THE IMPORTANCE OF HIGH OCTANE FUEL - 98 RON
 

Hi all,

We did some performance tests recently to demonstrate the difference between standard premium unleaded and super unleaded fuel such as BP Ultimate and Shell Optimax. The reason for the test was so that we could demonstrate to people why a tuned car, and indeed a standard car, should use 98 RON petrol.

This test was done with an ECU upgrade on an 1999 C70 T5, in comparison with the standard ECU. The results were indeed stagering, and will be detailed soon on the Volvo Tuning UK web site. But to summarise, the results indicated that on 95 RON fuel, the max power from the upgraded car was down by up to 40 bhp compared with running it on 98 RON fuel. This is because the highest performing ECU upgrades are designed for 98 RON fuel. Don't get me wrong, the cars will run fine on 95, but the difference in power is simply huge. For sustained power, you simply must use the highest RON fuel you can find, which in the UK is 98 RON. Germany is lucky enough to have 102 RON!!!

I will keep you informed on this thread when this feature will appear on the web site. Then you can read about this issue in much more detail.

For all those wondering where you can get 98 RON - you can use either BP Ultimate of Shell Optimax. It is slightly more expensive than premium, but you will get better economy as well as the full performance potential of your engine, especially when tuned.

Adam.

RE: THE IMPORTANCE OF HIGH OCTANE FUEL - 98 RON
 

shell will sell you 102 octane fuel , since thast what the WRC cars use and is made specifically to be very knock resistant . Of course you have to buy it in 25 litres and you end up with loads of containers hanging about . 102 octane is actually the highest octane the FIA will let you use .

of course , if you have a handy pharmacutecal company nearby , you can simply add some toluene to the correct octane you would like , toluene though exists inlots of things like cellulose thinners and even in electrical contact cleaner .

Since petrol contains toluene you are not in fact damaging your cat with it .

RE: THE IMPORTANCE OF HIGH OCTANE FUEL - 98 RON
 

Unless, that is you mistakenly put Tri-Nitro-Toluene in the tank. Very nasty and unstable stuff which removed one of my science teachers thumbs because he was not careful enough. It is worse than sweaty dynamite.

All the best, Peter

RE: THE IMPORTANCE OF HIGH OCTANE FUEL - 98 RON
 

I was wondering about this myself a couple of weeks ago. I had a long trip coming up (just got back from Scotland via Leicester to Amsterdam) and wanted to try out the nice fuels you have iin the UK now. But when I opened my filler I noticed a big stiker that says '95 RON FUEL ONLY' - so I was just wondering why Volvo have this in the filler neck when most people say I should be using 98 in my 2.0T? (BTW My bike says '98 or 95 RON FUEL' so there does seem to be a difference)

Stu

RE: THE IMPORTANCE OF HIGH OCTANE FUEL - 98 RON
 

You need to check your manual, because on most models it actually recommends 98 RON. You'll normally find this in the engine specification section. They may actually mean MINIMUM 95 RON. However, it is more important on tuned engines, although the standard cars will benefit too, and especially so on the turbo engines.

Adam.

RE: THE IMPORTANCE OF HIGH OCTANE FUEL - 98 RON
 

I'll get my other half to halve a look this evening (Manual is in Dutch and I don't speak it :))

Thanks

Stu

RE: THE IMPORTANCE OF HIGH OCTANE FUEL - 98 RON
 

Hi Stu.

The 2.0T says 95 ron only as a guide really. I think it is to stop people trying to put 4 star in!

Mind you petrol with lead in it is rare now, but even the lead replacement petrol can be hazardous to your cat I have heard.

Anyway, the point is, that to obtain full power levels on a 2.0T you do not need anything more than 95 ron. 98 offers no real benefit to it in standard form. There is ALWAYS an improvement but in the LPT car it will be too little to be readily noticed. You may notice it is smoother but probably nothing more.
however if you start to tune it then high octane becomes even more important in the LPT cars as they have higher compression ratios.

Use 98 on your 2.0T by all means but it will not benefit you as much as if it is tuned, or if the weather gets hot, or you drive hard all the time and underbonnet temps are consistently high. Under normal circumstances the 2.0T will produce its 160+BHP with 95ron no trouble at all.

Cheers,
Dan.

RE: THE IMPORTANCE OF HIGH OCTANE FUEL - 98 RON
 

A standard T5 can use I think 91 to 98 octane fuel. Fuel in the states is often a lower octane than in the UK this is why it runs on 91 which we dont have here. My Chevy Camaro said it could run on 87 octane but I think were getting close to parafin at this value.
The reason Adam finds such a big power gain with 98 octane fuel is because as he said the chip is tuned for that grade of fuel. If a lower grade of fuel is used the ecu will retard the timming to prevent pinking. The way it does this is not to slowly retard it but to do so by a large amount and then slowly try and advance it again.
This is what will cause the big drop in power.
I doubt you'll see as much difference on a stock engine but it depends how much the ecu is able to advance the ignition timing.
If your car says it needs 95 octane fuel you can use a higher octane value fuel but not a lower one

Simon

RE: THE IMPORTANCE OF HIGH OCTANE FUEL - 98 RON
 

Perol with TNT? Then you really would go like a bomb!

RE: THE IMPORTANCE OF HIGH OCTANE FUEL - 98 RON
 

As I work at cardiff airport, The main (sorry only) fuel company there is BP. Do you reckon JETA1 fuel will do the trick?? ;) If it was good enough to power concorde to silly speeds think what it can do to your car!!!!

Any how, when I swithced to usuing optimax I didnt notice any difference in performance at all. The only difference I noticed was a thinner wallet after paying for it.