I was told today I should not plan on installing cats again with my currently installed D1SC ProCharger (now with JetHot lts and non-catted y-pipe).

This winter I will be removing the 347 and installing a 408 HKE iron block. I have already purchased American Racing 1 7/8 LTS with their catted y-pipe. It will be connected to a Magnaflow cat-back.

I had mentioned that I wanted to go back to cats originally when I talked to a sponsor about installing a 370 and it was never mentioned or advised I should not install cats with the ProCharger. Now I'm told otherwise after I purchased the cats - cats are still in the box waiting to be installed.

The install will include EPP's FMIC kit, AlkyControl Methonal Kit, ProCharger D1SC, 408 HKE iron long block with about 9.5 compression ratio, American Racing headers with American Racing catted y-pipe, Yank PY 3400, mated to a level 3 PerformaBuilt 4lE60, followed up with a PST 3.5 driveshaft to a narrowed Moser rearend.

So why do I want cats? I am tired of the obnoxious rasp and noise and want a quieter exhaust. The Magnaflow is my second exhaust. It is not nearly as raspy as the Borla I had on before the Magnaflow but it is still annoying and too loud. I don't have any room left behind the y-pipe to add an additional muffler because I have an electric Street Pro cutout.

Do I care about some horsepower loss with the cats? No. Anything over 600 rwhp is more than enough for the car (1998 Z28) which will be a weekend summer cruiser only.

And I don't want to replace the exhaust with duals (third exhaust system if I were to do that and the only duals I would want would have to be over the axle).

Need opinions please - will I be OK with cats?

 

Solely based on sound, cats aren't the best way to deal with rasp. If you have any other issues (emissions, etc.) then the subject may be different.

 

If they are high flow cats I would be OK. If stock, then they are pretty restrictive.

Jim

 

IMO the majority of posts in 'Generation III External Engine' state the best way to get rid of rasp is with cats. All other ways are dependent upon the infinite number configurations of engine combinations, lts, y-pipe, and cat-back exhausts.

Yes - if I had deep pockets and could install any number of different combinations until I finally end up with one that eliminates rasp without cats - that I would do - but I don't have deep pockets.

Cats appear to be the surest way to get rid of rasp.

 

Cats are American Racing - so assume they are high-flow. I'll try to find out what brand. I'm assuming Magnaflow.

 

We've used factory cats without any problems, as well as aftermarket cats. The cats won't last as long with any type of forced induction, but the combination will indeed work. This C5 with 740 rwhp with an ATI ProCharger D-1SC has a 346 ci engine, shorty headers, factory cats, factory maf, factory throttle body.
http://www.exoticperformanceplus.com...Car.php?car=40 Bob

 

I am still running cats with a 408 and F1C setup.

 

Why is the life shortened? How long will the cats last?

 

+1 for that, wonder what would happen to them?

 

The increased exhaust velocity seems to tear apart the insides of them. We have had cars on the dyno spitting out pieces of the cats, something you wouldn't ever notice out on the streets. Bob

 

make sure the cats are metal matrix like the magnaflow cats. the reason why they come apart is due to the rich running conditions when under boost or a bad tune. i run cats and car runs fine. BUT again make sure they are metal matrix, ive gone through them and these from magnaflow have not blown out. the others were done in less than 1000 miles

 

I received a reply from ARH. They tell me their cats are "200 cell metallic substrate. They are the highest flowing and most durable cats available. These cats ARE NOT made by Magnaflow. ARH cats are proprietary as we are the only US based company that uses these substrates. They are also twice the cost of other metallic cats. Unless exposed to some kind of extreme tuning condition, the cats should hold up fine. Hope this helps."

ARH - top of the line LT's with top of the line cats.

 

nice!!!!!

 

Especially depending on power level and type of gas used.

 

No cats for me with my Borla. A little raspy but I am still alive. I guess I'll live.

 

I've been happy with my Random Techs. It has almost been 2yrs now. I've seen pics of most of the major brands having crapped out, but that's just how it goes I guess. Definitely expensive, but it was worth it to me.

 

no cats for me either, I run leaded gas now....

 

Bob - At what horsepower level does it make it impractical to run cats and a procharger? By impractical I mean not blowing them apart every 1000 miles and having to buy new ones. Dan

 

I've ran the Magnaflow cats in the Kooks Y-Pipe (catted Y) and went 10.teens with them. Spent a bunch of money going to a merged Y-pipe with no cats and a larger 3.5" I pipe with a DMH 3.5" cutout and didn't go any quicker at 9-10 psi. Waste of time and money....also had a Magnaflow cat back

Taking the cats off made the car stink while idling, didn't notice any rasp, car was louder and lost its stealth factor.

IMO, it was a bad move all the way around. Basically, the Kooks catted Y and and Magnaflow cat back is a pretty damn good set-up for bottom 10's at stock weight.

 

I am running the TSP y-pipe with the magnaflow high flow cats. I dont have any problems.