4in. vs 5in. exhaust

[DDarmos]

I am putting a different turbo on my truck a b-1-2 ex4. With a 4in. downpipe. Is there any benefit goin to 5in at the end of the downpipe our just leave it 4in. ? I am going with straight pipe either way. Turbo should be in at the end of the week and I want to be ready.

Thank You

 

[Snow man]

None whatsoever,IMO. i feel i lost Hp when i went to a 5" system,the truck was more responsive with a 4" system. Around 575hp,the 4" starts to become a restriction.

 

[thekidfan]

I think the easiest way to decide if you need 5" exaust is to ask yourself

1. ) Do I like drone? yes/no

2. ) Will I end up with twins? yes/no

If you didn't answer yes to either one of these questions don't even think about 5". I have a muffler and a resonator and the drone is still annoying at times, so straight pipe would be :{ good luck Jeff

 

[Mark Craig]

DDarmos,



The other posters are exactly correct, I will also add that we sell 97% 4 inch systems here everyday, we do sell 5's but not too many as compared. The "rule of thumb" is if you're not going to be at or over 500 RWHP yuo don't need 5 inch flow capability.



Mark @ DPPI

 

[SRadke]

Just heard about a test on a 600+ rwhp truck. Dyno runs with 4" and 5" on the same dyno amounted to 10-12 hp diffrence. Not worth the fight IMO.



-Scott