ga

My '86 Carrera just blew out it's catalytic right where it bolts up to the heat exchanger/cross over pipe. The cat is really just a straight pipe welded right into the muffler, so it's time to upgrade and change things around. Any recommendations on cats/bypass pipes & muffler upgrades?
Thanks, ga

ron mcatee

The Cat is welded to the exhaust pipes just after the point where the two pipes conjoin. If you have an O2 sensor, it will require a "bung" to screw the sensor into. The Cat guts are honeycombs of charcoal material that when clogged , affect the flow of exhaust and cause the engine to not breath effectively and affects normal operation. A Cat bypass, in effect, is a hollow tube with the conjoined pipes on the front where they mount to the heat exchanger and a rear flange welded onto the pipe that mounts to the muffler. The Euro premuffler is also hollow, but has a bulbous midsection and perforated internals to muffle the exhaust. It is welded in the same as a Cat bypass pipe. There are several Euro bypass pipes on the market. Fabspeed, GHL, Bursch, Dansk, B&B, etc., come to mind. If you use a Cat bypass pipe, you may get a lot of resonance inside the car since it only a hollow tube. I initially used a Bursch pipe and the noise at normal cruising highway speeds (55-70 mph) was annoying. I went with a Fabspeed Euro Cat bypass pipe and the resonance went away. I would suggest getting the Euro Cat bypass since it has the baffles inside. You'll spend an extra $75-100 bucks, but you will like it better, unless you like the annoying resonance. As far as mufflers are concerned, unless you change to SSI's or similar equipment, I would stay with the 1 in 1 out factory muffler. Fabspeed has them as well as Pelican (Dansk). Go to Fabspeed.com, Pelicanparts.com, Vertex.com or other sites and compare.

ga

thank's Spider.....I am looking at the Fabspeed Euro Cat ByPass pipe on their website, and it looks good. Just don't want too much sound inside the car, as it is a daily driver. Thanks again, ga

ron mcatee

ga, remember to put all new bolts, nuts, and gaskets on to make it a nice clean job. Good luck.

Jay H

When I bought my '84 3.2, it came with a Dansk Euro pre muffler and a single outlet Dansk sport muffler. I dislike a lot of aftermarket exhaust systems and figured I'd swap out those parts with factory parts when I got the car. I was not going to put up with a boomy exhaust system...

However, I absolutely love the sound of these two particular exhaust items. It makes the relatively weak sounding stock 3.2 motor sound much more pleasing. It's almost gutteral in sound; lots of bass overtones and very throaty without being annoying. It has zero odd resonance at any rpms. I drive my '84 as much as I can as a daily driver when the weather is nice and after a year of ownership, I refuse to remove that setup.

You may also want to check into a Steve Wong chip that is designed for exhaust modifications done to the 3.2's. It's been claimed that these cars run better with the SW chip and the non stock exhaust verses the factory programming...

Good luck!

Jay
90 964, 84 3.2

JV911

+1 on the Fabspeed

ga

Thank's for all of your imput.....great insight & help on this.....appreciate it all.

ga

m491driver

I went with a fabspeed premuffler, M&K single in single out muffler, and a Steve Wong chip for my '87 and I couldn't be happier.

Jim

ga

I finished off last night putting in a fabspeed cat by-pass (pre) pipe, onto a stock muffler, with a new o2 sensor. Holy #$*&, what a difference. Quiet at cruising, just throaty enough when on power, and I assume that the new o2 sensor smoothed out the power range. Was always moderate until about 4000 rpm, then it cooked. Now, it pulls more powerfull & steady from 1000 to redline. (or could it be just my imagination, after cutting off rusty bolts for an evening & inhaling the dust) Anyways, I am extremely happy with it. thanks all, ga

Amber Gramps

you guys are reading my mind. I am planning this exact build. I have a rather interesting power curve. almost night and day response. from 1,000 to 3,000 rpm is smooth and mild with only a couple of flat spots. 3,000 to 6,250 takes about 2 seconds and it hits the limiter. it's fun but wouldn't dare let my wife drive it. it's like it has an on-off switch instead of a gas pedal. I almost never give it more than just a mild pressing on the gas.

Crimson Nape Racing

best mod I ever did to my 84 (and I did a bunch) was the SSI's and a 2 in 2 out sport muffler. sound was wonderful and it made a big difference in power. I don't have to worry about emissions and it did take some ingenuity to get heat on both sides of the cabin. the stock manifolds are terrible.

john d 81SC

Are the SSI's REALLY an effective bolt-on for the Carrera's? While I added them to my SC (with a pre -73 Sport exhaust) and saw a dramatic improvement - both with dyno #'s and butt-dyno, I've been told by fellow Carrera owners that there is minimal improvement at best. I understand the most effective "bolt ons" are the Euro Premuffler with the sport exhaust. And the Steve Wong chip seems to be the finishing touch.

Crimson Nape Racing

I must admit I never had the car dyno'd, but my butt-dyno said it made a big difference. It also got rid of a bunch of weight. I couldn't chip the car because I was club racing at the time, so I have no opinions there. Did I say it sounded great?