db Posted April 28, 2004 Share Posted April 28, 2004 Ok. So I drive past many a good petrol station to put Optimax in my tank, but I don't understand why. What's the real difference between all these "super" fuels and bog standard 97? Or Tescos value 95? My ... Preciousss! Member #109** Link to comment Share on other sites More sharing options...
New Barbie Posted April 28, 2004 Share Posted April 28, 2004 marketing shrewdcookie - my Caterham site - now with carbon fibre airbox pictures ! Link to comment Share on other sites More sharing options...
db Posted April 28, 2004 Author Share Posted April 28, 2004 Oh good, I like marketing. It's worth a few extra pence. My ... Preciousss! Member #109** Link to comment Share on other sites More sharing options...
V7 SLR Posted April 28, 2004 Share Posted April 28, 2004 Plenty written about octane in the archive I'd guess. I personally don't believe one brand is better than the other. I'd prefer a higher octane regardless of brand. Octane reduces a fuel's tendency to self detonate under high pressure and/or temperature. It doesn't give you more power... but it might allow your engine to be tuned for more power. If it hasn't been tuned for it, it won't benefit in terms of power but it might help the engine last longer if you are already close to self detonation. It will increase the margin of safety. Whether you need that additional margin or not depends on the state of tune of your engine. By "tune" I'm talking about compression and ignition advance. Link to comment Share on other sites More sharing options...
db Posted April 28, 2004 Author Share Posted April 28, 2004 Thanks. Do you know anything about the "cleaning" claims? My ... Preciousss! Member #109** Link to comment Share on other sites More sharing options...
db Posted April 28, 2004 Author Share Posted April 28, 2004 Ok - did the search for "octane" - there are some great threads there. Was using a numpty search term before. Nuff said. Ta. My ... Preciousss! Member #109** Link to comment Share on other sites More sharing options...
I reply to every thread Posted April 28, 2004 Share Posted April 28, 2004 EVO looked into it & reckoned that the high levels of detergent in Optimax did keep engine clean & produced better running. Some say that these high levels of detergent can be harmful. Both my Cat & Subaru run noticably better on Optimax but I mix it with other high octane petrols on an alternate basis. Link to comment Share on other sites More sharing options...
db Posted April 28, 2004 Author Share Posted April 28, 2004 Sounds like an alternate Optimax and Ultimate strategy is good (excellent as I live between Shell and BP garages). Fuel consumption at the weekend was shocking (on an Optimax fill), but not sure if that was related, or some particularly hard sunny-weather driving. Only got a 213 mile tank (I expect 250). My ... Preciousss! Member #109** Link to comment Share on other sites More sharing options...
New Barbie Posted April 28, 2004 Share Posted April 28, 2004 I always use Optimax when I can, or at the least Super. Caterham recommend the car is run on this for track days anyway. I'm aware it won't provide more power but it should protect the engine better from knocking so I figure the extra is worth it. At track days, you will find everyone wants to run on Optimax so I guess it has built a solid reputation already. I'd swear my old P1 ran better on Optimax, smoother and better torqu but I think it's psychological benefit as much as a real difference. The cleaning aspect I'm not convinced but I suppose injectors and things can get mucky and Optimax might help, I don't think it would make a difference to the bores or anything like that. shrewdcookie - my Caterham site - now with carbon fibre airbox pictures ! Link to comment Share on other sites More sharing options...
AlanB Posted April 28, 2004 Share Posted April 28, 2004 I've read (in Telegraph motoring IIRC) that Texaco and Shell have better detergent additives than other brands - with supermarket petrol generally being at the opposite extereme. Link to comment Share on other sites More sharing options...
Myles Posted April 28, 2004 Share Posted April 28, 2004 Well, I play it safe and go for Optimax where possible... ...it might be completely unrelated, but my engine got damned good emissions results at its MOT last week (even given the fact that it's a std. 1.6k with a cat) Keep BC free and open for ALL. Membership No. 43xx Alcester Racing 7's Equipe - 🙆🏻™ Link to comment Share on other sites More sharing options...
Slipper man Posted April 28, 2004 Share Posted April 28, 2004 Does anyone know the octane rating of Ultimate? Link to comment Share on other sites More sharing options...
Ferrino Posted April 28, 2004 Share Posted April 28, 2004 "research octane level of 97" Link to comment Share on other sites More sharing options...
