Exhaust size?

[Newkid]

I have a stock 90 mk3 turbo. I have save enough to buy my exhaust now:icon_bigg But I have a question? What size should I go with? I was planning to use the rsr with a 3" downpipe and with a test pipe. Is that a good idea? will I lose power?

Thanks

 

[Ma70.Ent]

3 inch dia is usually preferred on turbos.

 

[Doward]

Get the 3" DDP from BIC Performance, and couple it with a 3" full exhaust.

 

[Newkid]

Get the 3" DDP from BIC Performance, and couple it with a 3" full exhaust.

So I wont lose any power? I thought I needed some back pressure because its stock?

 

[Newkid]

So I wont lose any power? I thought I needed some back pressure because its stock?

Never mind Im going with that down pipe. lol

 

[Ma70.Ent]

From everything I've read on exhaust theory, I feel confident to say that backpressure is not needed in ANY system.

 

[Newkid]

Thanks man! Thank you all

 

[brad92t]

From everything I've read on exhaust theory, I feel confident to say that backpressure is not needed in ANY system.

And even if it was, that thing hanging off the manifold provides plenty of it!

 

[GotBoost?]

One question for Newkid: are you still on the stock hg?

 

[DonS1mpson]

From everything I've read on exhaust theory, I feel confident to say that backpressure is not needed in ANY system.

Are you sure it's right to say it's not needed on any system? I'm sure there is a thread somewhere in the 7MGE section that features dyno chats showing a power drop on a NA car when a larger exhaust was used.

On a Turbo car however, I understand that bigger means better as turbos love to breathe.

 

[Ma70.Ent]

Are you sure it's right to say it's not needed on any system? I'm sure there is a thread somewhere in the 7MGE section that features dyno chats showing a power drop on a NA car when a larger exhaust was used.

On a Turbo car however, I understand that bigger means better as turbos love to breathe.

The only thread I know of shows the 3 inch being the same thing as a 2.5 inch one. Also, I'm sure there's ANOTHER few threads that point out it has nothing to do with needing backpressure.

 

[Newkid]

One question for Newkid: are you still on the stock hg?

Yeah is there a problem?

 

[Nick M]

From everything I've read on exhaust theory, I feel confident to say that backpressure is not needed in ANY system.

Yep.

You don't want backpressure. It is a common mistake of unknown origin. But if you go to big on the exhaust, you lose velocity. This is does not apply to a blown engine.

The dyno was a year apart from a 2.5 inch crimped exhaust to a 3 inch, and a gain of 1 horsepower. In other words, no gain over a bad exhaust.

 

[Newkid]

Yep.

You don't want backpressure. It is a common mistake of unknown origin. But if you go to big on the exhaust, you lose velocity. This is does not apply to a blown engine.

The dyno was a year apart from a 2.5 inch crimped exhaust to a 3 inch, and a gain of 1 horsepower. In other words, no gain over a bad exhaust.

SO whats too big? 4" maybe?

 

[GrimJack]

On a turbo car, the best exhaust is none.

That said, you'll see diminishing returns over 3 inch unless you're pushing big numbers - like over 600hp.

 

[IJ.]

3" and upwards are very hard to silence as well

 

[Newkid]

3" and upwards are very hard to silence as well

haha thanks

 

[IJ.]

I'm serious without making it stupidly restrictive a 3" muffler is going to be loud....

 

[theKnifeArtist]

the turbo's the only muffler i need :biglaugh:

 

[JesseH]

I'm serious without making it stupidly restrictive a 3" muffler is going to be loud....

When I first started my new motor with 3" turbo back straight pipe, then put a 3" straight though muffler on it there really wasnt that big of a reduction in noise...as IJ said there really is no silencing it.....just make sure you stay away from the gas petal when you pass the po po