JDM suggests using a 5-20 synthetic in thier motors because as engine parts move they create a wave, the thicker oil takes longer to fill back in and continue protecting parts compared to the 5-20....I thought the same thing too, thicker oil would be better for protection so I used to run 20-50 in most of my older cars...and because it helps restore compression temporairily lol.

Apperently there's been MASSIVE arguements over oil weights.

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Black 91 Mustang LX Coupe
2.3L Auto

Denonford 8250Ti
Focal Utopia 165W
Kicker SoloBaric 15" (round)
Rockford 301S
Memphis 75X2
JBL CSX200.1