I was looking at the specs for the 2006, and they say that premium gas with a minimum of 91 octane is "required" for the rx8... i got this off the mazdausa website... is it different in the manuel? cuz the 2004 manuels mention premium being "recommended" for top performance purposes... Are all the 2006 model year drivers using premium now?

 

you need to link that... it could be. but i doubt it..

beers

 

found it. and you are correct.... that is going to be a though sell...


beers

 

hmm...

 

because a lot of people blow their motor by using 87.

 

NAME ONE!!!

beers

 

i don't know their names, but Iast week I went to the dealer to pick up some parts and saw a 8 inside the garage getting the engin out. so I ask the service writer what happen and he explain to me that the guy use some cheap gas and it knock, next thing you know blown motor.

 

well the service writer must know a lot... i am not giving you a hard time, but the ecu can stop the knock... to a degree. and that has nothing to do with cheap gas.

it is a different problem...

beers

pm if you have more ?

 

the manual tell you no less then 87 oct. but they do recomende 91 oct. i had an 86 and 94 rx7 and i use 87oct most off the time, to save money. am using 87oct right now with gas prices. and my car does not knok. it runs great.19 to 21 mpg.

 

tell me something I don't know.
I got a 87 RX7 R&T car, it use 100 oct. My RX8 use 91 oct.
just tell me why buy a sport car if you use cheap gas. It's like buying a super car but only with one way insurance.

 

I've got an '06 and I bought it knowing it takes premium and that's all I would ever use. I don't see the big deal, the difference between a Regular fill-up that might foul my car and a Premium fill-up that won't foul my car is only $1.62.

If I can't afford an extra $1.62 a week to use Premium gas then I should've got a Prius and resigned myself to life in the slow lane.

 

Becuase it doesn't NEED 91 or higher octane. It has been asked many times before on this board and all of the knowledgable rotary guys say 87 works just as good as 91+ because of the design of the motor. Hell, Scott from Mazsport explained this in great detail somewhere on here.

 

but if the 87 is being used in cars that arent being driven hard and is contributing to the carbon buildup that is causing failures in places like vegas etc...

 

Sort of off topic. I took the head off a 1992 d16 civic motor that had 150K miles on cheap gas... Wow is all I could think. It was a V-tec head maybe it was bad flow design in some spots but I was chipping out carbon that was up to an 1/8 of an inch thick from the exhaust ports. The valves had about a 16th on an inch on them.

I'm sure I could run the cheap stuff on my 06, but as of right now I'd like to hold onto this car for a long time. This motor has pretty high compression and it 's rev's far beyond what most cars do. Those are to things I'd avoid with cheap gas.
Knowing how rich this car runs I wouldn't run the cheap stuff. I also can afford the extra 1-2$'s. I'd like this car to last a while.

On a side note the civic was probably a little faster before it blew due to all the carbon build up bumping the compression up.

 

My thought it that 87 octane gas would have less carbon buildup because it naturally would burn more complete. The 91+ octane would resist explosion more thus it would need longer and a hotter heat source to burn completely, unless the additional additives that some companies put in their high octane gas offsets this problem. I use 87 from Shell, Costco, & Accel gas stations without a problem, and run the car pretty hard in the process. Gas mileage is a fraction better with 87 and so is the throttle response, but then again that is just my car, and they all seem to be slightly different.

 

yea, i just posted this wondering what has changed from the 2004 to the 2006 versions to prompt mazda to require 91 oct or higher. Seems strange when the engine is exactly the same

 

they had problems with cars running low octane.

 

Their tuning sucks so they'd rather have you use a higher grade of gasoline than actually fix the tuning issue. It's all about emissions.

 

I only have 5k on my car. I started by running the 91, but now run 87. I am in colorado at high altitude which is supposed to negate the benifits of 91. Whatever the reason, I can not tell the diff between 91 and 87 in performance or milleage. No knocking either. I listen closely believe me.

 

Be your own judge. If it runs like crap on 87, dont use it. I use 87 in mine and I have no problems. Every now and then I use premium and run it hard to burn out any build up. I used to have a Corvette that only used premium ,so I thought I would treat my 8 the same way........ Until Katrina hit. Down here premium is 93, so when I evcuated, all I could find is 91. Sometimes 89. I had no choice, but my 8 ran fine. So since then its the cheap stuff since I fill up every 4 to 5 days.


lol.... I drive alot and kinda hard.