New Barbie Posted April 28, 2004 Share Posted April 28, 2004 Optimax claims 98 I think and Ultimate 97 (the standard for Super) I've also tried some lethal additive concoction that claimed to be developed by NASA, provide nitrous-like boosts and the like. total snake oil and made no difference at all - glad it was a free sample. shrewdcookie - my Caterham site - now with carbon fibre airbox pictures ! Link to comment Share on other sites More sharing options...
Nifty Posted April 28, 2004 Share Posted April 28, 2004 I'm convinced my 7 runs better on Optimax too. A sniff of diesel in the mix every now and then helps to keep the injectors etc clean. Keep off the straight and narrow 😬 Link to comment Share on other sites More sharing options...
V7 SLR Posted April 28, 2004 Share Posted April 28, 2004 BP claimed Ultimate was 99... nice..!! Count, your P1 may (likely) have had a knock sensor and therefore might have been able to self-advance until just before knock set in, therefore I'd have expected it to run better on hiher octane fuels than a Cat which has no such learning ability. The only way a Caterham would run better if on higher octane fuel is if it was tuned to use it. Therefore it is not running better, it is running RIGHT, and therefore on lower octane fuels it is runner poorer. Link to comment Share on other sites More sharing options...
edmandsd Posted April 28, 2004 Share Posted April 28, 2004 genuine leaded 4 star beats the pair of them Home of HTR700 Link to comment Share on other sites More sharing options...
pete east Posted April 29, 2004 Share Posted April 29, 2004 If possible a fill of leaded every now and then for non cat equipped cars is supposed to beneficial. Lucky enough to have several garages in the area which still sell leaded, but make sure you are sitting down when it comes to paying for it! Link to comment Share on other sites More sharing options...
Rob Board Posted April 29, 2004 Share Posted April 29, 2004 DB Regards your question about cleaning? I recently had a snag with my tin top and took it to an fuel injection specialist. After having a look at it, he asked me if I use supermarket fuel. "Yes, as it's cheaper". According to him, and the Dept Of Transport, (He informed me that they had just been sent a memo by them, regarding cars failing emmissions tests on MOTs, due to the Lambda sensors gumming up, due to poor detergent levels in supermarket petrols), the more expensive fuel IS better. However if it makes you go faster, who knows??? You pays your money you takes your chance. Cheers Rob Link to comment Share on other sites More sharing options...
Mick Day Posted April 29, 2004 Share Posted April 29, 2004 Although your Se7en may not have a catalyst it may have a lambda sensor. Lambda sensors do not like leaded petrol & will stop working if contaminated withe 4 *. Mick Link to comment Share on other sites More sharing options...
Nifty Posted April 29, 2004 Share Posted April 29, 2004 Supersport spec cars (and presumably any higher spec Ks) have the ECU set for higher octane fuel. Caterham told me you would not notice the difference unless trying to ring the last 5% out of it on track, however, I'm certain mine prefers Optimax. Keep off the straight and narrow 😬 Link to comment Share on other sites More sharing options...
Mick Day Posted April 29, 2004 Share Posted April 29, 2004 There's no setting in an ECU for octane. Petrol of a certain octane number is needed in an engine (any petrol engine) to prevent detonation. The higher the compresion ratio the greater the chance of detonation therfore a higher octane is required. In a regular car detonation can often be heard; it's far more difficult in a noisy Se7en. Therfore to be on the safe side it's wise to use a higher octane fuel. Mick Link to comment Share on other sites More sharing options...
Nifty Posted April 29, 2004 Share Posted April 29, 2004 Caterham told me the car was mapped to run on super unleaded but would perform quite happily on the road using normal unleaded. Keep off the straight and narrow 😬 Link to comment Share on other sites More sharing options...
Myles Posted April 29, 2004 Share Posted April 29, 2004 There's no setting in an ECU for octane. Petrol of a certain octane number is needed in an engine (any petrol engine) to prevent detonation. I don't believe this - although it might be a red-herring... My fathers old Cavalier SRI (Mk III IIRC) had a two-way connector in the engine bay - one way of connecting it was for 95RON and the other was for SUL (IIRC)... No cat to worry about - so what was it for if it wasn't to nudge the ECU in the right direction...??? Keep BC free and open for ALL. Membership No. 43xx Alcester Racing 7's Equipe - 🙆🏻™ Link to comment Share on other sites More sharing options...
adey Posted April 30, 2004 Share Posted April 30, 2004 On my tintop (205gti), I found the economy from tankful of Esso Superplus to be well down on the alternative: ordinary unleaded plus Castol Lead additive with octane boost. Works on the crossflow in the Seven too. And cheaper - about 4p a litre for the concentrate. Link to comment Share on other sites More sharing options...
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