A TECHINAL QUESTION ABOUT TODAYS ENGINES

In the rash of motors expiring there was a comment made that the cars run extremely low oil pressure at speed-- I was always under the understanding tht high temp along with low oil pressure describes destruction of the bottom end.. How do they live like that?

To get volume at low pressure you need clearance but at a cost , Any know the answer???

updated by @johnny-mallonee: 03/10/17 12:08:00PM

I don't know about the oil pressure, but what was the deal with all the vapor lock and miscalculation of gas mileage and low fuel pressure?

EFI???

--
"Any Day is Good for Stock Car Racing"

Fuel pick up was the culprit on some cars but they seem to have lost their calculator on figuring fuel . And this vaporizing thing must be a byproduct of the method they are using on the pump system. I thought the system was a continuous circulation system which wouldnt do that.

But what the heck IM still a carburetor and mechanical pump man.

Oh yeah my oil pump doesnt break its belts to often wasting a 25k engine either.

as far as oil pressure the rule of thumb is 10 psi / 1000 rpm as far as i know

During the race today there was a discussion about the water temp vs oil temp and low oil pressure was said to go along with extreme oil /water temp for survival

I am not an engine guru but bearings need a steady supply of oil. Tbey may try to run low pressure but it is a gamble for long distance events.Concerning fuel systems, the teams are still figuring out what to do and will get it soon enough. The EFI set up has been around for over 20 years and is obsolete. Direct fuel injection is the way to go and has been around for close to a hundred years.NASCAR's EFI program is a half attempt to go green or look green. The EFI is really a more efficient carbuearator that is electronically controlled. Fuel is still being dumped through the intake manifold as opposed to direct injection that feeds fuel directly into each cylinder which is common place on many current production models for sale to the everyday consumer.For certian a brand new car or truck off of the showroom floor has a better fuel.delivery system than what is being used in NASCAR right now.

Gettimg back to your original question of oil pressure and temps it is probable that engine builders are looking for the lowest possible oil pressure to reduce crank case pressure and increase horsepower and that is why the big boys use a dry sump set up which basically means the engine does not have an internal oil pump which robs hp.

There has been a few meltdowns this year and the engine guys know why. This could be due to the EFI system flooding or leaning out cylinders at high rpm. I recall customer complaimts of rough idle with cpi engines years ago and learned that this was caused because of fuel puddeling at the intake's floor causing a near missfire, whicb was a normal condition.
Of course the rough idle theory does not apply to an engine running at hi revs but fuel is still getting pump through the intake and for sure they are working on it.
For our daily driver it is not a big deal but at the highest level of competion it is. The engines built for Cup racing for instance do not like extended idle as the are built to run at high rpm.

Add a restrictor plate to the mix and it is time for some real homework.

You are close to having the answer in your hands. Low oil pressure and high fuel reserve setting around on a defunct plane manifold as described causes cylinder wash on left bank -- after quick stop n go situations this lean problem causes detonation which in turn causes yellow flag conditions for engine clean up .. Longevity vs money doesnt seem to bother deep pocket teams but I cant build one for you under this program.. I hear it regularly from guys begging for a 1/10 off their time.