FLP header? 3.5 main pipe ?
with 9.25 compression , and i will be running 15 PSI of boost. I am at 10PSI now on stock motor making 540 to the wheels. (methanol injected)
OK my current exhaust system consist of 1 3/4" Long tube FLP headers with 2.5" Y pipe (no cats) and my stock SLP dual dual Exhaust ( 3" main over the axle pipe and slp dual dual muffler.
I am thinking on having a 3.5" over the axle main pipe made up (I think 4" is over kill )and taper it down to fit my SLP dual dual stock muffler , I dont like the way SLP cushed the 3" pipe where it goes over the axle.
has any one done this? any sound clips , performance difference? etc.
I have been hearing my exhaust would limit my HP and power goals.
I might also have a custom 3" Y made up , the 2.5 FLP is ok but where it meets up a the main 3" over the axle pipe , there is a bottle neck there, i hear one guy that cut this off and replaced a 3" spool piece picked up 14 HP. Thats a lot of HP for removing just the bottle neck.
thank you for your help
I made my whole exhaust setup from scratch and it sounds pretty nice, although the fact that I have twin cats and a muffler kinda robs a lot of power. May sell the setup or hollow out the cats and use a cutout.
Here's how it affected power ... granted my setup isn't optimal right now 'cos of a mismatch of parts ...
TH350 w/3500 stall, true duals with dumps ... 401RWHP
T-56, above exhaust (to make it more family friendly ..
) ... 403RWHP 
Underneath car with 3.5' QTP electric cut-out. You can see I have it neck back down to 3" to go over the axle. (some stuff looks messed up because it was post accident.)
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Mufflex (sp?) makes a 3.5" catback and maybe a 4" system. I liked my system. Pretty quiet unless I wanted to let everyone know I was coming.
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My setup is a custom Mufflex. They do sell 4" systems aswell like you stated, that also fit over the axle.


