Glen220

I have seen several threads on whether or not any snythetic oil should be used in a rotary engine. I had an early 80's RX-7 and used Mobil1 in it with no problem. I heard that you should not use synthetic oil in a rotary engine, especially the RX-8 and I e-mailed Mazda USA for an opinion below is a direct cut and paste of the e-mail response:
__________________________________________________ _
Hello Glen,

Thank you for contacting Mazda North American Operations. I appreciate the opportunity to respond to you.

In regards to your inquiry, Mazda does not suggest synthetic oil use for the RX-8. The reason for this is that the Rotary engines must burn oil in the combustion chambers. Because synthetic oil burns at a high temperature it may not fully burn in the combustion chambers causing seals to stick.
__________________________________________________ _

I hope this helps end the debate.

Take care,
Glen

syntrix

Good stuff, and thanks for taking the time to email MNAO!!!

However, I still don't know why they haven't put "don't use synthetics" in the owners manual!!!

I've only changed with dino oil so far

bureau13

Of course the debate is not ended! Sounds like MNAO let that marketing intern answer the mail again. Has anyone ever heard of seals sticking as a result of using synthetic? Neither have I. As for synthetic burning at a higher temperature...I'll bet that's not even true, but if there was ever an engine that could burn it it would be this bloody furnace! :-)

jds

RenesisPower

This is very interesting!

1)
This is the very first "official" response I have seen from Mazda. I too have a hard time believing that synthetic oil will not burn easily, making the seals stick.

2)
However, I find it strange if a 19 year old intern is making this stuff up on his/her own and sending emails. It just doesn't happen, I hope it doesn't happen.

3)
Lastly, as said before why didn't Mazda put this in the owner's manual? Something like "Use of synthetic oil is NOT recommended".

I guess I am as confused as ever over this issue.

JINXRX

I too have confronted the dealership techs about synthetics cause I ordered a box of Royal Purple synthetic under the verification of the person who sold it to me that it was okay and even reccomended. When I went for my oil change and brought forward my own oil they said no synthetic because of oil having to burn. Royal Purple claims they see no problem using synthetics and that Mazda is full of it. Oh yeah and the techs at Mazda also said that (under the wraps ofcourse) that mazda hasn't/won't spend the money for tests on synthetics with their vehicles and there for says it is not allowed.

Chris - Midnight Black GT

RenesisPower

The only way to settle this is to wait for a year or two. There are most defenitely owners who have used synthetic in their Renesis and will share results, blown engine or nothing unusual.

The manual does say that it is normal for the engine to burn some oil which means 1) oil is entering the chambers to lubricate seals, 2) burns in the combustion chamber.

A synthetic oil 1) will lubricate better than organic oils 2) If not fully burnt in the combustion phase due its higher tolerance it will discharge in the exhaust phase.

I just don't see why synthetics are not recomended. Is this a myth or factual ?

paradigm

This is an ongoing debate with rx7 owners. Most are hardcore dino oil users. If you even mention the word synthetic the'll go on a 10 minute long tirade on how horrible it is for rotary engines. However I personally know a few people who made the switch, and they haven't looked back since. One of them even had their engine rebuilt, and it was in great shape when it was disassembled.

Nubo

Ha ha! Synthetic is too good?

It still does not make sense that Mazda would not stipulate this in the Owners Manual. They certainly have no desire to be replacing failed engines unnecessarily not to mention owner satisfaction. They certainly wouldn't only give out this tidbit to the 1 out of 10,000 owners who mail in an inquiry.

They did specifically prohibit synthetics in the past, from what I've read. That makes it even more unlikely that the omission from the manual is an oversight.

I speculate that whatever problem existed between the older rotaries and synthetic oil (excessive ash deposits is the most common reason I've read) had been solved by the time the API SL service specification came into place. If you look into the API service categories you'll see some of the recent ones do include lower deposits and residue in the list of improvements. In order to get the SL rating the oil has to test to the standard, regardless of whether it is synthetic or not.

r0tor

iTrader: (1)

grrrr....

Synthetics resist "burn-off" better then dino oils. Burn-off is oil vaporizing under intense heat.

