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Discussion Starter · #1 · (Edited)
The C7 is one of the rare cars for which there is a special chapter concerning the track use.

In some words, GM ask for:
Changing the oil for 15W50 and refill with the OEM grade oil after
Changing the wheels alignments and return to standard settings after
I think they missed to advise for a good upgrade of the brake pads, for example a Carbotech XP12 on the four corners, such good pads avoid long time brakings which over heat the discs.

I have a quite long experience of the track with different cars and it's clear that those changes are all necessary for any hard used sport cars, but I have never seen any problem to keep those settings for the road use and many times the advantages are clear, specially when you drive harder. The track alignments settings are making the chassis more "stickier" on the road. When the chassis is originally good, those settings changes don't change specially the tires wearing...
The only drawback could be a tend to be a little less easy to drive straight on roads which are not flat enough (damaged by the big trucks charges on them).

Regarding the oil grade, the choice of a 15W50 is just surprising for me as a 5W50 would work as well as a 15W50 : for the track the important oil grade is the 50 (for high oil temperatures due to the hard driving)
If a 0W50 would be used, the engine could run all the time with this oil and without any damage possibility but a better temperatures range allowing road and track use.

Regarding the pads, high performances ones should be changed after the track, quite easy with the Brembo calipers.

Those things said, what are you doing for your track days?
Do you follow strictly the GM indications?

Your comments are welcome.
 

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Discussion Starter · #3 · (Edited)
Yes Chip, I have read those pages but I think my questions and remarks are a complement to those ones :)
You will remark that they don't speak about the GM askings for the track use.
 

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Interesting theory with regards to using a 0W50 or a 5W50 etc instead of a 15W50. The only thing I can think of is the inherent disadvantage of a too wide viscosity index improver and its ability to be sheared. High revving at the track or spirited driving will tend to have a greater shearing effect on the VII's.

A Simple Explanation of Viscosity Index Improvers
 

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Discussion Starter · #5 ·
The shearing resistance is not a problem with a the good quality synthetic oils (ref. : oils manufacturers websites).

I have experience with the use of engines which require normally synthetic 10W40 and used on track and road since many years with synthetic 10W60...So why don't use a synthetic 5W50 in the LT1 ?
In the C7 manual, GM asks to not use 10W30, 10W40 and 20W50.... No mention of the 5W50.
 

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The shearing resistance is not a problem with a the good quality synthetic oils (ref. : oils manufacturers websites).

I have experience with the use of engines which require normally synthetic 10W40 and used on track and road since many years with synthetic 10W60...So why don't use a synthetic 5W50 in the LT1 ?
In the C7 manual, GM asks to not use 10W30, 10W40 and 20W50.... No mention of the 5W50.
Correct, they make no mention of 5W50 which means you use it at your own risk. However, since you are in Europe it's quite likely the specific oil GM specifies is not available to you. I would call or write GM for a specific recommendation. In lieu of that you can compare the specifications of the 15W50 Mobil 1 here to whatever oil you have available to you and get the one that most closely approximates it. Mobil 1? 15W-50

As to the other post regarding viscosity spread, I am/was of that belief as well BUT, I see that many of the pure racing oils have gone to 0W50 ratings which leads me to believe they have sorted out the additive packages since offroad oil doesn't have to adhere to the same heavy metal requirements of road oils.
 

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The shearing resistance is not a problem with a the good quality synthetic oils (ref. : oils manufacturers websites).

I have experience with the use of engines which require normally synthetic 10W40 and used on track and road since many years with synthetic 10W60...So why don't use a synthetic 5W50 in the LT1 ?
In the C7 manual, GM asks to not use 10W30, 10W40 and 20W50.... No mention of the 5W50.

If that's the case then have at er.
 

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Discussion Starter · #8 ·
mjw30: I'm OK with you.
The informations I gave regarding the oil grades are coming from a US C7 manual.
I still not received my car, so I don't know if the recommendations will be the same for Europe, specially regarding the Dexos1 labeling which will not be required for us I think (pure GM marketing spec. oil for US : many oil companies are “paying the piper” to make sure they have oils to meet these new specs for GM vehicles.)
 

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Swiss,

It will be interesting to see what the European manuals have to say about these and many other things. It will highlight what's marketing fluff and what's a real technological requirement.
 

