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Tuesday, February 20, 2018
  1978 Pontiac Trans Am
 
 

...continued from page 4

The dyno sessions

We brought the engine to Panaritis Automotive ( http://www.panaratisautomotive.com )for dyno testing. We timed the arrival of our engine during a slow period at their dyno so we could spend several days, if needed, to run various tests. Nick Panaritis set up the engine on the dyno and we were ready to start it up and break in the cam. Having previously wiped out a solid cam in a SBC years ago, and knowing how many people lately were losing cams on break-in due to lower levels of zinc in oil, we were very nervous about the break-in procedure. We were going to use stock rockers to reduce the spring pressure during break in, but the rockers wouldn't fit with the pushrods we were running. We thought about changing out the valve springs for weaker ones, but at the end decided with only 125 lbs seat pressure, we would chance it. We used Shell Rotella Diesel oil with one can of GM EOS, one container of Comp Cams Break In Fluid and 6 oz of Oil Extreme. The Oil Extreme is an additive that was recommended by David Vizard in an article a while back in Popular Hot Rodding magazine. In that article he stated that most additives are worthless, but two he found that actually worked were Oil Extreme (oil additive) and TK-77 (gas additive/upper cylinder lubricant). David Vizard is one of the very few automotive gurus whose word I will take without question. I did some research on the web and found the companies that make Oil Extreme ( http://www.oilextreme.com/ ) and TK-77 (ACES IV) ( http://www.bndautomotive.com ).

We started the engine, set the timing to 30° (locked distributor), and ran it between 2500-3000 rpm for about 25 minutes. The next morning we drained the oil and cut open the oil filter. Nothing unusual in the filter so we checked the valve lash. No significant change in the valve clearances so we figured we were good to go. We added 6 liters of Mobil One 5W-50 synthetic motor oil with 6 oz of Oil Extreme and brought the engine to operating temperature. We were ready for our first pull.

The first pull was with our HP750 jetted 82-89 and with a 6.5 PV in the front. This was mounted on our Torker II intake with a ½" wood spacer. We started the pull at 3100 rpm and stopped it at 5500 rpm. We saw 543 corrected HP and 583 lb-ft. The BSFC numbers were in the low .500's (slightly rich). We made a few more pulls bringing the maximum rpm to 5800 and trying timing at 32° and 34°. We made best power at 32° and left the timing there for the rest of the dyno session. After four pulls with the HP750, it was time to step up to our HP1000. We were rewarded with 584 HP and 611 lb-ft with BSFC numbers in the high .400's (better).

The next few pulls were spent testing a 1" aluminum Supersucker spacer and a Butler turtle in the intake plenum. No appreciable difference with either so back to the ½" wood spacer.

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