Ziggy*

Junk out of pre CAT



Inlet
Pulled the whole system off. Chunks laying in front of Main converter on my 86. 1 Pre cat toast.Other OK, Gutting the whole system, No smog checks in WV......Straight down pipe before main CAT sounded good ...Gutting my main CAT, reinstalling with Magnaflow rear pipes. Got my motor back....Been running like crap couple of years....Got my Problem solved

Renfield

I suspect to find that in my '96. Struggling to get 16 in the city and power is down.

Time to check back pressure. No smog here, so I'll gut 'em too before spending $300 on replacements.

SR71!

Out of curiosity how many miles are on the car? Just picked up a '96 with 23k and I'm compiling a short & long-term list of items to go through for maintenance.

Renfield

Sounds nice. Bought mine two years ago with 86K. It's going to hit 100K on this tank of gas.

Good luck and congrats.

mickey5

Took off the precats on my '90; now it burbles and pops on compression deceleration.

billschroeder5842

Me too.


I took off the precats and then put on a performance catalytic converter and left the factory mufflers. WOW. The car sounds great and you can feel the difference.


My muffler guy suggested this mod as he says he has been doing it for years on the L98. He said the pre cats are very restrictive and really don't do anything. He suggested the performance cat (with air bung) as he said that it will flow 6x better than originals.


I'm very happy with the way it turned out.

cv67

Good to hear, was your muffler full of that material?


Those old cats were really bad compared to whats out today!

Ziggy*

78000 miles on my 86. The main cat was changed before I bought it. ( it looked newer) The front screen on the main cat caught all the debris luckily. But I have material loose in the main cat, nothing got past the rear screen into the mufflers

Ziggy*

Gutted the precats. Gutted CAT on stock system. Flowmaster mufflers. Got my motor back.

billschroeder5842

Well done.

Boris is the only Cat I want on my engine.

Renfield

Dumb question. Boris probably knows. Will I have to source gaskets when I pull off the cats?

billschroeder5842

Boris suggests just cutting the cats off and putting on a straight pipe.

Renfield

That is a thing of beauty, without a doubt. Hats off to you sir. But I don't weld. I just want to unbolt the suckers, gut 'em and reinstall. And I'll do the fuel filter at the same time. Win-win.

Does someone offer bolt in straight pipes?

billschroeder5842

I don't weld either. I took it to a shop and they charged me $75 and they were done in 45 minutes.

Can't help you on straight pipes from the header, but I bet the parts suppliers will have them. I worry that they will cost more than a cut and paste job....

mickey5

[QUOTE=billschroeder5842;159559245
Can't help you on straight pipes from the header, but I bet the parts suppliers will have them. I worry that they will cost more than a cut and paste job....[/QUOTE]

Replaced the front Y pipe for one without precats. Billy's right, it cost about $150+install.

BrandensBeast

Guess I know what to do next on the Vette....91k miles, stock exhaust system back to aftermarket mufflers....wonder how much the car is being held back.

billschroeder5842

LOTS

I removed my precats and installed a performance catalysis and kept the factory mufflers. I was able to feel an immediate, no Sh*t difference.

Everyone asks "how much HP increase ??" I have no clue; only the SOTP Dyno for me.

Budget allowing please remove the pre cats and the catalysis. They both are super restrictive

belairbrian

Interesting. What is the intended purpose of the precats?

My 2001 MR2 has precats. Toyota used them to get a lower emission rating. They only serve a purpose during main cat warm up. On the MR2 they are Known to break up and can get sucked into the engine. Thus gutting them is pretty much standard.

I know that sounds odd but Toyota used their Variable Valve timing for EGR. When they want to draw exhaust back they delay exhaust valve closing into the intake stroke.

Goldcylon

I had that problem as well. Car sounded like a chock full of nuts and bolts for that matter were floating around in the Exhaust. GLad you found it. GC