You thin oil guys are a baddd influence :^)

[aquariuscsm]

I took some much needed vacation days (heading up to Nashville for the Nascar race). So I`m bored at home and started thinking how bad I wanted to tinker with my car! Sooooooo,I had some Valvoline 10W40 dino sitting around and well,out goes the 20W50 and in goes the 10W40. How do you say night and day diference????? Feels like a different car! Engine is so smooooooth and quiet! It felt really weird when I broke the rear tires loose accelerating in 3rd gear! Did the 20W50 really rob my car of that much power? If I`m really brave,I may drop down to their 10W30 next oci. Don`t know if I`m brave enough to try a 5W30 though,since the factory fsm says not to,although there`s a guy on one of the Z32 forums that uses Pennzoil dino 5W30 in his twin turbo Z and swears by it.

 

[addyguy]

I'm of the general opinion that DOHC cars have more to loose from a thicker oil that OHV 2-valve engines. DOHC engines have a lot more parts 'moving around' - 4 valves over each cylinder; 2 camshafts above each head, that can be slowed down by the 'drag' of heavier oils. An OHV engine just has the one center-mounted camshaft, and 2 valves over each cylinder, to be 'slowed down' by oil.

So yeah, I could entirely believe you'd feel a difference going from 20W-50 to 10W-40 in an engine like yours, but not so much in an OHV engine.

 

[demarpaint]

I'm not surprised. I think a good 10W30 synthetic will do you even more good. A good 5W30 synthetic should be fine too. JMO

 

[TallPaul]

Just be careful of the momentum. 10w30 is fine, but don't go beyond into the land of thin ice.

 

[ryland]

Dosent that car take 10w30 anyways? I would think a 5w30 syn would be the best choice IMO

 

[Mr Nice]

Why are you runnning 20w50 in the first place, isn't that a bit too thick for that non turbo engine ?

 

[aquariuscsm]

Originally Posted By: ryland
Dosent that car take 10w30 anyways? I would think a 5w30 syn would be the best choice IMO


Here`s a page from the 1990-1996 Z32 fsm:

 

[lexus114]

Because he lives in the great state of Texas,and he`s concerned about heat.

 

[addyguy]

I find that chart weird. Gives the usual warnngs about using thin oils for high speed/high heat driving, but then recomends straight 20-weight for the hottest temp. section.

Yes, I understand about a multi-visc. shearing down, but still, they rec. straight 20-weight, 20W-40 and 20W-50, but not straight 30-weight?

A HM 10W-30, or a HDEO 10W-30 between 11 and 12cst@100C would probably be IDEAL for that engine.

 

[Dominik]

Coworker of mine here in Canada Uses 5W-30 Mobil1 in his '1992 300ZX Twin Turbo. The car is never winter driven (still under 100,000 km on the odometer) And judging by his emisions and local specialty Nissan shop the engine is in A-1 condition

 

[HTSS_TR]

"Engine is so smooooooth and quiet!" is what I feel with PP 5W20 and M1 0W20 in E430 which had M1 0W40 most of its life as recommended by MB.

If you go with M1 0W30 next change, you'll like it even more.

 

[Dominik]

Well from the attached chart it looks like the 5W-30 is not ideal it kinda barelly passes for the turbo engines. The guy I mentioned does use the 5W-30 viscosity or that's what the local shop says they put in it and the engine is supposedly healthy. Then again he never boots it and his commute is something like 14 km or 15 min of city driving. Still I would have used something thicker

 

[ravenchris]

Not brave M1 0W-40. Brave M1 0W-30.

 

[lexus114]

Originally Posted By: ravenchris
Not brave M1 0W-40. Brave M1 0W-30.


The Mobil-1 0W-40 might be a real good choice for him.

 

[ryland]

If you follow that chart good luck to you. That chart is junk and is compleatly old school.

 

[440Magnum]

Originally Posted By: addyguy
I find that chart weird. Gives the usual warnngs about using thin oils for high speed/high heat driving, but then recomends straight 20-weight for the hottest temp. section.


I'm glad I'm not the only one that got a brain cramp. Typo? Makes one question the accuracy of the whole manual if so...

 

[Dominik]

15W-40 would be my choice. And yes that SAE 20 was a typo for sure.

 

[IndyIan]

I don't know about picking up significant hp going from 20W50 to 10W40...
I think its like washing a car, it always seems to drive better after.

According to redline
Quote:
Each reduction in viscosity grade allows 1-2% more power.
Redline racing oil site

 

[addyguy]

I doubt it. Reasoning probably is they still want an oil, even in hotter temps, that has a lower start-up viscosity than a straight 30-weight. They probably 'feel' 20 weight is good in even hot temps b/c it won't shear down at all.

 

[aquariuscsm]

Originally Posted By: IndyIan
I don't know about picking up significant hp going from 20W50 to 10W40...
I think its like washing a car, it always seems to drive better after.

According to redline
Quote:
Each reduction in viscosity grade allows 1-2% more power.
Redline racing oil site


You`re definitely right about the clean car effect.......as if our cars have "soul" and a clean car is a happy car