I can't find much info, but if you had a 2.5" exhaust, is it worth it getting the AAM or Forged Performance or (other manufacturer's?) Greddy downpipes with dumps. I already have SVRT dumps comming soon. So not sure which to choose, these downpipes, or just normal test pipes. By the way this is on a mildly built block hoping to pushing about sub 500 whp. Will it change spool time much even though I have a 2.5" exhaust?

Sooo.... with Greddy TT's get the 3 or 3.5" downpipes with open dumps, or get open dumps, block off the wastegate inlet and get 2.5" test pipes, either of those for about 500whp +-20whp and keeping a 2.5" exhaust?? Worth it or not?? TIA.

 

3" will give you faster spool times, 3.5 is even better. But there is a limit where you dont gain anymore power. But you should do 3-3.5" all the way back.

 

I whent with 3" I think its the best u get all what u need from it i'm pushing into 600 whp with a 3" and thats more than enough for ur set up.

 

I went with SVR tech 3 inch exhaust all teh way back, no need to buy test pipes. It is awesome and not that loud, honestly it is quieter than my old rsr gt2 exhaust with my TN set up.

It does appear to make the twins spool very very quickly. I was in 3rd gear at 1200 rpms when I was setting my boost, and I thought I would see how fast these twins really spool and matted it when my boost was just off of the wastegate's pressure and the car no joke hit 5.5 psi by 1700 rpms!!!!

I haven't replicated the test to see how it does with boost set at 7 psi, but I would imagine full boost somewhere around 1700-2100 rpms with my set up.

As far as open dumps, I will have those as well by the end of the year.

 

I went to 3inch exhaust in my 350z. I have the aps system, but it is the same goal. It spools awesome and the flow was such a big diff. from the 2.5.