Acceleration:

This time out we performed four acceleration runs. To relive the nostalgia, Chad re-created his first run from last time and marked his territory with 45' of petroleum products and cemented his position as the king of wheelspin. This, however, left him with a slower-than-necessary 15.3-second quarter mile.

The rest of the acceleration runs were a quite a bit faster, going from an unadjusted 14.66 seconds down to 14.05 seconds at 99mph! His best 0-60mph time was a 6.1 second effort. Unfortunately the runs were performed with the new firmware on my G-Tech, which (a) has RPM calibration problems, and (b) changes how the roll-out affects acceleration runs. It reported a 0-60 time of 5.4 seconds which we both were impressed by. However, that was not counting the roll-out period -- which doesn't follow most magazine practices. Sorry, Chad!

Power:

You remember that Chad re-jetted his carb for these runs, right? Well, it seems to certainly have had a positive effect. Unfortunately, since neither this testing session nor the last was atmospherically corrected (which all future sessions will be) we can't directly compare absolute output numbers. I would expect them to be in the ballpark, however, since I recall the temperature being about the same and hopefully the humidity and barometric pressure as well.

While we eventually appeared to get a good RPM calibration, if anything the readings may be 100-300 RPM low on the high side of the range since the new G-Tech firmware seems to throw some readings out when the RPMs get pretty high. Last session the output figures we ended up with were 194bhp @ 4450rpm, and 263lb-ft of torque @ 3350rpm. This session's power figures are all between 190-195 bhp, although the power peak was closer to 4200rpm this time around. I suspect this is mainly due to the RPM calibration changes, although it also could be due to Chad's carburation.

To better determine how the output changed, look at this comparison of power curves from the previous session and this one. Keep in mind that the RPM scales are different, so I've marked the cut-off in blue. However, you can clearly see that while the torque peak and RPM level is pretty much unaffected, both the power and torque curves fall off quite a bit more slowly now than in the previous state of tune. Now the power stays pretty flat from 4000rpm to about 4500rpm (and possibly beyond; we didn't rev the engine out there much) while torque falls off pretty gently. Compared to before when from 3900-4400 and fell of pretty steeply... So it looks like Chad got a nice boost of midrange- and high-RPM torque and a smidgen more power in the upper registers as well. Nice job, Chad!

If this actually is the case, we should see better top-end acceleration, right? And we do: if you look at this speed comparison between two runs from the last session versus one from this one. You can see the new Monte slowly but surely pulls away from the previous runs, even though other factors are the same. The reason we didn't see more of an improvement in the lower gears is that Chad modified his shift points for the new runs from last session's results, since we assumed the car would have overall the same profile. So, by shifting shorter he was robbing himself of his newly-enhanced powerband.

This can also be shown by looking at an RPM comparison of the runs. Note the RPMs are rising faster for the green (new) run than the other two, which is a sure sign he's making more power. I have "underlined" each RPM range in blue to show the point where the RPMs begin to climb less rapidly. You can see it much earlier and more obviously on the older runs than the new one.

Technique:

The first change that Chad can make is to his launches. You can see from this RPM and acceleration graph that two of his launches resulted in lots of time-wasting wheelspin. Because of this, he actually rolled onto the throttle on one of his better launches too slowly! To avoid this problem Chad has a couple of choices:

• Put on better, wider tires in the rear, or use narrower wheels, or some combination of both. The Monte simply needs more traction and the tires are the limiting factor. Being able to do a full power launch should drop the quarter mile by a few tenths, easy.
• Replace the Monte's 3-spd auto with a 4- or 5-spd manual. Not only will this greatly increase its quarter-mile acceleration (the current top gear is horribly tall, but still leaves the Monte nearly at redline at the end of the quarter!), but it will also allow better control of the launches. This also should drop the quarter mile's ET by a couple tenths.

Also, since Chad's motor has a better midrange and top end than before, it would be better to shift as close to the 5000rpm redline as he is comfortable with. As you can see, his current shift points dropped the RPMs to about 3500. This both misses the meatier high-end power he has now, and drops the RPMs below the instrumented torque peak.

Corrections and Other Factors:

Pretty much all the miscellaneous factors have already been covered. Given better gearing, tires, and optimal shift points I'd expect the Monte to cut off an easy half-second on the quarter mile. We did notice a full 10-degree difference between the inner shoulder on the rear tires and the tread middle, and a five degree difference between the middle and outer shoulder of the tread. For the last two runs we pumped up the tires from 30psi to 35psi which did act to stabilize the temperature across the middle to outer shoulder. There was still a 10 degree difference from the inner, though, which hints at a camber problem. Chad did say his air shocks are not at 100% and may be the problem.

Here is the data from his best run in original and weight-corrected form (I could not correct for atmospherics since I didn't have the equipment yet):

	Recorded Data	Weight-Corrected Data
Best Run	0-1/4 mile in 14.1 secs @ 99mph	0-1/4 mile in 13.8 secs @ 101mph