Royal Purple / Fact or Fiction

[JDoiron]

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Changed all my fluids from front to back to RP a couple of weeks ago. Never saw my MPG screen in the truck read better than 20. 6 in over 11 years. It is now on 21. 8 and still climbing. This is my work truck so my weekly trips have not changed during the life of the truck.

Go figure!!!!!!!!

 

[jelag]

I used to sell chassis dyno's for car testing years ago... I learned there was a lot of snake oil sold... . we'd run a vehicle for 15-20 min over a computer aided path and repeat the path after the changes... we found as an example that slick 50 improved performance in the engine but no enough to pay for the cost of treatment each oil change... . we found that some chemicals added to the transmissions and diff's would make a change... HOWEVER there was no way of telling if those slick products would damage any of the engine or other places they were installed... so over the years I've personally stayed away from them... .

because of CAFE, corporate average fuel economy required by CA & the Feds, if there was a product that was safe and would give say 5% change or even 2% change over the life of the vehicle you'd see it in the proprietary oils and chemicals in the engine and transmission just to improve the CAFE...

Just my thoughts...

 

[Bob4x4]

Back in 84 I converted all my fluids to synthetic it did make an improvement but was pricey. How many miles till it would payback????

 

[DNDracing]

Can't speak directly to fuel economy, but 10 years ago, in an AMC 401CID that is in the Gremlin listed in my signature, that we had running on an engine dyno, we produced 488hp and 495 ft-lbs of torque running conventional oil that we had in for engine break in (also probably still some assembly lube mixed in there).

We drained the oil out on the dyno, an put in Royal Purple, and the first pull with the cold synthetic, we jumped 7 hp to 495, and 8 ft lbs to 503. Once the stuff got warmed up, we saw a 12hp gain to 500, and 15 ft lbs to to 510, both about a 3% gain.

I asked the dyno operator if that was normal, and his response was, "yeah, that synthetic lube is slippery stuff" (don't ask me why I remember that exact quote, I think it was the way he worded it). He said some of the higher performance Chrysler Hemi's they have ran show 5 - 10% gains with the switch to synthetic. If I hadn't seen it with my own two eyes, I would still be very skeptical.

I run Amsoil in everything I have now (could get it quite a bit cheaper than the Royal Purple stuff) and I've been happy with it. Since I've run it in my 2005 in the signature since I purchased the truck, I'm not sure if it equates to any fuel mileage gains. I guess I could change to conventional a few oil changes and see, but I won't.

FWIW, get 16 - 19 MPG with my truck depending on season with mostly 2 lane country road driving, 10 - 15% freeway.