Who's had success with a 2.5" exhaust turbo m20

[jaywood]

The downpipe that came with my turbo is a 2.5". Would I be fine running a single 2.5" exhaust? I don't really want to make a new 3" downpipe.

I've read of people pushing 400+ hp on a single 2.5"

Opinions?

[Mike The Bavarian]

you can run it. a 3" is much more efficent for a turbo though.

[FrozenSolid]

you can have a 2.5 coming out of the turbo and make the rest 3", my old turbo had a 2.5 or a 2.25 outlet iirc, but 3" exhaust.

[Mike The Bavarian]

you can have a 2.5 coming out of the turbo and make the rest 3", my old turbo had a 2.5 or a 2.25 outlet iirc, but 3" exhaust.

it'd be better to have a 3"dp and then a 2.5 exhaust.

[FrozenSolid]

my comments where towards the downpipe.. as in cutoff the flange that bolts to the turbo and make the rest of the downpipe 3". an inch of 2.5 before it hits 3 wont make a difference. of course this depends on what the outlet size of the turbo is, and if hes worried about retaining the whole downpipe or just the flange section.

[Dj Buttchug]

just run 2.5 itll be fine

[Kvasi]

2.5" will do up to around 400hp.

[jaywood]

I'm going 2.5"
It'll make everything easier, and I'll have more ground clearance ;)

[Tchao]

How is it easier?
You are building an exhaust....I just dont get why people do shit the wrong way, or even ask for second opinions on the wrong crowd just to get an answer they wanted to hear.

FYI the downpipe is the easiest part of the exhaust.



The OP should of asked: Hi Im making an exhaust from scratch for my turbo M20. Should I do or 2.50 or 3.00? My ghetto kit came with 2.50 down pipe.

[jaywood]

How is it easier?
You are building an exhaust....I just dont get why people do shit the wrong way, or even ask for second opinions on the wrong crowd just to get an answer they wanted to hear.

FYI the downpipe is the easiest part of the exhaust.



The OP should of asked: Hi Im making an exhaust from scratch for my turbo M20. Should I do or 2.50 or 3.00? My ghetto kit came with 2.50 down pipe.

It's easier because I have the downpipe already made.


Correct ;)

[jaywood]

Maybe this will help people:

I'll be running ~10 lbs of boost on a t3 turbo. I'm looking for roughly 250 hp.

This isn't an all out performance car. It's my dd.

I know 2.5" will work. My question is, how well will it work? What performance gains am I losing (if any) from not going 3"?

[Toadleg]

electric cut outs are nice if your concerned about clearance. 3 inch down pipe cut out than 2.5 out the back or smaller..... my two cents

[Kvasi]

Maybe this will help people:

I'll be running ~10 lbs of boost on a t3 turbo. I'm looking for roughly 250 hp.

This isn't an all out performance car. It's my dd.

I know 2.5" will work. My question is, how well will it work? What performance gains am I losing (if any) from not going 3"?

You wont loose anything. Theres no reason for the downpipe to be bigger than the outlet on the turbo. Exhaust cool down on its way out and takes less room so you really dont need a big pipe at your numbers.

[jaywood]

You wont loose anything. Theres no reason for the downpipe to be bigger than the outlet on the turbo. Exhaust cool down on its way out and takes less room so you really dont need a big pipe at your numbers.

That's all I needed to hear.

I like explanations.

Thank you

[Tchao]

You wont loose anything. Theres no reason for the downpipe to be bigger than the outlet on the turbo.

Thats absolutely incorrect.

Like others have said, you rather 3" DP and 2.50 the rest.