I am planning to run a turbo LS/Vtec with pistons and rods (not sleeved) and hope for 350-400whp with Hondata.

SC34 turbo
Spearco FMIC
Hondata S200B
RC 550s
BLOX Mani

I was planning to run a 3" AC compliant DP with 3" cat and exhaust. But I was recently told that a 2.5" would make about the same power and that I would reach full boost sooner and that it would have more low end. And that would be better for take offs as its a daily driver.

Agree or no?

 

Your turbo will spool quicker with a 3" dp. I would go 3" with your hp goals

 

bigger downpipe and exhaust=better spool and more power

go with the 3" definitely

also I have some Eagle rods for an LS for sale never used make an offer if interested

 

3" > 2.5"

Anyone that tells you otherwise is WRONG.

 

The bigger the better.

Thats also...what she said. lol.

 

Ok, I am set on 3". Which sucks because I just found a slightly damaged (I have a welder to repair it) 2.5" DP for like $50....but a new 3" AC compliant one is $240...

Ok, I realize crushbend sucks...but would 3" crushbent be better than 2.5" mandrel ??? hmmm....

 

i would not use anything crush bent

as far as i'm concerned it is no good

mandrel is the way to go

 

I would say the difference is negligble...and not just because Im selling the DP

Bigger is better, but for your setup, I dont see 2.5" being a huge issue.

 

crush bent will restrict some flow, stick with mandrel bent

 

hell if a 4" fits use that instead.

 

question for all you guys.

If the turbine housing is only 2.5 outlet why would a person need a 3inch? would the numbers really be significantly higher? Yes bigger is better but is it logical?

iv'e got a gt35r with a 2.5 outlet. my shop says that a 3inch dp really wouldnt make a difference because the turbo is only 2.5.

 

no that is definatly not true. usually on exhaust bigger does not always mean better but on a turbo application bigger IS better. 3" for sure no doubt!