I agree - the radiator and cooling fans play a more significant role in cooling. A 160 t'stat regulates the amount of coolant that goes through the radiator, allowing it to flow at a slightly lower temperature, which is not to be confused with the actual water temperature in the engine, which may be at 198 degrees vs. 220 degrees with an OEM t'stat. By the time the coolant reaches its target operating temperature, the t'stat is already opened all the way.
People often reprogram their radiator fans to come on a few degrees lower in conjunction with the new t'stat. If high temperatures, e.g., 300 degrees, persist during extreme use such as road course racing, etc., then some will replace the OEM radiator with a higher capacity performance radiator. However, you don't want your engine to run too cool - below the suggested operating temperature. 198 seems to work very well on the LSx engines. My temps seldom exceed 240 on the track.
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[size="2"][font="Tahoma"]Michael Higgins
'04 Corvette C5 Coupe. ECS 383 Stroker; AFR 205; FMS Cam; DTE 3.42; T1 Springs & Bars; Pfadt Shocks, ARH Headers; CAI; RPS Clutch; and more.
HPDE 4/Advanced Group with NASA, MazdaDrivers, TrackDaze, PDA, THSCC, Chin Motorsports, NCM and SCMC.
Good thing you change it every track event... I guarantee you that your M1 oil is oxidizing & breaking down under those conditions. Not to mention for most V8 engines of this type, you really want 10-11 CSt or so of viscosity under operating conditions. The 5w-30 M1 is probably 3-4 at those temps.
Mobil 1 is a very good oil, but not great. There are better choices. It's basically a Group 3 oil with a couple % of Group 4 or 5 (can't recall which at the moment) base stock blended in, so it's really not a "real" pure synthetic oil anymore. Last time I looked into the info I found about their additive package was nothing special either. The only M1 that is a "real" synthetic is the 0w-40 European formula, which is made from Group 4 base stock (similar to Amsoil) along with a small % of Group 5 mixed in. The only bad thing about their 0w-40 is they add alot of VII's to it that can shear down under high temps, so it'll need regular changing with track use as well.
I've seen oil analysis from cars pushed with M1 and let's just say I don't run it any more.
I have had mine tested and Mobil 1 was fine. In fact it was good for 2500 miles on 10w/30 when adding less than a qt per day or 80 minutes running.
I have had mine tested and Mobil 1 was fine. In fact it was good for 2500 miles on 10w/30 when adding less than a qt per day or 80 minutes running.
Yep, Mobil is a good oil. I would figure 2500 miles woudn't be too bad on it. I used to run it for a few k miles too. After I switched to Amsoil, I started leaving it in longer and my wear numbers are slightly lower with it.
LS6 and LS7 wear numbers typically decrease with mileage and usually have little or nothing to do with oil brand as long as it meets the OEM requirements. Furthermore, some studies have shown engine wear may actually decrease as oil mileage increases. Oil analysis is still your best measure of oil life determination, however. Be aware that track use can decrease both engine and oil life significantly.
Mobil 1 is certified as meeting both GM4718M and GM6094M standards. Other oil manufacturers, although they may claim their oils meet the GM spec, may not be certified as doing so. Look for the Starburst emblem. Use of oils not certified by GM, although unlikely, could potentially result in warranty issues.
LS6 and LS7 wear numbers typically decrease with mileage
True, as it does with most engines...
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and usually have little or nothing to do with oil brand as long as it meets the OEM requirements.
Saying that engine wear has nothing to do with oil used overlooks the effect of a bunch of chemistry & is an over simplification...
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Furthermore, some studies have shown engine wear may actually decrease as oil mileage increases.
Ture, and the exact reason for this has been undergoing some debate in the oil industry. It also depends heavily on the oil used (both base stock & additive package) & conditions of use. This has led some to think that recycled oil _may_ actually be better than new if properly cleaned & a new additive pack is used, however, there is little evidence I have seen to support this.
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Oil analysis is still your best measure of oil life determination, however. Be aware that track use can decrease both engine and oil life significantly.
Very true, and this is how I determined that Amsoil held up better in _my_ applications before I ever bought a Z06. I have used Mobil 1 in many of my cars, and ever since they changed to a Group 3 base stock after losing the lawsuit to Castrol over "Syntec", I swear that some of my cars started shearing down the M1 sooner. UOA's verified this (along with a falling TBN and increasing wear numbers) so I decided to try Amsoil. It worked better for me for a greater number of miles. The only Amsoil fluids I didn't have as good of luck with is their transmission lubes, which seem too slippery for the synchros in some of my cars. I tend to drive my cars on street & track, short stops & then super high track temps. Kinda the worst of both worlds. YMMV...
