1993 BMW 325i oil for endurance racing

[chrisri]

40 grade is MINIMUM viscosity required by your engine manufacturer, and it's meant to provide maximal protection under normal conditions. Like street driving.
Track use or racing is not normal usage of car, and I would be inclined to step up in viscosity.
Castrol Edge 10w60 or Motul 300V 15w50 would be my choice for endurance race you will participate.

Also , you should invest in some better pads and DOT 5.1 brake fluid as brakes will be your weakest link on street car. Slick tyres are a must for any fun on a track.

 

[SliderX]

Originally Posted By: IndyIan
Lemons or Chump Car? Sounds fun anyways. I'd go for the 15W50, it will be plenty thin after the oil temp stabilizes at some very high number.
As for water temps, you can look up what water boils at a given pressure. I imagine you want to avoid localized boiling, so having some decent pressure in the system is a must I assume.
http://www.engineeringtoolbox.com/boiling-point-water-d_926.html
Have fun!


Yup lemons! And as others stated we can only run straight water due to track regulations. According to that water will boil at about 248F at 2 bar which what I believe the stock expansion tank is rated at, so we should keep it a bit below that, got it!

We did the race before with e30 m20b25 and m20b27 motors before with whatever synthethic or semi-synthetic oil change specials autozone had and they lasted quite a while. Last couple races we've had cooling system issues which lead to head gasket issues, our fault, live and learn. Brake pads and tires are all sorted.

For the oil we don't want to get too crazy with the expensive racing oils. An affordable full synthetic is what we're thinking. Mobil 0w-40 we've considered but I'm afraid that might shear down too much at high temps so that's why I was thinking going with something thicker like like the 15w-50 or rotella 5w-40 that would provide more protection when running hot. Am I incorrect in my assumption?

 

[Garak]

Originally Posted By: OVERKILL
They use M1 0w-40 in the 24hrs of LeMans and Daytona, though they probably have oil coolers.

Agreed. But, if there is real concern for shear, the Delvac 1 5w-40 you suggested might fare a little better in that regard.

 

[SliderX]

Originally Posted By: OVERKILL
Delvac 1 5w-40 would be my choice. Does this car have an oil cooler?


No oil cooler. So should I be looking for something with a high HTHS? Delvac is 3.9, T6 is around the same from what I can find. The 15w-50 is 4.5 http://www.mobil.com/USA-English/Lubes/PDS/NAUSENPVLMOMobil1_15W-50.aspx

 

[OVERKILL]

Originally Posted By: SliderX
Originally Posted By: OVERKILL
Delvac 1 5w-40 would be my choice. Does this car have an oil cooler?


No oil cooler. So should I be looking for something with a high HTHS? Delvac is 3.9, T6 is around the same from what I can find. The 15w-50 is 4.5 http://www.mobil.com/USA-English/Lubes/PDS/NAUSENPVLMOMobil1_15W-50.aspx


I think the D1 would be fine and a bit more shear resistant than the 0w-40.

 

[A_Harman]

Originally Posted By: SliderX
Originally Posted By: IndyIan
Lemons or Chump Car? Sounds fun anyways. I'd go for the 15W50, it will be plenty thin after the oil temp stabilizes at some very high number.
As for water temps, you can look up what water boils at a given pressure. I imagine you want to avoid localized boiling, so having some decent pressure in the system is a must I assume.
http://www.engineeringtoolbox.com/boiling-point-water-d_926.html
Have fun!


Yup lemons! And as others stated we can only run straight water due to track regulations. According to that water will boil at about 248F at 2 bar which what I believe the stock expansion tank is rated at, so we should keep it a bit below that, got it!

We did the race before with e30 m20b25 and m20b27 motors before with whatever synthethic or semi-synthetic oil change specials autozone had and they lasted quite a while. Last couple races we've had cooling system issues which lead to head gasket issues, our fault, live and learn. Brake pads and tires are all sorted.

For the oil we don't want to get too crazy with the expensive racing oils. An affordable full synthetic is what we're thinking. Mobil 0w-40 we've considered but I'm afraid that might shear down too much at high temps so that's why I was thinking going with something thicker like like the 15w-50 or rotella 5w-40 that would provide more protection when running hot. Am I incorrect in my assumption?


Out of those, I would go with the M1 15w50.

