DIY exhaust fabrication

[ricardofors68]

One of the things that I will be doing now before my next track event is to possibly remove my stock axle back and replace it with something lighter. Currently my car is catless, resonatorless. Main reason for removal is weight savings. Maybe I'm wrong but I think I want to give the engine a bit of back pressure and therefore was thinking of making my own axle back, looks are not a concern at all as it all will be covered by a diffuser.

Question is; Has anyone used anything specific to replace the stock mufflers? Aftermarket universal mufflers like Flowmasters, Borla, etc? Am I wrong to assume that back pressure is needed if I have stock manifolds and just run straight pipes? I know I shouldn't care but it would be a bit obnoxious straight piped, thinking of fellow track guys around me at 7-8am...

Thank you for your input

Ricardo

[roastbeef]

don't worry about back pressure and exhaust scavenging unless you are touching the headers. once you get past the headers, you're pretty much done with that.
the rear section doesn't do much, but there is a big opportunity for weight savings. custom fabrication on your own isn't going to yield much weight savings over readily available offerings.
probably the best bang-for-buck exhaust for sound and weight savings is going to be from megan. on the high end (price wise) is the akra. the akra is one of the lightest.
i have the vorsteiner type 1 titanium and it weighs 17lbs. it is the lightest rear section that i know of (short of straight pipes), but they don't come up for sale quite often.

[ricardofors68]

Thank you. I needed to know that.

[roastbeef]

Originally Posted by ricardofors68

Thank you. I needed to know that.

the oem rear section alone weighs about 55 pounds, by the way. the oem xpipe weighs just under 40 pounds.
i mention it because there is a lot of nonsense advertising with these parts sometimes claiming "light weight" when they are only like 15 lbs less.

[ricardofors68]

I knew about the weight savings, that's almost 100 pounds, plus whatever I replace it with

[roastbeef]

it gets expensive fast, the akra is about $6k unless you buy used, and gets rid of about 50 pounds. there are a few other titanium xpipe offerings, but i forget who makes them. i wasn't super focused on xpipe weight savings for the money it would have cost... afterall, it is from the lowest part of the car, and near the center of the body.
you usually still save a few pounds with just about any xpipe. i used the afe catted/resonated pipe (more metal) and still saved about six pounds.

[ricardofors68]

I have the race afe one, thinking of just doing straight pipe for now, there's plenty of axle back pipes to choose from. Even the crappiest system would be lighter than the stock stuff.