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Mobil 1 is certified as meeting both GM4718M and GM6094M standards. Other oil manufacturers, although they may claim their oils meet the GM spec, may not be certified as doing so. Look for the Starburst emblem. Use of oils not certified by GM, although unlikely, could potentially result in warranty issues.
There's really a lot more to these approvals than meets the eye. And though GM is tight lipped on the exact requirements of 4718, from what most can tell it requires the formulator to guarantee they will not change the formulation more than a percent or so without GM's approval. Most oil co's will not do this as the formulas change all the time. They also appear to have a cold flow & HTHS spec limit along with % of performance change within a certain age/use limit. All good stuff, but not necessarily a guarantee that an oil that has this spec is better than one that doesn't. For example, in Europe Chevy uses M1 0w-40 European formula engine oil, and it does not meet the GM4718 spec. Could it meet the spec? Maybe, but it apparently hasn't been tested or certified yet, along with many others from various mfg's.
Also, the starburst symbol is not a guarantee of greater protection, but just that the oil conforms to the latest ILSAC specs (at the time the oil was made). In some older flat tappet engines, these low ZDDP oils can occasionally cause greater wear, especially if they run hot like a Corvair or Porsche. The current starburst oils are low ZDDP designs that rely on the new FM package to make up for the reduction in anti-wear agents, but this also makes them a slightly better "fuel economy oil" due to the low viscosity & FM package.
Saying that engine wear has nothing to do with oil used overlooks the effect of a bunch of chemistry & is an over simplification...
I stand by the claim that as long as the oil meets the requirements of the manufacturer it is sufficient for the purposes for which the car was intended. Other use may or may not be warrantable.
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All good stuff, but not necessarily a guarantee that an oil that has this spec is better than one that doesn't.
I didn't claim it was better. GM states if it is not certified as meeting the GM4718M and GM6094M standards, as shown with the Starburst, it does not meet their warranty. Claiming to meet the GM spec and actually having the certification are not the same thing. However, I'm not claiming one oil is 'better' or 'worse' than another.
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I have used Mobil 1 in many of my cars, and ever since they changed to a Group 3 base stock after losing the lawsuit to Castrol over "Syntec", I swear that some of my cars started shearing down the M1 sooner.
According to ExxonMobil, Mobil 1 oils use Group IV base stock...
"Thank you for your inquiry,
Question -- Is Mobil 1 a fully synthetic oil?
Answer -- Yes, it is. To meet the demanding requirements of today's specifications (and our customers' expectations) Mobil 1 uses high-performance synthetic fluids, including polyalphaolefins (PAO), along with a proprietary system of additives. In fact, each Mobil 1 viscosity grade uses a specific combination of synthetic fluids and selected additives in order to tailor the viscosity grade to its unique requirement.
Mobil1 motor oils utilize the group IV basestock.
Thank you for choosing ExxonMobil products.
If you need further assistance, please contact ExxonMobil at 1-800-ASK-MOBIL"
For those who don't know the differences...
Group 1 - Conventional - Mineral oil derived from crude oil
Group 2 - Hydroprocessed - Highly refined mineral oil
Group 3 – Severely hydroprocessed - Ultra-refined mineral oil
Group 4 – Full synthetics (chemically derived) - Chemically built Polyalphaolefins (PAO).
According to ExxonMobil, Mobil 1 oils use Group IV base stock...
"Thank you for your inquiry,
Question -- Is Mobil 1 a fully synthetic oil?
Answer -- Yes, it is. To meet the demanding requirements of today's specifications (and our customers' expectations) Mobil 1 uses high-performance synthetic fluids, including polyalphaolefins (PAO), along with a proprietary system of additives. In fact, each Mobil 1 viscosity grade uses a specific combination of synthetic fluids and selected additives in order to tailor the viscosity grade to its unique requirement.
Mobil1 motor oils utilize the group IV basestock.
Thank you for choosing ExxonMobil products. If you need further assistance, please contact ExxonMobil at 1-800-ASK-MOBIL"
For those who don't know the differences...
Group 1 - Conventional - Mineral oil derived from crude oil
Group 2 - Hydroprocessed - Highly refined mineral oil
Group 3 – Severely hydroprocessed - Ultra-refined mineral oil
Group 4 – Full synthetics (chemically derived) - Chemically built Polyalphaolefins (PAO).
