Use of heavy weight oil in racing applications. (WRX)

TooSlick · Apr 19, 2003

Patman,

I don't think factory installed gauges are very accurate at their low/high limits. I'd pick the rpm range you normally cruise at, say 2500-3000 rpms and check the oil pressure at that point. If it's in the 45-60 psi range @ 3000 rpms, then you're fine with that grade of oil. If you run the same grade of oil year round, you might find you're down towards 45-50 psi in the summer and up towards 55-60 psi in the winter.

High temp/high shear , "HT/HS" viscosity correlates pretty well to oil pressure, so you can loosely predict what sort of pressure a particular formulation will give you, prior to using it.

I'd just pick a decent oil filter and stick with it ...that removes pressure drop as one of the variables you have to contend with.

Ted

jason07-1zzfe · Apr 20, 2003

With those oil temps, and that turbo, I would run Red Line 10w40. There should be no need for the 50wts. I wouldn't bother with the Race oil unless you ar racing for money. You will have to change the oil every week with that.
I would really be surprised if you have to rebuild in 30k (at least using RL 10w40)

An analysis sure would be interesting. I'd send it to Terry if you're really concerned about the motor. I would be after doing all those mods. Sweet!

mebanditws6 · Apr 20, 2003

Oil won't give that much of cooling no matter what viscosity you have. If you're worried about cooling, then run make sure your radiator is completely flushed out and void of debris and run distilled water and 2+ bottles of Redline watter wetter and no thermostat. That said, a 50wt oil IMO is a necesity because of such high oil temps. If you run too thin of oil, it's gonna break down at those high temps and oil pressure won't be where it should be when turning 7k+rpms continuously and main bearing wear will quite high. My recommendation is Redline 20w50 or Castrol Syntec 10w60 which is what all those M3's have.

Jason

Michael SR · Apr 21, 2003

quote:

Originally posted by mebanditws6:
a 50wt oil IMO is a necesity because of such high oil temps.

did i miss something? i thought he said 230° F oil temps at the track, and below (water) boiling point on the street. i would say those are exceptionally low oil temps. (my vette hits over 230° oil temps just commuting.)

of course, i guess we need to know how/where it's measured before the numbers are meaningful...

-michael

WeyounDS9 · Apr 21, 2003

My Passat GLX used to hit 225F commuting and 234F oil temps in hard driving.

Fred...

Bror Jace · Apr 21, 2003

Just like non-detergent oil which is misused more often than not, I can't think of an application off the top of my head in which I would use a straight 50 weight mineral oil.

The time for this stuff is past ... unless you are talking about a machine which is fired up, runs one constant speed for hours until it's shut down AND it's tolerances prefer that particular thickness of an oil film.

I think top-fuel drag racers use a straight 70 weight oil ... but that's as specialized as it gets.

Jeff, I'd get recommendations from every one of your component's manufacturers and then see if you can't find some common ground. I'd guess it'll fall somewhere on or between Red Line 10W40 and 15W50.

--- Bror Jace

mebanditws6 · Apr 22, 2003

Hmmm guess I sorta mis quoted him about high oil temps. Still though for that WRX that's modded and running on a track, I don't see how oil temps could only be 230 or so degrees. Either way, I think his engine will like 50wt much better when spinning 8k for 20-30min at a time.

Jason

Jeff Sponaugle · Apr 23, 2003

quote:

Originally posted by mebanditws6:
Oil won't give that much of cooling no matter what viscosity you have. If you're worried about cooling, then run make sure your radiator is completely flushed out and void of debris and run distilled water and 2+ bottles of Redline watter wetter and no thermostat. That said, a 50wt oil IMO is a necesity because of such high oil temps. If you run too thin of oil, it's gonna break down at those high temps and oil pressure won't be where it should be when turning 7k+rpms continuously and main bearing wear will quite high. My recommendation is Redline 20w50 or Castrol Syntec 10w60 which is what all those M3's have.

Jason

Sorry for not getting back sooner guys! Was out of town. It does seem like those are decent oil temps, but then again, those are from runs in the fall with outside temperatures pretty low. The stock WRX has an oil-water cooler, but it really doesn't do too much cooling.

I imagine on hotter days, the oil temp could climb as high as 120C. As a few other posters mentioned, temperature near the turbo would be higbher as well. I'm going to give some 15w50 Mobil 1 a try this weekend, since I have some here in the garage.

Like another poster said, I could just change the oil every race day, which isn't really that big of a deal. From that of course is the question of what to run on the race days.. I'll give some redline 40W a try and see how it turns out.

As far a monitoring goes, I have a DEFI recording gauge set, so I can record oil temp and pressure, as well as peaks. Stock WRX oil pressure is about 28psi kgcfm at idle, and peaks to about 92psi at redline.

Thanks for all of the information guys. Very helpful stuff.

Jeff

Jeff Sponaugle · Apr 23, 2003

quote:

Originally posted by Michael SR:

quote:

Originally posted by mebanditws6:
a 50wt oil IMO is a necesity because of such high oil temps.

Click to expand...

did i miss something? i thought he said 230° F oil temps at the track, and below (water) boiling point on the street. i would say those are exceptionally low oil temps. (my vette hits over 230° oil temps just commuting.)

of course, i guess we need to know how/where it's measured before the numbers are meaningful...

