Acceleration:

In total, Mike made six acceleration runs trying nail down the best launch technique. The challenge in launching any AWD/4WD car is that there is normally so much traction that it's difficult to get any wheelspin, which means the engine often bogs unless it's extraordinarily strong on the low-end side. The stock specs on the 3000GT quote a torque peak of 315 lb-ft at only 2500rpm, but he still has a turbo engine which means that launching at 2500rpm does not mean you have 100% power -- the turbo still takes a bit to spool up, and that makes launching difficult.

Overall, Mike was very consistent. His runs were nearly all within a few tenths of a second. His average was about a 15.0 second quarter mile at about 94mph, with 0-60mph coming up in 6.5 seconds. His fastest one was his first run (probably due to heat build up in the intercooler and turbo), which was 14.9 seconds @ 95 mph.

Power:

In addition to the acceleration runs we performed Mike also did one full power run, which yielded a measured 201bhp @ 6000rpm, and 212lb-ft of torque @ 4500rpm. After corrections (including a new, somewhat-experimental AWD correction) the calculated output is about 260bhp @ 6000rpm, and 275lb-ft of torque @ 4500rpm. If you recall, that is about 60 bhp and 40 lb-ft lower than the stock specs, in spite of his modifications. However, Mike has been chasing down an intake tract leak and is sure he's losing a few PSI of boost. Otherwise, his power and torque curves follow the stock specs -- a very flat torque plateau from about 3000rpm all the way to nearly 5000rpm. This is very impressive output for a turbo-motor.

Within a few weeks Mike expects to have higher-flow injectors and will replace the leaking intake tract connection. This should allow him to crank up the boost and hopefully put him into the 350-400bhp class. Of course we'll be G-Teching again afterwards to document the changes! :)

Technique:

As I mentioned before, Mike had his hands full launching with enough RPMs and clutch slipping to keep the motor in its powerband. The 3000GT VR4 street racers out there prefer to rev the motor to about 5000rpm, drop the clutch, and hold on. Either their driveline disintegrates, or they get a 0-60 time of about 5.5 seconds and a quarter mile in the 14.0 second @ 100mph range. Since Mike would like to remain on speaking terms with his car for more than a few runs he opted for a more discreet approach.

As you can see from this launch comparison, Mike tried varying the RPMs between 3000-4500rpm, but used a bit of clutch slip to save his drivetrain. The amount of throttle and clutch action was pretty hard to repeat exactly, but his 60' times varied between 2.2 and 2.3 seconds, a nice close group. Unless Mike wants to play gearbox hand grenades this is the exact technique he should be using.

After checking the first run results, I noticed that Mike was shifting about 6500rpm. Given the specifications for torque peak (2500rpm) and power peak (6000rpm), I asked Mike to try shifting closer to 6000rpm. While it was a reasonable suggestion, in this case it didn't work. Since power drops off after 6000rpm and the shift drops the RPMs right into the middle of the torque peak the shorter shift should have been faster. However, keeping the acceleration on until 6500rpm gave more thrust and faster times.

Once again, I believe the turbo lag is the culprit here: Mike could not shift quickly enough to keep his car from completely stopping to accelerate between gears. Whether this was aggravated by the boost leak or not is unknown, but he may be able to keep power on better by practicing mild powershifts. Powershifting is where you do not release the throttle at all between shifts; keeping the throttle on somewhat should keep the turbos spinning and help keep some momentum.

Overall, Mike's technique was very solid. Once he fixes his boost leak and puts in the new injectors and what-not he will have to modify it somewhat since it's almost certain it'll modify some powerband characteristics, but he was very consistent and quite quick given the lower boost.

Corrections and Other Factors:

Since Mike's runs were so consistent, I've only used his fastest one for normalization. While removing the extra weight from myself as passenger and some extra gas helped, since the temperature was only 57 degrees that also boosted his power output. Overall the effect was a wash, but here is the data from the best run in original and corrected form:

	Recorded Data	Corrected Data
Best Run	0-1/4 mile in 14.9 secs @ 95mph	0-1/4 mile in 14.7 secs @ 96mph

So Mike proved that he was fast and consistent, but he needs to attend to his boost leak and of course give me a call for a re-test! It'll be even more fun when he's pushing more towards the 350bhp mark...