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Intake Pipe Size

VR_IV_MR

Well-known member
Is there any benefit in running a 4" intake pipe when your turbo inlet is 3.5"? Should I just get a 3.5" pipe?



And for the compressor outlet... if it is 2", should I just run 2" intercooler piping? How much power could 2" intercooler piping handle?
 

SleepinGVR4

Well-known member
Most people run a larger intake pipe so if they upgrade later they don't need a new intake. Plus all you need a silicon reducer to make it fit.

Same with intercooler piping. Most people start off with at least 2.5" and that's plenty for most cars on this forum. The hot side of your intercooler piping (coming off your turbo) can be pretty tricky. I had a custom piece made by a fellow member. But any fabrication/welding shop should be able to figure something out to make it work.
 

VR_IV_MR

Well-known member
Ok how about a breakdown similar to the way Jacks Transmissions does a breakdown for clutch selection:

</font><blockquote><font class="small">Quote:</font><hr />
1) Up to 275HP AWD or up to 300HP FWD: OEM factory clutch from Mitsubishi (the dealer). Cheap autoparts store or ebay clutch is NOT recommended.
2) Up to 300HP AWD or up to 350HP FWD: ACT 2100 with street disk and XACT flywheel. Good enough for low 13 second passes at the drag strip.
3) Up to 450HP AWD or FWD: ACT 2600 with street disk and XACT flywheel. Good enough for 11 second passes at the drag strip.
4) Up to 500HP AWD or FWD: ACT 2600-2900 with 4-puck solid hub disk and XACT flywheel. Good enough for 9 second passes at the drag strip.
5) Over 500HP AWD or FWD: ACT 2900 with 4-puck solid hub disk. If you want to shift at a stupid high RPM, for some reason, it is highly recommended to go with a 7.25” twin disk clutch from PTT or QM

<hr /></blockquote><font class="post">

Could I get a breakdown for intake and intercooler piping similar to this? I don't want to sacrifice any spool up, and I want the proper size piping for the setup.


I am thinking about a BW EFR 7670 Twin scroll T4 1.05a/r on the JMF top mount exhaust manifold with Kelford 272 cams. Id like to run somewhere from 20-30psi and may or may not run meth. This turbo has a 3.5" inlet, and a 2" outlet.

Is there any reason I should run larger then a 2" pipe from the turbo to the IC?
 
Last edited by a moderator:

AnotherNewb

Well-known member
I hate dsm tuners. Everytime I find a good informative thread I can never find it again. Anyways the jist of it was that people were achieving faster spool by using the larger intake pipe with a smooth transition coupler. On the other hand those using the fp 4" intake pipe with their ofset reduction coupler experianced a later spool up. I believe it has more to do with the transition into the turbos inlet than the size of the pipe in many cases.
 

4thStroke

Well-known member
I would think that having a larger pipe being reduced to the inlet size would be ideal, the coupler almost acts like a velocity stack in which a larger volume of air is being reduced to a smaller volume and increasing inlet speed.

English did some unofficial testing with and without inlet pipes, spool was hurt without an inlet pipe.

I cringe when I see people using 3"inlet pipes on a 4"inlet, running the reduction coupler in reverse.
 

JSchleim18

Well-known member
Quoting AnotherNewb:
I hate dsm tuners. Everytime I find a good informative thread I can never find it again. Anyways the jist of it was that people were achieving faster spool by using the larger intake pipe with a smooth transition coupler. On the other hand those using the fp 4" intake pipe with their ofset reduction coupler experianced a later spool up. I believe it has more to do with the transition into the turbos inlet than the size of the pipe in many cases.



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