bigdaddyvtec

So Ross and I are in a debate.... He feels im ------- retarded if I do a 4" DP.... The housing is a 3" vband and I made a really nice 3-4" reducer for the 4" already.... Im interested in thoughts on spool and efficiency as well as HP... Not how it will ------- sound. I dont care.

So the question is:

4" Downpipe vs 3" ?
4" Exhaust (Aluminum to trry and shave some pounds) vs the 3" steel I have...

Thoughts Please only those who have more ------- knowledge than do I reply ( I know thats ------- too much to ask)


I dont care much how it sounds (obviously) Ill do a muffler, but I know its going to be loud


The other option is to trade my current exhuast for a stock one, do the 4" DP weith a cut out and run some sort of actuator to kick it oppen when approaching AATM presure in the manifold

I know, I know/// Im .

R-MAK

4" all the way. Big boys run big pipe son.

IntaCooler

4" *****

j3w

you could just hop on the treadmill for a week and lose the weight difference

Hellbert

i believe i seen a link to it on here a few years back could have been somewhere else idr. but someone did a test on size and length vs spool and HP. from what i can remember they did 3 and 4 inch OPEN DPs and 18 24 and 36 inches long. now i dont remember the exact numbers on HP but i know they said the car spooled a lot sooner with the 4 x 36inch. it was something about length that increased velocity of the exhaust and the size that cut back on back pressure. they went into all the physics of it and had back pressure gauges set up and a flow meter of some kind. ill look later and see if i saved the site somewhere but it may be on my other computer.

i know i dont have more knowledgibilities than folk like yourself but whatever son. thats my input on the situation, take it in stride... but ill look and see if i cant find it for you.

Tom-Guy

4" exiting in front of the tire.

If you want to do the cutout deal... I know you like your stealth... get a 5-6 psi actuator and use it to open a $30 LS1 TB.

bitchM0VE

3" transitioning to 4" will give the fluid exiting the turbine room for expansion resulting in a lower pressure and overall lower enthalpy post turbine. Plus the larger tubing will shed more heat, further reducing the enthalpy post turbine. Delta h is where it's at. Transition back to 3" later whenever you need to for clearance.

Tough-guy

Win

bigdaddyvtec

I dont need clerance its like 4532523532 feet in the air...

lol

Chris Harris

4" up pipe out of the hood please