 jyrki
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 Reheri uus tech artikkel
Actually, about 15 years ago the PS engines turned more rpm than a few years ago. Meanwhile they realized the importance of volumetric efficiency, the rpm's cam down a little but the power went up beacause volumetric efficiency was better, and the torque curve was wider which made the average power better and driving easier. Previously it was very important that you shifted very accurately; if you went above the shift point the power fell dramatically and if you shifted too early the engine wasn't able to recover on the next gear. Chryslers new PS "Hemi" was the first one to raise the rpm level again. The volumetric efficiency initially suffered a little, but has been brought back closer to the numbers they were during the "old" way of thinking. While the "hemis" made the same or better power from the beginning, the cars were slower because despite of the rpm level only a few hundred rpms more than before, nothing in the drivetrain worked with them. Beginning from the chassis everything needed different solutions and the cars reacted differently to adjustments. The hardest parts were the clutches and the centrifugal forces that add clutch pressure; all had to be tested since there was no information or even parts available. Early this season Larry Morgan didn't qualify in the races. He took his engine to several other dynos (for example Reher Morrisons) and gave nice hints to others about the new "hemis" and what Greg Anderson had realized and done before in the engine technology. It wasn't until Bob Glidden came to help him when he could get the car run, there was no changes in engine power but suddenly Morgans cars performance was up to par with the leaders of the class and he ended the year in top 5. |
