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Hey C3 peeps. any suggestions on upgrading the stock cat system on a 1982 Crossfire vette? Headers? Cat upgrade? Mufflers? ex tips?
In the past i've tried to stick to pre-75 vehicles so enlarging the system was easier . on a '79 i even went to a combo muffler/cat converter setup, but i don't think it was legit by smog regs
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Originally Posted by Peterbuilt
Good question, how do you check the back pressure?
Pete.
Just use a pressure tap into the exhaust pipe (I weld an O2 fitting onto all of my exhaust systems), and plumb that to an appropriate range pressure gauge. This Magnehelic gauge is 0-40" H2O (about 1.5 psi), useful for normal exhaust systems (and other pressure differential circumstances), and I use the higher range gauge to measure turbine inlet pressure and boost pressure on my C4. Not terribly expensive gauges, but handy quite often. (This is an old picture. A forum member informed me at the time that the Magnehelic gauge should be mounted vertically for best operation, and I've since modified the bracket.)
i'm a little concerned that if the CC was missing that might be an obvious problem. like on a safety inspection where smog levels themselves are not checked, in MD as an Historic vehicle (limits on annual mileage etc) i believe there's no scheduled smog check
good suggestion! pretty sure a set of 1 5/8 headers is the minimum i want for opening up the breathing on the L83, but not looking for a mega hp street/track car. the '82 is just too sluggish for my tastes. i've had a beefed up L48, a ZR-1, a LS5 a L98 and two L76, one of which was replaced with a ZZ383. but the wife really likes the '82, it has a nice automatic and it's PURDY!
Velocity is King. I'd say 1 5/8" is the MAXIMUM that I'd want with a stock-ish or mildly modified L83.
https://www.facebook.com/BrewsHeadersBruce Reed makes perfect fitting Tri-Y headers that are perfect for stock and mildly modified L83s, IMHO. Helps provide torque that those baby rear gears need and helps keep the TC locked and the trans in OD longer for highway fuel economy.
They're not cheap, but they're NICE.
American Racing Headers 1 5/8" headers also are a great option.
Only a slight bit off-topic, check out the absolutely GORGEOUS exhaust system designed by a group in the Netherlands for C6 Corvettes. A great high-velocity exhaust system. Slip-fit stainless-steel 4:2:1 / "Tri-y" headers, then a titanium mid pipe that merges the two banks into a single pipe and then splits again into two pipes with nearly non-existant mufflers out the rear.
Make sure you can pass and Md **** smog regs. A high flow cat in place of the factory (or remove yours and gut it so it passes a visual check) I would think a set of better flowing mufflers (of your choice) would give you what you want.
Headers always make more power but can be a hassle.If it is stock(ish) it may not be worth the $$$ unless you just want them. Some shorty or mid length headers may be easier to fit than full length.
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Originally Posted by REELAV8R
1.5" at idle? What should it be at other rpm's/throttle openings?
I had to go out and look at my notes (written on the car trailer interior walls ). I didn't write down what the idle backpressure happened to be, just the high RPM WOT reading on the main straight of the track I frequent. It was 10" H2O (about 0.36 psi). This is on a system that I've had compliments on how (comparatively) quiet the car is at WOT.
Zero backpressure is certainly the goal, but it gets expensive, difficult, and heavy to construct a zero backpressure system that's also quiet, and vice versa.
Velocity is King. I'd say 1 5/8" is the MAXIMUM that I'd want with a stock-ish or mildly modified L83.
https://www.facebook.com/BrewsHeadersBruce Reed makes perfect fitting Tri-Y headers that are perfect for stock and mildly modified L83s, IMHO. Helps provide torque that those baby rear gears need and helps keep the TC locked and the trans in OD longer for highway fuel economy.
They're not cheap, but they're NICE.
American Racing Headers 1 5/8" headers also are a great option.
Ditch the cats if you can.
i'm hoping i can get a set of two (smaller) hi flo cats and go to a true 2 1/2 in dual exhaust system w/ some decent headers. i used doug's headers on my latest '65 and they seemed to work very well
C3 exhaust performance
). I didn't write down what the idle backpressure happened to be, just the high RPM WOT reading on the main straight of the track I frequent. It was 10" H2O (about 0.36 psi). This is on a system that I've had compliments on how (comparatively) quiet the car is at WOT.