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We did some track testing of PerTronix products at Lebanon Valley Dragway, West Lebanon, NY, on June 16, 2000. We had rented the track for the day along with a small number of other drivers so we were able to get in 23 passes. That's either me or my co-driver/wrench, Dave Westlake, in the far lane in the '69 Corvette. We didn't want to run anything exotic. Though it is a Corvette, the mild 350 Chevy engine is as mainstream as it gets and engine modifications were nothing out of the ordinary.
Nine runs were made with a good set of heavy duty points and a stock replacement coil, then we switched over to an 1181LS Lobe Sensor Ignitor and Flame-Thrower coil and made another ten runs. Finally we made four passes with a prototype of the Ignitor II and the low resistance Flame-Thrower II coil. Everything else was kept the same - same wires, same plugs, same timing, same carburetor settings. The results are below.
Vehicle: ’69 Corvette coupe
Engine: 350,
originally base 300 hp. Modifications: pocket porting, Crane H-266-2 cam, Edelbrock
Performer Drivetrain: M-20 wide ratio 4 speed, 3.08 posi rear . Tires and wheels: Cooper Cobra GT, 245/60/15, 15 x 8 original Corvette rims.
Configuration 1:
Configuration 2:
Configuration 3:
* We also had a run in Configuration 2 of 14.717 @ 95.27 which would raise the average MPH but also increase the average e.t. Using this time slip in would give Configuration 2 an average of 14.642 @ 95.91
Discussion: The points and coil were removed and replaced with an 1181LSC Lobe Sensor Ignitor and a 40011 Flame-Thrower coil. Air temperature by now was at the high point of the day, about 91 degrees. At 1:08 PM we recorded our best ET and MPH with the Lobe Sensor setup - 14.588 sec @ 96.49 mph. Later in the afternoon we changed over to a prototype of the Ignitor II and a low resistance Flame-Thrower coil that PerTronix had sent us for evaluation. We only had time for four runs. Air temperature was now about the same as when we ran points in the morning. At 4:26 PM we ran the best time of the day - 14.446 sec @ 97.62 mph. Experienced racers will tell you that MPH numbers are more indicative of engine horsepower output than elapsed times (e.t.). The e.t. will be more strongly influenced by launch technique and traction than MPH would be. Since we were running street tires we had to be careful at launch to limit wheel spin with the manual transmission. Keep that in mind when comparing the results of the different configurations presented above. To be honest, I was surprised to see any improvement at all with the Lobe Sensor setup (Configuration 2) over the good heavy-duty points. The track was getting hotter as the day went on. Temperature went from about 84 in the morning when we started to about 91 when we finally got to try the Lobe Sensor, and it was humid - not a comfortable day at all. When we ran the Ignitor II and coil the temperature was about 85-87 degrees, down just a bit from when we ran the Lobe Sensor and about the same as when we ran points. The Ignitor II produced solid gains in both e.t. and MPH. It should be noted that since we were RPM limited by valve float and not points bounce, the Ignitors never really got to show off their biggest advantage over points - high PRM performance. But, this was the real world, no laboratory experiment, no dyno pull with controlled conditions. We run what we brung, as they say, and have simply presented the results. We went back to Lebanon Valley Dragway with this car on Sept. 29, 2000. Under ideal weather conditions and with a little more tuning we ran a best of 14.013 sec. @ 99.23 mph with the Ignitor II/Coil II combo.
Carl Dudash
More Track Testing, 2001 On May 12, 2001 we headed up to Lebanon Valley Dragway intending to do more comparisons between points and PerTronix ignition systems. After a few passes the water pump started to squeal so we had to call it a day very early. Hey, it happens.
October 11, 2001 we were back at the track with a new water pump and some minor tweaks to
the Corvette. That's me in the near lane, the Corvette now in primer,
showing a little tire smoke off the line. The day was quite warm for that time of year - in the 80s. We
were able to make a good number of passes with points and with the Ignitor II/Coil II
(Configurations 1 and 3 as described above). We cleaned the points before running so
they were as good as they could be. We noticed early on that the engine wouldn't
pull past 5000 RPM with either points or the Ignitor. Valve float was coming on
about 200 RPM earlier than the first time we ran (see above). We were still running
the old lighter valve springs, lighter than what the cam calls for, for fear of pulling
the pressed-in rocker studs out of the head. 50 + passes down the 1/4 mile seem to
have taken their toll on the springs. Traction was still a problem with the street
tires so we were pulling mediocre 60' times.
Looking over the 3 runs of Configuration 1 you'll see that the last one is a couple of tenths worse than the others. That's why I've included the average of the best two runs so that the points get the benefit of the doubt. In fact, the best run with points had a very good e.t., but what is telling is the MPH. As racers know, and as we pointed out earlier, MPH is horsepower while e.t. variations are indicative of traction and launch technique differences. Even using the average of the best two runs we still see almost a full mile per hour improvement with the PerTronix system.
More testing is
planned for next year. Hopefully we can get some screw-in rocker arm studs and the
proper valve springs in the heads on the Corvette. With some cool weather maybe the
old coupe can get into the 13s. We're also working on a big block Buick to go into a
'70 GS455 automatic - nothing wild, just a slightly warmed up street engine. Stay
tuned.
2002 and 2003 at the Track
We made a couple of trips to the track in 2002, May 10 and September 20.
The plan was to just run the Ignitor II/Coil II combo and fine tune the
setup to try to get into the 13s and over 100 mph. Our times in May were
disappointing. The engine seemed to lay down at 5000 rpm. My initial
thought was the old valve springs were getting really tired and we were getting
valve float (see my excuses for Oct. 11, 2001 above). This, however,
turned out to be an incorrect diagnosis. |
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