Inline pro thank god helped me rebuild my blown s2000 it's a beast now like 447whp. I asked Tom from inline what weight to use because I used to use mobil 1 10w 30sae thats when I only was on 7 pounds, Tom told me to use 10w 40sae he gave me a couble of brands mobil 1 does not make it only for high milage and he told me today to try vavoline syth power but they don't make it in 10w 40 either, I spent alot on my new engine and i am only used to 10w 30 mobil1. what should I get the only thing I can find in 10w 40 is castrol syntec full synthetic. IS that good I can't find anything else in 10w 40 unless it's for high milage. What do you guys recommend. THanks sorry for going on and on.

 

I used the Castrol Syntec 10w40 for years with no problems. I just now switched to Amsoil full syn 10w40, which is way more superior over Castrol.

 

10-40 weight oils that I have, and would use again:

Motul 300v

Brad Penn <using it for the fist time now.

Amsoil

RedLine

 

Im with Spoolin, I have AMsoil 10w-40

 

Amsoil 10W-40 is the way to go. That is also what I use.

 

I have always used 20w50 valvoline racing oil. That's what my motor builder says to use. (Cortney Green)

 

What a 10-40 over a 10-30? Is this mainly for turbos since the oil will get alot hotter?

 

We used this in all of our race engines at the last shop I worked at but mostly because of the high zinc content and it's benefits in flat tappet applications. I don't think it would be quite the miracle oil on a modern car. I use Amsoil Dominator 15w50. I've also had good luck with Brad Penn oils but again because of the high zinc content. Not that there is anything wrong with zinc in a modern motor it's just not a necessity like it is for the historic stuff. Id rather have the great shear resistance and temperature stability of Amsoil.

 

^^Also, 20w50 would be good for an engine thats built for boost since they are built looser but I wouldnt use it on our stock engines that are tighter.

Yes, Kyushin, 10w40 would be better for turbo applications. The 40 is for hotter running situations.

 

Yeah I only use it in my race car I would run 10-40 or even 10-30 in my street car. The 50 weights are more applicable when your oil temp is always high. I do run the 50 weight in a stock motor but at consistently extreme temperatures.