GrantG

225% as much kinetic energy and stress on engine reciprocating parts.

gago1101

I would let the oil temp get to above 205 at least before pushing to 9k rpm. Below that the oilpressure goes above 70psi into the red zone.

My car has made blue smoke at start up twice. What I had noticed is that in both occasions I had pushed the car when the oil temps were in low 190s. I think this has to do with too much pressure at high rpms. Since then I have been paying attenation and if I am above 205F temps the oil pressure is lower at 9k rpm, but still encroaching the red zone. Of course this is a none-issue at the track where your temps are in 220s and 230s.

Thicker oils may be good for old school low rpm cars and race cars, but I think oil flow is key in high revving engines. I remember reading somewhere that F1 cars have to have oil that is almost water consistency to be able to provide adequate flow at rpms that they run.

mwar99

205 for oil temp seems high. I don't think I saw that in 50 miles of driving today...

gago1101

That is exactly what I see. You need to apply lots of load get the temps up. And hence my point, I think the oil is too thick at low temps to be revving reliably at 9K rpm.

NateOZ

Well in 2000 Honda was supplying a 18,500 rpm 3.0L V10 in F1, they knew how to build high rpm engines.

GrantG

I wasn't maligning Honda - just showing how hard it is to rev large cylinders real high. Much easier to rev an engine with 300cc cylinders than 633cc cylinders...

A 911 motor with cylinders that size would only displace 1.8L. Just as a curiosity, the first famous Ferrari (166MM Barchetta) had a V12 with under 2.0L

ipse dixit

About 3000 revolutions.

Per minute, that is.

96redLT4

I've always been curious if there is any inherent benefit to a flat 6 as opposed to a V8 especially with higher RPMs?
Jim

GrantG

For a given displacement, the advantage goes to the V8, because each cylinder is smaller. But not sure about the configuration itself (i.e which could rev higher 3.0L F-6 vs. 4.0L V8 with same bore x stroke)? The shorter crank of the F-6 probably helps a little...

And not sure about F-8 vs V8 which I hope we get to sample in a Porsche in the near future...

armbar

Lower CG

ipse dixit

Not certain how it compares vis-a-vis a flat-6, but Ferrari's use of flat plane crankshafts in its V8 engines, which have no counter balance weights, allow them to rev higher than typical cross plane V8s found in most American makes.

Shahano

To rephrase my question, Let's say my car is only driven on track (of course all service and warm up done) how many miles would it last before giving up?
In other words, how many track miles can the engine handle. 50,000 miles? 60,000 miles? 100,000 miles?

GrantG

If I had to make a wild guess, I'd say somewhere around 100-200 hours of track driving with every shift at 9k, before top-end rebuild at minimum. Porsche race cars that redline at 9k rarely allow 100 hours before rebuild (some as short as 40 hours).

If you average 85 mph then that makes 8,500 to 17,000 miles.

This is one of the reasons that extending the 4 years 50k mile warranty to track use is so generous (though very few people use their road cars exclusively on the track and do so that often).

Shahano

That's really not very much....

GrantG

Racking up 15,000 miles at 10/10 on the track is not as easy as it sounds. That's 30 times the Indy 500 (and a bunch of those miles are under Yellow Flag)...

Driving at 8/10 on the road is not just a bit easier on the car - it's WAY easier and car will last much longer.