Originally Posted By: CATERHAM
Originally Posted By: irocurpony
Ive read on here that mobil 1 5w30 isnt the best option for lt1/ls1 motors people claim its too thin. Is it the 5w30 weight that is too thin or just mobil 1 5w30. I searched pds and mobil 1 has more viscosity 100c cst and hths then Pennzoil plat, qsud, synpower, and syntec 5w30. I cant find hths for royal purple but cst wise mobil is thicker.
The KV100 spec' is of no importance in terms of operational viscosity, but the HTHSV 3.1cP that most 5W-30 oils like M1, PP, PU and the rest likely have is more than adequate for a street driven LT1 and LS1.
A_Harman has experience running M1 5W-30 on the track with high oil temp's in his Chevy that you will never see on the street, without issue.
Bottom line, for the street, running an oil heavier than the 3.1cP spec' is counterproductive.
^^^^Quite true.
BUT, if I were going to use M1 for a LOT of combined street/track use, in the heat, I would opt for their exemplary 0W-40, or at the very least, M1 5W-30
HM, despite the great luck/results A_H has had with plain old 5W-30 on lapping days/HPDEs.