New member! Exhaust help!

[Schneidy95]

hI everyone! Im from Wisconsin, I recently bought a 91 N/a with 120,000miles on her. Picked it up for around 3g's. It has brand new 18' battle axe rims with new rubber, other than that shes stock! So far I love it!
My last car was a 95 integra ls that I turbocharged by myself. stage 3 turbonectics t3/t4 turbo front mount intercooler, tail wg, greddy bov, 440cc R/C inject 3' thermal research exhaust... blah blah blah.. anyway, im excited to start working on the ZX. Ive already started maintenance, changing all fluids, tuneup..
To get to the point, the stock exhaust is in pretty bad shape, so im trying to piece one together. So far im going with stock headers, megan down pipes, and new stock mufflers.. What I need help with is fitting it all together. the Down pipe should bolt to the headers? then basically stop were the stock cats were? what do I need to complete the mid section? (from were the DP ends to the mufflers). Any help is much appreciated, tired of researching..
Thanks!

[Schneidy95]

heres a pic of the car!https://scontent-b-iad.xx.fbcdn.net/hph ... 3976_n.jpg

[solaire]

Nice Z. White is my fav.

I'll go ahead and tell you you're in for a fun time. Headers with engine in the car are not easy. To put the megan downpipes you'll probably have to delete the AIR system because there's nowhere to hook the pipes from it. For behind the cat go get an ebay exhaust and you can modify it if you don't like it, add resonators, different mufflers etc. But if you had a sooped up honda then I'm sure you'll like how these cars wound with ebay exhaust.

[Schneidy95]

Thanks Solaire for helping me out! When I took off the cats, they were completely melted inside.. you couldn't even see the honey comb, or any daylight through it either. Guess the AIV wasn't doing its job anyway.

[t.mcginley.jr]

Like solaire said, headers are a royal PITA with the engine in the car. Not so much getting the new ones on, but getting the old ones off. Honestly you won't feel much if any difference with new headers since the stock ones are basically shaped like headers. A larger diameter exhaust from there back will help it breathe better. Are you going to be just bolting this stuff up or are you going to weld it yourself?

As for the melted cat, I doubt a non-working AIV system caused that. That sounds like a symptom of running too rich for too long.

[Schneidy95]

I never said i was going to change the headers.. Sorry if i typed that wrong! Anyhow, i ordered Megan down pipes that i will bolt to the stock manifold. I also ordered a cat back off of Ebay that i will bolt onto the DP. I am planning on cutting off that crappy 4.5in pop can that the Ebay exhaust comes with and I'm going to weld quad tips on the mufflers. 3 of my spark plugs were white so i have a vacuum leak somewere. So its running lean.

[solaire]

I'm betting it's got or had injector or O2 issues. Melted cats is caused by a rich condition. I've never seen lean melt cats since they're made to withstand heat (lean condition) but they aren't made to withstand fuel touching them which is what usually melts them. It's possible the O2 sensors are switching between bias rich or bias lean or 1 or 2 injectors are getting stuck. Could be lack of spark from PTU corrosion too. With these cars it's hard to say what causes a rich or lean condition. They're very very sensitive and age + weather = corrosion in the electrical system which could cause a nightmare. Trying to fix one thing could cause the car to run worse than before and then you're in for a ride and have to go all the way to finish fixing it to get it right. That's why people tend to give up on these cars and why they can be so expensive. I've got a 91 now I'm working for for a guy and just doing a plenum pull for v/c gaskets. Since it sat for over a month and I disturbed the harness now it needs injectors after i replaced the corroded electrical connectors. I spent weeks cleaning corroded connectors, closing up spread female pins, and making broken ones fit like they should.

Only real gain from headers is they dump straight back instead of swooping up then back down like the stock headers do. Won't notice a difference unless you do a very very extreme NA build which will still be outdone by a turbo model with light mods.

[Schneidy95]

It may have been running rich at some point.. But the right side of the engine(driver side) the plugs look good. the Passenger side is lean on all 3 plugs. The car does shake quit a bit until 2,600 rpm's. ill try and find a vaccum dia. and see if I can find a leak. If not, in guessing its the coil wires..

[solaire]

Somthing like that could be O2 sensors if it's different based on bank 1 or 2. It also could be coincidence the injectors are acting up. I've got a 91 that's doing that. It barely runs and shakes and sputters til about 3000 rpm and I've got injectors on the way for it. Mine has 2 wet plugs on one bank, one good plug, and 1 lean plug and 2 wet plugs on the other bank