Engine

Chip Set Testing

I've been busy the last month or so, testing various chips. This was not done in my 88 S4, but in a friend's 90 GT (he volunteered). We didn't dyno any of this, but we did make speed runs, and timed the following: 0-60, 0-100, 0-150, 60-90, 80-120, 100-150. For several hundred dollars, I want to be able to see, feel and otherwise notice the difference without having to rely on some ambiguous numbers on a dyno sheet.....even though they're good to have. The speed runs were made under very similar conditions, we would even fuel between runs to ensure the same weight, kept track of wind and temperature conditions.

Some chips gave "inconclusive results". Some chips were junk. The chips which provided the most noticable difference provided that difference in a very limited range, and had very adverse effects on the engine.

The chips which gave inconclusive results were the most benign. Maybe a dyno would show a few extra hp to fill a dip somewhere in the curve, but the same results could probably be achieved by proper sealing of the air filter housing, or by cooling the air into the filter, new plugs or coils. Nothing you could feel.

The "junk" chips. These were engineered (and I use the term very loosely) in a down-and-dirty fashion. Without going into detail which would put everyone to sleep, including me, let me compare it to a wiring harness. If you want to repair or upgrade a wiring system, the proper way would be to rewire the whole system, instead of just putting jumper wires or splicing into existing wires. This is what some of these chips do in a coded way. Performance enhancements generally come from a very unreasonable timing curve. This works only to the point of matching octane levels of the fuel being used. I made some custom blends with toluene and xylene, raising the octane to around 97, and the car did run stronger, but with a very scary increase in engine temperature, attributable to the timing, not the toluene or xylene. This would not be good for long term ownership. These chips were not even written with proper check sums, in that they would only give a "1111" code when trying to pull codes out of the computer.

Another chip increased power at a certain band. It gave a lot of "oomph" after 5200 rpm....but the idle and low rpm (up to 2500) was crap. It didn't miss or hesitate, but for lack of a better term, I would say it ran
"unorganized".

These chips were supposedly designed for that particular make and model year, but were off-the-shelf units to fit into all 90 GTs, none were burned for that particular vehicle.

All chips have been returned to the vendors, and all but one have refunded our money.

Since I'm not willing to pay for custom mapping for my 928 (lot of otherenhancements can be had for that amount of money), at this point I will have to defer to the expertise of the folks at Porsche and say "ya done good".

Maybe someday, someone will build the better mousetrap..........

Walt Konecny
88 S4 A/T...........stock chip and runs great