rrounds

Back in the 70's we always had to mix two different weight gear lube's to get the weight we wanted. I still mix my own motor oil since they took Zink/Phosphorus out of over the road oil.

How about a 50/50 mix of M1 75w/140 and M1 75w/90 that will work in cold weather and will not thin down as much in the summer as the 75w/90 would. This is what I'm going to run as both are API GL-5 gear lube. When we go for a drive, most of the time it's 400+ miles and the rear end does get hot.


Specifications and Approvals

Mobil 1 Synthetic Gear Lubricant LS meets or exceeds the requirements of the following industry specifications: 75W-140
API GL-5
Typical Properties
Mobil 1 Synthetic Gear Lubricant LS
SAE Grade 75W-140
VViscosity (ASTM D445)
cSt @ 40ºC 170
cst @ 100ºC 24.4
Viscosity Index 175
Pour Point, ºC (ASTM D97) -48
Flash Point, ºC (ASTM D92) 207
Density@15.6 ºC g/ml (ASTM D4052) 0.872

ROD

Swiftoy

Why not look at amsoils SG75/110 or any of there severe gear oils for that matter they all have been reformulated and from the test I saw they were far better than mobil 1.

CarbonCrew

While it's no longer a wildly popular practice, I do not think you would have any issues mixing similar oil with different viscosities, especially within the same brand. Base oil and add. packs should be near identical and, I think, would have no compatibility issues. Mobil specifically states in their FAQ that mixing engine oils poses no issues. I see no reason that a gear oil would be any different.

Also, I found a calculator that predicts a final viscosity for an oil mix. A 50/50 mix of 75w-90 and 75w-110 yielded a viscosity of 19.14 cSt at 100 C. SAE J306 specifies a viscosity of 18.5-24.0 cSt at 100 C. It would seem reasonable that if you were looking for something a bit thicker one could up the quantity of the 140 weight oil.

I like your thinking. I too would like a 110 weight gear oil but I've never been a fan of mail ordering boutique brand oils. I'll be curious to hear your results. Please keep up posted.

Swiftoy

Here are the specs.

Carbon Crew it really isnt a big deal to order on line, if you become a preferred customer it is only 10.85 per qt our diff only takes one quart. Regular price is 14.05 a quart. Place an order and it shows up on your door step no different from ordering anything else mail order.

If you dont believe in the product, well then thats a different issue



TYPICAL TECHNICAL PROPERTIES

AMSOIL SEVERE GEAR® Synthetic Extreme Pressure (EP) Lubricant 75W-110 (SVT)
Kinematic Viscosity @ 100°C, cSt (ASTM D-445) 20.4
Kinematic Viscosity @ 40°C, cst (ASTM D-445) 141.3
Viscosity Index (ASTM D-2270) 167
Brookfield Viscosity, cP (150,000 Max) @-40°C 118,500
Flash Point, °C (°F) (ASTM D-92) 150°C Min. 220 (428)
Pour Point, °C (°F) (ASTM D-97) -48 (-54)
Copper Corrosion (ASTM D-130) 1b Max @ 121 °C (250°F) / 3hr 1b
Falex Procedure B (ASTM D-3233) (failure load, lbf.) 2500
Foam Stability (ASTM D-892) (20/50/20 maximum) 0/0/0

zeroptzero

do this

flyingtoaster

Can you elaborate? The only tests I know of are UOAs and virtually every oil does very well.

rrounds

Swiftoy,
It's not that I don't believe in Amsoil it's that the auto makers like other oils and they can use what ever they want to. The Callaway twin turbo Corvette had to have M1 or the warranty was void same for the Saleen S7 that came with 750hp and 700lb-ft Torque. I don't know of any car maker(exotic or not) that says to use Redline or Amsoil or any of the other small oil company's oil or the warranty is void.
If M1 is good enough for a 250k Porsche GT2 RS it's good enough for my 20k Honda.

Here is just about every gear lube there is and there is a lot of them
http://www.lubritecinc.com/PDF/2010synapigl5.pdf

ROD

zeroptzero

I like Mobil1, I think it gets a bad wrap unjustly from people that want to blame it for everything under the sun. It's a great oil, maybe they enter into agreements with certain manufacturers to recommend their oils but no auto company is going to risk using a bad oil just for marketing deals, so it has to perform well at the end of the day, which it does.

Some of the boutique oils won't or can't afford to pay for API certification. Some oil manufacturers also do not want to be hamstrung with lowered additive levels that API certification requires everytime standards change. They can also be great oils but they wish to operate by different rules and no large auto manufacturer could recommend them for that reason.

Swiftoy

Flying toaster if I can find the info on the new formulation Ill scan it to you.

Rrounds my statement was directed at carbon crew in regards to ordering boutique oils.

For the record I never said anywhere M1 was a bad oil did I. I have used it quite a bit over the years never had any issues. I prefer the Amsoil product as it generally our performs the competition. You posted a question I gave a response it is a great gear oil. Our car is specd for 90wt gear oil not a multi weight I believe, correct me if I am wrong. The 75/110 comes pretty close to that 90wt spec. Mix and match all you want but as good as most products are today your 1970's thinking is outdated in 2010.

High levels of Phosphorous can damage catalytic convertors. High Zinc levels are more or less for flattappet camshafts or muscle car applications. Disco is dead man!

Regardless of what auto manufacturers choose to use for Motor oil I have yet to see a better 10/30 wt oil than Amsoil 10/30ATM.

JFUSION hit the mark in regards to boutique oils.

rrounds

"High levels of Phosphorous can damage catalytic converters", yup sure can if you get a lot of oil past the rings or valves. So if the motor does use a lot of oil you have bigger problems. Phosphorous and Zinc offer more lubricating qualities under high pressure and I think that the S2000 engine operates under high pressure. Just because the gov. takes it out does not mean I can't put it back in. If it was not for the new type of cat(and the gov.) Phosphorous and Zinc would still be in oil today at the higher levels of a few years ago(like when the S2000 was first made). I have around 100k miles on a after market high-flow cat and it still passes smog just fine even though I use a high Phosphorous and Zinc mix of oil. In older over the road trucks the new oil(low Phosphorous and Zinc) is destroying the engines in as little as 30k miles. Some have gone 200k with no problem but a lot have been destroyed in a relatively short time.

I won't know if my "mix" will lower the temps in the rear end or not till I put it in. I only have 9 temp. readings of my rear end so far, I will get about 20 before I switch to the "mix" if it lowers the temps(less friction then I will post back(but this will take some time) if the temps. go up then I'll try something else. Straight 90w gets real thin at the temps I have recorded so far.

As an old drag racer(form the 70's and 80's) I kept records of all my runs and what changes I made and if it helped or hurt the car(times).

Just like on the motorcycle forum's if you want to start a fight, start a post about OIL
I aways like to read opposing or alternative views on something I post, God knows I made enough mistakes when I started racing.

ROD