C66 Racing

One of the most common questions I get as a forum AMSOIL dealer/vendor, is what oil to use in my Vette that I both drive on the track and the street. Unfortunately, I haven't had a good answer because for the track, I'd recommend a high ZDDP oil but AMSOIL only had these in 40 grade and racing formulations, neither of which is quite right for a street driven car. Note that none of the below oils meet GM standard 4718M (or the new dexos1) which requires meeting current API specs, which in turn limit phosphorus to 800 ppm, which in my opinion is not nearly enough for the track.

AMSOIL has had the AMSOIL SAE Synthetic Premium Protection 10w40 (Product Code AMOQT) which was probably my most common recommendation has it has high ZDDP (zinc 1378 ppm, phosphorus 1265 ppm) and the detergents and dispersants needed for street use. The better overall choice for the track is the AMSOIL Dominator Synthetic 10w30 Racing Motor Oil (zinc 1575 ppm, phosphorus 1474 ppm) I use in mine. But, this doesn't have the detergents and dispersants needed for street use.

I have submitted several suggestions to AMSOIL to come out with a high ZDDP oil in 30 grade formulation for street use and this week they released these two new offerings:
AMSOIL Z-ROD 10w30 Synthetic Motor Oil (Product Code ZRTQT)
AMSOIL Z-ROD 20w50 Synthetic Motor Oil (Product Code ZRFQT)

While I don't know the exact zinc and phosphorus content of these two new oils yet, I asked AMSOIL if they would be added to their Technical Services Bulletin for oils recommended for flat tappet cam engines and was informed that they would. Currently the lowest of the oils on that listing has zinc of 1377 ppm and phosphorus of 1265 ppm, so I suspect these two new oils will be in that ballpark. Will post an update when they update their TSB with the actual numbers.

For any forums members who'd like to try these new oils, I'm happy to get them at dealer wholesale, about 25% below retail, for forum members via the AMSOIL Preferred Customer Program. Drop me a PM if interested.

P.S. Viscosity is my next most common question and the answer depends on oil temp. 40 may be right for cars without oil coolers. I have submitted suggestions to AMSOIL to come out with 40 grade versions of both the Dominator racing oil and this new Z-ROD oil.

Rob Willis

Cool. Sounds interesting. I'll be listening.

Might be time to finally leave Mobil1.

C66 Racing

Update to the above, AMSOIL has updated their Technical Service Bulletin on applications requiring high ZDDP oils such as flat tappet cam engines, and now lists the Z-RODs oils has their primary recommendation for this application. The TSB lists that these oils have zinc – 1440 ppm, phosphorus 1320 ppm.

For comparison, here are Mobil 1's ZDDP levels:
Mobil 1 ZDDP Levels

fperra

Why not just add some ZDDP Plus to your Mobil1 oil?
http://www.zddppluscentral.com/

C66 Racing

I've seen tests that show just having more ZDDP by itself doesn't perform as well as a well blended oil. As seen on the above link to AMSOIL's Dominator Racing oil, it outperforms others, including the Mobil 1 racing oils, that have more ZDDP.

And in more detail, in both these AMSOIL commissioned tests which list the actual zinc in many various brands and the related wear test results, you can see that higher zinc by itself doesn't equate to less wear. While many will discount these tests as they are commissioned by AMSOIL, even if you ignore the AMSOIL results, I think it is apparent that just adding ZDDP doesn't necessarily result in the best wear protection by looking at all the other brands in these tests:
AMSOIL Motorcycle Oil “White Paper” (1 MB pdf file)
AMSOIL Gear Lube “White Paper” (2 MB pdf file)

Corvee

PM sent

aggie_corvette

Do any similar test results exist for automotive (gas or diesel) oils?
Those were very helpful.

Any reason we can't put motorcycle oil in our cars?


Will

SouthernSon

I am not sure why you would want to second guess the purpose blended amsoil. Around these parts the syn. motorcycle oil costs more than the amsoil.

C66 Racing

Will,
They do similar tests, but haven't put them into as comprehensive a document, possibly because there are so many variations on motor oil (automotive including current API spec, non-API spec, racing, etc; diesel oils including API CJ-4 and the older CI-4, etc). In some of their literature a few of these can be seen such as the wear test on this product page:
AMSOIL Dominator Synthetic 10w30 Racing Motor Oil (Product Code RD30QT)

I would not recommend using a motorcycle oil in an automotive application - the additive package will be very different. An oil like the Z-ROD listed above will have an additive package designed specifically for automotive applications - and is less expensive than AMSOIL's 10w30 motorcycle oil.

rustyguns

pm sent

jon6.0

Just saw the Z-Rod oil tonight while looking for brake fluid. PM sent.

boblackhardtop

What about zinc & phosphorus content of the Z-rod 20w-50 ?

Black89Z51

I'm in the process of finishing up my track only car. Would you recommend the 10w30? It will have an oil cooler, turing approximately 5800-6000 rpm.

On a side note, would you recommend putting an thermostat in the oil lines to bypass until temp rises?

It's a carbureted L98 with hyd. roller cam.

C66 Racing

Same as the 10w30: zinc – 1440 ppm, phosphorus 1320 ppm

Those are hard questions. I feel that what is most important is your hot viscosity which is both dependent on the grade and hot temp of the oil. Lower viscosity grades flow better, remove more heat. Higher grades will have a much higher fluid flim strength for a given temp, but will have higher pumping and friction losses and will likely heat up more than a lower viscosity grade would.

Also keep in mind that the grades have a large variance. For example, a 30 grade is defined as a viscosity of 9.3 - 12.49 cSt at 100C (212F). That's about a 35% spread. So if someone says they are using a 40 grade (12.5 - 16.49 cSt) and someone else says they are using a 30 grade, you might think one has much higher viscosity than the other, but unless you get down to the details, you really don't know. The 40 grade could be very low in the 40 grade band (as Mobil 1 0w40 is) and the 30 grade could be very high in the 30 grade band (as AMSOIL's Dominator Racing 10w30 and ZROD 10w30 are), and thus they are much closer in viscosity that you might realize.

If your bearing clearances are stock, and you have an oil cooler, I personally would start at a high viscosity 10w30 and evaluate oil temps (keeping in mind that ambient temps play a roll). If they are above about 250F or so, I'd try a higher viscosity oil and compare. I've run everything from a 0w30 to a 20w50 in my 02 Z06 with racing radiator and dedicated oil cooler and found my lowest oil temps (about 245-250F at most tracks) with 10w30. Your experience may vary and not all engines are the same, particularly in bearing clearances.

If your car will be track only, I don't think you need a bypass valve. I warm up my car well before each track session, and even in the races where we really only get part of a lap (pace lap) before the green flag, I can always get my oil over 150F before I hammer it at the green flag. On the street, different story. In the very fews times I've driven my car on the street (and its been years now as I gave up trying to keep it licensed and insured), I never could get my oil warm.

Stan78Vette

More than interested Zrod 10w 30 for 78 Silver anniversary edition