-michael

Interesting... I too thought these were lower temperatures. I am measuring the temperature at the oil filter with a sandwich adapter, and an electronic DEFI oil temp and oil pressure gauge. This location is right after the oil/coolant cooler, so that might explain the lower temperatures.

I may try relocating the temperature sensor somewhere off the block, to get a better sense of the internal temperature. According to my datalogs, coolent temperature during hard runs is about 95C.

Also, as I mentioned in a post a few seconds ago, these runs were on cold days (well, cold for a track day here, about 50 degress). When the outside temperature hits 85 or 90, I think things will be different. Furthing that thought, I was also running less boost in previous days. I'm set right now at about 24psi, and will be at 26 as soon as I get my upgraded water injection setup and a 3 bar map sensor.

Needless to say, 480+HP out of 2.0Ls is some significant stress on the internal componets.

I'll do some more testing, and send some samples out for testing as well. Now I just need to figure out where to send the samples too....

Jeff

jason07-1zzfe · Apr 23, 2003

Red Line told me a while back that the ideal oil temp was around 190F after the cooler, ideally a little hotter. So you have the sensor in the right place. And you are running pretty hot. Red Line 10w40 or 15w50 is to be considered IMHO. You can email them also. They are very helpful.

If it were my engine, I wouldn't use Mobil-1. I know of two people that have spun bearings while road racing with M1 15w50. That was the tri-syn. But supersyn isn't leaps and bounds above. Additive levels arent that much higher. If you still feel the need to use M1 I would definitely add some Schaeffer's #132. I'd actually feel better running Schaeffer's 20w50 racing oil than M1. But personally I'd choose Red Line.

Ferrari · Apr 23, 2003

Why don't you try Motul 300V 15W-50? It's 100% Ester based, made SPECIFICALLY for racing, and the Subaru WRXs in the Canadian Rally Championship all run this oil. I talked to one of the mechanics that was setting up a WRX for a night race, and he said that they wouldn't put in anything other than Motul 300V 15W-50.

jason07-1zzfe · Apr 23, 2003

But they probably run dry sump systems also, so there is about zero risk of starvation. You could run anything.
Besides, they are French...I've got a pretty good idea what to do with that oil...

sprintman · Apr 23, 2003

Saw Motul 300V 15W50 ester at Autobarn. A$40 for 2 litres!!. I bought 5 litre jug Synergie 6100 PAO for A$55 a little more in my price bracket.

TooSlick · Apr 23, 2003

Jeff,

You posted some numbers for both oil pressure and oil temp. What SAE grade oil were you using when you recorded those numbers? That would give me a much better idea about the best grade to run in this situation. If you were only seeing 110C with a 15w-50 or 20w-50, those temps really aren't very high. The numbers you posted for oil pressure seem more than high enough.

TooSlick

Jeff Sponaugle · Apr 24, 2003

quote:

Originally posted by TooSlick:
Jeff,

You posted some numbers for both oil pressure and oil temp. What SAE grade oil were you using when you recorded those numbers? That would give me a much better idea about the best grade to run in this situation. If you were only seeing 110C with a 15w-50 or 20w-50, those temps really aren't very high. The numbers you posted for oil pressure seem more than high enough.

TooSlick

Those numbers were with Mobil-1 10w30. Interesting that the Canadian guys use the Motul. I've seen it around a few places, but never given it a try. The Redline sounds like a good alternative given the engine load. I'm also in progress of making a real oil cooler which should help out some....

TooSlick · Apr 24, 2003

Jeff,

If you are seeing 90+ psi with Mobil 1, 10w-30 at full throttle, that's pretty decent. I'd be tempted to just run the Amsoil or Redline 10w-30 and see how they do in terms of bearing wear. Both are about 15% thicker than Mobil 1 under high shear rate conditions, which may be all you need. I might also run one of their 10w-40 synthetics and see if there was any noticable difference in operating characteristics. But I honestly don't think going to a 15w-50 or 20w-50 is necessary or even desirable in this high rpm motor. With a 50wt, I think the oil pressure relief valve is going to be open a lot at high rpms, so you are just generating excessive pumping losses and extra heat with the thick oils.

TooSlick

Jeff Sponaugle · Apr 28, 2003

quote:

Originally posted by TooSlick:
Jeff,

If you are seeing 90+ psi with Mobil 1, 10w-30 at full throttle, that's pretty decent. I'd be tempted to just run the Amsoil or Redline 10w-30 and see how they do in terms of bearing wear. Both are about 15% thicker than Mobil 1 under high shear rate conditions, which may be all you need. I might also run one of their 10w-40 synthetics and see if there was any noticable difference in operating characteristics. But I honestly don't think going to a 15w-50 or 20w-50 is necessary or even desirable in this high rpm motor. With a 50wt, I think the oil pressure relief valve is going to be open a lot at high rpms, so you are just generating excessive pumping losses and extra heat with the thick oils.

TooSlick

Yea, the oil pressure did seem a bit high. Before the track day Friday, I changed the oil to some Mobil-1 15w50 I had here. At startup, oil pressure is about 3 kgcm (42psi), and peak oil pressure at redline is 7.0 kgcm (99.56psi). That is pretty high.

Peak oil temperature during a 20 mins session was 107C (224.6F). That is pretty reasonable given the power level. Outside air temps were cool, so this isn't indicitive of the summer temps we will soon be seeing.

I'll try some 10w-40 at the next session and see how it runs.

Jeff

Use of heavy weight oil in racing applications. (WRX)

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