[IL] AMSOIL DEALER
10-30-2014, 07:28 PM
#2
Instructor
Member Since: Oct 2014
Location: Illinois
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11-01-2014, 12:49 PM
#4
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C66 Racing #66 NASA ST2, SCCA T2
AMSOIL Dealer (Forum Vendor)
AMSOIL Ordering Information (Retail sales using reference #1206638 benefit the forum.)
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C66 Racing #66 NASA ST2, SCCA T2
AMSOIL Dealer (Forum Vendor)
AMSOIL Ordering Information (Retail sales using reference #1206638 benefit the forum.)
AMSOIL Preferred Customer Program (Members buy at Wholesale - a savings of about 25%)
AMSOIL Catalog
11-03-2014, 08:04 PM
#5
Burning Brakes
I'am using 10-40 redline for a SC LS7(rebuilt) is amsoil better for my engine? It's a serious question. All the new stuff is really confusing. I'am currently using 3 different oils for my vehicles. Mobil ESP-5/40-14 glk250. Liqui Moly-5/40-11.A3 and redline -08 z06 sure would be great to finally settle on one. I have no issues with costs just whatever is best.
11-09-2014, 08:57 AM
#7
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ToppThat,
My personal thoughts on oil choices.
Viscosity
Many recommend going up in viscosity in demanding applications, and even GM now puts in the C7 owner's manual to use Mobil 1 15w50 at the track. I don't think it is that simple. I lost an engine my first race season (2003) running Mobil 1 15w50 as was recommended to me at the time. Since then, I've switched to AMSOIL and dropped in viscosity to 40 grade and then 30 grade which I have been running since ~2007 without failure.
If you are using stock bearings in your SC LS7, then your bearing clearances where designed for a 30 grade oil running at an oil temp of ~212F. The 30 grade viscosity spec at 212F is 9.3 - 12.49 cSt.
Like all fluids, the viscosity of oil drops as temp increases. At 300F, a typical 30 grade fluid has lost about 70% of its viscosity. The 30 grade viscosity spec at 300F is > 2.9 cSt.
The 40 grade spec is 12.5 - 16.29 cSt at 212F and > 2.9 cSt (0w40, 5w40, 10w40) and > 3.7 cSt (15w40).
The actual specs for the Red Line 10w40 you are currently using are 15.1 cSt at 212F and 4.4 cSt at 300F.
So I think the question most don't ask is - what is your oil temp?
If you daily drive and your oil temp stays around 212F then I believe a 40 grade oil has too high a viscosity which leads to lower oil flow, thus lower heat removal and increased pumping friction losses. In this case I believe a 30 grade is the better choice. If you drive your car such that your oil temp is consistently well above 212F, then a higher viscosity is probably appropriate.
My personal thumbrules (assuming stock bearing clearances): 30 grade ~212F-260F, 40 grade ~260F - ~280F, 50 grade ~>280F. These are thumbrules, not hard numbers.
As an example, I took my 02 Z06 with a heavily modified LS6 (410 RWHP) but stock bearing clearance to Summit Point for a track day. I ran AMSOIL Dominator Racing 10w30 and my oil temps were 253-255F, right at the top of where I am comfortable with a 30 grade oil.
Final comment on oil viscosity. The API spec bands are very wide as you can see from the above. I think it is important when considering which oil to use to look at the actual spec for your choice.
Anti-Wear Additives
My 2nd consideration for engine oils is anti-wear additives.
Phosphorus, along with zinc, in a compound called ZDDP, or or zinc dialkyl dithio phosphate, forms an oil's primary anti-wear additive. Unfortunately, phosphorus slowly poisons the cats and prevents the catalytic exchange that allows them to function properly. To ensure auto companies could meet the EPA's 100k+ emissions requirements, the API has slowly been dropping the limit on phosphorus.
From 94-97, the API SH spec allowed up to 1200 ppm phosphorus for 5w30 and 10w30 and didn't address other 30 grade viscosity like 0w30. In 97, API SJ dropped the limit to 1000 ppm, but still did not address 0w30. In 01, API SL kept 1000 ppm phosphorus, but added 0w30 to the spec. In 04, API SM further dropped the limit to 800 ppm, but for the first time set a floor at 600 ppm and advertised that oil's were better. Essentially they were capping how much phosphorus the better oils could have and mandating the lowest amount the cheapest oils must have. The current API SN spec still has the band 600-800 ppm phosphorus.
As GM used to spec an oil meeting current API spec, and now has its own spec (dexos1) which also caps phosphorus, if you follow the owner's manual requirement you are limiting ZDDP.
In demanding applications, even with our roller cam engines, I think ZDDP is important. The AMSOIL Dominator Racing 10w30 I use has zinc – 1575 ppm, phosphorus 1474 ppm, well over current specs.
The Red Line 10w40 is recommended by Red Line for API SN which would imply it has less than 800 ppm phosphorus, but I have seen many used oil analysis reports showing it has more than 800 ppm. That bothers me as I don't think Red Line should recommend it for a spec it doesn't meet.
The Red Line 10w40 is a good oil and is probably a good choice for your car. I recommend at your next oil change you get a used oil analysis sample. I use Blackstone Labs. I would get a sample with TBN.
Not knowing how you use your car, and thus what your typical oil temps are, I hesitate to give a recommendation. With the limited info, I would probably chose this if it were my car (and noting this oil doesn't meet API SN or dexos1 specs):
AMSOIL Z-ROD 10w30 Synthetic Motor Oil (Product Code ZRTQT)
(zinc – 1440 ppm, phosphorus 1320 ppm)
This oil is very similar to the AMSOIL Dominator 10w30 I use at the track. It's viscosity of 11.8 cSt at 212F is high in the 30 grade band and it has a good High Temp High Shear viscosity of 3.6 cSt. The Z-ROD has sufficient detergent and dispersant for 3-5k mile (or one year whichever first) oil change intervals whereas I change the Dominator at about 500 track miles or so.
