Again that depends on your operating temp... just arbitraly picking an oil because you think it sounds right is wrong.

here is from the Factory Turbo manual (87 Turbo supplement):



You'll clearly note the call for 20W50 for over freezing.

 

I have the owners manual and it does not recomend 10w-30 specifically for an NA. All it does is show a chart with temperatures and viscosity and it says to use the best to match the temperature of your area. I use 10w-40 all year around and I have had no problems at all in either of my second gens.

Ike

 

'89TII-Orig owner slight mods 157,000 miles-Never had to add a quart of oil between changes (3,000 miles).
20-50 Summer...10-40 Winter
When the vehicle was new, up to @ 100,000 miles, I only used an oil with not only the highest "S" rating, but also a "C" rating a/c the turbo. Thought this might be overkill because I don't drive the car hard (143,000 miles on the original clutch), so since that time I opted to use only an oil with "S" rating.

 

if you live in hell like me, you can use straight 50 weight

 

what you guys think about 15w 50 synthetic.

thats what i use

the fisrt number 15w means flow when hot right

the second number 50 means flow when cold

is this right?

 

wrong grim-ripper:
15/50
cold/hot

 

I use Valvoline 5W-30. Always works for me!

 

i found this

Multi-weight oils (e.g. - 10W-30) are a new invention made possible by adding polymers to oil. The polymers allow the oil to have different weights at different temperatures. The first number indicates the viscocity of the oil at a cold temperature, while the second number indicates the viscosity at operating temperature. This page offers the following very interesting description of how the polymers work:

 

so when you 1st start your engine you want your oil to flow good so a 15/50 oil will do just that, right!

and when your engine is at operating temp. you want the oil to be thicker for better protection. so the 15/50 will be good for miami weather.

im trying to figure all this oil stuff out!

 

The NAPA autoparts part guide says to use 5w-30. They have never failed me before!!!!

 

wouldnt str8 50 be bad since at start up it will be to thick to protect?

 

And wouldn't there be a difference between what is good for a n/a or a turbo? How about engine age and mod level? How would these effect oil weight needs?

 

not here bro, the devil actually carries a heavy supply

10W40 is the WORST, stay away.

A BIG gap in oil viscousity is NOT good, 20 is the max acceptable(10W30, 20W50, etc.), since the polymers break down too quickly in lets say 10W45..

I recommend you use 20W50, personally I like Castrol and Mobil/Exxon.
just don't use synthetic oil or blends/additives
and make sure you change the oil filter.

 

so i shouldnt use 15/50 mobile 1 thats a difference of 35. anyone else have a good reply to this ?

is 15/50 that much diff. from 20/50 remember i use full synthetic so there arent as many polymers in the oil, right?

 

If you're using synth, don't bother worrying about the viscosity diffference...



-Ted

 

i found this

One distinction: According to the laboratory tests, Mobil 1 and Pennzoil Performax synthetics flow exceptionally easily at low temperatures ---- a condition our taxi tests didn't simulate effectively. They also had the highest viscosity under high-temperature, high-stress conditions, when a thick oil protects the engine. Thus, these oils may be a good choice for hard driving in extreme temperatures

here's the site

http://www.scuderiaciriani.com/rx7/oil.html