Optimax: Is yours running rougher ??
07 April 2002, 12:53 PM
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Going to Chris' questions:
Easy one first: I haven't looked into it thoroughly, but AFAIK 97RON is normally not 95RON with 'enhancements' but real 97RON. So it doesn't 'age' - at least not like Optimax/other octane boosters (it is more expensive to refine a minute amount of fuel at a different rating to the bulk than to add a few chemicals to enhance the standard stuff!). These guys are petrochemical manufacturers. They don't pay our prices for the chemicals, but they do pay a significant amount to refine differently (for a mass of different markets remember - Optimax in particular has endless variations on its octane rating!)
Benzene... well, there's benzene, & there's benzene with bits (Optimax is very like an octane booster here - the same principles apply). I think I'll just go back to quoting - much easier! And my spelling always goes wrong with organic chemistry anyway...
In describing the ingredients of Millers CVL (which contains xylene, manganese tricarbonyl and methylcyclopentadienyl):
The flame front here is described as he's actually not having a go at Optimax but at octane boosters not boosting octane as such, but changing the flame front so that the detting is not recognised by the sensors. And it just so happens that Optimax is described by Shell as 95RON with octane enhancers (so read octane camoflage) which happen to be the typical chemicals used in octane boosters (also in Redex on the cleaning side of things).
Sort of throws a new light on things. I'm still trying to work out if the boosters - although not actually boosting - are doing the equivalent job because of the 'softening' of the flame front; the excessive pressure is still there, but is it less potentially damaging because the build is slower? The researcher is getting hold of a digital knock sensor now, which won't be fooled in the same way, so could give some interesting results!
[Edited by nom - 7/4/2002 12:57:41 PM]
Easy one first: I haven't looked into it thoroughly, but AFAIK 97RON is normally not 95RON with 'enhancements' but real 97RON. So it doesn't 'age' - at least not like Optimax/other octane boosters (it is more expensive to refine a minute amount of fuel at a different rating to the bulk than to add a few chemicals to enhance the standard stuff!). These guys are petrochemical manufacturers. They don't pay our prices for the chemicals, but they do pay a significant amount to refine differently (for a mass of different markets remember - Optimax in particular has endless variations on its octane rating!)
Benzene... well, there's benzene, & there's benzene with bits (Optimax is very like an octane booster here - the same principles apply). I think I'll just go back to quoting - much easier! And my spelling always goes wrong with organic chemistry anyway...
In describing the ingredients of Millers CVL (which contains xylene, manganese tricarbonyl and methylcyclopentadienyl):
The CVL is just a boost of the additives already present in OPTIMAX type fuel, the xylene is just a 'hot' benzene that is meant to 'free' the Magnesium held in a safe compound that is the methylcyclopentadienyl bit. The manganese tricarbonyl is the main lubricant and is kept to minimum in 'normal' fuels because of its 'acidic' action. It is useful in getting rid of hot carbon particles left over from combustion, these particles can cause early detonation of the fuel/air mixture. These particles for reasons of ionic attraction like to 'hang around' the valve head this stuff gets them out of the way. Too much of it and the valves will pit badly.
The reason for the magnesium (in 'liberated' form) is to change the flame front and to fool the knock sensor, there will be very little in the way of 'octane boost' except possibly if the suspension fluid is toluene based, which I think it might be as the carrier fluid would need to be of that family of chemicals and it is the most suitable.
The reason for the magnesium (in 'liberated' form) is to change the flame front and to fool the knock sensor, there will be very little in the way of 'octane boost' except possibly if the suspension fluid is toluene based, which I think it might be as the carrier fluid would need to be of that family of chemicals and it is the most suitable.
Sort of throws a new light on things. I'm still trying to work out if the boosters - although not actually boosting - are doing the equivalent job because of the 'softening' of the flame front; the excessive pressure is still there, but is it less potentially damaging because the build is slower? The researcher is getting hold of a digital knock sensor now, which won't be fooled in the same way, so could give some interesting results!
[Edited by nom - 7/4/2002 12:57:41 PM]
07 April 2002, 02:36 PM
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Found this article whilst searching around. Even more relevant, because the tests were carried out on a Scoob.
Chris
[Edited by Chris L - 7/4/2002 2:38:12 PM]
Chris
[Edited by Chris L - 7/4/2002 2:38:12 PM]
07 May 2002, 09:29 AM
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John Banks has suggested that maybe Optimax has dislodged deposits already existing within the engine and this has somehow accounted for a rougher ride and loss of performance.
[Edited by Mickle - 7/5/2002 9:32:51 AM]
07 May 2002, 05:11 PM
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Put some in mine just now for the first time. It is a bit smoother - been running for a week on just SUL. Also seems to overboost a little more - 21 PSI peak rather than 20.5 PSI - better sort that out 
Need to log it to see what the timing is doing. It is certainly not rocket fuel anyway 
[Edited by john banks - 7/5/2002 5:13:59 PM]
Need to log it to see what the timing is doing. It is certainly not rocket fuel anyway [Edited by john banks - 7/5/2002 5:13:59 PM]
03 July 2002, 08:03 AM
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After filling her up twice now with Optimax (ran SUL before), I've noticed an improvement in performance, but also she appears to run a little rougher on acceleration. Can't quite put my finger on it tho, just a feeling.
Has anyone else found this, or can explain ?
Is it the A/F mix and would resetting the ECU do the trick ?
(I have a LambdaLink sensor which also appears to have changed it's readings)
Cheers
Has anyone else found this, or can explain ?