 

[SR5]

Castrol Edge 10W-60 with Titanium. API SN, ACEA A3/B4
TBN = 11.2, HTHS = 5.1

I ran it for 10,000 KM in a shared sump motorcycle and unlike most oils, it never sheared down enough to give gear change problems. The Edge 5W30 did shear down pretty quick.

No, it did not cause my wet clutch to slip. Thanks for asking.

I still think Castrol 10W60 is a good race oil for the road.

Here is a VOA from a few year a go.
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2988455

aluminum 8
iron 1
silicon 7
titanium 47
moly 198
boron 59
calcium 2823
phosphorous 804
zinc 922

vis 100 C 20.7
base number 10.8
oxidation (abs/cm) 8
nitration (abs/cm) 4

I would also fit fresh brake pads and brake fluid.

Have Fun at the Track !!

 

[Thebimmerfan]

Originally Posted By: Joshua_Skinner
... The revised rod bearings also had a greater clearance...


No, their clearances are almost identical. S54B32 main bearings oil clearances in inches are 0,0007-0,0020; M50B25 are 0,0008-0,0023.

 

[Thebimmerfan]

Originally Posted By: SliderX

For the oil we don't want to get too crazy with the expensive racing oils. An affordable full synthetic is what we're thinking. Mobil 0w-40 we've considered but I'm afraid that might shear down too much at high temps so that's why I was thinking going with something thicker like like the 15w-50 or rotella 5w-40 that would provide more protection when running hot. Am I incorrect in my assumption?

It's your car and your money, but for a 8h race the last thing I would save money on would be the engine oil.

 

[RoadRaceJosh]

Originally Posted By: Thebimmerfan
Originally Posted By: Joshua_Skinner
... The revised rod bearings also had a greater clearance...


No, their clearances are almost identical. S54B32 main bearings oil clearances in inches are 0,0007-0,0020; M50B25 are 0,0008-0,0023.



Why do you keep up with the OT stuff? Bringing up main bearing clearance specs shows you haven't absorbed that the S54 had a connecting rod bearing problem. A problem that the earlier M engines did not.

Speaking to the topic at hand. The oil isn't going to shear from temperature, but from use. If you want a greater HTHS I would use a 20W-50 motorcycle oil. Mobile 1 V-Twin evidently has a 150° C HTHS of 5.8 cSt. http://forums.pelicanparts.com/porsche-9...sm-oils-11.html

 

[Thebimmerfan]

Originally Posted By: Joshua_Skinner
[
Why do you keep up with the OT stuff? Bringing up main bearing clearance specs shows you haven't absorbed that the S54 had a connecting rod bearing problem. A problem that the earlier M engines did not.


I keep up with "the OT stuff" because you kept up claiming that "the revised S54B32 rod bearings also had a greater clearance" which is not true, and perfectly know that the reason why BMW changed their engine oil recomendation for S54B32 had nothing to do with any difference in its main bearings clearances (because they are not so different) but because of other reasons. By the other hand how can I miss absorb the fact that S54B32 had a main bearings problem if I spoke about said problems first...Nevertheless, I see it's iseless, regards.
P.S. Many oil brands (like Fuchs to give an example) now recomend 10W-60 even for the older M3 E36 S52B30.

 

[SR5]

So Mobil 1 0W-40 has a HTHS of about 3.8 (Castrol Edge 0W-40 would be similar).

M1 V-Twin 20W-50 has a HTHS of 5.8
Castrol Edge 10W-60 has a HTHS of 5.1

I don't do oil mixes, but may people here are OK with it. With these four off the shelf products you could easily mix up a batch of oil with a HTHS in the mid 4's if that is what you are after.

I would just mix like with like, and only mix Castrol with Castrol and M1 with M1. But that's just me, I think the add chemistry works better that way.

 

[Jetronic]

I'd use v-twin straight.

edge 10w-60 seems mighty thin (hths) to me. Thinner baseoils than the v-twin most likely.

8 hours is a long time, consider noack and other ways to consume oil...

 

[lubricatosaurus]

Originally Posted By: Jetronic
get a motorcycle oil maybe? M1 0w-40 might shear down quite a lot, and you definitely don't need the low pour point unless the race is held in antarctica.

Mobil makes a very high HTHS 20w-50 motorcycle oil, I'd add a can of MoS2 or similar and be done with it. API SJ as well, which was current in 1993 I believe. Last oil spec focused on performance, and not emission equipment protection.

