Thread: Question on 3" setups

I need to clarify some specifics around the 3" exhaust setup please.

When you guys say you run a 3" exhaust, does that mean it's only 3" from behind the cat and backwards? or is the cat also 3"? or does the 3" piping start further forward?

My car is going for a new exhaust soon and I want to go 3", but because we don't have cats in my country, I need to clarify this. Generally our headers are much shorter at the bottom. They pretty much end right after the engine bay area, where as I think yours typically continue right up to the cat, which is sort of in the middle of the car if I'm not mistaken. In my case, I will have a silencer where your cat typically sits, and then a rear silencer off course.

So should I have the exhaust fabricated in 2.5" up to (and including?) the middle silencer, and then go 3" from there back? or 3" from behind the motor all the way back?

Please clarify this for me. Thanks

run as much 3 in piping as possible that means before the catalitc converter.

If you guys dont have any cats in your coutry I can send you one they are cute and they do meow.

I don't wanna guinea pig it. I need to know where the ones that dyno more than the 2.5" start from.

So far every shop I've spoken to tells me I'm mad to want to run a 3" on a N/A 2000cc car. Bear in mind it will be full mandrel bend.

(anyone ever managed to post up a 2.5" vs 3" dyno of the same motor?)

run 3 inch. It makes more power than 2.5

Well if they think your crazy tell them

Yes I am!

But seriously 3inch from the collector back.

You want as much 3" as you can get (like the others have said). There is no situation where 2.5" makes more power (or torque) anywhere in the rev range. Once the exhaust has left the header/collector you want the biggest pipe you can fit.

Edit: This applies for N/A engines of any displacement.

3" sir tested and proven...... and its not as loud as everyone keep saying. run it into a oval pan and u good. u will feel the difference in mids and up top....dre told me, i did it, im VERY happy.

great.

thanks for the info. Guess it's 3" all the way!

I'm getting mine this week and I can't wait! I currently choking the VE with 60MM.

SGTSR20 please give your impressions on the setup when you get it in. Thanks!