Almost done with break-in miles on my miata and want to run Amsoil this time around. In the past I used T6, Mobil 15w50, royal purple. Im torn between the Amsoil Signature series 5w50 and the Dominator Race oil 15w50. I dont plan on tracking the car, but it will be driven in a spirited fashon on the street. I like the 50 weight stuff for increased warm oil pressure it makes me feel all warm and fuzzy inside. The Signature series seems like the choice here, but the Race oil probably has a better additive package and I plan on changing oil every 3000 miles anyways. What say you guys?

 

Race oil won't typically have additives to buffer acid formation and some other things generally desired in a street engine. It is designed to run a handful of sessions between changes. Bear that in mind.

 

Where do you live, and what oil temperatures do you see? Hard to get oil really hot on the street.
Might be better off with a much thinner oil. Spec Miata guys run 20 and 30wt at 300*
Even the 10w40 Amsoil https://www.amsoil.com/shop/by-produ...?code=AMOQT-EA has great pressure at 280* depending on your clearances and pump. All depends on sustained temps and if by built you mean tight or loose?
Race oils need a race maintenance schedule.

 

Spec Miata guys rebuild engines very regularly. Not a great pattern to emulate for a street car. Racing is about sacrifices.

 

Louisville KY. Honestly I have no idea what my oil temps would be, I don't have a way to monitor that currently. Motor is built...wiseco/Manley/acl bearings on the looser side of the spectrum. So maybe I'm better off with their street formula rather than the dominator. Makes sense that's kinda what I was thinking initially.

 

From what I have heard, the Dominator oil has more zinc in it. Works great for older engines. A link I came across recently claims Amsoil Signature performed better than the Dominator. I have not had a chance to actually read through this, but it is something to look over.

https://540ratblog.wordpress.com/201...-test-ranking/

 

That was a good read, I went with Amsoil 10w30 signature, their oil filter, their MTG 75w90 for the 6 speed, and their diff fluid.

 

I'm still on the brotella bandwagon t6 for the engine, which is nearly impossible to beat at $23/jug at wally world.
Amsoil for the trans/diff.

 

+1 I run that in my WRX and ran it in the miata before I built the engine. Only reason Im not going back with it this time around is I read that recently they changed their additive package and its not as good as it once was. Ive been trying to find recent reports on its film strength, etc but cant find anything definitive.

 

I'm gonna ask for proof, because that last part is bogus imo
In fact, we recently discussed this and concluded that nothing truly important actually changed. Tons and tons of discussions about this on all forums, including bitog

 

I did infact search maybe I need to be more tryhard. Good to know its still good stuff.

 

to be clear, I'm talking about the 5w40 t6, not the new 5w30 they just released.
the 40 remains as a diesel oil, whereas the 30 is actually approved for gasoline engines

 

right, the 5w40 is what Ive always used in my WRX. I know they changed the formulation to meet CK-4 standards I honestly cant find exactly what changed.