andy-gts

very cool thanks for the info all. This whole quesiton in this thread really has to do with me finding out alot of the owners of stroker engines have oil consumption issues. and I wondered if there was something inherently wrong with design or build. or is the design of the porsche 928 engine have an inherent design flaw as the high revving engines don't necessarily consume oil unless pushed hard....

maybe that is it , we have stroked motors and push them more for the fun of it and therefore consume more oil just due to what all have pointed out.

thanks to all!!

GregBBRD

A F-1 engine doesn't have a very big bore...which makes oil control past the pistons a bit easier to manage.

slate blue

The 2009 Toyota engine was 96.8 mm from memory so around 928 standard sizes very close to the 928S, point taken, Nascar is closer in terms of the strokers and revs, they experimented with 2 ring pistons but have gone away from that.

In regards to more than 3 rings, no way, the friction in that area would be horrible, these days the rings are much thinner and closer to the top of the piston to stop the gas getting in the area from the top of the piston to the top ring land. Even shorter skirts are used to combat friction and tighter tolerances so that every part is controlled better.

High oil usage on the 928 is down to type or grade of oil and lack of a proper lubrication system, my guess is when I get my dry sump done, that has 5 suction stages, oil usage will be minimal. You get to use much lighter ring tensions when you have a well setup dry sump system, again indication how well they can control oil.

Greg

James Bailey

Smog legal street engines MUST feed the blowby back into the intake which means under deceleration the engine sucks has vacuum to the crankcase. Stroker engines due to the block dimensions use short pistons and less than ideal connecting rod lengths. This causes more rocking of the piston from side to side. Also stroker cranks have a bigger radius on the crankshaft which hits the oil more whipping it up to be ingested by the intake.

andy-gts

So the higher the rev's the more aerosolization , therefore more available to not only get past the rings but also get sucked into the intake,

thats why the scraper systems seem to help cut down on oil consumption esp on high revving engines.

Sorry to all, I am not a quick study it seems....!!!!!!


andy goetting

James Bailey

Pretty much how it is. Think about how roadracing stresses the engine. High RPM followed by hard braking, hard cornering, downshifts with engine braking (vacuum) and there is an oil storm going on in the crankcase....which is why race engines are drysumped even the NASCAR engines

mark kibort

I dont seem to have this issue with the new stroker, almost 3 seasons of racing now under its belt, and my previous stroker. it does go through near 1 quart a weekend of racing. in fact, i ran with anderson during those (2) 50 min pro races at laguna and only used a quart. street driving, havent seen much oil use at all, but im changing out the oil after 3-4 weekends and only drive it a little on the weekends, so im not a good test case for street oil use. however i do have friends with GTS's that use 1 quart every 500 miles or so, and I dont have that issue.
all my breather lines are alll stock. nothing modified on the engine, but the stroker and larger (too large) injectors.

hacker-pschorr

First we should define "high revving" since 7k RPM would be high.....for a diesel engine.

My fathers 8,500 RPM 3.5 liter V8 is very easy on the oil usage. He checks it often and almost never adds any. Granted it's a factory dry sump.

mark kibort

and our motors , especially strokers, really dont make power in the high RPM anyway, unless it is a really tuned set up like Anderson/Fans with the CF intake. it pays to shift at 7000, but then its really not a HUGE advantage.. my motor only needs 6500rpm max RPM and the gains are slight over 6200rpm, and Ive been shifting at 6500rpm with no issues for years with no issues.

andy-gts

It would be cool to video you and your driving in the cabin with rpm, mph etc to see your technique so we could learn what you do that makes your style easy on the drive train.

andy