Oil viscosity: 5w20 vs. 5w30

[MrClean]

So in warmer climates, like the Houston area, wouldn't it be a worthwhile trade-off to give up a little mpg to protect the engine to a greater extent by using 5w30 instead of 5w20?

I'm running Royal Purple, BTW. and will be switching to RP tranny fluid and rear diff fluid as well (it comes with the friction adder already).

Your thoughts?

 

[VSOP]

Because of the VTC I would stick with the 5w20...

 

[MikeVistaBlue06]

Most 5W-30 oils will shear down into a 5W-20 anyway. These oils also have newer additives to prevent wear and such.

The tolerences are tight on these modular engines, so I'm up here in Dallas using 5W-20 year round and no problems thus far. In fact, I have 5 cases of 10W30 oil for my truck that will probably take me years to use! My new Lincoln MKZ, the 'Stang, and the old lady's Honda all use 5W-20!

Here is a good oil site for everything you want to know about oil, but were afraid to ask!

www.bobistheoilguy.com

Thx,

Mike

 

[Hawgman]

Hell, just move up to Dallas and don't worry about the heat. It was snowing a couple of hours ago.

 

[3V_V8]

Because of the VTC I would stick with the 5w20...

+1 it has been said that the thicker oils mess with the VCT.

 

[Larry_H]

The thicker oil does play tricks on the VVT and Overhead cams need lots of oil....volume...not pressure

 

[thump_rrr]

So in warmer climates, like the Houston area, wouldn't it be a worthwhile trade-off to give up a little mpg to protect the engine to a greater extent by using 5w30 instead of 5w20?

I'm running Royal Purple, BTW. and will be switching to RP tranny fluid and rear diff fluid as well (it comes with the friction adder already).

Your thoughts?

I would not replace the transmission fluid with anything other than what tremec recommends. Mercon/Dexron III

 

[MikeVistaBlue06]

It was snowing a couple of hours ago.

No shit Doc! I told the old lady it was snowing yesterday and she looked at me as if I were on crack or something and mumbled something like it ain't cold enough to snow.

Good to know I wasn't seeing things!!!! Thought I might have to give up the booze!

Mike

 

[MikeVistaBlue06]

So in warmer climates, like the Houston area, wouldn't it be a worthwhile trade-off to give up a little mpg to protect the engine to a greater extent by using 5w30 instead of 5w20?

I'm running Royal Purple, BTW. and will be switching to RP tranny fluid and rear diff fluid as well (it comes with the friction adder already).

Your thoughts?

I would not replace the transmission fluid with anything other than what tremec recommends. Mercon/Dexron III

+100000000000

You're asking for it when you mess with something other than the OEM transmission fluid. I learned this the hard way on a Chrysler!!!

Mike

 

[94tbird]

snow in dallas huh? damn i figured you guys would be too far south to see that

 

[MrClean]

Thank you gentlemen, I'll heed your advice: OEM fluids in tranny & rear diff, and 5w20 in the engine.

thump_rrr; good to see you here!

 

[don_w]

The thicker oil does play tricks on the VVT and Overhead cams need lots of oil....volume...not pressure

Hmmmm... on my "non-stock" shortblock, I've been running 15w-40 dino oil, and now 20w-50 Lucas Oil synthetic. Adam built the motor, and recommended the heavier weight. I've noticed zero issues, and I've been running it like that for over 10,000 miles and almost 400 passes at the track.

 

[Cali HP Addict]

I have been running Royal Purple Synchromax in my 5sp for 4000 miles w/no issues.

 

[MrClean]

I have been running Royal Purple Synchromax in my 5sp for 4000 miles w/no issues.

Thanks for the input; notice any change? Did the shifteing get smoother? hp increase due to lower friction?

 

[Cali HP Addict]

The shifting defenately seemed to improve. I wouldn't have been able to feel a couple hp since I was over 400rwhp when I swapped.

 

[MikeVistaBlue06]

I have been running Royal Purple Synchromax in my 5sp for 4000 miles w/no issues.

Thanks for the input; notice any change? Did the shifteing get smoother? hp increase due to lower friction?

Changing fluids in the manual transmission or rear-end probably won't hurt.

I was cautioning folks on changing fluids on an automatic transmission! Clutch plates and such in those are picky about the fluid!

Mike

 

[Larry_H]

The thicker oil does play tricks on the VVT and Overhead cams need lots of oil....volume...not pressure

Hmmmm... on my "non-stock" shortblock, I've been running 15w-40 dino oil, and now 20w-50 Lucas Oil synthetic. Adam built the motor, and recommended the heavier weight. I've noticed zero issues, and I've been running it like that for over 10,000 miles and almost 400 passes at the track.

Don, Have you had it on a dyno with 5w-20 and with the 15w-40? I wonder what the difference in viscosity is doing as far as changing the cam timing curve, if any change at all....

 

[94tbird]

The thicker oil does play tricks on the VVT and Overhead cams need lots of oil....volume...not pressure

Hmmmm... on my "non-stock" shortblock, I've been running 15w-40 dino oil, and now 20w-50 Lucas Oil synthetic. Adam built the motor, and recommended the heavier weight. I've noticed zero issues, and I've been running it like that for over 10,000 miles and almost 400 passes at the track.

Don, Have you had it on a dyno with 5w-20 and with the 15w-40? I wonder what the difference in viscosity is doing as far as changing the cam timing curve, if any change at all....

now thats an excellent question!

 

[don_w]

The thicker oil does play tricks on the VVT and Overhead cams need lots of oil....volume...not pressure

Hmmmm... on my "non-stock" shortblock, I've been running 15w-40 dino oil, and now 20w-50 Lucas Oil synthetic. Adam built the motor, and recommended the heavier weight. I've noticed zero issues, and I've been running it like that for over 10,000 miles and almost 400 passes at the track.

Don, Have you had it on a dyno with 5w-20 and with the 15w-40? I wonder what the difference in viscosity is doing as far as changing the cam timing curve, if any change at all....

now thats an excellent question!

It's never had 5w-20 in it all. Adam used the heavier oil from day 1.

 

[MrClean]

Hmmmm, this couls turn out to be a good thread...maybe we can coax a stillstock S197 owner to dyno it with the regular dino oil just before his oil change, and then dyno it again immediately after the oil change to RP 5W30...preferably on the same day to limit the environmental effects....