Royal Purple fuel mileage RESULTS

[Solo2driver]

Just got back from a road trip from Southern CA to Denver, CO along the I-15 and I-70, about 2300 miles round trip including street driving in Denver and 7 hours of idling traffic back from Las Vegas. Wife's '95 Saturn DOHC with 152K miles.

Last road trip from San Diego to Phoenix, average 24mpg-28mpg similar weather and road/traffic conditions other than mountains, Mobil 1 10w-30 and regular Mobil ATF.

THIS road trip, 30.586mpg worst and 32.488mpg best with nothing done differently but Royal Purple 10w-30 and RP MaxATF. Includes the Rockies and A/C on for most of the trip.

FWIW, we used to get 36-40mpg San Diego to Austin, TX on our road trips, no mountains and A/C on but car was in much better running condition and 60K miles

I know that there are other variables (altitude, 85 octane fuel and different fuel quality levels), but I think the overall increase and also what has been seen on the street is a good indication of an economy increase. UOA will show if its shearing out of grade or not, we'll have to see.

FWIW, my 200K Mazda RX-7 picked up about 2mpg in mixed street driving with RP 15w-40, and had a stellar 25.8mpg road trip mileage one time (with Mobil DC 20w-50 all I could manage was 22mpg or so highway).


-JamesW
www.DaveTurnerMotorsport.com

 

[JHZR2]

royal purple in the diff of our 94 previa has kept it nice and quiet and picked up 1-2 MPG. NJ driving, mostly highways, though some of them we go on have a good deal of 'big hills'

RP is good stuff.

JMH

 

[Jim 5]

I can believe it, but can somebody explain why?

I saw an episode of "Horsepower TV" on Spike in which they dyno'd a mustang or camaro with it's factory lubricants. Then they put Royal Purple syths in the crancase, gearbox and diff (with equivalent grades to what was in there) and redyno'd.

Nothing else was changed on the car. The car gained something like 8 HP with just a lube change. They were quite surprised and so was I.

I've read throughout the BITOG forums that synthetic doesn't lube better or reduce friction better than dino..it just stands up better to abuse.

If this is true, then what explains in increase in HP...or in your case, the increase in MPG?

Come on oil wizards...how does this work?

 

[rugerman1]

quote:

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Originally posted by Jim 5:
I can believe it, but can somebody explain why?

I saw an episode of "Horsepower TV" on Spike in which they dyno'd a mustang or camaro with it's factory lubricants. Then they put Royal Purple syths in the crancase, gearbox and diff (with equivalent grades to what was in there) and redyno'd.

Nothing else was changed on the car. The car gained something like 8 HP with just a lube change. They were quite surprised and so was I.

I've read throughout the BITOG forums that synthetic doesn't lube better or reduce friction better than dino..it just stands up better to abuse.

If this is true, then what explains in increase in HP...or in your case, the increase in MPG?

Come on oil wizards...how does this work?

---

Host Viscosity and additive package composition

 

[Mitch Alsup]

quote:

---

Originally posted by Jim 5:
I saw an episode of "Horsepower TV" on Spike in which they dyno'd a mustang or camaro with it's factory lubricants. Then they put Royal Purple syths in the crancase, gearbox and diff (with equivalent grades to what was in there) and redyno'd.

Nothing else was changed on the car. The car gained something like 8 HP with just a lube change. They were quite surprised and so was I.

---

It would not surprise me at all if the original oil in that vehicle was overly thick (like 2 grades) in both the engine and tranny and maybe in the diff.

Then switching to the normal RP grades would liberate useful HP, just like using a xW-30 liberates power from a 20W-50 oil.

So the 8 HP the measured could have come from:: 2HP from RP (guess), 2 HP from correct oil grades in engine, 2 HP for correct grade in tranny, 2 HP from the ambient conditions at the time of the second test or running the seond test will fully warnmed up engine/driveline!

I might also note the dyno they use has a 3HP margin of error for back to back runs, and a 5 HP margin of error for runs several hours apart even under identical air conditions. Heck, we have seen 2-3 HP differences (on an identical dyno) by adjusting the air pressure in the tires!

A dyno is a tool, a wonderfully useful tool, however it is NOT a number generator, and the SHAPE of the TQ and HP curves tells you a lot more about any change in actual performance than the peak numbers. Which is all that shows like HP TV* allow you to see! Why, because it might lead to haveing their bluff (of thier sponsors bluff) called!

[*] I happen to like HP TV and watch it all the time, however, I watch it with a grain of salt in my hand at all times.

 

[bulwnkl]

Red Line has similar dyno numbers with (IIRC) a fairly late-model Corvette. Nearly all of the dyno gains in these scenarios are from the tranny & diff. Engine oil change alone yields them something like 1-2%.

My own personal WAG estimate (and that's all it is) is that the increases are chiefly due to the superior low-temp flow characteristics of a synthetic (including GIII) fluid. IOW, I think that since a synthetic fluid will appear "thinner" at any given temperature below the 212F at which viscosities are rated, you get more hp through the tranny and diff. I also think the bulk of the hp increase will disappear once 212F is reached with all the fluids.

Please also note that the significant gains are ALWAYS achieved with "old-tech" large-displacement, rwd American iron.

 

[Steve S]

quote:

---

Originally posted by Jim 5:
I can believe it, but can somebody explain why?

I saw an episode of "Horsepower TV" on Spike in which they dyno'd a mustang or camaro with it's factory lubricants. Then they put Royal Purple syths in the crancase, gearbox and diff (with equivalent grades to what was in there) and redyno'd.

Nothing else was changed on the car. The car gained something like 8 HP with just a lube change. They were quite surprised and so was I.

I've read throughout the BITOG forums that synthetic doesn't lube better or reduce friction better than dino..it just stands up better to abuse.

If this is true, then what explains in increase in HP...or in your case, the increase in MPG?

Come on oil wizards...how does this work?

---

Could the mpg increase come from a a lower viscosity?