andy-gts

well just like the title.....does a high revving engine always burn alot of oil.

does drysumping change oil burning issues or is it strickly rings against cylinder walls that is the issue.?

or does anyone have a link

IcemanG17

good question......my "guess" is yes... I wonder how much oil NASCAR or F1 burn..since I never see them add any during pit stops?

andy-gts

it seems alot of racing oils are very heavy weight. does that protect somewhat from the inevitabel oil getting past the rings at very high revs.??

andy-gts

or is it just a fuel dilution issue needing higher wt oils?

Brett928S2

Hi

Difficult question to answer...but in my opinion yes....

When I do my high speed (and revs) runs at well over 6000 revs I usually use around 1 to 1.5 ltrs for less than 10 miles road mileage...lol

BUT...my engine "uses" a fair amount of oil anyway.... but I KNOW it uses a lot more at between 6000 and 8000 revs...

All the best Brett

mark kibort

load dependant too

IcemanG17

I recall a 928 engine builder telling me that when he drove his 928 GTS and kept it under 6000rpm it didn't burn nearly any oil....above 6000rpm the consumption went way up

Another concept is when Devek was designing all their strokers and high HP stuff they always tried to make peak power at 6000rpm not more.....there must be a reason?

Daniel Dudley

Most 928s eat oil more than they run it past the rings. I guess some GTSs may be the exception.

Dave Roberts has a nice set up to update the oil breather.

andy-gts

great info, thanks all!!!

are rings, or lands , or machining diff on 10k revving engines machined to higher tolerances

Cheburator

I am not sure - my BMW Z4M revs to 8000rpm and it needs to rev all the time since it makes 343Bhp peak power at 7900rpm and does not use oil between services. My brother's supercharged BMW Z3M Coupe revs to 7750rpm and it makes 510bhp at 7500rpm and still does not use oil between services.

My race dry-sumped GTS engine did not use oil and it constantly revved to 6750rpm...

slate blue

As a general rule a higher revving engine will use more oil, more power strokes, so more oil usage. However control of the oiling can stop it getting out of control, for reference a F1 engine will use around 1.5 litres in race of 300 kms distance. That's about as high revving as they get.

Greg

RKD in OKC

Is it the high revs or lifting off the throttle at high revs?

Brett928S2

Hi

On mine its both...under hard acceleration while on Nitrous at high revs it smokes and lifting off it also smokes....

All the best Brett

andy-gts

I guess you mean sucking past the guides when you lift off the gas, (ie more neg intake pressure), while getting on the gas causes more neg combusiton chamber pressure on all up strokes....do I have it close.

if so has anyone designed 4 or 5 ringed pistons or would that just cause more friction and be counterproductive?

thanks for everyones input.

andy

Brett928S2

Hi Andy

Dont forget my engine has HUGE pressures due to the Nitrous... for example, on my last high speed runs it blew both rear cam cover gaskets (the cork ones) ...not quite sure why...they were changed around 4 years ago but maybe they were on there last legs and the excess pressure took the line of least resistance....

Regarding the 4 or 5 ring piston, although there were pistons with 4 or 5 rings in the old days they were usually on slow revving engines like diesels.....also dont forget there is only so much room on a piston for rings and there must be some solid piston between each ring or they wont work at all...so size is important....old diesels (big pistons) high performance high revving engines (small pistons) comparatively...lol

All the best Brett