Flatsixer

I am wanting to swap out my stock exhaust ( 90' C4 Targa ) for more performance gains, enhanced sound and reduced weight. I had my mind set on the single outlet Fabspeed exhaust with a Cupstyle airbox and BMC filter (maybe a cat bypass in the future). I was talking to a fellow at Windward performance today and He strongly recommended the Euro pre muffler/ Cup bypass setup with a Cone filter and Autothority chip mapped for this setup. I had not even considered this before. This would mean the removal of my Catalytic Converter, which I don't mind doing ( We don't have emissions testing here). I just want to know if anyone has this exact setup on their 964 ? Any feedback would be great. The fellow at Windward noted significant "seat of the pants" gains with the latter setup which is appealing to me. As I am a Novice, I need some sound advice. I do not intend to track this car at all, just want a great street performer. Regards, Brady

Bill Gregory

Brady,

You should search the Rennlist 964 forum for dyno results on various upgrades - there's no magic solution for extra hp, without spending a bunch of money and making some compromises (which may be OK for you). A cupstyle airbox, IMO, is a waste of money. Drill holes in your existing cover, or buy a used one, and save the $175. Do replace one of the two mufflers, cat your choice. In looking at any chip, be sure you understand the gas octane requirements, and, unless you're rebuilding the motor for it, I'd strongly recommend a chip that doesn't raises the rev limit, which some do. You may want to read the August 1999 article in the PCA Panorama on 964 engines, which covers the various options. Talk to more than one vendor, too.

Jeff Curtis

...certainly, replace EITHER one of your mufflers - there's more of a weight savings if you replace the Primary muffler (rearmost and center) but survey says better sound if you replace the Secondary (right rear quarter).

Several 964 owners that have replaced either unit have gone on to changeout the converter with either just a bypass or a "European-Premuffler". The Euro-Premuffler has small baffles to "tune" the sound a bit better when compared to just a straight-thru bypass, so the car will be a <tad> more quiet.

Myself, I have eliminated my SECONDARY muffler and installed a Fabiani Primary muffler that has their tip welded in place so I did not require a secondary bypass.

I also have the European Pre-muffler in lieu of the catalytic converter...and I really like the setup.

As for "seat of the pants" performance gains...I dunno, but it goes like hell and sounds sweeeeeeeeeeet!

Might I add that I have a custom-burned chip for a 964 w/"free-flow" exhaust and a lightweight "Cup" style flywheel/clutch assembly.

Arjan B.

You will use to all the modifications you will do, you want always more.

I have the prim. cup bypass and the drilled filter, now I want the sec. pipe too, but I hassitate stil.......

I am hounest to you, the primairy cup and the drilled airfilter are just fine to drive also with your wife or evt. passengers of you should.

Flatsixer

Thanks for the Replies. Correct me if I am wrong, does the Catalytic converter serve any other purpose than the environmental aspect ? Could I have any potential operating problems removing it and replacing with the "Euro-pre muffler " ? other than the impact my 964 will have on the environment with increased emissions. Thanks again, Brady

Adrian

Dear Brady,
The cat is just for emissions. What you have to be careful of when replacing things like cats is that you use the correctly designed replacements. Our rennlist sponsors GHL have such parts. Might be worth checking them out as well.
I am interested in you statement of the "Euro" pre-muffler. Every 964 delivered was fitted with a cat EXCEPT the option M150 versions and some early RHD deliveries to the UK. You might be interested to know that option M150 versions do not use an O2 sensor but they use an altitude compensator instead. Does a similar job to the O2 sensor hooked into the DME. The DME has to be configured to be told it now has an altitude compensator.
I do not recommend this unless you live in the mountains and it is a bit of messing around.
Back to your original question though. I recommend you replace your exhaust components with parts which have been designed and tested for each part you wish to replace.
Ciao,
Adrian
964C4

Christer

Brady

If you are going to replace the exhaust, get a complete system with headers.

Christer

p.s. if you are doing this for gains, then get a before and after dyno so you can sue for misrepresentation if it all goes **** up.

joey bagadonuts

Adrian, the Euro pre-muffler refereced is a version of the cat bypass sold by Fabspeed. That's what Jeff has on his car.

joey bagadonuts

Flatsixer

Adrian, Thanks as always for your insight and advice. Christer, I appreciate the Header idea, but probably a bit to extreme for my street only 964. I will do a little more research before committing to either option. Regards, Brady