Have Cyntex with Light flywheel..should I switch to Wong?

[bigchillcar]

Going back through my prior owner receipts, I found that in addition to the rear muffler bypass pipe mod and K&N air filter that a Cyntex performance chip was purchased in 2000 for my '90 964 C4. Wondering if I should switch to the Wong chip? I do have a hunting idle issue, but I'm guessing there's an intake leak somewhere and that it's not related to my setup. Just want your thoughts...what would you folks do?

[slammed1000]

i have heard of a lot of bad issues with the early version of the cyntex chip. i run a steve wong chip in both my cars. it would be nice if you could dyno it and get some a/f ratios. it might be difficult finding a awd dyno but would be worth the drive if you can send that info to steve when he makes you a chip.....

[kang]

I had problems with a Cyntex chip. I switched to a GIAC and it was much better.

[Bill Verburg]

I have a Cyntex in my 911 & 993. I'm pretty happy w/ them.

[bigchillcar]

thanks for the replies, guys. slammed - i don't know when an 'early chip' might be..mine was purchased in 2000 though. bill - i would have thought that you'd be running a wong chip. have you tried one? what's your feeling about the available chips on the market? is yours newer or older? i'm guessing mine may be an older one?

[Bill Verburg]

There is no magic in a chip, they tweak the fuel and ignition maps a bit just like we did mechanically on our Fords and Chevys back in the '60s

I'm sure Steve W. provides a nice chip, so does Cyntex and Giac.

If you are unhappy w/ your chip by all means try one of Steve W's

I have an off the shelf Cyntx 3.6 993 chip, that seems to be a little livelier than the stock one was, and I have a custom one burned just for my 3.8 on a dyno.

[bigchillcar]

hi bill, thanks for the reply. the car came with the chip..i didn't know until last night when i found it in the rather voluminous service records. so, i have nothing to compare it to..i suppose it's doing a fine job..the car hauls as far as i'm concerned, but then again i moved up from a base '74 911 so who knows. i do have an idle hunt issue confirmed pretty much as an intake leak with brake cleaner..i just haven't dug into the system to find it. i'm still in the 'intimidated' stage by the new motor.

also looks like i may be having to replace my evaporator..the system held a weak vacuum for just a couple of minutes. no way it's only gonna be just an o-ring, right? lol. where would you look for a replacement? i hear the replacements are all aluminum at least and not made of leak-prone incompatible metals..

[Tyson Schmidt]

Having seen the maps for the Cyntex, I'd go with a Steve Wong chip.

I won't go into detail, but Syeve puts a lot more thought into his maps.

Bottom line is that Cyntex makes a broad brush stroke with the timing, then adds extra fuel in the areas of the rpm curve where they need to prevent detonation.

The Cyntex makes more power than stock, but Steve's chips make more power on average throughout the rev range, and usually a little more peak too. And without resorting to over-richening the fuel curve in critical areas due to too-aggressive timing maps.

[bigchillcar]

thanks, tyson. are these chips soldered into place in the dme or do they both just plug in?

[Bill Verburg]

Originally posted by Tyson Schmidt

The Cyntex makes more power than stock, but Steve's chips make more power on average throughout the rev range, and usually a little more peak too. And without resorting to over-richening the fuel curve in critical areas due to too-aggressive timing maps.

and the difference is how much? the stock chips are good, there isn't much left on the table anyhow.

964 has a plug in chip

[Tyson Schmidt]

Bill, I'm more worried about the long term effects on the engine from the way Cyntex maps the ignition and fuel.