Help On RB20DET Downpipe N Exhaust Size

[Moses Lai]

To All RB20DET Sifu
Currently i'm doing my project on my RB20DET manual, i'm upgrading to Garret T3/T4 turbine with 42mm external wastegate.

My question is, wat size of downpipe n exhaust pipe should i b running n i prefer my car to have more torque on low end, i guess is more suitable for town drive.

Currently i'm running 2.5 inche downpipe n exhaust pipe, can i still maintain this size coz my foreman advice me stick to tis size so that i can cut down on my turbo lag.

BTW, wat's d pro n cons if i install d AFM after d intercooler?

Thanks.:stupid:

 

[stormlcc]

with a 2 litre engine, 2.5" of downpipe and exhaust is enough if u want the performance to be based on low end torque, but if u want a bit of both worlds (low end torque and a bit high end power), then u can try 2.5" at the front and 3" at the back of your exhaust

 

[Moses Lai]

How bout if i run 3" piping n 2.5" centre n back box, wonder how would tat turn out? heard from someone tat some jap does tat for best of both world, is tat true?:hmmmm:

 

[stormlcc]

How bout if i run 3" piping n 2.5" centre n back box, wonder how would tat turn out? heard from someone tat some jap does tat for best of both world, is tat true?:hmmmm:

i don't quite understand, either u run 2.5" or 3" all the way, or u use 2.5" from exhaust manifold to mid, then 3" from mid to muffler (smaller piping at the front, larger for the back/exit)

 

[julie2121]

hi there , last time i also used 2.5 piping all the way to the back and now just changed to 3inch piping from the exhaust manifold straight up to the back. the car acts better , boost coming in smoother. rb engines love big exhaust :)

 

[CraZieThug5057]

bro mine is 3" all day from the exaust to the back no issue rev is smooth n still want sumore egine stck turbo rb20 and stock wastegate without downpipe sumore

 

[jameswwt]

Hey Moses,great thread...Well,im in a mid of transplanting a SR20DET engine...Ya,i do hope to find out abt the exhaust stuff to...Just wonder do we need to send our car for ECU tuning after changing the exhaust and air filter? Im just using stock ECU...

Bump: Btw,wat is turbo lag? and how to prevent it?