What fuel grade do people use?

[mmalbon]

I try and put super unleaded in (97, 98 or 99) but sometimes have to put 95 in as I can't get super. I can't really tell any difference between using 95 and super, but I guess you don't notice unless you really nail it!

I was just wondering what other people used? What difference they could tell?

[Corky]

I use both, haven't noticed a great deal of difference really.

[Torquemada]

My 500 definitely 'pinks' more with 95.

[Mark_G]

Shell v-power only!

[lockhart flawse]

I occasionally have to put in £5 of 95. Mine hates it and pinks under any sort of hard acceleration. My car seems to prefer BP Ultimate to Shell V-Power I think. Notice also that the influence of the £5 of 95 seems to continue long after topping up with 99 which implies that it doen't mix up a lot in the tank. Hope that's not too technical for you.............

On the other hand my previous 4.0 Chim had no problems with 95 and so I used it all the time.

L.F.

[350Matt]

If the car 'pinks' / detonates / pre-ignition then either retard the ignition a few degrees or stick to the expensive 97/98 grade

Matt

[Simpo Two]

Mine has been adjusted to run on 95. It still goes plenty fast enough and I save money.

[dnb]

Same here too. There's 15 or 20 bhp at the top end I can't have with 95 RON, but they're only useful for track days anyway...

[Uncle Fester]

This is one of the advantages of replacing the old Lucas ECU and distributor with a fully mappable modern ECU. Especially if you have multiple maps and can switch them from the dashboard.

One map for 95 and one for 99 octane. Why choose between power and economy when you could have both?

[Hoover.]

Four star is my choice locally..... or highest grade available any where else

[jeffsy]

Any brand of Super for me...

If I HAVE to put in 95 I always put a pot of octane boost in first. Never had any problems that way

Graham

[lockhart flawse]

When you say that it has been adjusted to run on 95 do you mean that the timing has been adjusted to run on 95, the ECU has been adjusted to run on 95 or you have a new ECU that can be programmed to run on either 95 or 99?

L.F.

[chrispitman]

The lucase systems is only fuel, it's the ignition (Spark) that changes between 95 and 98 ron, so if the car was setup for 98Ron and you want to use 95Ron Fuel you need to decrease the ignitiona advance by a few degrees.

This is why the after market ecus are much easier as I have a map for VPower, a second map with reduced ignition advance for 95Ron, also a 3rd map with slightly less advance again for driving it wet to try and reduce the torque/power of the engine.

[blitzracing]

Not the 14cux, its fuel control only. You need an ECU with switchable ignition advance curves for different octanes.

[m4rk]

Mine (Chim 500 HC) always had pinking problems on anything less than 98 ron. Now I am in Austria 100 Ron is easy to find. No problems. I carry a bottle of octane booster for emergencies and had to use it once when in Italy. It got me home without pinking.

[mmalbon]

A lot of interesting responses. Maybe mine has had the ignition timing retarded slightly to run OK on 95RON as I don't notice any obvious pinking running 95. It's hard to notice 20BHP or so missing with a powerful car like the griff.

[Pasco]

Mark_G said:

Shell v-power only!

Yep thats the only way imho

[mt10argyll]

Never noticed any difference so I just use 95

[Uncle Fester]

lockhart flawse said:

When you say that it has been adjusted to run on 95 do you mean that the timing has been adjusted to run on 95, the ECU has been adjusted to run on 95 or you have a new ECU that can be programmed to run on either 95 or 99?

L.F.

I mean that I a Emerald ECU that can hold multiple maps, plus a switch on the dash.

[ESDavey]

I was at Silverstone earlier this week & they were selling 102RON - anyone tried this grade ?

I always use 98RON, mostly vPower from Shell