Would rotella synthetic 5w-40, 10w-30 or 15w-40 be good? And if so, which between the three?

 

5W-40 is the best of those options for an FI car.

 

thanks- thats what I ended up getting- the rotella synthetic 5w-40.

 

Most motorcycle oil's have high levels of Zinc & Phosphorus(much higher than Shell Rotella) and there made for bikes that turn 15,000+ rpm's.

ROD

 

well I actually changed my mind. I spent the last couple hours doing research on this and according to the tbn ratings amongst other things, you guys are right: amsoil seems to be the best oils for FI/E85 use.

I got a hold of an amsoil distributor and ordered 8 gallons of the fully synthetic amsoil SAE 10w-40, which has a very nice 12.1 tbn rating (as shown in the link)
http://www.amsoil.com/storefront/amo.aspx

Eventhough the rotella seems to be e85 decent, I'll be returning it tomorrow so i can stick with the better amsoil from now on. The funny thing is the distributor actually recommended my OCI's could be every 5000 miles because of the quality of the oil and my driving style/use of the car (which is moderate daily driving and cruising/ frequent or occasional racing) and some other technical stuff, etc, etc. which makes me happy because the longer OCI's will compensate for the expense of amsoil if this is the case.
Some of the guys on the evo and Z forums seemed to agree with these OCI's too, especially after I saw the results of their many oil tests from blackstone per 5000 miles. Ironically, the amsoil seemed to be doing MORE justice the longer the interval changes were (just not too long). If this is true, it would seem on the contrary with most of you e85 gurus who are saying interval changes should be every 1500 miles AT MOST. I guess some are just more anal than others, or im missing something again.

Either way, I can't wait to get some new blood of life for my car.

 

Good choice!

I'm sure you could run the Amsoil a lot longer than 1500 miles. I'm just very anal and I only put about 1000 miles on the S a year anyway, so that's why I change mine every 750-1000 miles or once a year.

 

saying you HAVE to change it every 1500 is overkill, but it'd probably behoove you to have a UOA done after 1500-2000 miles to be sure

 

Yea that's understandable

 

for me having the same question...

So it looks like Amsoil is best, but what are the 2nd and 3rd best options? Brad Penn and Rotella respectively or what?

Also, is 10W40 too heavy for ball bearing turbos? I thought I read that that weight was recommended for journal bearing turbos and 10W30 was for ball bearing turbos?

 

I'd like to know the same thing