96redcamaro

iTrader: (1)

I was wondering if someone could guesstimate how much hp I am loosing with this exhaust

current setup: true-duels under axle all the way out back
pacesetter long tube's, to 2.5" piping, to a 3" x-pipe, then back to 2.5" piping, to 3" dynomax bullets, then back to 2.5" piping then out to the back of the car.
(its was only $175 and is acually done very nice)

vs.

new setup maybe: true duels dumped before the axle
3" piping all the way through, with x-pipe, and dynomax bullets, then dumped before the axle.


so... how bad is my first setup hurting me?

motor: 383 - JE Ultralite Forged Pistons, Forged eagle H beam, Forged eagle crank, 48 lb injectors, MSD ignition, 58mm BBK throttle body, walbro fuel pump, 230/240 .516/.522 112lsa, BRODIX heads 292 cfm @ .500 lift, P-to-P matched Intake, P-to-P matched headers, lots of other stuff, but that should be the major stuff... i think...

the builder swears up and down it would put some where around 450 to the wheels, but I have not dyno tuned it yet. (and he also does not know about the exhaust)

thanks in advance for you guys input.

urbanhunter44

iTrader: (1)

well 2.5 would probably work fine for you, I just don't like the 3" Xpipe, the gas has to expand and then contract again..

it's probably not worth much but if you want every bit then why not?

siniSSter

iTrader: (2)

You don't think the 48lb. injectors are to much for your application.

96redcamaro

iTrader: (1)

I think I am going to spray later on, so i wanted to be ready.

why, there not hurting me are they?

Cole Train

iTrader: (30)

well if you go wet setup like me you don't need bigger injectors. and a dry setup, i've read, doesn't work well in the LT1 intakes because of the elbow

96redcamaro

iTrader: (1)

hmmm, yeah I will most likely go wet. The injectors are already there, so I'll just leave them as long as there not hurting me.

thanks for the info though.

Formula350

iTrader: (3)

48lb is hurting you NOW, sure. It's just way too much lol. Think of it like having dual-quads @ 800cfm each

Unless you're running boost, then it seems alright.

96redcamaro

iTrader: (1)

what about the exhaust?

and how bad are the injectors hurting me?

DroppedM6Z

iTrader: (5)

I think a 383 flows about 1200+ CFM and for true dual 2.5" i think it's some where around the 1200-1300 CFM range. I think your fne but if you went to 3" duals you'd be good to support 800HP

InsaneAuto86

iTrader: (60)

From lt1engine.com...
A 2.75” (stock) single system is good for a 310hp engine with zero loss…
A 3” Single system is good for a 370hp engine with zero loss…
A 3.5” Single system is good for a 503hp engine with zero loss…
A 4” Single system is good for a 657hp engine with zero loss…
A 2.25” dual system is good for a 457hp engine with zero loss…
A 2.5” dual system is good for a 513hp engine with zero loss…
A 3” dual system is good for a 812hp engine with zero loss…
So if your putting down 450 it looks like your fine with your current setup.

96redcamaro

iTrader: (1)

so is mine still good for 513hp even though it goes to 3" in some parts of the exhaust (x-pipe, mufflers)?

96redcamaro

iTrader: (1)

so....

Gun5

iTrader: (37)

how about me... Y pipe 3" to borla 3"

landstuhltaylor

iTrader: (6)

i believe those numbers listed above are for flywheel hp, not rwhp. having said that, you cant be losing much at all from the size, the biggest parasitic area would be the two 2.5-3 and 3-2.5 transitions.

Irish350

iTrader: (14)

yeah. on duals youre good with the 2.5, but if i were you id swap the 3" parts to 2.5

and i wouldnt think the big injectors would hurt you.. someone before said it was like having dual quad 600 cfm carbs.. but that sounds like more of a "too much air thing" (like running a 120mm TB or something )

idk, maybe its just me. im no expert though

Gun5

iTrader: (37)

shouldnt hurt u though more air more exhaust.. unless backpressure in exhaust...

96redcamaro

iTrader: (1)

hmmmm. well... I'm starting to feel better about my exhaust now lol