CanAmJohn

I've always called Mobil 1 wee wee, for obvious reasons.

Some of the corners at the 'ring i expect to be entering at 150MPH, maybe quicker if i get the car handling as i hope it will. The 928 sump certainly looks prone to oil surge issues compared to some stock arrangements.

Acusumps you have to be careful of when using them with the electric valves they supply, if you don't use a pressure switch in series with the valve and just power it up, you get worse surge than not having the acusump at all, because of the way the valve flows when energised/not energised. It's not a simple open/shut valve but in fact has quite a complex flow characteristic which is different in either direction and when powered/not powered.

mark kibort

"wee wee". thats funny!

Anyway, I dont think the speed entering a corner has anything to do with oil starvation. does the engine know how fast you are traveling, or the G forces it sees. maybe the duration of the Gs could be longer in some cases, and certainly there could be faster decelleration rates from the higher speeds with down . is there another factor of high speed turning that im not taking into account?

As it is now, there are plently of turns that range up to 4-5 seconds at max g loading of around 1.5g's a the tracks we visit. Traditionally, i cant think of longer, high rpm turns than willow springs turn 3, and 8 or the carocel of road america and Sears Point or even turn 2 of Thunerhill. Which turns would cause a higher g force or oil sloshing at the "Ring"?

Mk

force and air resistance helping out.

Cheburator

John,

There are only two corners at the Ring where you will be going faster than 150mph and to get to that speed you need to know the track and the car very well. The corners are the approach to SX and the Fox Hole. You need a car with more bhp than stock and I guarantee you will not get oil surge in neither of them, even with the stock sump.

Where you will get oil surge is at the Steilstrecke, which you will be approaching in 5th (assuming something similar to my car with around 320rwhp) at about 5000rpm, braking really hard, droping into 3d and taking the uphill hairpin in 3d with 4500rpm.

The next corner where you will get oil staravation will be Eiskurve where you will have hard braking from 6000rpm in 4th, then left-right uphill transition, taken in 3d at about 5000rpm to 6600rpm.

The last corner with oil surge is Schwalbenschwantz - funnily enough - a 5th gear approach at 5000rpm, hard braking, 3d gear, up-hill right-left transition.

Mark - do you notice a pattern - you only get oil surge on transition corners, where the oil gets a chance to whip around the pan. Not on the sustained high G corners...

mark kibort

But if it is quick, doesnt this solve the issue as the pump, could be sarved for a fraction of a second and then recover?

show me the turns on a video of the Ring, and ill show you a turn that might simulate it at one of our tracks. after all , a brake-turn 1.5g transision is kind of universal for most tracks.

Mk

CanAmJohn

Yep, i know the track very well, i went through a stage of driving there every two weeks when i was a bit more flush. Every trip i learn something new, especially when i share a car with a friend who does the 24hr's in quick stuff like the M3GTR, last trip out there we ended up showing Troy Corser the circuit in an M3 CSL, he was quite impressed.

I'm aiming for about 480rwhp which should be enough to make things interesting on the run into SX and the foxhole, my old cosworth turbo westfield was silly into there but didn't have any weight to worry about so i expect the 928 to be quite a challenge by comparison.

As you say the fast stuff isn't really the issue, it's the transition load corners where i expect there to be potential problems. I'll be surprised if the baffled sump kit cant cope with that on road tyres, but a dry sump is always well worth it when you start to generate some grip with good tyres, brakes and suspension. I don't know what these engines are like with regards to filling the heads after sustained high rpm use, thats another area that can cause surge issues when the level in the sump drops, wet sumped Chevy's are terrible for this.

drnick

interesting anecdote on the subject of drysumps - when its installed you can hear the oil being pumped into it. the scavenge points are on the right hand side of the pan (as you are sat in the car) and when you go into a sustained R) hander the sound of oil sloshing into the tank stops for a while.

CanAmJohn

You need less silencing.

The good thing about dry sumping is it also helps evacuate the crankcase gasses, if the tank is designed properly you can end up with zero oil in the catch can too.

I love the colour of your car Nick, it's looks fantastic.

Cheburator

The Ring with 480rwhp in a 928 will be interesting to say the least... I reckon you will get proper air going into Flugplatz, Schwedenkreuz and Pflanzgarten 2

I think the fastest I got out of the BMW in my sig was the limiter at 165mph over the crest on the approach to SX and about 150mph into FH. The 928 will do the same - it needs another 50-75 odd normally aspirated ponies courtesy of a GTS engine with wild cams and heads to be fitted this winter...

Since I fitted the dry sump to my 928, oil consumption has been negligible - 500ml for 6000km and the catch tank on the back of the oil tank is bone dry. I use a large tank - 5 US gal and Castrol RS 10W60. Also very keen on the Motul 15W50.

Mark, will dig up the youtube videos with the corners hen I get home from work today

stuartph

Looks like there will be some big power 28's at the ring next year

CanAmJohn

Hopefully, i go there a lot with the racing cars but don't get much time to drive myself these days, i'll make a bit more of an effort to do that once i get myself sorted with the new car.

Have you had any issues with the car bottoming out? I would have thought through the foxhole and Pflanzgaten1 it could be a problem.

Cheburator

Yeah, it does bottom out, but mostly on the approach to SX - in the dip before the crest at around 155mph The FX is not a problem - it mostly scrapes, rather than hard hits, and then it also scrapes at the transition between Breidscheid and Ex-Muhle.

Bear in mind, mine is a full on race-car with 110mm ride height all round, running 800/550 springs. No idea what a standard car will be like - it was ages ago when I did it in a normal 928 in maximum attack mode.

Which 928 did you buy at the end?

CanAmJohn

I haven't bought one yet, it's not for a lack of trying!

Cheburator

hopwood on here has a 1987 white S4 5spd for sale - I have worked on it and it is a stonking car for the money. In fact I would go on to say that it is the best value for money 928 in Europe. Drop him a pm, you might be surprised with the amount of work done on the car and most importantly the great price...

CanAmJohn

I've already been for a run in Joel's car, not quite what I'm looking for but a good value car as you say.

stuartph

John

What kind of car are you looking for