 

here you go.

https://www.rx8club.com/showpost.php...&postcount=480


"Let me say that this low octane/low advance high octane/high advance debate has been going on between rotary engine builders and tuners for ever. I personally have known people using additives to lower the rating below 87. What I have not told you guys is that this was the second dyno session. Wed. afternoon was the 93 octane high timing tests. I advanced the timing up to 38 degrees at one point from 7-9k rpm and the motor hated it! It was not pinging but lost alot of power, I went in two degree increments up and down from 30 degrees, adjusted the split between 5 and 15 degrees. I also have the ability to vary the amount of fuel per pair of injectors and therfore can select and change the volume and how fuel enters the intake runners/ports. I still beat the Factory computer up top and through the midrange on 93 but was less than happy with the difference. So thursday we empied the tank and filled it with 87 and returned to the dyno. In the past when trying to build the worlds strongest stock 13B in the SCCA ITS class I found 87 made the more power than 93 and after last night I found the new motor likes it as well. Sure there is a 25 cent savings per gallon but that really has nothing to do with it, the engines produce less heat because of the lower timing, and therefor run better longer. The bottom line is this, I found better results using 87 octane. I have owned and been involved with high performance rotary powered cars since the late 80's. Maybe someone out there who has no history with how they work will come up with a whole new approach and look like a Rotary God with kerosine? What I have brought to the table is a plug and play increase in performance. The Interceptor-X is not a SuperAFC or a SuperAFC with a laptop interface. It is a full standalone in a plug and play configuration that will allow users to tune, yes really tune the ECU to their specific car,fuel and collection of components. Back to the shop,Scott"

 

the higher octane means 91 is less prone to pre-ignition or ping/knock then 87. if the higher altitude negates this benefit in 91 meaning the 91 is more prone to ping then elsewhere, then wouldnt the 87 be even more prone to ping and so even worse for your car?

 

he found better results usign that particular 87 than the particular 91 he used previously. i dont think scott would go racing with out good high octane race fuel. so he is not saying 87 is ALWAYS a better choice especially in california where everyone agrees the gas mostly sucks. also i dont htink Scott has been the one cracking open the failed engines and doing the investigation into what causes the carbon build up etc etc

 

There is no reason on a naturally aspirated RX8 you need to run premium fuel in theory. People make our 10:1 compression ratio sound like its stratospheric, its not. 10:1 will be perfectly happy with 87oct. At some point high compression will force you to use a higher octane, but 10:1 is far from it.

Now, for emissions reasons, Mazda uses a ridiculous timing curve that advances the timing way beyond what it did before for rotaries, again, for emissions. This issue is, most folks will find because of this the car runs and idles poorly on 87oct because the ecu doesn't adjust for lower octane like alot of piston cars. If you have a Honda Accord and put premium in the engine, it adjusts the timing and actually can make a bit more power….www.vtec.net proved this.

With my N/A interceptor, I can run 87oct with no issue what so ever. Almost every stupid thing about our car Mazda engineered wasn’t an accident, its emissions related, everything is governed by emissions. Its an automakers first concern when they get up in the morning and the last issue they worry about when they leave. Power, fuel economy, safety, speed all take a backseat to emissions.

Most gas companies put a higher detergent package in their premium fuels, which they claim makes them cleaner....I’ve yet to see that really proved out to make a real world difference in our cars. Wanna avoid carbon buildup? use a good oil and drive the car aggressively once and a while. Use a good fuel injector cleaner every 5K miles. Its pretty simple.

 

a. there is no magical octane detector in ANY car. they may have a knock startegy built in that dials in advance until it detecgts a knock then drops of a little. the new mustangs do this. the rx-8 doesnt it has a set timings that are retarded if it detects knock.

b.many people who own this car drive it like a regular car- especially AT owners. the only time they jump on it is to pass someonme and that is rarely . those people will never do a fduel injection cleaner unless the service people upsell them on it in a weak moment. those vehicles need a better quality gas than the average 87 octane. Mazda also notes in several places that 87 octane may damage emissions related equiptment. obviously they wish to furhtur avoid these issue by putting a premium designation. because they arent doing it for people who find this forum- they are doing it for the other 50%