ealoken

What oil do you guys use on your 951's?

Im doing some trackdays, with a bigger oil cooler, so i dont think oil temp will go above 110 c ( Metric )

Engine will make aprox 400-430 bhp.

Im thinking of Gulf Racing 5w-50.

What do you use?

Thanks.

Erik

gruhsy

Joe Gibbs breakin
Joe Gibbs 15W50 XP4
then once broken in....
Millers 20W50 nano

These oils have high ZDDP levels just to add

JET951

Do not use 5w-50 in a 951 at the track , you're oil pressure ( hot ) will be too low & the risk of insufficient oil pressure to no 2 con-rod bearing

Minimum oil viscosity at the track is a 20w-50 & I mean minimum

On that subject , how old are the con-rods in the engine & age of the con-rod ( big-ends) bearings ?

The reason I asked is }

A) old con-rods metal fatigue

B ) old con-rod bearings that are 25 years old and are already badly worn & No oil will save that engine on the track

V2Rocket

^^shouldn't 20W50 and 5W50 perform approximately the same at warm temperature, based on the "convention" of multi grade oil?

Ifly951

Use Millers if you can spend the $. But then again an engine doing some track time $ should be spent.

odonnell

I ran Redline 5W-50 in my NA for a while. I remember comparing the viscosity levels between it and similar XW-50 oils and it was significantly thicker at 100 deg C. These figures are of course published in the oil datasheets which are online generally. So for a track car, Redline 5W-50 may actually be a better choice than a typical 15W-50 or something. For most of us, they're all fine, just depends on local availability and price.

rlm328

Correct the second number is the warm temperature viscosity. The x W number is the cold start viscosity, where W actual stands for winter.

JET951

With a workshop oil pressure gauge connected on a last century Porsche & at 95 deg cel oil temp , every 5w-50 we have tested in the last 15+ years reads a lower oil pressure than a 20w-50 ( same brand )

You're average 5w-50 is more like a 7.5w-43 oil viscosity ( the numbers on the bottle "5w-50" are just rounded off )

You're average 20w-50 is more like a 20w-48 oil viscosity , a 20w-50 at high oil temp will always give better oil pressure

A typical 5w-50 is really just a 5w-40 with more Vii's ( viscosity index improver's )

For a deep last century Porsche engine you must keep the oil pressure up when oil temp is above 100 deg cel

For one of our own or a customers 951 that's to be used on the track , I would only allow a 5w-50 to be used in the car park only

rlm328

Well Eric you have opened a whole can of worms with this question. Use a high quality motor oil, either natural or synthetic. Please note that these engines are loose tolerance engine. If the engine has some miles on it I would stick with natural motor oil as their molecules are of various sizes. If it is a recent rebuild then go with either. A lot of the more modern oils have eliminated zinc which was used as a lubricant for the moving parts such as the cam / valve tappet interface.

I have a recent rebuild and I am running natural oil through it now as I am changing it out every couple of outings. I will switch to synthetic some time later this year.

V2Rocket

That's interesting, thanks for sharing your results.

I'd like to go to my auto store and ask for 7.5W43 oil now..

rlm328

Bruce not trying to start a war here so let me preference by saying I live in Houston and agree with the W number, but like Sydney winter is pretty much no-existent. Eric is referencing metric so I am assuming he is in Europe some place where they have a real winter and therefore needs a lower number so he can get the motor to turn over.

Then again I could be mistaken and he is really from Alice Springs I which case he would be nuts for not using a high W number.

ealoken

It has 160 000 km on it's back.

Since i deal Gulf Oil where i work, im going to use that.

In Considering 15w-50

http://www.opieoils.co.uk/pdfs/gulf-...data-sheet.pdf

Monstrous4Banger

Brad Penn Break in.
20w50 amsoil z-rod.

JET951

Erik , I take it that it has 160,000kms ( 100,000miles ) , do you mean the con rods & the con-rod bearings are that old , with the extra HP that it now has ?

ealoken

Yes, it has been tuned since 2007.

I dont know about the bearings.