gt20 exhaust system

[Chris_90]

So slowly getting my gt20 ready for bolting on I'm doing a 3 inch down pipe with flexible joint, then gonna reduce to 2.5.

What I'm wanting to no will it be ok to reduce again to the standard system size near the back box area? Or will it be to restrictive and best to stay 2.5 all way back?

[Dale]

So slowly getting my gt20 ready for bolting on I'm doing a 3 inch down pipe with flexible joint, then gonna reduce to 2.5.

What I'm wanting to no will it be ok to reduce again to the standard system size near the back box area? Or will it be to restrictive and best to stay 2.5 all way back?

3 inch down pipe is abit extreme I bet the elbow off the blower isn't much bigger than 65mm! Don't forget if you drop back to std near the backbox not only will you need a train of reducers it will flow no better than a std system it's only as restrictive as the smallest parts!

[spike2002]

Just run 3" turbo back will sound mental my mate has got his 3" straight thru and is awesome haha

[Chris_90]

Just run 3" turbo back will sound mental my mate has got his 3" straight thru and is awesome haha

Not wanting to go for loud, got a baby coming.any min now and I don't finsh work till late so don't wanna be pissing the street off all tho if I could I would

[Piggy]

Run with 2.5 if you can. Iirc 2.25 is standard.

[HDIkyle]

I run a 3" to tank then reducing to 2.5 i think as i dont want a deep tone. Any videos of a full 3" system compared to a 3" to 2.5" system?

[Chris_90]

If I have to i will it's just the cost of 3 inch and 2.5 inch silencers there not cheap. Just gonna take abit more saving then.

[silverzx]

For a GT20 I'd of thought 2.5 would be plenty big enough?

Just extra hassle to fit 3"?

It certainly won't have any negative effects being 3" though.

[Chris_90]

I'd have 3 inch all way though if I can get some decent silencers that reduce the noise level alot.

[Piggy]

just use 5 cherry bombs and a couple 3" bends

[HDIkyle]

I think i will go 3" no box's even with no back section its not loud at all

[Chris_90]

I think i will go 3" no box's even with no back section its not loud at all

Have to have a listen of it, but ash23's estate with 3 inch down to 2.5 is loud.

just use 5 cherry bombs and a couple 3" bends

Hmmmmm wonder how much the cherry bombs are

[simonh]

A bore reduction at the back end of the system isn't nearly as restrictive as at the front end as the exhaust gasses are cooler so far more dense. At the turbo/ hot end of the system the gasses are expanded so need more space to exit the turbo efficiently.

That's why a good elbow and downpipe design even with the standard exhaust bore size will give a noticeable improvement on a turbo car but adding a 3" system to a standard elbow and downpipe will have very little effect.

[Mike]

I think i will go 3" no box's even with no back section its not loud at all

Kyle.. I've got a 3" turbo back. I can say it is fair loud. To kinda define loud.. People can hear me coming from a fair distance away.