1991 NA Exhaust replacement. Imput appreciated.

[Whippy]

I have vehicle inspection due within 45 days, and I know I have a rotted out exhaust pipe. I believe it to be the pipe that connects with the manifold on Right hand/pass side. After looking it over today, I have the tools, and have no question that I could not remove this from the car with little effort, but Is there anything special I should know about this pipe.

My goal is basic. Id like to replace the whole system from the manifold back. How hard would this be to do? Is it possible to remove the manifolds from the bottom, or does the intake plenum need removed? (Also, where can I get an aftermarket intake plenum?)

And just to see If I am getting this.

The NA exhaust setup consists of the manifolds, into the cat pipes, into the x looking pipe, and onto the mufflers?

Thanks for your time

[stewartmotorsport]

Are you in California? Better leave the stock manifolds on (at least until you get past smog) and the cats too.

If your state is not as stringent with smog requirements, there are tons of places to get an exhaust system. Look on ebay. Stillen also makes a GREAT exhaust system (pricey tho.) So does Jim Wolf I think. Google them.

You do not need to pull the plenum - the plenum does not connect to the exhaust manifolds in any way. To take the entire exhasut system out is not that hard - it's just time consuming. The hardest part is the exhaust manifolds.

As for an aftermarket intake plenum...um...I have never seen one. That does not mean they don;t exist - I am sure they do. But I've never come across one.

[Whippy]

I am lucky enough to live in a lax area. A car of this vintage only requires no exhaust leaks and cat-converters...there is no "test tube" as it only visual. So hypothetically, a test pipe setup will pass because it resembles a high flow cat.

but time consuming is a-ok. I didn't know if I needed to get stuff on the intake side out of the way or not. Great info, and I will report back.

[stewartmotorsport]

I just remembered something: Z1 Motorsports does some intake manifold modifications that are really beneficial. They also sell updated 58mm throttle bodies. It's not really an aftermarket plenum per se, but their mods keep it looking stock but help with performance.

[NolimitZ32]

SMS got it right with all the exhaust stuff as for AM intake: there are aftermarket intake manifolds but I have never seen one available for sale (means you gotta do a lot of legwork to find one) and more importantly you will lose your pants and left nut to pay for one and gain nothing by it especially since you are NA. I'm curious why would you want an AM intake?

[Whippy]

I'm curious why would you want an AM intake?

Im sticking with NA. I have no time for the track, and overall this thing already is testing my maturity. Id love to find an AM Plenum/intake just to give it a bit more breathing room. It may only be good for a few extra horsies, but it could give a bit beefier of a growl.

[NolimitZ32]

Well GL finding one, as for more breathing room you need to get bigger TBs before you even consider a bigger plenum, or just wait till I can finish my ITB setup (hopefully I can get back to it soon).

[Whippy]

I have no problem getting larger TB. Ive also looked at fabricating a single TB unit out of 316ss plate and pipe, but most of the designs require changes to the hood. The "Batwing" design is efficient, and if it was "refabricated" with similar size pipe and tubing, it would be astronomically better due to the smoothness of pipe.....But it would take an immense amount of planning and "hood" time.

Thats the serious trade-off.

I live in a mountainous region of PA, and most of my travels never exceed 75, even on the highway. Our roads are terrible at best. Turbo would be a waste of a perfectly good engine. Engine is not top priority, as much as suspension and brakes. I drive about an hour and a half to work every day, and some of the roads are just a joy to drive on, but 75-80 is really pushing the limits of gravity on the side of the car.

Id be thrilled to have 190-200ish RWHP as a final goal.