So this is what I currently have.





I was building this exhaust when I thought this was going to be a CMC car. My buddy said he'd weld for beer, and this was the end result. This was my first time building an exhaust so no need to tell me how amazing the work is. I already know.

It doesn't sound too bad around town. Needs a cat to mellow it out a little. That's a 3" straight through Borla muffler with obviously a stock at pipe and stock manifolds. I will say though, on the track at WOT it's bad ass. It's loud, sounds awesome, it pops, it bangs, and it shoots fire. I have people tracking me down to tell me how great it sounds. I'll take it.

Two problems. I need a cat relatively soon, and I'm getting too many fumes in the car. So I need to run the exhaust over the axle. I think the easier option is to replace the muffler with a high flow cat and use a stock over the axle exhaust pipe (I have one) and run the muffler straight out the right side of left side of I need the room.

Two quewtions.

1: how much hp will I loose? This is a bone stock LT1 with said exhaust and a Moroso intake.
2: wound it be worth it to get cheap eBay headers and Y pipe? Then I'd need two cats and a tune. But maybe it'll add enough hp to make it worth it?

I'm planing on switching to an LS1 soon. But at the same time this junk yard LT1 is running awesome. No smoke, burns maybe 1/2 quart of oil a day at the track and doesn't miss a beat. Kinda hard to justify spending the money when I have a perfectly happy engine. I'd rather put that money towards more track days.

Thoughts? Opinions? Good or bad, I want to hear (unless you're taking about my fab skills)!

Point it out the side and it'll be a lot quieter in the car. If you're cheap, don't buy oval pipe, just beat it oval with a hammer.

Thought about that, but I can't figure out where to put the cat.

Can you put a 3" cat at the end of the y pipe (in approximately the stock location)? Then I'd consider going back to a real cat back exhaust and making it "drivable". It's a little weight and all that, but it's worth it to me for a car I'm going to drive. Besides, if you're running HPDE events and not race events there's no real reason not to. HPDE events are "practice" and you can't "win" practice. I've seen a lot of guys get caught up in "winning" (FTD, etc) HPDE's and it becomes the "super unlimited" class very quickly. At that point, racing is cheaper....

Yeah I think a cat at the end of the Y where the muffler is the only option. Then the muffler will be after the axle. The car is a weekend toy but also I'm going to race it in TT3 which has a power to weight restriction.

Ah, ok. That changes things a little (but I don't know what the power/weight break is for that class). I had a 3" Magnaflow on the Corvette and it didn't impact my injector duty cycle numbers at all compared to the straight pipe that was on the car. It was making ~400 hp or so. The point is, it didn't seem to cost me any power and I figure I was making more power than you are right now. It was the "non airtube" version of the 3" Magnaflow. I bought it from Jegs. Unfortunately, I recycled it when I couldn't sell it (or I'd have sold it to you for $20, which is what I got for it). They run about $99 new.

Is it bad to have the cat be directly upstream of the muffler? If I can do that, I can run an oval pipe out the side just in front of the right rear tire.

Or what about directly after the muffler?

Cat before the muffler, directly on the end of the Y-pipe. You want to keep as much exhaust heat as possible to get the catalyst up to operating temp. The cat will mellow it out, so you might be able to go with a 3" bullet muffler if space becomes tight.

Will the heat from the cat cause any problems with the muffler being so close to it?

It shouldn't unless the muffler is packed with fiberglass (which I highly doubt).