Here’s one for all the Royal Purple fans out there.

[Zonaman]

I wanted to see for myself if there was a significant difference between the more costly Royal Purple synthetic motor oil and the less expensive but ever popular Mobil 1. I had two samples of 10w30 motor oil from my ’69 C-10 analyzed by the good ol’ boys at Oil Analysis Lab, Inc.
The first sample was Mobil 1 synthetic @ 3,400 miles. That sample was driven over cooler months in Arizona from 12/06-5/07. The second sample was Royal Purple @ 3,000 miles. Over the hot months, 5/07-1/08, with more towing. I meant to go 3,400 but misread the odometer but don’t think the 400 miles will be too significant here.

Their claim is that “…It increases horsepower and torque, saves fuels and reduces heat, wear and emissions. It has unsurpassed oxidation stability that allows for extended oil drains and fewer oil changes,…” I don’t know if these claims are relative to other synthetics or not but I’ll report the significant results:

It increases horsepower and torque- If it did, I’d need a dyno to see the difference on my truck. I couldn’t say I noticed any difference.

saves fuels and reduces heat- At first I could swear it squeezed out a about 1 mile to the gallon, then later not. It’s hard to say- too many variables effect mileage. Naturally, it runs hotter in summer. I put in a 4 core radiator and that's cooler- so I can't say it's the oil. My guage is stock so I can't report in degrees anyhow..

It has unsurpassed oxidation stability that allows for extended oil drains and fewer oil changes- Here’s a real interesting result: The Mobil 1 had a FT-IR Spectrophotometer Oxidation Reading of “9” (normal range) while the Royal Purple measured “33” (moderate). Nitration came in higher too- “8” for Mobil 1 and “18” for Royal Purple. Both in the normal range, however. I will say the Royal Purple was put through an Arizona summer with lots of towing up mountains, so even with 400 fewer miles maybe that would account for the difference? Also, I think I read somewhere that the first go with Royal Purple can yield some weird results. I’m hoping one of the knowledgeable guys here can chime in on that.

Now for the big one, in my mind at least- What about bearing wear? Lead is main measure of that and here’s what happened- Mobil 1 tested at 47 ppm while the Royal Purple turned in 22 ppm. Even taking into consideration the 400 mile difference that's a significant indication the Royal Purple protected better.

Emissions- no significant difference at the Maricopa County test station.

The other significant difference was Silicon. 11 ppm for Mobil 1 and 23 ppm for Royal Purple. I’m not sure about this one- both samples used the same K&N cotton fiber air filter and NAPA Gold oil filter (new oil filter each oil change). It’s possible that it’s an anti-foaming additive in Royal Purple. But it probably has more to do with road conditions and the state of my air filter.

For you paper vs cotton fiber air filter fans out there, here’s the results of the particle tests (ISO 11171) on the K&N:

@ 0-3,400 miles (with Mobil 1) >4: 27,156, >6: 1,701, >14: 216, >21: 159, >38: 64, >71: 38. ISO- 22/18/15

@ 3,400-6,400 miles (with Royal Purple) >4: 152,678, >6: 4562, >14: 463, >21:220, >38: 122, >71: 49. ISO- 24/19/15

The oil sample with 6,400 miles on the air filter is a lot dirtier with more “chunks” of every size in there than at 3,400 miles. This compares to the paper filter with 5,500 miles the first time I reported on K&N vs. Paper. So I’d say nothing to go to the press with there.

I’ve got another 5 qts of Royal Purple in there and I’ll test that later and report to you all. Anyway, I’d appreciate any of your takes on all this.

Thanks.