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Discussion Starter · #10 ·
I will try to arrange something to have those informations before my car delivery but I can't guarantee...that interest me a lot too :rolleyes:
 

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In racing my Corvettes since 1984 C4 used Mobil I it was clear that using the lighter viscosity becomes blowby real easy
so day of racing sees that oil as PCV venting and with the engine reverb these newer engines have will find more air heading to aircleaner

Example when I raced my ZR-1 in 60-80 mile ORRs running speeds 160-180 MPH the 5W30 could lose 1 quart or more
when using 15W50 or 10W40 did not
I used what Team Corvette and Mobil I racing told me back in the 1990s was mixing Mobil I grades to get a 10W40

GM is suggesting what they have history on in their own racing,

15W50 will reduce the oiling issues through PCV and reverb

Bit of a negative is the thicker viscosity is the slower it flows through system such as cooler so it retains more heat and can increase oil
pressure a bit.

Serious racing we all run higher flow volume of radiator, heat exchangers for oil cooling so 15W50 then not a heat issue.

Also in my 99 C5 racer to help keep oil temps down the oil filter was relocated to front/left corner of car,
added oil lines and heat exchanger increased oil volume to almost 8 quarts.
 

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Discussion Starter · #13 · (Edited)
So in this article about "track brake pads", when did they seat the pads before hitting the track? Is that why they had such poor performance from the carbon pads?
I think you are referring to the Edmunds first track session report...
The surprising problem they had with the brakes, even fitted with Carbotech XP12 and XP10 was not caused by the pads or the brake fluid.
The tell tale sign there was the fluid leaking out of the bleed screw (they have a leak)... So a mechanical issue, certainly due to over-tighten bleeders.

Apart that those pads are Ceramic and Metallic brake construction, no carbon and iron in their compounds ;-) (if I well understand your reference to the carbon pads)
The ones they fitted on the Z51 were pre bedded at the factory, gain of time vs bedding process after the pads fitting.

J.R.
Thank you to share your experiences, it's interesting to know.
 

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GM says to switch back way from Mobil 1 15-50 when back off the track. Also says to switch back to normal brake fluid afterwards. Why? I'm going to put in the 15-50 and DOT 4 before next weeks track day.
Is this really necessary. My 2015 is also my DD. Planning on several track days this summer. Too much work.
Also, are the fans really that necessary? I'm not going to be pushing the car real hard compared to experienced trackers. Just want to have some fun and stay safe.
 

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Any updates on this topic? I am thinking of tracking but all this prep back and forth. That's a lot of hassle.
 

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I just re-read the manual.

I just had my 4th free oil change. If I change it to the higher temp oil why can't I just leave that in as long as I don't drive it on cold days which I don't because of the tires?

Since my car came with the cooling rings I suppose I have the dual rotors. So why can't I just keep the rings on? And where do I buy the wire?

I suppose the car has DOT 3 brake fluid! Are there any issues if I just put in Modul 600 or regular DOT 4 and leave it in there?

Changed the camber setting. That is nor really necessary unless you are an expert right?
 

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I just re-read the manual.

I just had my 4th free oil change. If I change it to the higher temp oil why can't I just leave that in as long as I don't drive it on cold days which I don't because of the tires?

Since my car came with the cooling rings I suppose I have the dual rotors. So why can't I just keep the rings on? And where do I buy the wire?

I suppose the car has DOT 3 brake fluid! Are there any issues if I just put in Modul 600 or regular DOT 4 and leave it in there?

Changed the camber setting. That is nor really necessary unless you are an expert right?
Seems like rust was the reason for removing the cooling rings?
 

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I am about to track mine and had the same question about changing out the oil. I have been told if you run the 15-50 make sure you thoroughly warm the car up every time you start it up. Keep it under 2500 rpm and be very easy on it until 100 degrees minimum.

This was good for me to hear since I'm not big on warming modern motors up normally, but that's another thread.
 

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Seems like rust was the reason for removing the cooling rings?
Correct. I actually found that in print from GM somewhere. I will check them but I think they are aluminum and the wire stainless so the corrosion concern must be the face of the rotor. In my dry climate I doubt that is a big deal.
 
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