Hymee

iTrader: (1)

I'm probably happy compromising slightly higher consumption for the low center of gravity and ideal weight distribution that gives these cars the great handling that they have.

Not to mention I can short shift at 7000RPM and still go like the clappers. (ROFL)

Cheers,
Hymee.

DaBlkKnight

Hi All,

Basically RON numbers are for a lower rpm/load and Optimax, Synergy and Ultimate are all 98 RON and so should have the same response at lower rpms. The difference is in the MON which is for higher rpms/load. Here Optimax 98RON has the same MON as its regular 95RON petrol, but Ultimate and Synergy have a higher MON, and therefore the extra response for higher rpm speeds. This is why people feel that Ultimate and Synergy are quicker than Optimax as the rotary is such a high revving engine, and also is why motorbikes generally dont recommend Optimax. However, Optimax also has extra detergents that clean your engine and hence it is good for every third or fourth tank. Also, some batches of Optimax tend to have more sulfur content than others, depending on demand.

Hope all the talk of RON and MON isnt too confusing.

Wildcard

I know this thread is getting old, but I've been doing some experimenting:

I tried 1/2 a tank of 91 RON ULP 2 weeks ago, then 2 tanks of BP Ultimate and now I am on a full tank of 91RON ULP again. Initial findings:

IDLE: The car seems to idle lower with ULP (800rpm) than it does with PULP (1000rpm). No noticable difference in it being a 'smoother' idle with one or the other.

NOISE: I've done 5000km now and I have to say that the exhaust note sounds louder running on ULP. Does this mean more power? I don't know.

EXHAUST: Not sure yet if there is less soot on the pipes.

PERFORMANCE: No noticable difference power between the two fuels.

ENGINE: The engine purrs beautifully with either fuel. No knocking, pinging or funny noises running on ULP.

Conclusion? The jury is still out.

sco

Hmm... mine idles at 800 with BP Ultimate

Kev

Mine sits smack on 1000rpm while running on BP ultimate. Has 1230km on the clock.

I notice a difference (I think) going from BP premium to ultimate. I'll experiment a little no that I've got fresh oil :D

Hymee

iTrader: (1)

Bzzzzz Mine idles at 800 im pretty sure. I haven't noticed any difference between fuels, but I have mainly been using BP Ultimate.

Thanks for having the guts to try 91 DGW. You da man!

Cheers,
Hymee.

PS - Nearly 4000 km on the clock.

Wildcard

I gave Madza a call today regarding this issue. I was told by the guy on the phone that the ECU is designed to run on 95 RON, so that's what you should use. I asked him about lower octane and mentioned the discussions in the Forum, to which he had no comment other than to say that he was telling me what was told to them my Mazda Japan.

I haven't seen enough difference between the two fuels to warrant sticking to 91RON against Mazda's recommendations. Hence once this tank is gone, I'll probably go back to PULP.

That being said, I haven't had any bad experiences on regular unleaded and indeed the engine ran just as smooth and fast as ever, so if you ever find yourself in the middle of nowhere with no access to PULP, don't fret. IMO the RX-8 takes 91RON fuel in it's stride without a problem.