N2 motor complant RPM

Why is it that the motor blows when you go over 10,000 Rpm. In the first place that a little high for the red line. In the real world after you hit the red line or max. power that the engine will develops you would float the valves and the power would drop off. Now I tried what the book says to be at 8,000 RPM at the end of the Straight-aways. Now I think that a bunch of bull. People will blow right on by you. If anyone racing on line is using this as a red line and getting good results set me straight. Now I think the driving of the car is pretty true to life. Need a new engine builder that one I've got working for me is going to quite over worked.

> Why is it that the motor blows when you go over 10,000 Rpm. In the first > place that a little high for the red line. In the real world after you > hit the red line or max. power that the engine will develops you would > float the valves and the power would drop off. Valve float is not necessarily experienced right after red-line. Red-line could be set by other mechanical limits in the motor. In any event, the power does drop off in the Papy motors above 8400 I believe. Power drop-off is almost never caused by valve float (since motors with floating valves don't last very long, even on a dyno), but by volumetric efficiency, head flow, camshaft design, and fuel delivery concerns. I don't know what book you're reading, but I think 9000 at the end of the straights is a better shot for sprint races and 8700 or 8800 for long races. ---Jim

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> > Why is it that the motor blows when you go over 10,000 Rpm. In the first > > place that a little high for the red line. In the real world after you > > hit the red line or max. power that the engine will develops you would > > float the valves and the power would drop off. > Valve float is not necessarily experienced right after > red-line. Red-line could be set by other mechanical limits in the > motor. In any event, the power does drop off in the Papy motors above > 8400 I believe. > Power drop-off is almost never caused by valve float (since motors > with floating valves don't last very long, even on a dyno), but by > volumetric efficiency, head flow, camshaft design, and fuel delivery > concerns. > > Now I tried what the book says to be at 8,000 RPM at the end of the > > Straight-aways. Now I think that a bunch of bull. People will blow > > right on by you. If anyone racing on line is using this as a red > > line and getting good results set me straight. > I don't know what book you're reading, but I think 9000 at the end of > the straights is a better shot for sprint races and 8700 or 8800 for > long races. > ---Jim

While you're on the thread, Jim.. I used to race Sears P a lot, and after a while, I started a habit of changing quite early (say 8-8500), and found my laptimes improved, but, it also seemed like the car spun its rear *** more. How is torque "tuned" in the Papy engine? I ceirtainly use a lot less fuel when running low RPMs.. Best, Matt -- ------------------------------ Matthew Birger Patrick Knutsen (http://sofus.hiof.no/~matthebk "Racing cars is like dancing with a chainsaw" -Cale Yarborough Cheek Racing Cars (http://home.sn.no/~kareknut/ Please Remove "NoSpam" from my E-mail adress when replying! -------------------------------

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> While you're on the thread, Jim.. > I used to race Sears P a lot, and after a while, I started a habit > of changing quite early (say 8-8500), and found my laptimes > improved, but, it also seemed like the car spun its rear *** > more. How is torque "tuned" in the Papy engine? I ceirtainly use a > lot less fuel when running low RPMs..

Torque peak is (obviously) below HP Peak. I think HP peak is 8400, and torque peak is somewhere in the 6500-7000 range. (I think, it's been a while...) Fuel burn is roughly proportional to HP output. Since you were running in a lower HP region, your fuel usage should be a little less. ---Jim