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I was at VIR last weekend running the full course in my Z51 7-speed and temps were in the mid 90's with moderate humidity.
Upon reviewing the PDR data, I saw in lap oil temps ranging from 250 to 268 (the latter with Mike Skeen at the wheel). Track sessions were ~30 minutes each with lap times for me running 2:17 & for Mike 2:09 on street tires.
Running Mobil1 15w-50; anything to be concerned about (i.e. like the need to add an additional oil cooler)?
I was at VIR last weekend running the full course in my Z51 7-speed and temps were in the mid 90's with moderate humidity.
Upon reviewing the PDR data, I saw in lap oil temps ranging from 250 to 268 (the latter with Mike Skeen at the wheel). Track sessions were ~30 minutes each with lap times for me running 2:17 & for Mike 2:09 on street tires.
Running Mobil1 15w-50; anything to be concerned about (i.e. like the need to add an additional oil cooler)?
Thanks.
You should be fine a lot of guys run much closer to 300 consistently with the LT4s. Only on extremely hot days we get to 270 oil. We run a 2015 Z06 at Watkins Glen and just got back from testing for two days a cooling system that should not effect the warranties. We have CNCd cooling fins that attached to the factory oil\ water cooler with a thermally conductive adhesive like a heat sink. I will post more about it all soon as a bunch of guys are interested in the kit. I usually post on the Z06 side.
BTW did you run 80 to 90% water to coolant mix, helps.
You should be fine a lot of guys run much closer to 300 consistently with the LT4s. Only on extremely hot days we get to 270 oil. We run a 2015 Z06 at Watkins Glen and just got back from testing for two days a cooling system that should not effect the warranties. We have CNCd cooling fins that attached to the factory oil\ water cooler with a thermally conductive adhesive like a heat sink. I will post more about it all soon as a bunch of guys are interested in the kit. I usually post on the Z06 side.
BTW did you run 80 to 90% water to coolant mix, helps.
Thanks.
I am interested in your cooling idea.
I did not change the coolant mix, but did add a bunch of Royal Purple Ice to the tank. Max coolant temps were 208 I believe.
Somewhere along the way, I read something that said, oh, must have been NASCAR qualifying, anyways, high oil temps are faster, it sheets off the bores, saves HP.
And by hot, I'm thinking well over 300, more like 350 or so.
I'm sure there info about this online somewhere, as well as the limits for your oil. I presume you change out the 15-50 when you're done, so any baking the oil suffered gets dumped.
Now YMMV, proceed cautiously padawan. But anything under 300F, if the water is cool should not be a problem other than for oil life.
Nothing to be worried about. I've ran in the high 260's and 270's without any issues (Mobil 1 15w-50).
Prior to my C7 I had a '13 ZL1 and ran 5w-30 which got up to around 310* a few times. Always did oil analysis reports, oil came back fine with only minor increase in mineral wear which would be expected for a track vehicle.
Newton, Here's a pic of the fins on the cooler. This is our test cooler they install on the car with a thermal adhesive, easy. Were just back from Watkins Glen running in the 90's with high humidity. On our Aim data recorder highest water temp 225 and oil 273. This was on many hot laps of 2:10 seconds no short shifting, red line 3 times every lap, half hour sessions, 150 back stretch speeds!
Our car has all stock cooling but use the heat sink fins with a 3 inch hose blowing fresh air on to it from the grill area. Also cat covers and titanium rapped exhaust. PM to get on the list for when I get the kits completed.
I was at VIR last weekend running the full course in my Z51 7-speed and temps were in the mid 90's with moderate humidity.
Upon reviewing the PDR data, I saw in lap oil temps ranging from 250 to 268 (the latter with Mike Skeen at the wheel). Track sessions were ~30 minutes each with lap times for me running 2:17 & for Mike 2:09 on street tires.
Running Mobil1 15w-50; anything to be concerned about (i.e. like the need to add an additional oil cooler)?
Thanks.
Those oil temps are fine. Mike Skeen would probably push the car hard enough to get the temp up even if he wasn't driving it to the limit.
I have the GM Secondary Radiator on my 15 Z06 M7. The last time I was at VIR I was running 2:08 to 2:10 lap times, the ambient temps were in the mid 80s to low 90s and my coolant temps were in the mid 220s and the oil temps in the mid 270s. Those numbers were well within what I consider to be a reasonable range.
Bill
Last edited by Bill Dearborn; 08-22-2016 at 10:14 PM.
