Jared, I did the following, in order... Cat Bypass, then Dansk sport dual out, then Steve W chip to optimize all. I wanted to keep heat - and use something that was easy to change back, if necessary. 5-8 start getting invasive and expensive.

I'm with you Jeremy, Same order I did mine and noticed an improvement with each modification. If you do the exhaust first, Steve will sell you a chip optimized for a free flowing exhaust system, saving you the expense of a new chip after exhaust mods. The SW chip was the best mod overall, IMHO.

THanks. Prior to this, my first thought had been to chip it, but the thing holding me back (aside from cost) was the prospect of changing it for another when I went further.

who makes a good cat bypass?

Here are Test pipes:

http://www.pelicanparts.com/cgi-bin/dbsql/db.cgi?db=partsearch&mh=20&view_records=yes&uid=de fault&description=test+pipe

However, you gain little if any (may even lose) power from this modification.

so the cat bypass only works well in conjunction with a sport muffler?

JG,

This is debatable. Going with a premuffler seems to be the ticket. But again the gains are relatively minimal. I chose to stay with my Cat. Besides I wont have to swap out for inspection.

ok, I'm showing my cards of ignorance here, but could someone explain the difference between a cat bypass, a premuffler, and a muffler?

Thanks. Just think -- an investment of a couple of words now will save you countless dumb questions later.

Cat bypass is just a steel tube that replaces the cat converter. A premuffler is what it says, a smaller cylindrical muffler that replaces the cat converter. The muffler is that big banana shaped thing at the back of your car that the cat, bypass tube or premuffler attaches to.

I understand there to be a performance difference between the euro pre-muffler and a cat bypass. Again, there has been much debate over this issue; here is an example: http://forums.pelicanparts.com/showthread.php?s=&threadid=143837&highlight=premuf fler.

As you can see in my first post, I believe the pre-muffler to produce more gains, purely from the information I have gathered from other much more engine savvy individuals than I, here on Pelican.

The Catalytic Converter goes before the Muffler. It can be replaced with a Cat Bypass (aka; Test Pipe)...it's just a pipe. The Cat can also be replaced by a Pre muffler which is a bit quieter and reportedly affords modest gains. The pre muffler was used on Euro cars in place of a Cat.

Does anyone know how much louder the car would be with a test pipe versus a CAT?
The pre-muffler by it looks, looks likes it tones things down a little.

Easy. Get a SC.


:D

Hardly :eek:

I went with a Fabspeed pre muffler and I like it a lot. With a pre muffler, you are less likely to get some annoying resonance, and they do give a gain compared to a test pipe for some reason. I also chose a Dansk sport muffler, one in one out, the aluminized version with the 70mm tip. It was much more economical than the full stainless steel version with the same sound and flow chricteristics. I got it from our host at a cost of about $350, though they had to special order it for me.

I appreciate the clarification. I was good on the muffler's location etc. but never understood the difference between the cat bypass and the premuffler, as well as their uses. Much obliged.

Now all I need is some money for this stuff. You know what would be good, is if a chip maker agreed to let you return your old chip as part exchange for a new one as you progressed through the upgrades. That would earn some loyal customers.

Jared

Steve W will reprogram your chip for a fee as you do other changes.

Autothority will exchange a chip as well.

A test pipe will be a little throatier, but not too loud. Lots of Carreras will pass emissions inspection without a cat.

As someone who has certainly been down the slippery slope of 3.2 hp mods, I'd suggest the cheap and easy stuff first. Gut your cat or throw on a test pipe, drill your airbox, maybe chip it and see how it feels. MAF and SSI's are real nice too, but they cost some bucks. Next step after that is bigger cams. I had Webcams 20/21 and they were nice. Then you can always add carbs. There's just about no end to the possibilities. When I toured the Ruf shop, they had a 3.2 on the bench they were making into a 4.0L. That would probably be the ultimate. Eventually, you'll spend enough money that a 3.6 conversion or outright 964 or 993 purchase would have made more sense. I ditched my Carrera for a V-ram 993 and don't even think about HP-increasing mods anymore. I'm cured!

So Leland - you still pushing or you have that thing running now?

I'm not looking to heat things up, but I'd like to hear a little more on the airbox drilling. I've got a Fabspeed Euro PreMuffler, a second outlet pipe to the stock muffler and a Steve W chip in the garage.

John