So I've been reading the archives. Again. This time looking for chip advice for my '95. From the threads I read, it seems that

a) GIAC is a pretty well regarded chip.
b) Priced charged for GIAC chips vary widely.
c) No no no, some GIAC vendors have chips that are "special" wink wink, nudge nudge. The evidence for this seems to be mostly butt-dyno testimonials.

So I e-mailed GIAC and asked them. Here's what they said:

Take that for whatever it's worth. Maybe things were different before. But for now, I'm going to buy a chip from my local GIAC dealer (who's also among the cheapest, conveniently, and their AWD dyno doesn't hurt either).

 

I went through 2 Chip dealers and 3 actual chips (2 from 1 and 1 from the other). My 95 C4 had check sum issues with 2 chips on the market. Rev. limiter kicked in at 6000rpms exactly (down to the second) 9 minutes after starting. Turn on, turn off-9 minutes later rev limiter kicked in. I dont know who they were but they lit up my car. My current chip is a Rennsports.

 

Which is GIAC. Glad to see they worked out the bugs.

 

No they weren't and when it was pointed out a few people were almost stoned to death. There is actually a whole lot more to the story but I don't feel like dealing with threats of a lawsuit or starting WWIII around here.

 

I have, from what what was researched, a rare computer in my car which didnt like some chips but I never did ask my mechanic which brand were the ones that didnt work. I might have to hit up Steve W. when he gets back.

 

What's the Bosch and Porsche part number? The reduced rev-limiter problem happens when the person modifying the software forgets (actually "doesn't know" is a better description) of an additional checksum that was added to the post-964 OBD1 993.

 

Im not sure what the part #'s are. This issue went from Steve W. to people in Germany with inside tracks to Porsche. Both chip manufactures never heard of the problem happening on 95. I even did my homework and called 2 other tunes-Speed Tuning USA was one-and they had never heard of the problem. I have spoke to several others with the same car and no problems with chipping either. Its been 3 years since i had it chipped and all is fine now.

 

Just to confirm--the Rennsport/GIAC chip worked. It was the others that had the problems?

 

No issues with Rennsport. The first 2 chips that I had lit up my car in the lower gears and Steve programs his to mid range power, if Im not mistaken.

 

I have the GIAC chip from Steve at Rennsport and couldn't be more delighted. I have a late build 95 C4 as well...

 

My 95 also had a Rennsport chip, the car felt more responsive than my unchipped 98

 

ditto, Steve W chip on my 993.

 

One more happy consumer of a Rennsport chip.

 

Jon

Who are you using locally for your chip?

Jeff

 

AWE up in Willow Grove. FWIW, they're one of the other vendors (other than Rennsport) who claims to do custom programming on GIAC chips on their AWD dyno. I think that was for Audi S4s though.

Not that I need anything custom or special for an otherwise stock 993. Just trying to differentiate hype from actual product. Seems Garrett Lim was everyone's roommate in college or best man at their wedding.