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Hi,

Tracked my M-5 for two days at Summit Point. Awesome. The DSC was particularly impressive on the skidpad (no, I don't leave it on normally on the track).

After doing a few fairly tight skidpad circles, I got an oil pressure warning. There was plenty of oil. I thought the M-5 design anticipated sloshing oil under lateral acceleration.

Any comments?

js
 

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I'd be very careful about doing continuous skidpad work in most any street car you care about.

Lots of engines tend to blow up after a while, either because the pan can't keep the pump inlet in oil, or because the lateral Gs keep the oil up in the top end of the engine and won't let it back to the pan.

Old '70s Pontiac Trans Ams - with unbaffled pans, traditional Detroit 5-quart (small) oil capacity, and what was for the age a lot of lateral grip - used to pump all the oil out of the pan into the outside valve cover under skidpad conditions, they'd (a) start blowing smoke out the tailpipe as the oil ran down the valveguides and (b) blow up shortly thereafter. I think magazine road testers used to treat it as a game to see how fast they could pop the engine.

Even the best wet-sump configurations - the M5's electronically-controlled oil pickup, the baffled, gated, scrapered 8-quart Canton pan in my track Mustang - are going to have problems keeping the engine oiled in *continuous* high-G use.

You need a dry sump for that, and depending on the engine design you may need special attention (separate scavenge-pump lines to the valvetrain area?) to ensure the oil gets back to the sump.
 

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Has anybody else skidpadded their M5? Crazy this happened even back in 2000 when tire technology was not all that sticky.
 

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i have, only error i got was tyre pressure issue as the pressure went high on the rears due to the heat. the skid pan i went on was a low friction surface not a wet area
 

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What, exactly, is a skid pad? Is it a slick or wet black top, intended to kick the tires out easier, so you can simulate high G driving?

I drove a skidpad simulation car one time, where it had shiftable weights and arms to throw the car into over and understeer.

I, so badly, want a place to test the limits of the M5. Sometimes when it rains, I will take the M5 into one of the empty parking lots at work and throw it into a slide to get a feel for it. I know the techniques to pull a car out of under and oversteer, but haven't had anywhere to practice them other than in the simulated skid car.
 

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Hi,

Tracked my M-5 for two days at Summit Point. Awesome. The DSC was particularly impressive on the skidpad (no, I don't leave it on normally on the track).

After doing a few fairly tight skidpad circles, I got an oil pressure warning. There was plenty of oil. I thought the M-5 design anticipated sloshing oil under lateral acceleration.

Any comments?

js
If you were pulling more than 0.9 g, when the light came on, it might be worth pulling the two oil changeover solenoid valves in the upper oil sump and checking they stroke OK with 12 V applied. They are supposed to switch over at 0.9 g so the two scavenge pumps in the oil pump draw oil from the cylinder head and section of the sump that is on the outside of the curve.
 

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68FB, this post is a bit ancient.
 
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If you were pulling more than 0.9 g, when the light came on, it might be worth pulling the two oil changeover solenoid valves in the upper oil sump and checking they stroke OK with 12 V applied. They are supposed to switch over at 0.9 g so the two scavenge pumps in the oil pump draw oil from the cylinder head and section of the sump that is on the outside of the curve.
1) this post is ancient
2) Those solenoids were not designed for real track work with sticky tires....they were added in order to avoid having to baffle the lower oil pan
 

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1) this post is ancient
2) Those solenoids were not designed for real track work with sticky tires....they were added in order to avoid having to baffle the lower oil pan
So what do you suggest? Please do not say "Dry Sump". The scavenging solenoids are good from 0.9 to 1.2g, that's it.
 

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What, exactly, is a skid pad? Is it a slick or wet black top, intended to kick the tires out easier, so you can simulate high G driving?

I drove a skidpad simulation car one time, where it had shiftable weights and arms to throw the car into over and understeer.

I, so badly, want a place to test the limits of the M5. Sometimes when it rains, I will take the M5 into one of the empty parking lots at work and throw it into a slide to get a feel for it. I know the techniques to pull a car out of under and oversteer, but haven't had anywhere to practice them other than in the simulated skid car.
- Swinging the rear end out = cold wet or snowy, empty parking lot
- Testing the limits of the car = track or, I guess, autocross event

I have begun having alot more fun getting my rear end out with the winter tires: I can do it on demand, with no squealing (they don't squeal), and with ridiculous confidence and control on these tires. With my summer tires (PSS as you know!), the limits were so high I had to be stupid to get the rear end to step out for anything more than second.

The other thing is that with the winters, once it starts sliding, I can lift off the throttle a bit and it'll continue to slide. With the summers, the second I reduce the throttle it grabs again and snaps into line - wasn't nearly as fun.

If you are still running that summer setup I shipped you, it just ain't gonna happen easily :)
 

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So what do you suggest? Please do not say "Dry Sump". The scavenging solenoids are good from 0.9 to 1.2g, that's it.
Where'd you get that number from? They're marginally acceptable up to .9g, they are too small to handle much more than that. They do ok for small amounts of steady state loads, but are not sufficient for a long high-G corner. If you run R-comps, forget about those things being good enough.

The real solution is a proper oil pan baffle. Dry sump just isn't practical on our cars if you intend to keep them street driven.
 

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Where'd you get that number from? They're marginally acceptable up to .9g, they are too small to handle much more than that. They do ok for small amounts of steady state loads, but are not sufficient for a long high-G corner. If you run R-comps, forget about those things being good enough.

The real solution is a proper oil pan baffle. Dry sump just isn't practical on our cars if you intend to keep them street driven.
I got those #s from BMW M literature. It activates at 0.9g and works up until 1.2g. The problem is most of us don't even know if our solenoids are still working (e.g. does your oil change use 6.5L, 7.25L or 8.0L of oil?). Do you have a baffled pan? I think jrhaile runs a custom pan, but haven't heard others. You've convinced me R-compounds is a no go.:sad3:
 

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I got those #s from BMW M literature. It activates at 0.9g and works up until 1.2g. The problem is most of us don't even know if our solenoids are still working (e.g. does your oil change use 6.5L, 7.25L or 8.0L of oil?). Do you have a baffled pan? I think jrhaile runs a custom pan, but haven't heard others. You've convinced me R-compounds is a no go.:sad3:
Im not sure how BMW tested that with street tires on the car...as a stock M5 with even the stickiest street tire will struggle to make .9G on a skidpad. Momentary g loads arent such a big deal, it's the steady state that really kills. I agree that most cannot confirm 100% their solenoids still work.

James is the only one (that I've heard of) with a baffled pan.
 
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