F1 engine RPM

[ESPImperium]

I remember Toyota experimenting with gasoline, RPM and F1 engines and maxed out near 22k rpm. After that the fuel used had a problem with the combustion rate... I can't remember where I heard this or where I read it...

The problem will be the flame front speed. In order to burn all of the fuel in the short time available you need high flame front speeds. High engine speeds require higher flame front speeds. But if you go too far you end up with detonation (which is effectively a supersonic flame front) rather than conflagration (i.e. burning, which has <supersonic flame front). Detonation is extremely unhealthy for the engine, obviously, and thus the engine speed is limited to how close you can get the flame front speed to detonation. If the rules limit your bore/stroke then your max revs are limited by flame front speed (assuming you can't improve the combustion conditions in the cylinder any more).

I now await being shot down in flames myself... :lol:

22,000rpm is arround where the apex of a engine can go to. The V10s in 2005 were apexing at arround that and the V8s can go to 20,000rpm as well. The diffrence in power is arround 200hp at the peak, and for comparison thats about half to eight tenths of a second a lap.

Cosworth can go to 20,002rpm, and they were finding their engine in 2006 wasnt getting enough air to make the fuel combust in the complete manner they need to get the fuel to make that bang quick enough. I cant remember if it was density or volume that they were saying at the time.

Honda said once that their RA80x V8s could go to arround 20,500 and then experienced problems.

I think its right that we have a RPM limit in F1, however id like to see the engine RPM raised to 19,000rpm for the next 2 seasons as we have the relyability now in the blocks i think.

[Robert.Gardner]

With regard to conrod length/stroke ratio, having a longer conrod length for a given stroke means that the piston will dwell at/near the top & bottom of the cylinder for more degrees of crankshaft rotation. By doing so, as the combusted gases expand, due their now increased heat, the conrod applies its force on the crankshaft at a nicer angle, yielding a higher torque output.

But longer rods weigh more, need a taller block deck height, and often a more closely packed ring-set on the piston. So typically ratios mostly remain in the 1.7-2.1 to 1 area. Higher ratios in road cars have caused drivers to complain about unmanageable torque, particularly in wet weather, in pre traction control vehicles.

As to how high an F1 engine could rev without any rules restricting it, as any engine passes it peak volumetric efficiency (closely related to peak torque rpm), it will still make more horsepower, until the drop off outstrips any yield from increasing rpm. We know that we can make engines rev harder, but that’s not necessarily the right way to win races, when fuel consumption rate increases and reliability decreases.

I have worked on some of the 2 valve/cyl Phil Irving designed Repco Brabham heads as used to win the 1966 & 1967 F1 titles, while the more complicated 4 valve heads of 1968 & 1969 were a dismal failure, in racing terms. So the pure simplicity of the 2 valve heron head (completely flat without any combustion chamber), remains a reminder of the old KISS acronym (keep it simple, stupid).

[Owen.C93]

I have a feeling 3 litre 22krpm engines offered a bigger delta in between on and off throttle as well.

[megz]

I have a feeling 3 litre 22krpm engines offered a bigger delta in between on and off throttle as well.

No 3 Litre engine that I'm aware of broke the 22,000rpm barrier. At best the BMW engine of 2004/5 got past 20,000 but none that high. Not sure that even the revviest of the V8's made that sort of RPM.

[raymondu999]

IIRC the Cosworths back then hit about 21000k. Or was that BMW?

[Nando]

Edit: my numbers in my head were wrong, check below for some facts instead.

[zyphro]

IIRC the Cosworths back then hit about 21000k. Or was that BMW?

BMW@MONZA.

[mcalex]

I could sware that Mercedes went over 20000 rpm.

[MarkedOne8]

I could sware that Mercedes went over 20000 rpm.

Me too.

[steve12345]

I was sure it was the cosworth.... checked the web and sure enough all reports state that it was the highest revver in 2006 and possibly most powerful.

[raymondu999]

Yeah. Now that I think of it I'm sure the CA2006 was the only one to truly breach 21k.

[PlatinumZealot]

I could sware that Mercedes went over 20000 rpm.

BMW has the record. In an actual race it went to 19,800 rpm IIRC.. anybody have a source?

[Nando]

BMW has the record. In an actual race it went to 19,800 rpm IIRC.. anybody have a source?

What year?

Maximum engine speed for their absolute most hardcore engine the P85 had a maximum engine speed of 19.800rpm.
This engine never raced due to unsuspected regulation changes on engine life.

BMW was the first though to crack the 19.000rpm limit with their P82.

[Agerasia]

I'm still stumped as to why people keep saying hitting the rev limiter will damage the engine, especially commentators and now that Renault article on the front page.
It's an artificially imposed limit, well below the design spec and is electronic.

[aussiegman]

Its not hitting the the RPM LIMIT, which as you said is typically under the max RPM value, that does the damage, its the effect of hitting the RPM LIMITER and the resulting sudden deceleration/acceleration of the various components (valve train, piston/rod assembly etc) from having either spark and/or fuel cut to the engine. It's not the same as a gear change or deceleration event. The engine drops rpm and reverses loadings very quickly and is then it is reversed and loaded up again as the RPM drops under the RPM cut in rapid succession multiple times causing severe loadings in opposing directions and resulting is huge stresses on various components.

I have seen first hand the effect bouncing an engine off the RPM limiter can do in a both a large capacity V8 and a modified Honda K20A with a 10,500RPM limit. The Honda sheared off the retainers and valve tips (quality titanium/inconel units) dropping a number of valves into the engine. Suffice to say there was little left to use again.