow of 3" was lost with higher intake temperatures. just a thought
The the stock intercooler piping has alot sharp bends, which might be why the factory went with a slightly larger pipe. The bends create more restriction which the 2.75" helps make up for.
Less area to fill = faster response.
3" would have better flow characteristics and thus a higher top end power.
EDIT: that is in theory that 3" would have a higher top end power because of increased flow. i've seen dyno results (i would post them but they are on another car forum) that show no increase in power going from 2.5 to 3", and actually had an increase in intake temperature w/ 3" piping. the theory behind the higher temperature was that the higher flow wasnt allowing the intercooler to pull the heat out as effectively as the 2.5". and maybe because the turbo has to work slightly harder which generates more heat. So maybe any HP increase from the higher flow of 3" was lost with higher intake temperatures. just a thought
The the stock intercooler piping has alot sharp bends, which might be why the factory went with a slightly larger pipe. The bends create more restriction which the 2.75" helps make up for.
Last edited by Dudemaaanownsanrx7; Apr 26, 2008 at 05:15 PM.
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Thread Starter
Joined: Nov 2001
Posts: 2,239
Likes: 1
From: Watertown, NY
to answer the question you asked...if you're looking for response the 2.5 " would be more responsive then 3".
Less area to fill = faster response.
3" would have better flow characteristics and thus a higher top end power.
EDIT: that is in theory that 3" would have a higher top end power because of increased flow. i've seen dyno results (i would post them but they are on another car forum) that show no increase in power going from 2.5 to 3", and actually had an increase in intake temperature w/ 3" piping. the theory behind the higher temperature was that the higher flow wasnt allowing the intercooler to pull the heat out as effectively as the 2.5". and maybe because the turbo has to work slightly harder which generates more heat. So maybe any HP increase from the higher flow of 3" was lost with higher intake temperatures. just a thought
The the stock intercooler piping has alot sharp bends, which might be why the factory went with a slightly larger pipe. The bends create more restriction which the 2.75" helps make up for.
Less area to fill = faster response.
3" would have better flow characteristics and thus a higher top end power.
EDIT: that is in theory that 3" would have a higher top end power because of increased flow. i've seen dyno results (i would post them but they are on another car forum) that show no increase in power going from 2.5 to 3", and actually had an increase in intake temperature w/ 3" piping. the theory behind the higher temperature was that the higher flow wasnt allowing the intercooler to pull the heat out as effectively as the 2.5". and maybe because the turbo has to work slightly harder which generates more heat. So maybe any HP increase from the higher flow of 3" was lost with higher intake temperatures. just a thought
The the stock intercooler piping has alot sharp bends, which might be why the factory went with a slightly larger pipe. The bends create more restriction which the 2.75" helps make up for.
eddie
Sorry for hijacking this thread. I had a question.
How do you guys cut those pipes?
I need 6" and 4" couplers. I can gett 1ft but Making nice clean cut is a challenge.
