I have used several oils and change them about every 2500 miles on average and test them often. Currently I am using Rotella T6 5W-40 and no oil that I have used has had any effect on gas mileage, I average 13-14MPG combined no matter what. Oh, and I track every tank of gas. I can get 20MPG on the highway with the cruise on but that is rare since I have a heavy foot.

 

Anyone who insults RP had better not be using ANY conventional oil in their engine is it is better than 100% of the conventionals out there. There is not a single conventional in existence that is better. Ignorant owners who don't know how to take care of their engines will typically blame their oil (or maybe their tools?) after they do something stupid. This too happens 100% of the time.

Film strength is also not determined by viscosity but rather formulation. Here's something that will mess some people up. Your viscosity requirements change with temperature and load. An engine that is lugging along in 6th gear at 25 mph needs a THICKER viscosity oil than one that is full throttle at 8000 rpm. There was a link a while back to another forum where a doctor gave his opinion on oils and weights. He stated that since an oil was thinnest when hottest that this was proof that this was all the viscosity the oil needed to be anywhere which is why thicker at colder temps was bad. This is fundamentally flawed logic!!! FWIW: An oil's viscosity is considered useful down to 2 cSt. However film strength of each formulation will have effects on various oils making some more useful than others per any viscosity.

I have no desire to get into oil chats anymore so I'm leaving it at that.

 

But oil chats are fun

 

I love you, RG.

 

Fred, it's posts like this that help me maintain my sanity.

I admit that I switched from RP at about 40,000 miles after using it since I bought the car because I felt a dramatic difference in the car's behavior after just 3,000 mile oil changes. I felt, at the time, that the oil was breaking down faster than I had expected but I had no actual lab testing to back up those results. BHR has done engine rebuilds with motors that used RP and they were in perfect shape.

 

You are wrong. all wrong !!!

You know why? Cuz you don't have a Doctor degree!(maybe u do I dunno) so yeah, you're wrong.

As long as people have a Doctor degree, they can say whatever they want, 5w20 is ok for that V12 560 bhp Ferrari man ! Come on !

You and the BHR crew are wrong. You guys got no DR degree nor u guys drive Ferraris ! WRONG WRONG WRONG !!!!!

 

I bet that "doctor" is a chiropractor, not a real doctor.

 

I got the same issues with RP, not in the RX, but in another piston engine...it seemed very sluggish after a few thousand miles.

 

Personally I wouldn't run anything lower than 40 for summer or if you are doing sustained high rpm revving. I know its stupid to draw conclusion and believe what I saw in videos but after watching BMI Enduro Challenge that includes the RX-8, I wouldn't touch anything <40.

Again I admit I'm a retard in this kind of discussion so feel free to correct me.

 

When I get bored and want a good read to make me laugh, I pull up these oil threads. Love em.

By the way, which brand is best????? just kidding.

 

Then don't come asking the BHR team for advice anymore since we have no idea what we're talking about.

No soup for you!

 

bhr?

 

slightly touching the ground inside front and rear tire oil syn.com. that is your answer!

beers

 

i remember reading a tech paper titled " Developing a Motor oil for the rotary engine".
No lie.
It was about 6-7 pages long and it had a LOT of really good info. Needless to say it was very well researched and written.
To sum it up
1- rotary engine needs at least a 40 wgt oil for bearing protection
2- the heavier the wgt oil used the more carbon buildup in the apex seal grove3
3- synthetics using the poly somethings composition--cant remember specifics but i know Redline oils use it--- causes less deposit buildup.

This was on a rotary that did not see a 9K redline (imho a big mistake by mazda--the 8 engine is not designed for 9K operation --again imho)
OD