Interesting, but if you read carefully their response states they "use high performance synthetic fluids including PAO's"... I remember seeing a spectral analysis that indicated (and somewhere a M1 tech admitted, as their MSDS also verifies) that the current M1 formulations are mostly Group 3 fluids with some Group 4 or Group 5 (a couple % only) added in as part of the additive package. They add the Group 5 esters mostly for seal swell. Their old oils used to be Group 4, but no more. The only current M1 oil that is Group 4 is the 0w-40 European Formula, and I believe the Delvac (which also shares its formulation with the turbo diesel truck formula). This Group 3/4/5 debate on M1 has been reviewed elsewhere multiple times, and multiple sources have concluded their current make up appears to be mostly a Group 3 base stock. M1 is a very good oil, but not as great as it used to be, or as some others.
Remember, that the law now agrees with Castrol's position on marketing a Group 3 as a "fully synthetic oil", and many others are now following suit. The Penzoil Platinum, Mobil 1, QS and almost everyone has a Group 3 "full syn" now.
the law now agrees with Castrol's position on marketing a Group 3 as a "fully synthetic oil", and many others are now following suit. The Penzoil Platinum, Mobil 1, QS and almost everyone has a Group 3 "full syn" now.
Yes, in 1999 the National Advertising Department of the Better Business Bureau ruled that Group III base oils can be considered 'synthetic' because modern oils made using hydroisomerization technology have most of the same performance features of the early synthetics.
(Note the use of the word "synthetic" with no "fully" preceding it)
A little history...
"The word 'synthetic' in the lube industry has traditionally been synonymous with PAO, or polyalfaolefins, which are made from small molecules. The first commercial process for making PAO was pioneered by Gulf Oil in 1951. In the 1960's, Mobil patented an improved process. In the 1970's, Mobil began to market their product as 'Mobil 1'.
Since then, the demand for PAO has grown and some base oil manufacturers began using higher VI feedstocks to make mineral oils with VIs that matched the PAO's. These new Group III oils were not manufactured from small molecules like traditional synthetics but they bridged the performance gap at a lower cost. Some lubricant manufacturers began replacing PAO's with Group III base oils in their "synthetic" engine oils. This created a controversy in the lubricants industry because some believed that PAO's were the only true synthetics.
What qualifies as "synthetic"?
Some manufacturers contended an oil that had been manufactured using base crude but had subsequently undergone hydroisomerization and was hence classified as a Group III oil was in fact no longer a naturally ocurring product and should therefore be deemed a synthetic product. The 1999 ruling supported their contention, while still others believed that only polymerized base oils qualified as true synthetics.
Current Mobil 1...
Currently, ExxonMobil's 'Mobil 1' SuperSyn is made using 100% Group IV PAO basestock. Thus, it is a true synthetic oil, not simply a Group III oil meeting the legal definition of synthetic in the U.S in accordance with the above 1999 ruling.
This screenshot is from an AMSOIL dealers website. Note that under "COMMON 5W-30 SYNTHETIC OILS" Mobil 1 is listed as "Group IV/PAO". Even the competition agrees.
Interesting... so maybe they recently changed their formula back to a Group 4. I know some MSDS's I have buried somewhere listed "highly refined paraffinic" oils., etc, which is one of the dead giveaways for a Group 3 base, which matched several analysis I have seen others perform over the past few years. I even have some data from M1 that previously listed their 0W40 & Delvac as the only Group 4 oils they made.
Whatever base stock M1 has used, some of the cars I have previously used it in sheared it down to nothing in a few thousand miles. That's why I switched, based on direct analysis of the oil & wear metals in my engine. One of my supercharged engines used to shear it's load of M1 5w-30 down to a 5w-20+ within a few thousand miles. The dead giveaway was that the engine would slowly get noisier & rougher. Then the oil would proceed to lose most of its TBN and the combination likely contributed to the somewhat higher measured levels of iron, aluminum, copper & lead wear metals. Regardless if the M1 formula I was using was Group 3 or 4, it was unable to cope with my driving conditions in that vehicle, which led me to try several other oils, including Motul, Redline, and Royal Purple (was going to try Schaeffer's too, but stopped before I got there). Now I settled on a custom blend of Amsoil, which held up better even though I left it in for _nearly_ 1.5x the mileage. I know of others with similar high shear engines (like Nissan VQ's) that prefer to use Penzoil Platinum as they had better results with that, than M1, and it's still available off the shelf.