"Burning" is a different thing. A synthetic will burn just as easily as a dino when put in a flame. For gods sakes, most synthetics is just dino oil with all the impurities ripped out, its still a hydro-carbon that will burn.

s1mike22

when i got my car, the salesman told me not to ever use synthetic. i'm gonna play it safe and not use it.

RX7FD3

I agree with MAZDA Synthetic oil kills rotary engines little by little. You might not notice it until you reach 50.000 Miles or so and believe me, your engine will not reach 70.000K if you use syntetic oil.

PLEASE DONT!!!

mikeb

BINGO

islandsoon

My salesman also said things like "one push of this button disables the traction control" "Don't worry, this car has 250 hp after it gets broken in, Mazda is very conservative" "Take her up to the red line and see what she'll do" "It's the same engine in the automatic as the 6 speed, just doesn't rev as high to save the tranny" and on and on... So much for what your salesman said.

Tom

Nugs

To those asking why its not in the manual...its easier to put things in the maual that you should do then all the things you should NOT do.

RX7FD3

You lost me there, But just for the record. Automatic RX8s have been made in a way that an automatic should not be reved as hard or driven like the manual for the simple reason of fuel injection. The cars ECU in the automatic models doesnt allow the transmittion to rev as high due to the fact that the car will run lean in fuel. The fuel injector will cut off at a certain speed. That wont mean that car wont do it, it will...but belieeve me, we are going to see blown engines left and right.

You guys should learn a lot about rotary engines before upgrading, driving hard, or taking the vehicles to speeds they have not meant to go without upgrading the computer mapping and fuel injectors

RenesisPower

This issue will remain a mystery to me till official word from Mazda comes confirming that Synthetic is good or bad for the Renesis.

BTW, since when car salemen know anything about the cars they sell. They would be the last person I would take advice from on a technical issue like this.

At this point I have no factual data on this issue, so I am going to play it safe and use organic oils till proven otherwise. This is unfortunate since I have used Mobil 1 for a few years and really believe that it is a great lubricant.

Over and out.

khoney

Where did you come up with that bulls**t? I have a 17-year -old RX-7 with 160K that has seen nothing but synthetic. I hate it when people talk out of their ***.

Glen220

I see a debate is going even though my intent was to give the "official" word from Mazda USA on my e-mail question to them about the use of synthetic oil.

As I started my original post with the fact I had an 80's RX-7 and used synthetic (Mobil 1) oil in it the entire time I had it (about 50,000 miles) and never had a problem. It was later (with the 90's models) I heard you should NOT use synthetic oil in them. I also read it on the Mobil1 web site with the statement that Mazda did not recommend synthetic oil in their rotary engine (this is pre-RX-8).

I have seen the Mobil 1 commercials where it shows the synthetic oil in a frying pan next to a pan of conventional oil and the conventional oil is smoking and bubbling where the Mobile 1 is not. It does lead me to believe the Mobile 1 had a higher ignition point than conventional oil. Additionally, my Mazda service department said DO NOT use synthetic oil in the rotary engine, this is after I had received the e-mail from Mazda USA stating the same thing.

I am a HUGE fan of Mobil1 oil and have used it in every car I have had since 1977. But I will take a wait and see attitude with my RX-8, there must be some reason Mazda doesn't want it to be used.

For those who are going to use it please keep us posted on how it works, I really would like to use it but am erroring on the side of caution for now.

Take care,
Glen

Gord96BRG

Well, you certainly lost any credibility you might have had right there! You should follow your own advice - you obviously know very little about the RX-8, and are spouting heresay and gibberish as if it were fact.

Here's your for the record - the 4 speed automatic trans in the RX-8 can not take the high RPM of the high-power engine. It has absolutely nothing to do with fuel injection - your statement makes absolutely no sense. The transmission is rev limited to under 7500 rpm - therefore Mazda did a low-power (actually low-redline) version of the Renesis engine specifically for the auto trans. In some markets (not North America), Mazda is also selling that less-expensive low-power engine as an entry-level model in the RX-8 lineup. The differences between the engines are that the high power engine has 3 injectors per rotor instead of 2 (the third is only used at high rpm (again, which the auto trans can't handle); the high power engine also has a 3rd intake tract vs. just 2 for the low power; and the high power engine is equipped with 2 oil coolers vs. just one on the low-power auto trans cars.

