I found the threads on this forum fascinating
http://www.bobistheoilguy.com/forums...Board=3&page=1

FDs are well known to be exceedingly tough on oil, likely one of the more severe tests in the production street car world: blow-by, high fuel dilution, elevated operating temps, etc, etc...so, I'd like to see if there is any interest in a group of us FD owners sending in their oil to these guys for analysis
http://www.blackstone-labs.com/free_test_kit.html

 

A few have sent ours to Royal purple for testing with David Canitz a few years ago. The FD and rotary in general has fuel dilusion issues so it's best to change your oil every 3k at worst, even in the RX-8. Wait 5k on the 8 and it's not really much oil left for lubricity.

Tim

 

do you recall what your % fuel dilution was?

 

As I remember, the fuel dilution of the tested oil was running around 10%.

People get all **** about their oil on this forum, and most do change at 3k miles. But you don't see oil related engine failures being reported, so you can relax a bit.
It's your coolant mix you should be getting persnickety about.

 

most FD engines fail prematurely for other reasons

 

As far as fuel dilution:
https://www.rx7club.com/showpost.php...7&postcount=11

 

the real question is what are the long term risks associated with high fuel diltuion? I was looking over the Blackstone Labs comments and they don't seem to think it's a big deal, but then again it was no where close to 10%

 

I'm currently in the (long) process of testing and sampling a few oils in my car.

My plan is to run my current oil (Mobil 1 10w-40) for 2k miles and take a sample at 1k and 2k, then repeat with Idemitsu (for it's extreme rotary-ness) and RLI Biosyn 5w-40 because of it's supposed superiority for tolerating heavy fuel dilution. I won't have my results for a year since I barely do 5k/year.

 

Yeah, but engines are suffering cooling disasters long before there are any oil related failures. It's like you're worrying about eventual termite damage while your house is on fire.

 

imho,

the rotary destroys oil quickly. In 2k miles the oil smells like a gas can. Therefore, it doesn't matter much if you have expensive sythetic oil or castrol gtx at 3k miles because the gasoline kills the lubrication.

I buy cheap 20w50 castrol gtx and change it every 1-1500 miles. Costs 15 bucks total with the filter and is cheaper and more effective at lubrication then spending 30 dollars on sythetic and changing it every 3k

 

speculative comment with no facts in hand...high gas dilution reduces apparent viscosity, it does not "kill lubrication [properties]", furthermore it is not necessarily true that all oils perform similarly when exposed to high fuel dilution

 

imo,

this talk about fuel and oil is beating a dead horse. this HAS been discussed many times. especially about oil sampling


everyone is going to have their own experiences about oil change intervals and relative fuel dilution.

 

plenty of subjective opinions, few facts...the testing proposed by dgeesman will be interesting

 

That's how the RLI Biosyn is claimed to be different - based on end-user testing in the Audi RS4 race engine (another fuel dilution nightmare), the engine wear data was much better than they had seen before. Mine will be a test of the claim for our application. By no means will I "prove" anything using my one car and 3 oil changes driven over 3 seasons of the year, but it should at least be interesting. http://www.bobistheoilguy.com/forums...6906/site_id/1

My goal FWIW is not to extend oil change intervals (at 5k/year that's barely twice a year anyway), but if during that 2k I can get better wear numbers I'll absolutely continue with that product.

Dave

 

Apparently you missed the "IMHO" part...

Personally, until Dave's results come back, I'll be following Howard Coleman's advice in this thread:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/you-need-know-about-reformulated-oil-revisited-again-july-08-a-770726/

 

We *could* open a can of worms and have people doing UOAs and posting them for discussion. But because of all the inherent variability, those discussions tend to waste time and teach nothing. And all for what we know is mostly a trivial issue in these cars.

Dave

 

come on its 20 bucks, change the damn oil!

 

agreed

that wasn't my intent, my primary interest is to see if high end oils perform better than conventional oils when exposed to high fuel dilution