Aaron,

Would a 500whp car pick up from making the switch from 3" to 3.5", or is this something that only a high HP car will benefit from (if a dump is being used).

 

didn't DB do some testing that proved the 3" to 3.5" didn't matter at almost 700whp on his low reading mustang dyno.not saying by any means that one thread is the gospel,but curious now.

i guess all cars are a little different,but i figured the 3" all the way systems were OK for 700+ after reading that thread.now not so sure.

i assumed OP had a dump already.i'm guessing his 6262 has a 2.5" outlet,seems like 3.5-4" would be overkill on the down pipe?

give us a little more info if you can.just trying to learn all i can.i have a 2.4LR with a 6464 about to go in my car and my system is 3" all the way back with no cat.i was hoping/assuming i wouldn't have a restriction there,but now maybe?

 

My issues started above 650whp and/or 26psi on my car. Divergence only got worse as the boost went up but the 3.5 with the 12909 Magnaflow was fine up to that point.

My test didnt coincide with what Dave found, not saying he is wrong, but I didnt test the same style of muffler either. I used an offset entry vs a straight thru which will definitely lose power as the flow through it goes up.

 

thanks for the info.

offset into the muffler or early in the system?

my system is a BB 3" with no cat.i was really hoping not to have to get a bigger system.i guess we'll see when i dyno it.

 

John,

if my 6466 has a 3" outlet and my DP is 3",do you think i could gain from the rest of the system being 3.5"?or am i already bottlenecked at the DP?

BTW,i just went out to the garage to check mine out and the muffler has offset entry.the pipe goes in on the right and exits in the center,you think a straight through muffler would be better?