i guess most (or all?) of you will be using premium unleaded petrol but I am curious to find out you guy's preference.

I used to like Shell Optimax coz it seemed to burn up real clean and give good power and economy. Now I mostly fill up at Mobil mainly coz I get extra points with Visa card =)

so what are you guys' preferred petrol station for your beloved RX-8 ??

 

BP Ultimate for me. It was the favourite amongst the LS1 guys, and they reckoned it made better power.

Maybe I might run a few tanks of Craptimax through my '8 and give it another go.

Cheers,
Hymee.

 

I have mainly settled on Ultimate, except when the price is really steep, in which case I'll settle for Craptimax or Vorcrap

 

I have been using Caltex PULP, primarily since the local indy is a Caltex agent. However, he has introduced a new pricing policy where it won't go below 84.9c/L (or 83.9 with the customer card). Guess I'll be trying other brews now.

 

i USE Utimate and given up the Craptimax... found no difference though

 

Just to note... I found myself between Broken Hill and Adelaide and no Premium Unleaded around...so I used a tank of Regular Unleaded.

Seemed to cause no problems, and couldn't detect any difference, but I wouldn't do it regularly.

 

BP Ultimate, when the engine of my dearly beloved race car was being built and on the engine dyno, we found that Avgas aside, BP Ultimate gave us the best results.

 

Just to give you guys some info..

A few years ago I was contracting at an oil refinery (won't mention the name but it wasn't BP). Anyway, while there I got to know all important people of the company and found out that the cleanest fuel around comes from BP. That's why I only use BP and only ever will.

 

interesting. sounds like most of u guys prefer the BP ultimate.
It's good to know what other's preference are, because some of my mates prefer Optimax and some says that Caltex vortex is best etc etc. from the sounds of it, BP ultimate seems to generate cleaner and more power?

 

I use BP Ultimate exclusively as I have a BP fuel card. No complaints here.

 

what is the BP fuel card? do u mean like a credit card or just a card exclusive for fuel??

 

It's a card typically used by companies for business vehicles... basically you pay for your fuel (and other things depending on how it is set up) using the card and typically you give an odo reading as well so they can track economy and/or look for misuse. I'm pretty sure it means the company gets a discount on the fuel also. BP site probably has more info.

 

ah.. you mean for like novated leased car etc right?

 

I've steered away from Optimax, mainly because of the bad wrap it has recieved on the forum. BP ultimate is my fuel of choice, but I also use Caltex Vortex or Mobil Synergy 8000 when there's no BP around.

I'm actually considering going back to 95 RON PULP for a while to see how that goes. I'm still running in to the odd comment about rotaries getting better power out of lower octane fuel due to the faster flame front.

The only thing that keeps me away from regular unleaded is the recommendation in the manual to use premium, although I too have used several tanks of regular unleaded in my 8 with no difference in the way the engine ran.

 

Just for your info.
I'm working for a major oil company and it is very common for oil companies to exchange fuel. So you may be filling up with BP ulitmate but it may really be Mobil 8000 etc.
I've seen it for myself at the terminal, opposition trucks rolling in and filling up with our fuels.
So you may not always get what you think.

 

I guess the issue then becomes whether you choose to use 98, which is probably either Ultimate or Mobil 8000 in the main, or 95.

I have tended always to use 98, but occasionally have to fill with 95 on account of the little orange light and no BP/Mobil stns around.

I can't say I have noticed any difference -- have never used regular unleaded.

My main goal is to ensure clean, high quality fuel. I think there has been enough evidence (avgas, methanol issues) to show that can be a problem in Australia, hence my use of the highest grade where possible.

 

that's an interesting inside info.. =D

 

I had a bit of spare time at work the other day and tracked down the specs of all the PULP available in brisbane / SEQ.

The key difference is that BP spec their 98RON as a minimum of 98RON whereas Shell specify Optimax as an average of 98RON.

The best of all were Caltex who specified a minimum MON and RON rating but they were only 85 & 95 respectively so they're no good for me.

-pete

 

The reason why you wont notice a difference is due to the way a rotary engine develops its compression. Many years ago, Curtis Wright in the USA did testing with various Octane ratings on there RC2-60 engines

RC= rotary combustion - 2= twin rotor - 60= 60ci

They did testing with 85 to 103 octane & found the power difference was just a couple of horsepower. The engine didn't ping but they did note re-jetting of the carby (talking early 70's here) made the engine run smoother on the higher octanes. A piston engine would have pinged itself to death under these conditions.

When you have a turbo rotary, the compression is artificially enhanced, so its a good idea to run the Ultimate/Optimax for anything over 0.5bar.

On that subject, people say they notice a difference between the 91 & 98. An industry friend has pointed out that may be due to the quality of the fuel & not the RON. Apparently its a get what you pay for thing. Pay more for better quality.

The same friend says that regular testing has proven the BP Ultimate to be a higher rating fuel. Some times, the Optimax can be found at 95 RON where the Ultimate is consitently 98 or above.

Optimax is simply so successful due to the marketing campaign behind it. Hell, I still buy it if a BP isn't handy (my 20Btt Cosmo runs 0.85bar boost)

 

hmm... the mazda guys have all insisted that Shell Optimax was rated as the best but I'm going to have to now give Ultimate a good workout I think..

++post guys!