Seeking C2 exhaust upgrade recommendations

My 1994 C2 cab (964) has a Mass airflow meter with K&N cone installed by PO. The exhaust system is stock. It seems that the performance intake benefits may be further enhanced with corresponding exhaust mods(?).

If this is true, can you suggest some reasonable exhaust mods that might help further improve performance? One important consideration is that I'll still need to pass Georgia emissions testing. Perhaps there is a simple CC bypass that is reversable for emissions testing? Open to suggestions.

Thanks, Mike

There are many opinions on this subject. Joe Fabiani recommends one of his mufflers and a cat bypass, the price is certainly the lowest, and putting the cat back in, at least temporarily for emissions inspection is easy. A big step up in price and complexity is the B&B header (44.5 mm), with a high flow muffler from B&B or Fabiani. This is what I did to my '93. I havn't done the MAF kit yet and am torn between the Autothority with the best price and the FVD which is the most stock looking. Any suggestions or feedback? A third even more expensive setup is the FVD header (42mm) with a muffler from FVD or Fabiani. The above all assumes that you wish to retain heat, if not get the factory Cup/RSR headers (42mm).

Hi Mike,

I have a 90 C2 and I have been playing with the exhaust to come up with the "right" combination that sounds nice and adds power - gauged by my totally accurate "BUTTDYNO".

Without making recommendations about what you should do - here is what I have found. I have drilled out the airbox, but I don't have a chip.

First, I replaced the primary muffler (the one across the back of the car) with a "cup pipe" - nothing more than a straight pipe. The result was a nice throaty sound and increased throttle response.

Next I replaced the cat with a bypass pipe and it made the car sound really nice, but noticably louder. Your not going to sneak home late with this pipe on your car ! You will set off alarms going through parking lots with this on. And your neighbors will take an instant disliking to you - especially if you leave for work at 6 AM ! I pulled that off this last weekend.

I tried the cat bypass and cup pipe combo without the secondary and it sounded like crap - REALLY bad. You essentially have straight pipes at this point.

I tried it with the cat back on, cup pipe and no secondary - still sounded like crap.

I am now back to the cup pipe and the cat and I think it maybe the right combination - for me anyway.

I have a secondary bypass pipe being shipped to me right now. I am going to try the OE primary (with the cat in place)and I will post the results.

I hope this helps. You can save a lot of money if you pass on the cat bypass. I think the best combination is in the primary or the seconday being bypassed with the cat in place. Or you can go for a Fabspeed or GHL muffler - $275 vs $800. It's your money

One way or another it looks like I will have a bypass pipe to sell when I get done - I just don't know which one yet.

Tom Sharpes
90 C2 Targa
http://members.rennlist.com/5150targa

Tom,

I like the idea of leaving the cat in place. Am I safe in assuming that emissions testing will be unaffected? Where did you get your bypass pipes from? What was the cost? On a scale of 1 - 10, where would you place the acceleration improvement? I tend to think it might be even better with an MAF system. I'll eagerly await your final results with replacing the secondary muffler instead of the primary. I also like this idea because it sounds like something I can do myself (does this mod impact heat exchanger at all?)

Bill, I'm a bit embarrassed, but, I don't know which MAF is on my car. It looks just like the one in the Performance Products catalog. Also don't know if there is a chip in the car (although I believe that a new chip is part of the MAF installation). How can I tell? Any suggestions? BTW, whatever MAF it is, the acceleration above 4K is almost scary. No complaints although my car idles at exactly 1000 rpm.

Thanks again, Mike

Oh yeah, one other question. . .will the computer automatically optimize the fuel/air mixture after the muffler is replaced? My old Triumph motorcycle required rejetting after changing exhaust.....Ok, I realize that we're comparing the incomparable, but just thought I'd make sure.

Thanks, Mike

Your MAF is probably the Autothority one and it does come with a cutom chip. The DME and Oxygen sensor work in concert to keep A/F ratio at the optimum. I had a Bonneville bored to 750cc. Great bike back in the stone age.

Hi Mike,

In the past I haven't been one for the emission controls that CA heaps on us continually, but believe it or not it actually bothered me to run the car without the cat ! This coming from a guy that used to run blown 502's in my boat at the river and haul it out there with a dually !

The car with the cat bypass was just waaay too loud. I drove home today after I wrote that post and I actually enjoyed the throaty tone of the car with just the primary bypass and the secondary muffler in place. The acceleration is noticably improved over the stock setup - no doubt about that. And I don't have a chip or MAF.

I am not sure of the difference between the primary and the secondary as far as restriction, but I think it is probably pretty close so regardless of which one you replace I think you will get similiar results. If anyone knows more, please chime in here ! I'd like to know too.

As for price I paid around $300 for my primary bypass and the same for the cat bypass. I am trading the cat for a secondary bypass so one or the other will go on the block after next weekend.

Hope this helps ! Any questions, just email me!

(By the way Wayne - the spell checkr id grat it make us lok intelagent ! Tanks )



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Tom Sharpes
90 C2 Targa
http://members.rennlist.com/myc2

[RW964]

Hey to ya a few words I was wondering what the car sounded like with just a sec pipe bypass as I am looking to put a G pipe on my car all else stock. If you have done this how does it sound. I know this is a old post but just found it. If you have a line on a G pipe send a line thanks ............. rwags@sbcglobal.net