I would appreciate any advice between a couple different options.

I have a very nice 1992 Trans Am with the 5.7. It's pretty much all original right down to the exhaust system from manifolds to tailpipes. Since the original system only had mild corrosion I was hoping it would last many more years. It was always fun to shock people at car shows who had never seen an f-body from this generation with its factory exhaust. However, while on a trip in it I (somehow) damaged one of the cats and now the catalyst inside is loose and rattling. I'm rather annoyed, and baffled, this happened but I have to do something.

Obviously the original GM units are long gone and despite me trying to keep it as factory as reasonably possible it's time to embrace the modern aftermarket. I thought about just buying two of the magnaflow direct fit cats (https://www.summitracing.com/parts/m...model/firebird) and having them welded onto the original pipes since they're in pretty good shape. However, magnaflow does make a whole converter/y-pipe assembly as well (https://www.summitracing.com/parts/m...model/firebird).

I think I vaguely recall someone complaining about clearance/fitment issues with the magnaflow setup around the oil pan and possibly the hangers on either manual or auto transmissions? That 23479 does look like a nice setup and since I assume I will one day have to replace the cat-back system if I keep driving the car it might be a nice start.

Since originality is out the door now, what are your recommendations? Will it be easier to just weld in two cats to the factory pipes? Has anyone else actually bought the magnaflow 23479 and fit it to the original manifolds? I'm just trying to do this right the first time and get something that's going to work the best and not give me a lot of headache in the install or further down the road. I also do not want to lose any ground clearance. Any small gains I get will just be added bonus!

Also don't just tell me to gut the cats or buy an off-road y-pipe!

Thanks all!

 

I used the magnaflow dual cats on an 88 IROC Conv and on an 89 IROC Conv
The guy who installed the 89 didn't do any custom bends and it hung way to low. The second installed custom bent a couple of the magnflow system and it came out beautiful, so much I had the 89 redone by him.

Hope that helps

 

How much custom work was required? It didn't hit on the body or frame anywhere when you were driving? I really want to avoid it sounding like a hack job and vibrating against the frame. The shop I use can't make custom mandrel bent pipes. They can cut, flare, and they could probably tweak or move the pipes a little but if it requires some pretty significant custom bending to keep it from hitting stuff and keep clearance they may not be able to do it and keep it mandrel bent. At that point I'd probably just have them weld in new cats to the original pipes to avoid the headache.

Can you or anyone else chime in with just how significant the custom bending was to get it to fit like the original?

Thanks!

 

TPS,
The problem that occurred was exiting from the exhaust manifold, where the system would hit the frame, to avoid doing that the first clown aimed straight down, giving 4 inch clearance under the frame, result no vibrating against the frame, but ground clearance was only 2 inches.

Now this second guy doesn't have any bending equipment. Wasn't even a muffler shop. He didn't even cut the pipe, but instead heated it with the torch to bend it into the correct position. Once that was done, the system fit beautifully under the car, no vibration to the frame. There was plenty of room for dual converters. System I used was WALKER 16101 Stainless steel from Summit Racing, Walker runs rebates a lot of the time, so you could save money, think Summit shipped for free.
You know, if you just replace part of the system, another part will rust through or break, probably better and cheaper to do it all at once.
My cars are definitely are not hack jobs.

 

Thanks, I really appreciate this info. Not saying your cars are hack jobs, it sounds like you've got the same concern as me so I value the input.

Sounds like it fit with some heating and persuasion which I know this place can certainly do. I know I saw a thread somewhere where they said it didn't fit around the oil pan and frame. If they got it in with no cutting and it fit that well I guess I'll go with the magnaflow system. Seems to be highly recommend but haven't seen any details on how the install went in other threads.

I'll see if anyone else comes in with their experience by Monday but thanks for the input!

 

Okay, I will likely make a new thread so members can search for it. I got the magnaflow setup. Definitely a quality piece (so far) but my experience is that this is definitely NOT an easy direct bolt-on piece. We had a few really tough problems to solve with the installation. I would still recommend it so far, but be warned you are in for a tough job to make it fit correctly.

Thanks Catheran! Look for a full review in another thread.

 

I look forward to the full report.