Oil Temperature and OCI

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I have 2001 Audi S4 twin turbo with steady diet of GC twice a year(5-6K OCIs). Car takes 7 quarts of oil and is modified to put out 350HP and 400ft/lb of torque. It also has oil temperature gauge and during the around town driving oil temp will be in 200-220F range, highway 220-230F. I do UOA once a year and they confirm that engine likes this oil.

I recently started tracking my car and on my first track event I saw oil temps in 250-275F range by the end of each session. This was 2 day event with 5 20min sessions each day. So little over 3 hours of high engine stress(most time spent in between 3000 and 6000 rpm) and high oil temperatures.

Oil and filter was changed just before the event.

So my question is what kind of effect these high oil temperatures have on length of OCI one can safely run with high quality A3 rated oil?

After the event oil temps are in their normal range as described above.

Should I leave the oil in the car for a usual 5-6K OCI I normally do or should I consider changing it earlier?

 

[Bryanccfshr]

I would not be concerned about those temps with GC. The additional fuel burned should be factored in as the byproducts of heavy throttle use will use up additves.

 

[Steve S]

What is one of the advantages of syn oil? it takes higher temps 275* isnt'that hot .Do a uoa to prove to your self if the oil is holding up that would be the best way.

 

[Gary Allan]

I'd say do a one time Dyson analysis just to get all the fatigue factors in one UOA.

 

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Originally Posted By: Bryanccfshr
I would not be concerned about those temps with GC. The additional fuel burned should be factored in as the byproducts of heavy throttle use will use up additves.


Good point, there is a lot more blowby in these conditions but wouldn't high oil temps help evaporate most of unburned fuel that gets by?

 

[Bryanccfshr]

Eventually yes but the unburned fuel and combustion byproducts still interact with the oil and the additives react with them.

 

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Originally Posted By: Bryanccfshr
Eventually yes but the unburned fuel and combustion byproducts still interact with the oil and the additives react with them.


so let's say GC is good for 10K interval on this engine under normal driving conditions and due to the high oil temps and this additional blowby its service life if reduced by 30-40% that still leaves me with 5-6K OCI?

 

[Bryanccfshr]

Sounds like a good estimate but if you want to know for sure how the oil reacts to performance driving in yor application you need to do a UOA under those conditions, probably around 5-6 k to see how it handles it. Alot depends on the frequency you go to the track and other variables that would make it hard to estimate. You can always revert to the fuel usage formulat that is on this sight somewhere that estimates OCI based on engine size, sump capacity Horsepower, fuel burned and a constant forthe quality of the engine oil.. it would be a good starting point and this early in the morning the author of the formula escapes me. .

 

[johnd]

Temperature "Idiot" lights come on at 345 Deg. F. as 350 is the temp when conventional oils begin to fail as a lubricant. With a synthetic, the critical temperature is considerably higher. I wouldn't worry about a synthetic under 300 Deg. F. This could be considered "normal" conditions. Run a UOA after a track event if you are worried about it but I don't think you are going to see any problems.

 

[steve20]

would you have a link, reference point, or manufacturer's data sheet for the temp = 345 ?

 

[zoomzoom]

I will definitely do UOA after this OCI and compare it to the previous one I did just before I put this oil in.

All looked good in that one:

 

[mechtech2]

In Chemistry, every rise in temp of 17 deg F [approx.] will double the speed of a reaction.
Therefore concerning the components/structures of the oil that are heat related, keeping it 20-40 deg cooler is substantial for longer life and protection. This is evident in automatic trans fluid - cooler is much better once it reaches a decent operating temp..
275 when racing doesn't sound abnormal, but it depends on where you measure it.
Oil life? I can't guess. In this case testing in street and racing conditions, then comparing, is the only way.
If it were mine, I'd simply change it more often and add it to the cost of racing/performance. As you know, you have to pay to play.

 

[tdi-rick]

Originally Posted By: Gary Allan
I'd say do a one time Dyson analysis just to get all the fatigue factors in one UOA.


Agree.

 

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I have run oil for 5K after track event and UOA came back looking pretty good:

 

[Jaymus]

Call me blind, but isn't the HDEO doing the best job? Maybe your car needs that extra viscosity while being driven hard.

 

[addyguy]

It was only run for 1,900 miles. Others were run much longer, and if you look at metals/miles, it didn't do THAT well...

 

[zoomzoom]

That is what I thought as well but wear hardly increased with track use

I am thinking running redline 5w-30 to see if I can lower the oil temps a bit and maybe reduce wear numbers..

 

[webfors]

nothing wrong with any of the GC reports, including the post track report. I wouldn't change a thing... switching oils might just add a new variable making it hard to trend... for the first few oci on the new oil anyway.

 

[Jaymus]

Originally Posted By: addyguy
It was only run for 1,900 miles. Others were run much longer, and if you look at metals/miles, it didn't do THAT well...


Doh, I looked for how long it was run and didn't see it. Yeah, seems like GC is doing just fine, then.

 

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GC is Rocking