Performance (HP) Chip

[CrossT]

I've installed a HP chip in the DME unit of my 86 Carrera Coupe. It's clear to me that the car runs a bit more smoothly and seems to have a bit more oomph. But, once the car warms to operating temp (where the oil temp gauge sits about horizontal) I get pinging/detonation on medium to strong acceleration -- the pinging doesn't occur with lower eng temp. I have added an octane booster and still get the same results. I can only get 91 octane fuel here where I live. Needless to say, I have to sort this out.

I have called the supplier of the chip and they suggested that I remove the black cover on the air flow meter and relieve the tension on the gears inside by 4 or 5 teeth. I have no idea what this part does or what this procedure will accomplish, and, therefore wanted to check to see if anyone has had experience with this type of situation before I start messing with the car in this way.

thx for any info/suggestions

[ChrisBennet]

Moving the spring in the air meter will richen (or lean) the mixture out over the complete range. It sounds like your chip just has too much ignition advance for your fuel quality. Any reputable vendor will take the chip back. A good vendor will insist that you not to run that chip with your 91 octane fuel because they know the damage it can cause. I would send it back.
-Chris

[jester911]

I am sure others here with more knowledge will give you more info but first off the octane booster is a waste of time and money
Do a search on it. There was just recently a thread about how much of that stuff it actually takes to change the octane in a tank of fuel. It is a lot more than the 8 oz or whatever that comes in a bottle.
From what I understand it is very important to run the 93 octane the chip calls for. You may need to find a station that sells the higher octane.
The thread I mentioned also talked about mixing your own booster but I personally don't think a few more hps are worth blowing yourself out of the garage.
just my .02

[North Coast Cab]

What other modifications have you done, ie. exhaust or air?

JG

[CrossT]

Thx for the responses confirming my expectations on the chip. If only I could get 93 octane fuel here in Tucson, but I guess I'll be swapping back the orig chip this weekend. Can't get HP for cheap...

There is no problem returning the chip (fortunately).

Insofar as modifications go, I've made only one to the engine besides the chip; a K&N air filter. Other mods are to the suspension; turbo tie rod ends, Konis, Strut brace. Other mods include a static condensor for the A/C and a lower vent, neither of which seem to have resulted in A/C that cuts it in the summer in Arizona. Before next summer I will need to address this (with the help of this excellent forum). I avoided the car as a result this year!

[Steve W]

Who's chip is it? Some such as the ones seen on Ebay are way too advanced in their ignition timing. You need one more accomodating to 91 octane.

[CrossT]

The chip is from Vertex. They seem to be quite surprised of my problem almost as if it was a first for them, though they are very accomodating of a return. They were surprised that I couldn't get anything better than 91 oct though. Quite frankly, it surprised me too.

If you know of any 'more forgiving' chips, that would be interesting...

[ChrisBennet]

The extra horsepower is a function of the ignition advance so if you take out the advance so it won't ping on 91 octane you're also taking out the horsepower.
-Chris