In a year or two (2006 model year?), Mazda will release a 5 speed auto trans for the RX-8 that can handle the 9500 rpm rev limit of the high-power engine. They will also be releasing a 6 speed semi-manual gearbox (computer controlled clutch and shifter, a la Ferrari F1 and BMW SMG systems).

Now, what would you have us believe about synthetic oils again? Never mind, it's not like we can trust your word or opinions anymore...

Regards,
Gordon

RX7FD3

Im not talking out of my ***, Ive owned 2 Rotary vehicles and i know what im talking about. If you have a 17 yr old RX-7 is more likely to be a 1st gen right?? Well those cars arent exposed to as much HP as the RX-8 or even a and FD...so i know what im talking about... Ive been building these things up for years.
1st gen RX-7s are known to last up to 250K miles... If you lower the amount of HP of a RX8/fd and run it at a lower amount of hp, i can assure you it will last forever as well.

and if you were to know rotaries you would know that synthetic oil requieres higher temperatures to fully burn in the combustion chambers and add to that the amount of HP an FE or FD develop you will easily cause seals to stick

RX7FD3

You are right, i dont know FE's just yet so i dont know the internals for sure. Yet the rotary basics are the same,
I have worked on FDs and FCs for years. Apex seals and oil burining at a certain temperature in the combustion chamber. It is common sense to use something that will burn faster so the apex seals wont stick...Thats just common sense. That didnt apply to FB's because they didnt generate that much power nor were exposed to the amount of HP generates in FEs and FDs.
Thats just rotary engines 101.

RenesisPower

Guys,

I saw this on: www.pettitracing.com

This a lubricant that is added to the fuel to reduce friction and wear on the seal.

I have never heard of these guys and this product. What do you think?


Rotary Engine Tech Tip

The rotary's oil injection system operates like this: Oil is fed via the engine oiling system (crankcase) to a variable ratio metering pump. From there, it is routed to the engine where it trickles in, partially mixing with the onrushing air-fuel mixture. Fuel-to-oil ratios of 400:1 and higher are common. With over 20 years of rotary experience, we have seen the harsh effects of insufficient lubrication on the delicate internal components of rotary engines. To add to this condition, fuel is of the unleaded variety and designed to CLEAN. High combustion temperatures produced by rotary engines break down the oil film, then today's super fuels finish the job, leaving internal components, i.e. apex seals, side seals, corner seals, etc, void of lubrication. As a result, friction and wear increase, performance and efficiency decrease. Because of this, Protek-R was developed. By adding only 4 ounces to the average fill-up of 15 gallons of fuel, the fuel-to-oil ratio is improved by 100%, bringing the ratio to 200:1 or better. Protek-R can extend rotary engine life by 30% or more, depending on your driving habits and consistency of use.

- Extends engine life
- Reduces internal friction and wear
- Less drag and more power
- Full protection against rust and corrosion
- Blends completely with fuel
- Easier starting
- Carbon free
- 100% synthetic

Look for Protek-R under Lubricants

rxtreme

iTrader: (1)

As this debate rages on, I thought about a compromise between the two. I'll be changing my oil every 2500mi in the rx-8: Once by me and once by the dealer. If I were to make one oil change fully synthetic (Mobil1) and one with dino, would I be getting the best of both worlds? Or just risking the problems the naysayers-of-synthetic speak of reduced by 1/2? I really believe in synthetic and I have yet to see any hardcore evidence suggesting it can't be used effectively in the rx-8 or causes damage if used. I have only seen it in print in the rx-8 service manual, with no explanation as to why it shouldn't be used.

RenesisPower

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I have only seen it in print in the rx-8 service manual, with no explanation as to why it shouldn't be used.
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Where in the manual does it say this? Thanks.

RX7FD3

please read above, it tells you right there why.

To make them easier i will put it in simple english.

Synthetic oil is great for piston engine because it burns a higher temperatures making it last longer. In rotary engines, we need oil to burn in the combustion chamber proccess, thats why we need to add more oil more often. Having said that, if you have a syntetic oil, it will take longer to burn if it does at all, causing your apex seals to stick.

There has been a debate for years about this amoung RX-7 performance shops but the basics of rotary 101 will tell you, that you need to burn oil and is a lot harder to do so with snythetic oil.....completly the opposite of piston engines! that rotary for you!