YMMV, so run whatever works for you that you believe in! I base my usage on test data for my application. If you can't/don't test, or don't know what you're doing, sticking with the factory rec (as you suggested) is a safe bet for most average users. People that race or subject their engines to severe usage would be wise to test their oil & make sure it's viscosity under operating temps is where it should be.
Guess the next time I see some M1 at the store I'll have to look & see if they put back the "100% Synthetic" claim (with an asterisk) that they used to have on the bottles. They dropped this claim whey they were using Group 3 base stocks. They also used to claim "excusive of carrier oils" after the previous line. If they've put it back, I'll believe they switched back to a Group 4.
The TBN based on the ASTM D4739 test* for the Mobil 1 5W-30 used in my '07 Z06 after 5,000 miles was 4.9. As to shearing, the SUS viscosity at 210 degs. F was 61.4.
*Be aware the varying methodologies used by different labs will result in different TBN numbers which are not comparable. However, by itself this does not mean one lab is 'better' than another.
To reiterate, as long as the oil used meets or exceeds the manufacturers specification, it is sufficient for the purposes for which the vehicle was intended. In this case, Mobil 1 meets the GM4718M spec required in order to meet GM warrany requirements for this vehicle.
As of May 2006 the following oils were certified as meeting the GM4718M specification and are labeled as such:
I wouldn't give any credence to the AMSOIL Dealer's website you quoted above No Doubt - he's just a guy like me who may or may not have his website up to date. I suspect the later and base this on the same info quoted by 4wheels above indicating Mobil 1 has gone to Group III basestocks.
Mobil 1's literature is very vague these days. They say the use Group IV, but not how much. Despite a pretty hard press from many of the guys on the oil forums, they will not outright say they don't use Group III. My personal conclusion is the same as 4wheels - they use a mix of Group III, IV and V and the mix is mostly III.
I also wouldn't get hung up on the "fully" synthetic vs just synthetic or 100% synthetic. Group III, IV and V are all synthetic according to previously established court cases (which you mentioned above), so any oil that doesn't use Group II can be called "fully" or 100% synthetic. Synthetic blends use Group II and I think the advertising nomenclature of "fully" or 100% synthetic came up to distinguish synthetics from synthetic blends.
Finally, no where in the owner's manual does it say anything about using an oil certified to meet GM Standard 4718M, just to use one that meets it. I feel that GM is making money from that certification list.
I realize this thread degenerated into another oil discussion, but at the risk of answering the original posters question ...
There are a few things you can do:
1. Get an oil integrated radiator. My C5 ran high temps my first day out. I dropped in an LG Super Cool 2 and temps are back down to 260 F. range on a hot day when I am on it. For the C5-6, Ron Davis also makes a good product.
2. With the radiator in place, you can have your high speed fans programmed to stay on after the water temperature rises to 190 F. The combination of the fans and radiator keep my water around 210 F. I run two bottles of Red line Water Wetter in 30% DexCool / 70% Distilled Water.
3. An alternative to 2...turn on your AC to MAX, sure you lose 5 HP or something trivial like that, but the high speed fans are on and with the oil integrated radiator, you will see oil temps drop rapidly - and the cool air feels good.
...back to the oil. Be sure to use at least 10W30. Perhaps an oil analysis will make you feel better (or worse) about your oil choice. You will then have the knowledge and be able to compare results for yourself. Alternatives are (in no particular order) RedLine, Amsoil, Royal Purple.
Good luck.
Last edited by kmagvette : 05-31-2008 at 07:05 AM.
I'll share my experience from Bondurant's school back in 2004 as a data point. Their C5s (at the time) were running Mobil 1 15W-50 and the one I drove was seeing peaks of ~315degF on the DIC.
I spoke with the shop guys, they said they'd blown two engines early in the program (#4 rod bearing if I recall right) and GM investigated. No oil cooler was recommended, just the heavier oil. No blown engines from that point onward.
Their cars get the snot beat out of them for extended periods of time, by the end of each day the brakes were all hot and stinky, rotors were torn up, tires were gummy, gas tanks were empty. I figure if M1 15W-50 holds up to that kind of prolonged abuse, it's suitable.
I realize this thread degenerated into another oil discussion...
That shouldn't come as a surprise since the thread is about high oil temps during track days. Thus, the door is open to discussion of those things that affect oil, including the, are you ready?......oil itself.
Shudder.
Seriously, you can't legitimately discuss oil temps without talking about the oil too.
It's like talking about submarines without ever talking about water.
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