The MoS2 or similar is just in case you pull repeatedly high G corners or braking and starve the pickup from oil. I'm guessing no baffled or dry sump.

https://mobiloil.com/en/motor-oils/mobil-1/mobil-1-v-twin-motorcycle-oil


Originally Posted By: Joshua_Skinner
Speaking to the topic at hand. The oil isn't going to shear from temperature, but from use. If you want a greater HTHS I would use a 20W-50 motorcycle oil. Mobile 1 V-Twin evidently has a 150° C HTHS of 5.8 cSt. http://forums.pelicanparts.com/porsche-9...sm-oils-11.html


I'm liking the chorus of "Go Thicker" answers, because by hour 6 of a race with an old BMW, fuel dilution could be heavy. Motorcycle Mobil 1 oil is the best answer for an older engine.

For a tight new engine, M1 0w-40 has been proven:

They trust M1 0w-40 in 24 Hour LeMans GT and IndyCar.

"Porsche 996FL Engine test. This test will last 203 hours. The engine, and the oil, will go through: - 4 times the simulation of 35 hours of summer driving, - 4 times the simulation of 13.5 hours of winter driving, - 40 cold starts, - 5 times the simulation of 1-hour sessions on the “Nürburgring” racetrack, - 3.5 hours of “running-in” program Measurements on the engine and on the oil will be done at regular intervals, and the following parameter will be taken into account to grant the approval or not: - torque curve (internal friction), - oxidation of the oil, - Piston cleanliness and ring sticking, - Valve train wear protection. Cam & tappet wear must be less than 10 µm. - Engine cleanliness and sludge: after 203 hours, no deposits must be visible. - Bearing wear protection: visual rating according to Porsche in-house method."

And M1 0w-40 is factory fill in the Mclaren P1 and Nissan GT-R.
http://share.jayeapps.com/uploads/7afc11...hallenge_JP.PDF

Originally Posted By: oliver88
Interesting. I have seen M1 0w40 being used in Porsche GT3 RSR's and Cup Cars, as well as the Porsche RS Spyder...These are full blown race cars. Indy series uses it as well in their Honda engines.

 

[camrydriver111]

I'd use the M1 0W40 and post about it on BITOG afterwards.

 

[mattf2]

Usually a lemons engine leaks more oil then it burns.

Unless you're running at redline all 8 hours, any good oil will work just fine. We usually put a good synthetic (M1 10-40 high mileage) in initially, then top off with mobil 10 40 high mileage dino during the race.

YMMV

 

[ddombrowski]

We just finished (well, almost finished, broke the trans) a 14 hour Chumpcar race in our Porsche 944 down at Sebring in FL. It was around 80F outside, so pretty warm to start out with. We ran Mobil 1 15W50 with I think 1 quart of some leftover Valvoline VR1 50wt for the ZDDP.

Compared to other 944 engines out there, ours actually makes pretty good oil pressure (almost always at 5bar). Even so, during the hottest part of the day the pressure would drop a little at idle down to about 3 bar. The heat definitely starts affecting things, and one of my next projects is to find the 944 Turbo oil cooler to put on it.

Also, our engine burns around 1/2 quart per 1.5-2 hour drive session, so we made it part of our pit stops to add 1/2 quart at the driver changes. For a 170K motor, you should definitely keep track of how much its burning and make sure you have plenty of oil to top it off with. Keeping the oil full will do well to keep the temperature down and alleviate starvation issues on stock oil pans.

I would definitely favor the 15W50 over the 0W40, but either one is probably okay. As others have said, its endurance racing. The key to doing well is to be out turning laps, not in the pits with a rod knock.

Actually, wait...you're running an E36? You should probably run 0w20 in that engine......cheater.

 

[SliderX]

Thanks for the advice everyone, went with Mobil 1 15w-50, car ran great the whole weekend, only used about a quart maybe quart and a half of oil the whole weekend. Coolant temp stayed under 210 the whole race, 190 when not in traffic. Oil pressure was 57 at 5000rpm. 14.5 hours of racing it handled it great.

 

[BrocLuno]

Good on you - well done

 

[Thebimmerfan]

Originally Posted By: ddombrowski
Actually, wait...you're running an E36? You should probably run 0w20 in that engine......cheater.


944 is such a great car. Your Porsche is making a healthy oil pressure, the engine must be in good condition.