I had run 2 consecutive 8,000-9500 mile intervals with Pennzoil Platinum 5w20. I have 114k currently on '05 Base. I caught Royal Purple on sale at NAPA for or $5/qt but they only had 5w30. So after putting that in my car, my engine ran noticably smoother and quieter. I also was getting a good 1-2 mpg. On long hwy trips I would top out at 27-28 mpg with the PP but now I was getting 29-30 consistently. Man that feels good! In stop-go I had been getting 20 to sometimes 22mpg. With RP, 23-24 was normal and now, after 9k miles, I am getting 22-23 city. So still noticably smoother and better mpg.

Now for the test: That was going from PP 5w20 to RP 5w30. Now I ordered Royal Purple 5w20. I am very curious to see A) if my engine runs smoother or not as smooth. and B) a difference in the mpg.

I am very in tuned with my engine and will be able to recall if it is better or worse that the PP 5w20. I'll update later.

 

 

thanks for using ur car as the guinea pig ... keep us updated with the results

 

I used RP in my previous car, g35. That engine loved RP. It idled smoother, pulled cleaner, and generally felt better. I'm not sure about the gas mileage, 'cause I was always driving it hard.

I just got my Type S - so it hasnt gotten its RP yet. I've bought it though... just waiting till its oil change time.

 

I'm glad you didn't say the car felt faster with RP. Glad you like the oil! I always tell people experimenting with oil to find one they like and stick with it. Also, make sure you research independent studies on oil so you don't pay too much for something that you could get cheaper with a different manufacturer. Not that it matters, but I'm a die hard mobil1 fan. All of the necessary and unnecessary being said, I'll be watching this thread to see your mpg results as you test. Have fun!

Also, it's a good idea to keep a log of all oil changes and fill ups to see how your mpg averages as your mileage changes. It's good information to have and if you decide to sell, that's just one more thing that says "I care".

 

You really need to send your oil into a lab and let their results speak for the effectiveness of the oil. Oil isn't really a "seat of your pants" kind of thing......
Blackstone Labs or some other similar.

http://www.blackstone-labs.com/free-test-kits.php

I've always loved Royal Purple, just never enough to pay for it. But we don't want to go all "oil thread" on everybody, eh!

 

I have been toying with the idea of getting an oil analysis. However, I don't know how much it will tell me considering I have nothing to compare it to. No matter what it tells me, I don't think the results are going to be completely damning of a higher quality oil like I have been using. At 114k miles, I guess I would find out if something catastrophic was happening in my engine, but I don't think small differences from one test to another are that significant. I don't want to get caught up in worrying about microns of Tin.

Plus spending $25 will make this oil change about $40+$6+25= over $70.

 

 

Oil Analysis would be a great tool to help you understand the wear in the engine as you change oils. It doesn't take too many samples to build a trend, and then you would be able to see the effects different oils have on wear. You may find a lower priced oil offers the same protection as RP, which could help offset the cost of the UOA. Similarly, you may find that you can extend the oil drains, again lowering the cost of your changes.

 

I highly doubt you are truly getting better MPG soley by switching to a higher viscosity oil.

 

I honestly think going to the 5w30 helped smooth out the motor. But increase in mpg is odd.

PP is a superb oil, I'm actually going to use 5w30 PP in my TL (damn MID is at 100% )

 

I went from 5w20 syn blend (M1) to 0w40 full syn (M1). Can't tell a difference in "smoothness"...If anything, MPG has gone down.

 

I'm not saying I might be getting better MPG, I definitely am. I have calculated every fillup in my car (via dashboard) since I've owned it. I absolutely did not like the PP 5w20 in my car. I could tell the oil contributed to a sloppy feel to the valvetrain and engine. I don't know if it is b/c I have an aging engine and this particular 5w20 was on the thin side or what.

My theory is that if the engine is not running smoothly, then it is not running as efficiently as a smooth running engine to a certain extent. I do not think that "the thinner you go the better MPG you get only at the expense of wear."

Now I did switch to the Redline ATF about 3k miles before switching to RP. That could also be contributing. The transmission is a resistance to the flywheel thus the engine, and could lead to a more efficient system i.e. better mpg. That is part of the reason flywheel and rear-wheel hp are different.

That being said, as a general rule of thumb you are absolutely correct that a thicker oil would been more resistance and less mpg. BUT I am getting the feeling that smoothing out my engine's performance may be contributing to 1 or even 2 mph when hwy driving. Either way, I am happy about it no matter what the reason! I haven't gotten mpg like this even when I bought the car at 74k miles. And like I say, it has been cosistent for the entire 9, 000 or so miles.

Thanks for everyone's interest, I know I have an interest in the oil research here and even at BITOG sometimes (although I usually don't admit it!)

 

Also, I do want to mention that I was fully expecting a slight decrease or at the least, no change in mpg. I had been putting 5w20 every time. I do not think I will be able to conclude with some revolution applicable for everyone's car, just mine. I also do not think smoother engine means better mpg, just in my case.

 

so if you want to put royal purple but your engine currently has something else, whats the procedure to convert it over? Does it need to be flushed or something?(sorry i dont know jack about cars)

 

Just your standard oil change. Drain old oil. Put in new oil.

 

I used to run RP 5w-30 on my Cadillac Deville and I was so in tune with that car that I could feel a difference compared to 5w-30 full syn mobile 1 it felt cleaner and smoother in every which way. I cant wait till my TL is ready for her first oil change since purchase to switch to something better then what the dealer put in there. Only a couple hundred miles more. Have you used the RP oil filter as well I heard that was one of the best available right now.