200 mph Porsche
It Don’t Come Easy
Photos by Odoreeda Voidman
July-August 1987, page 32
I remember as a kid listening to the older guys talking about their hot muscle cars. One guy’s 4-4-2 was supposed to be able to do a hunnert and fifty easy, but even he allowed that his car wasn’t the fastest one around. Of course, a lot of that speed was gained by creative exaggeration piled atop massive speedometer error. I never actually saw any timing slips.
It is a different matter when you are going for a speed record and at the end of the run is a speed trap wired with sophisticated and highly accurate electronic equipment. Suddenly there are all kinds of things that become factors. Wind resistance is the big one. Gearing and engine redline must be at least close enough to allow you theoretically to reach the speed you are shooting for.
The one thing most people don’t think too much about is having enough road to reach that velocity. Say, for example, you were going to take a modified street car to 200 mph. Could you do it at Bonneville? Could you do it on one of those extra-long military runways? How about on a piece of asphalt 2.2 miles long. All the way to 200 mph in 2.2 mph. Oh, and don’t forget you have to come back down to a stop in that distance, too. It’s all part of the deal.
If you think that doesn’t sound like enough room to run, you haven’t talked with Bob Holcombe of Motorsports Design in Scottsdale, Arizona. Starting with a 911 Turbo with 935 front sheet metal and rear body work, Holcombe added a thoroughly warmed up street-going 934 motor with twin spark plugs, intercooler, trick camshafts, and special exhaust. Estimated horsepower was 450. Considering the Ruf Turbo with 375 hp hit 187 mph in Germany, the extra horsepower should prove to be enough to push the 911 up to the 200 mph mark, even if the Ruf-powered car did set its record with the narrower 911 body.
But we’re getting ahead of ourselves, because that 450 hp was, after all, estimated horsepower, since there was no time to dyno test the engine. Out to the Chrysler Proving Grounds they went, and with John Stanchina at the wheel the car got up to just over 164 mph on the first pass. Disappointed, they decided on a second pass, even though the rev needle was not reaching swinging upwards the way it should have. The second run produced the same result. The fuel warning light had come on during the second run, however, so before the third run they replenished the car with some 100 octane avgas.
Run three made it to
only 167. Still, the big needle was stopping at 5800 rpm. Run four was an almost anticlimatic 164 mph but it was to be the last run of the day. The 3.4 liter turbocharged 6-cylinder motor was smoking when it went through the traps, ringing down the curtain on today’s speed attempt.
The motor had to come apart, of course, a time-consuming and expensive proposition. Not to worry, Holcombe was told by AutoWeek Magazine, who was also interested in the story, he had four weeks or so to get everything whipped back into shape for a second run.
Holcombe never got his four weeks, however. With the motor all apart, AutoWeek called one Monday to explain that the car was to appear on the cover of the April 6 issue, which meant that the final test run had to take place on Saturday, six days away. By Friday, Holcombe had the engine back together, although the expensive 3.4 liter pistons and cylinders had given way to a more readily available 3.3 liter set. Friday afternoon on the dyno Holcombe could see the writing on the wall. The horsepower peak was at 5000 rpm, 2000 rpm below redline, and 1700 rpm below what Holcombe felt he needed to break the record. With the Yokohama A008G tires in 255/50VR16 size, the 0.65:1 fourth gear and the 4.22 rear end, at least 6610 rpm was required. Holcombe wanted a little extra for good measure. This motor had neither.
Still, deadline pressure often does not allow for intrusions of reality, so Saturday morning found them out at the Proving Grounds once again. The first warm-up run at part throttle gave them a reading of 184 mph. This was an auspicious beginning. Stanchina’s second run set everyone back on their heels with a staggering 244 mph reading on the timing equipment.
After considering everything it was decided that something was wrong. Checking the timing equipment they found that the traps had been set 100 feet apart instead of 132 feet apart. The third run showed a true 181 mph, short of the record set by Ruf but still mighty impressive. The dyno numbers had called it, however, and the culprit looked to be a restrictive turbocharger inlet. To cure the problem, the entire turbocharger would have to be redesigned.
Thus ended day two of testing, but Holcombe isn’t done yet. He’s going to try again in a month and a half with a different car and with a twin-turbocharger set-up that will be tuned to put the horsepower (he is looking for 600 hp this time) where he wants it.
For test three, Holcombe isn’t just changing the motor. He is changing the rules, too.
We’re going to shorten the run to 1.5 miles, he says.
If the car can’t reach top speed in that distance, the extra speed is not really usable. At 180 mph you travel a mile in 20 seconds. If you don’t get the car up to speed in a hurry you are going to run out of road before you get to use the power you paid for.
That sounds reasonable, doesn’t it? Best of all, that 2.2 mile track at the Chrysler Proving Grounds will be plenty long to do the testing. And we thought he was running out of room.