apw964

All,

I decided to try a chip from cyntex after Jeff's recent post. I called Paul and informed him that I have a primary bypass pipe and drilled airbox and he subsequently informed me that he could burn a chip to take advantage of my setup.

The chip arrived today, but it states on a sticky label that the chip is for a "Cat Bypass"

I'd like to put the Chip in this weekend to try it and I'm not sure it's the right one ???? Anyone got any opinions, or will I need to wait till Tuesday to contact Paul at Cyntex.

Guess my thought is maybe the mapping for a cat bypass and a primary bypass are very similar ????????

Thoughts ?, Advise ?

Thanks

Andy

Bill Gregory

Andy,

I would try the shop tomorrow morning around 9am. Else, I'd call him on Tuesday to clarify.

Of course the other path is put it in, try it over the weekend, followup with a call Tuesday, and worst case you'll have to swap it out if there is a mistake. If not, you will have had the weekend to enjoy it.

(That's a cover all bases answer!)

Lorenfb

As you may have read (systemsc.com), I'm not
too positive about late model cars with knock
sensors and after-market chips. I hope that
there are some exceptions. I've worked with
many 964's thru dealers and indep. shops,
and have had many problems; pinging, fault
codes, & bad idles.

Let us know what happens. In my involvement
with shops, I'm often asked about good chips.

Good luck
Lorenfb@aol.com

joey bagadonuts

Here's one way of looking at it. Once you've taken the DME unit apart for the first time, swapping chips takes 5-10 minutes. The DME housing is held together by appox 12 metal tabs which are bent to keep it together. That's the toughest part about accessing the chip.

I'd give the chip a try. Pre-programmed EPROM's have multiple maps to adapt to fuel/air mixture, atmospheric conditions, intake, exhaust, driving style, etc. in pursuit of perfect combustion. There may not be a big difference between the chip you received and others offered by Cyntex (only they can tell you that) but their adaptability suggests it might work just fine.

Of course, you won't know if it's the best Cyntex chip for your car until you talk to them.

Jeff Curtis

As a recent "chip-changer-outer"...I'll second Joey's comments.

JUST DO IT!

I'm sure that a chip burned for a cat-bypass is similar to one for a "free'r flowing" exhaust.

David K.

Removing the cat will give you freer flow then just by-passing a muffler or changing to a freer flowing exhaust. The car needs more fuel the freer the exhaust system gets. So a chip for a cat-bypass would be richer then just a muffler change chip. I would check will Paul at Cyntex. BTW, Paul does all my dyno tuning on my RSA he knows his stuff.

pzull

David,

I've always wondered about the fueling bit. Doesn't a stock chip already do that? ie. if the exhaust or intake is free-er flowing, then the VAF/MAF would already sense that and increase fueling. The only time that fueling may be off is at full tilt when the barn door is open fully and any increase in air flow from free exhaust will not be compensated for.

I think maybe most of the benefits may be from advancing ignition timing?

But i do have the RUF chip and have felt a diffreence from stock.

David K.

The DME chip has a set of tables that have predetermined values for fuel and timing for different rpm and loads and other stuff which is over my head. You only get the predetermined amount of fuel for the give load/throttle position/rpm.

Lorenfb

Let's end the debate! Put it on a dyno.

Lorenfb@aol.com

apw964

Ok - Here's the results !!!!

I spoke to Paul at Cyntex on Saturday morning - he informed me that the chip was the correct one for my setup.

The Chip went in today.

I conduct 3 runs with the stock chip. Rather than a 0-60 I performed a 10 - 60. Basically rolling up to a line at 10mph then pressing on full throttle to 60. My friend sat in the passanger seat timed the runs. Although this is not the quickest way to 60 my theory was that it was the most consistant taking dropping the clutch out of the equeation.

So the results;

Standard Chip :

Run #1 10 - 60 : 6.1 sec
Run #2 10 - 60 : 6.3 sec
Run #3 10 - 60 : 5.9 sec

Cyntex Chip :

Run #1 10 - 60 : 5.7 sec
Run #2 10 - 60 : 5.5 sec
Run #3 10 - 60 : 5.3 sec

The standard and cyntex runs occured within 1 hour of each other on the same stretch of road.

Overall I am pleased with the mod - the car definately feels more responsive especially after 4000 rpm. For the $320 - a mod worth considering

Andy

Lorenfb

Why is the best time with the stock chip only
.2 slower that the worst case with the special chip?
I'd still put it on the dyno.

If you're happy, that's all that matters.

Good luck
Lorenfb@aol.com