hi,do these work ok?,do they give good flow? or are the 3" reducing to 2.5" ones much better?

 

2.5" is good up to 400-450bhp and 2.5" is little bit louder than 3".




Jura

 

damn,i was hopeing that the 2.5"was quieter.

 

Yes will be if you are go for resonated center pipe something like this with good backbox






Jura

 

no i am going to leave the oe system on,by fitting a mild steel 2.5"(all the way through) decat downpipe and leaving the oe system on will it still be nice and quiet?

 

Yes will be quiet with OE system.But you will need remap or drive off the boost matey.

Jura

 

i know that mate,just need to know that a 2.5" decat will do the job to reach 300 bhp,and if it will be quiet with the rest of the system being oe.

 

Yes will reach 300BHP and pass 300bhp with right mods,and don't be restrictive for some point later.
I don't think so will be loud


Jura

 

so what are the gains/why do they make them 3" reduceing to 2.5 aswell? whats the point?

 

Why?
Here is mine answers,some people have OE Spec system(backbox and center pipe) and want use with new decated downpipe 3" or 2.5".
Some people say about 3",its due back pressure,and i would recommend go for Bellmouth,because is less restrictive like standard DP
Here is picture how it looks



Jura

 

ok thanks.

 

2.5 = more noise? I never knew that. I assumed it would be the other way round.

 

me too.

 

Some 2.5" exhaust are really loud,but this is depended on backbox and center pipe,not on just downpipe.



Jura