Quote:
Originally Posted by austins z
Correct. But this was due to them pushing there rpms over 8k. the harmonics and vibration of the crank around 8100 (quoted from JWT) is very stressful and causes fatigue and eventually cracks. When you have a Nissan backed budget supplying them with 10 billet cranks, who cares? I will get around this issue by staying under 8k and running a suckerpunch billet pump/gear set. Most VQ's will make peak hp under 8k anyways.
Side note: Doran is very close to me. Check out my profile image. It is one of there front bumpers straight off there Pirelli challenge car. Haha. I've got a lot of "intel" from the Doran guys on different things they experienced, parts used, and trials and tribulations to there builds.
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When a rotating mass (crank) goes up in rpms. It goes through what is call a critical stage at different rpm limits. Some worse then others. You never want to operate at one of these critical stages for any length of time. A critical stage is when a shaft starts to stress it's self. Basically going from a solid shaft to a flexible shaft. It bends and bows. The stock crank has one one these critical stages just above 8,000 rpms. Doren was operating at this rpm. This is also why you see problems with the oil pumps too that had been here.