Ok, well ive been thinking and discussing with other people, but i still havent come to a conclusion on what i am going to do. Would a 3" dp and exhaust piping give me more whp on my f23? or should i just save the time and money and get a 2.5" dp and exhaust? The main reason i am leaning towards 2.5" is because i want to be able to use a greddy evo exhaust...but what do yall think?

 

You could still use your Evo with a 3" DP it would just have to have a reducer into the cat. Or straight pipe if you choose that route. I am using a tananbe racing medallion and I really, REALLY wish I would have gone 3" Thermal. Speaking from experience I strongly suggest 3" exhaust.

 

would it be bad to have a 2 1/2 inch dp to a 3 in exhaust? with turbo

 

if you are going low boost such as 5-7psi, will it tend to creep if you run a 3" dp + exhaust? I am in the same boat... I have a 7psi tial 38mm and have the means to do a 3" downpipe and exhaust , but im afraid it will creep...so im trading with my friend for his 5psi tial 38mm... from what ive heard, backpressure is the enemy with turbo, so if you run a 3" downpipe + exhaust it will help spool up time and increase possible power to be made...but im still afraid of it creeping, hence the 5lb spring, so if it creeps i'll still be safe...

 

I am pretty sure the only major factor that causes creep is a shitty wastegate. I took off my old one and put on a Tial 38 w/ a 7.25lb spring and there is NO creep. My old one used to spike all over the place. Just go 3" all the way and dont look back!

 

go 3" if you have the option....

3" DP at the VERY least.

2.5" DP into 3" system works, but you'll notice MUCH better spool using
a 3" DP.

Jeffrey Atwood

 

Just go with the full 3"

If im not mistaken the greddy evo is 2.36 not 2.5.

 

no creep or nothing on my b18b running 8lbs with 3 in downpipe and exhaust