I should know this by now, but I never really paid much attention to how oil weight can affect hp. I saw a commercial for royal purple saying their light-weight synthetics can improve hp, supposedly by lowering the mass the oil pump has to churn. I'm running a synthetic 20W-50 right now...should I go lower? How low is too low? It's getting time to change the oil and plugs so I figured I'd figure this out before I bought a load of oil.

 

amsoil 0 weight , you wont

 

I won't what?

 

i remeber when i had my prelude, if i used thick oil, the revs were not as fast as the light oil.

 

the difference in HP is more than likely not noticable.... Just play to safety first..... Ya wouldnt fly an airplane with thin oil for 3% more HP, we mighta died when we went WOT during that close call....

 

It doesn't ADD HP, it decreases resistance, which means you rev up quicker, there is less drag on the engine.

 

oh , I see so having less drag dosent give you more power ???? this is new to me , well there have been alot of tests using lots of different oils you should do a google check.

 

i do agree on the better safe then sorry use thicker oil.
i use 10-40 in the 1jz. when i get the money to replace all the seals and gaskets and rings i am going to start with moble1 full synthetic. only after the rebuild though.

 

i had the full synthetic in the 7m, 10 30 mobil 1, worked awesome. then noticed oil pressure wasnt as high as i wanted when it started warming up outside, so I switched to 10 40 then 20 50, im going to go back to the 10 40 when its not so hot out, but the mobil1 was by far the best you can really feel the difference... oh yeah I have all new seals, and gaskets (no 17 year old ones left $$)

 

it also really depends on how the motor was built, if your not driving a race motor with super exact bearing clearances and a balance rotating assembly the lighter oil is going to allow your engine to vibrate more, and at higher rpm eventually that vibration leads to a impact of the rod bearing and the crank journal, aka spun bearings. stick to 10w-30 and over, thats my opinion