10w40 vs 20w50 for track use
 

I have done a few track days and I'm hooked :D. My car has basic engine mods (exhaust, intake, tune) and I currently use Amsoil Z-Rod 10w30. I live in SoCal and the temps last weekend were 106*F and my oil temp was around 230-250*F. From reading around, seems most recommend either 10w40 or 20w50. Which would be better for my application? I can't remember the thread, but there was a concern about running a 50 weight in a stock tolerance motor. Any help would be greatly appreciated.


PS my car has 104k miles if that helps.

Tracked my car for 4 years at Fontana & always ran the 10w/30. Stock motor w/all bolt-ons & E85 tune

I always looked for a good 10w/30 with high ZDDP. With the built motor, now I just run rotella T6 (probably not a good winter oil, but car isn't driven in the winter).

You'll be fine with 10w30. With the abuse of a tack day, I would put an actual racing oil in the motor. Something like amsoil dominator 10w30.

A friend just sent me a link to some recent oil testing:
https://540ratblog.wordpress.com/

It's super long but eventually gets to some interesting results.

I always told people not to run diesel oil. Gasoline engines have far different demands.


153. 5W40 SHELL ROTELLA T6 Diesel Oil, synthetic, API CJ-4, CI-4 Plus, CI-4, CH-4, SM, SL = 67,804 psi
zinc = TBD
phos = TBD
moly = TBD


I'm glad to see amsoil scored well in his tests. :)

Nice article, stupid long but didn't take long to find some good info in there. Maybe Ill switch back over to Mobile 1 5w30 since its easy to get and #5 on the list.


I did find the max RPM section interesting. Build 2.3/2.4 at 90 f/s would be 8230rpms. I'm babying it at 7800!


94mm crank would be 8750.

Seems I made a good choice using Z-Rod 10w30. Scored in the top 5 in almost every test. Thanks for the help.

One of us is gonna have to cut/paste the info.
Om my cell phone, I scrolled down to the good stuff then hit "back" by accident. Gave up. LOL

also interesting that an 88mm crank would be 9350@90fps or 8300@80fps.

TL;DR for the OP.
neither 10w40 nor 20w50 seem like the correct oil to run based on that guy's advice. mobil1 5w30 (new formulation with dexos1 approval) is one of the highest ranked oils in his testing.

http://wpc.1c96.edgecastcdn.net/001C96/G-Items/Performance%20Testing%20Archives/g3115-5w30-study-archived-2013/files/html5/index.html


A 5w30 review but same idea.

I'd have to check BITOG but I think this test has been discredited as that one-arm bandit test or something, no?

I've done track days with ZROD and immediately sent out the oil for UOA.

https://r56hs.com/2015/10/25/evo-uoa-3/

looked perfectly fine. I am switching to redline 5w30 though moving forward. i'll know for sure by july, but IMO better additive package, slightly higher (thicker) viscosity at 100cst, lower viscosity at 40cst, and better HTHS number (crucial for our cars)

::
to be specifically on topic - stock block, stock head, I think 30wt oil is good.

If you read my link above Redline actually came near last place. But I've been running amsoil dom 15w50 for years on the stock block.

interesting - I'm going to be doing a back to back track day in July. I'll run zrod one day and redline the next and see how the UOAs come out.

What about our turbos? The ONLY reason I'm running 50w VR1 is because FP recommended it for my application.