Stever Posted May 9, 2003 Share Posted May 9, 2003 Would anyone have had any real advantage from this or other 'advanced' fuels? I may be a little cynical in this area but not caring too much about what I put in my company tin top, I am prepared to pay more at the pump for an actual increase in power / engine benefit for the 7. Any comments please? Free The Caterham Seven Link to comment Share on other sites More sharing options...
rgrigsby Posted May 9, 2003 Share Posted May 9, 2003 Test in EVO magazine suggested that it did make a difference in terms of clearing deposits in the engine and a marginal improvement in fuel consumption. In terms of power gains unless the car has a knock sensor and is set-up to deal with higher octane fuels you won't see any change at all. I had an Audi S3 a few years back and there was a noticeable difference between standard unleaded and super, although the difference between super and optimax was harder to spot it was still there. Cheers Rob G www.SpeedySeven.com Edited by - rgrigsby on 9 May 2003 20:38:20 Link to comment Share on other sites More sharing options...
mav Posted May 9, 2003 Share Posted May 9, 2003 Personal experience only - no science involved: Throttle response seems crisper, the engine runs smoother, pulls better and provides marginally better MPG. Regards, Martin Link to comment Share on other sites More sharing options...
Baby Bucket Posted May 9, 2003 Share Posted May 9, 2003 Anyone know the octane rating for Shell Optimax - is it 97 (doesn't say so on the pump) Cheers, Peter Link to comment Share on other sites More sharing options...
mav Posted May 9, 2003 Share Posted May 9, 2003 Peter I believe it is 98 Link to comment Share on other sites More sharing options...
mav Posted May 9, 2003 Share Posted May 9, 2003 Peter: here says: What is the Octane level of Shell Optimax? Shell Optimax has the highest octane specification of any petrol in the UK. It is greater than 98 Research Octane Number (RON). Regards, Martin Link to comment Share on other sites More sharing options...
normalbloke.29 Posted May 9, 2003 Share Posted May 9, 2003 Optimax is rated at a guaranteed 98RON, but is generally believed to be closer to Avgas, i.e 100. Link to comment Share on other sites More sharing options...
Chelspeed Posted May 9, 2003 Share Posted May 9, 2003 If you have a car with a knock sensor that can push ignition timing to the limit of det then it will be of benefit. If you have a car mapped on normal unleaded with no knock sensor then it will be designed for 95 octane and any extra capability will not be used so you'll be paying for something you can't use. That said my cars is mapped for SUL, 97 octane, but I stick optimax in it whenever I can as 98 (or 98.6 as I'm told it really is) gives you more margin to det which can't be a bad thing. Link to comment Share on other sites More sharing options...
Stever Posted May 9, 2003 Author Share Posted May 9, 2003 Thanks everyone so far. Just having a standard 1.6 K series R'sport I guess the cleaning agent may be the only real advantage then. Regards Free The Caterham Seven Link to comment Share on other sites More sharing options...
Nick Woods Posted May 9, 2003 Share Posted May 9, 2003 ISTR that Caterham recommended super unleaded a while ago, and they hinted that Optimax was their preferred choice. i'll see if I can find it and will post it later Nick P8MRA - Red and Black 1.6K supersport, back on the road at last. See pictures of it being rebuilt here Link to comment Share on other sites More sharing options...
Mr Locust Posted May 9, 2003 Share Posted May 9, 2003 In the heavily modded Triumph engine of the Locust, the inlet ports and vaves were spotless after using optimax. The previous time of removing the head (when using 4*) the back of the inlets was coated in tarmac like sh1t. Went better too...... Link to comment Share on other sites More sharing options...
SvenDriver Posted May 10, 2003 Share Posted May 10, 2003 In my 1.8K I use Optimax if I can. The acceleration is much better. The engine sounds nicer. The torque seems better at higher revs with no hint of strain under hard use. If I go back to ordinary unleaded (and some garages are worse than others) the car feels sluggish. Link to comment Share on other sites More sharing options...
The_ASH Posted May 10, 2003 Share Posted May 10, 2003 Used normal Unleaded at first and then have always used Optimax since, there was a noticable difference between the two. Have also tried it in my Seicento Sporting which is only 54hp and is single point fuel injected, catalysed but does not have a knock sensor, the most benefit seems to occur after 2 tankfuls have passed, the car either goes better when being thrashed or alternatively goes further on a tank typically 20 or 30 miles, biggest range improvement occurred in the summer on a motorway run when the car went another 65 miles on the usual 30 to 33 litre fillup (the tank is only 35 litres). Unfortunately this means the stuff never pays for itself in an economy car so i've gone back to using Tesco's paintstripper el cheapo bootpolish stuff. As far as the Seven goes it's Optimax every time, the need for Performance far outweighing the cost penalty ! plus I'm sure it is recommened by Caterham for Supersport engined cars. Ashley Webster. 1400 Supersport Link to comment Share on other sites More sharing options...
Mike C. Posted May 10, 2003 Share Posted May 10, 2003 I usually try to fill up with Super Unleaded for track days as I feel the advantages are more apparent at peak rpm. I was also told by an engineer that the engine runs slightly cooler on higher octane fuels (don't ask me why). Mad Manx Link to comment Share on other sites More sharing options...
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