My 2 cents on the subject:
270 degrees or so is perfectly fine. In fact, I bet that if you ran Mobil1 0W-40, it would be even 5-10 degrees lower, and you'd not have to change back and forth. In my opinion, the only reason GM switches from 5W-30 directly to 15W-50 is since that's the only one available with Dexos approval (0W-40 is European formula, which is ironically what Euro-spec GM cars come pre-filled with). 0W-40 already provides very high HTHS protection, and obviously you don't have to drain it, if the Euro spec Corvettes' LT1 is perfectly happy with : p
My 2 cents on the subject:
270 degrees or so is perfectly fine. In fact, I bet that if you ran Mobil1 0W-40, it would be even 5-10 degrees lower, and you'd not have to change back and forth. In my opinion, the only reason GM switches from 5W-30 directly to 15W-50 is since that's the only one available with Dexos approval (0W-40 is European formula, which is ironically what Euro-spec GM cars come pre-filled with). 0W-40 already provides very high HTHS protection, and obviously you don't have to drain it, if the Euro spec Corvettes' LT1 is perfectly happy with : p
I ran 0W-40 earlier this year with no problems. OK, I did break an aftermarket valve spring, which ended my weekend.
Kind of gun-shy to go back even though I know the oil had nothing to do with a defective spring.
I have some events coming up in the fall so I may switch back to the 0W40.
Just curious why you thing the lighter grade oil would run cooler?
I ran 0W-40 earlier this year with no problems. OK, I did break an aftermarket valve spring, which ended my weekend.
Kind of gun-shy to go back even though I know the oil had nothing to do with a defective spring.
I have some events coming up in the fall so I may switch back to the 0W40.
Just curious why you thing the lighter grade oil would run cooler?
It's a fact I've learned in the Miata world, back when I supercharged the engine and started running into overheating issues. I've also tested it out on my Camaro 1LE. Thicker oil causes more friction and back pressure, contributing to the temps. In my tests, there was about 15 degrees F difference in max temps from 5W-20 to 0W-40. And yes, cold viscosity has little to no impact on the temps; it's the hot oil index (20 vs. 40 in this case) that makes the impact. I used to think that 0W-40 is a thin oil just because it starts with 0W...
My 2 cents on the subject:
270 degrees or so is perfectly fine. In fact, I bet that if you ran Mobil1 0W-40, it would be even 5-10 degrees lower, and you'd not have to change back and forth. In my opinion, the only reason GM switches from 5W-30 directly to 15W-50 is since that's the only one available with Dexos approval (0W-40 is European formula, which is ironically what Euro-spec GM cars come pre-filled with). 0W-40 already provides very high HTHS protection, and obviously you don't have to drain it, if the Euro spec Corvettes' LT1 is perfectly happy with : p
Actually you really don't need to switch back and forth. GM recommends that because it reduces gas mileage and affects catalytic converter life which might increase the number of warranty replacements they would have to make. See the Ask Tadge forum to see his answer on this subject.
Actually you really don't need to switch back and forth. GM recommends that because it reduces gas mileage and affects catalytic converter life which might increase the number of warranty replacements they would have to make. See the Ask Tadge forum to see his answer on this subject.
Bill
Yeah, I remember his response; it was not very clear, but he did not say engine would be damaged by leaving it in, either. He also mentioned 0W-40 not-so-negatively in his answer:
Tadge answered:
GM Propulsion Systems has validated all Corvette engines to operate with the DEXOS 5W30 for all but the most extreme track conditions. We recommend the use of Mobil 1 15W50 when the vehicle is going to be used for high temperature track operation as the higher viscosity range provides a greater degree of protection under the extreme stresses of that duty cycle. We like the extra lube performance in those conditions because, unlike some other manufacturers, driving on the track does not automatically void the warranty. However, daily driving use of the Mobil 1 15W50 on the street has not been validated, and as such we do not recommend its use where the operating temperatures can run lower. Some contributors to the thread correctly point out that few Corvette drivers operate their vehicles at extremely low temperatures, but as the manufacturer, we have to protect for that possibility. Another issue is that the 15w50 oil has higher phosphorous and ash content than we specify for factory fill. That is ok for track usage, but in long term street usage, those chemicals can compromise catalyst performance. As the manufacturer, we are expected to meet EPA emissions for a very long time. Lastly, the higher viscosity will also result in a small loss of fuel efficiency.
As for the Mobil 1 0W40, it was not available when we validated these engines and, in its currently available formulation, it also contains more phosphorous and ash than we specify. So, even if we validated the 0W40 for track use, we would still have to recommend reverting to a DEXOS 5W30 for daily street use.
Like all aspects of the auto industry, lubricants continue to improve over time. We work with Mobil and others to elevate the performance of their products and hence ours. We will continue to do that and when we have a better oil to ship in our engines or recommend for use on the track, we will do so.
Yeah, I remember his response; it was not very clear, but he did not say engine would be damaged by leaving it in, either. He also mentioned 0W-40 not-so-negatively in his answer:
It was very clear in what he didn't say. Their issues were all related to regulatory items such as fuel mileage and the 8 yr/80K mile warranty on cats.
Yeah, I remember his response; it was not very clear, but he did not say engine would be damaged by leaving it in, either. He also mentioned 0W-40 not-so-negatively in his answer:
It was very clear in what he didn't say. His response was very politically correct but also conveyed a non politically correct subtext.
08-22-2016, 12:37 PM
Oil temps on road courses
