It has taken me a while to fit my chip - due to work, travel, baby daughter etc - but it was finally completed today.
I did back to back runs over my regular circuit and various accellerating tests in different gears. So what is the verdict? As a starter, I am pleased I bought the chip and would recommend it to others. However, the pure performance benefits are in my opinion not crystal clear.
For starters, if you think that a chip is like bolting on a turbo, well it ain't. The improvements are quite subtle and to be honest, I could not swear that the car is quicker in full throttle accelleration above 4000rpm. It is IMHO too little to accurately guage with your butt. I believe that only racing drivers who are used to back to back testing of the same car can pick gains of 15hp or less - so no shame there. I think there is enough dyno evidence from other Steve Wong users to show that there are some benefits and car certainly does not feel slower. I think it feels a touch faster - but I can't be sure.
However, there are some real benefits that are unequivocal and easy to feel.
First is mid range response. In the 2000-4000rpm area the car is much more responsive to light throttle openings - even a flex of the big toe gets results. Similarly, giving it the full jandal at 2000rpm in 3rd is now rewarded with much faster accelleration. Accellerating from 2000 to 3000rpm now feels more like 3000 to 4000rpm. So, everyday drivability is improved. Pottering along in 2nd or 3rd in traffic and it is easier to go for that gap.
Secondly, smoothness in stop start traffic and in the midrange is much improved. This was unexpected. My car has always suffered from a bit of "shunt" in slow stop and start traffic, particularly when close to idle in 1st/2nd. This is drastically reduced. My car also has a kind of hesitancy between 2200 and 2800 rpm. It feels like slack in the drivetrain and is most noticeable in 4th/5th with a light throttle opening/closing - like when caught behind slow traffic at say 50-60mph and still in 5th. Now gone - completely. I would buy chip for this alone.
Thirdly, the rev limit is increased - 6840rpm. I didn't hit the new limiter but I must have come close and the car pulls strongly thru 6500rpm. This will be useful on track where the (relative) hole between 2nd and 3rd can be annoying. I hope the little bit of extra midrange will also help fill this hole. I find on track that unless a section of track dictates holdiong a gear (or shortshifting) that I naturally change at about 6200-6400rpm but now changing at 6500ish feel natural. Not sure if this is psychological or not.
Just by way of background, my car is a late 1989 car that has done 70,000 miles and uses basically no oil at all. It occasionally has a little smoke in the exhaust at start up if it has sat for a couple of weeks of so. I belive it is in good health but have not had a dyno test as its rear anti roll bar (non-OE) is too low to clear the dyno rollers! I have no problem keeping up with 964s in straight line drags on the track and my mechanic after driving the car asked if it had a chip and cams done already. So, it may have just been a relatively good motor to start with. But, it has the DME labelled 911.618.111.19 which is the DME option for inferior fuel and the fuel quality switch was set to position 4 which retards the ignition timing by 3 degrees. So, there should have been plenty of scope for improvement.
In summary, there really aren't any negatives with the chip and there are clear positives but it does go to show that at full throttle, there are not many free horsies left on the table without making more substantial changes. I hope my comments don't sound negative as the bottom line is that I am happy with the chip. The three benefits listed above are real and I *think* that full throttle above 4000rpm is also better - I just can't be sure. It would be interesting if someone had a g-tech I could borrow.
HTH
Richard
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