Is it the A/F mix and would resetting the ECU do the trick ?
(I have a LambdaLink sensor which also appears to have changed it's readings)
Cheers
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03 July 2002, 12:44 PM
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Interesting you think your lamdalink displays differently, I found the same when using Optimax. I initially ignored it because of the temperature sensitivity of the O2 sensor, I thought it was perhaps due to the 'slightly' lower EGT I seemed to get with Optimax.
I also initially ignored the fact that it was recording less G force on Optimax (assuming I was just crazy) and that it did really 'go faster' cos that's what Shell brainwashed me to think.
Interested to know if you thought your Lamda read higher or lower ? I thought higher, indicating a richer mix - or a more efficient burn, using up more of the available O2 ??
I also initially ignored the fact that it was recording less G force on Optimax (assuming I was just crazy) and that it did really 'go faster' cos that's what Shell brainwashed me to think.
Interested to know if you thought your Lamda read higher or lower ? I thought higher, indicating a richer mix - or a more efficient burn, using up more of the available O2 ??
03 July 2002, 01:36 PM
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I think Optimax is too unpredicatable to actually judge anything by. I thought it was just me - some tanks run very well (typically ones filled up on a motorway) whereas others are not good at all.
It seems that this is right from looking at various discussions/details on the stuff - someone (who works in a chemical lab, or at least I hope he does
) has done tests on it & agrees with what Shell says officialy about the product - it is enhanced 95RON fuel. The 'enhanced' bit is additives to normal 95RON which actually degrades over a couple of weeks - hence if you get a fresh tank (from a fresh tank at a petrol station!) and use it fairly quickly, you get the whole 98.6RON. If you get it from a petrol station where it has been sitting for a while, you may be filling up with something closer to 97RON which continues to drop RON whilest in your tank.
Something to think about (or ignore) The chemistry does make sense to described the situation above, but it's pushing what I learnt at uni (and that wasn't modern history ) to the limit so it's probably not worth trying to describe 
It seems that this is right from looking at various discussions/details on the stuff - someone (who works in a chemical lab, or at least I hope he does
) has done tests on it & agrees with what Shell says officialy about the product - it is enhanced 95RON fuel. The 'enhanced' bit is additives to normal 95RON which actually degrades over a couple of weeks - hence if you get a fresh tank (from a fresh tank at a petrol station!) and use it fairly quickly, you get the whole 98.6RON. If you get it from a petrol station where it has been sitting for a while, you may be filling up with something closer to 97RON which continues to drop RON whilest in your tank.Something to think about (or ignore
) The chemistry does make sense to described the situation above, but it's pushing what I learnt at uni (and that wasn't modern history ) to the limit so it's probably not worth trying to describe
03 July 2002, 03:24 PM
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Nom,
If it's essentially enhanced 95RON, is it safer to keep her going on 97RON SUL instead then ?
I think Esso and Texaco still supply it (Shell have stopped in favour of Opti), although they're harder to come by, I'd have to drive a fair bit to find one.
Andy F,
I think it read more lean, I'd have to give her another run to check. The only reason I noticed was I never got flashing LED's when just driving and they were never static long enough for me to notice, but they now seem to "hang" around long enough for me to take note. I'm not too up on the sensor since I've only had the car a month (MY00)
If it's essentially enhanced 95RON, is it safer to keep her going on 97RON SUL instead then ?
I think Esso and Texaco still supply it (Shell have stopped in favour of Opti), although they're harder to come by, I'd have to drive a fair bit to find one.
Andy F,
I think it read more lean, I'd have to give her another run to check. The only reason I noticed was I never got flashing LED's when just driving and they were never static long enough for me to notice, but they now seem to "hang" around long enough for me to take note. I'm not too up on the sensor since I've only had the car a month (MY00)
03 July 2002, 03:42 PM
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Devil's Refugee,
Like you I'm on my second tank of optimax, I've switch over from SUL because of everyone raving about it and it's safe to say my cars rough as F**K in the mornings
I've got flat spots and lack of power. Car is a P1. I thought it might just be getting used to it but I reckon I'll be switching back to the SUL as soon as this tank is through.
Mike
Like you I'm on my second tank of optimax, I've switch over from SUL because of everyone raving about it and it's safe to say my cars rough as F**K in the mornings
I've got flat spots and lack of power. Car is a P1. I thought it might just be getting used to it but I reckon I'll be switching back to the SUL as soon as this tank is through.
Mike
03 July 2002, 04:09 PM
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Hmmmm, sounds like a long-term test is needed by someone who ain't biased.
I basically wanted to use Optimax because of it's higher RON and the fact it was supposed to clean out the car in the process and reduce deposits.
Back to SUL until there's some decent explanations for me I think.
I basically wanted to use Optimax because of it's higher RON and the fact it was supposed to clean out the car in the process and reduce deposits.
Back to SUL until there's some decent explanations for me I think.
03 July 2002, 05:27 PM
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That envy won't last for long. What scott doesn't know is that the Saxo was sold last week and I'm now in the market for an MY99/00. He'll just love it when that burbles up to his front door
I'll pass the message along
I'll pass the message along
03 July 2002, 05:29 PM
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Optimax mainly did well in the EVO test because they liked the cleaning properties. 'Clean' for too long with the chemicals that they use in it & it can lead to pitting in the valves (especially in Jap cars, from what I remember, because of the metals used). Most of the comparisons they did were to 95RON not 97RON. And they may well have filled up a lot at (the expensive - but they don't pay) motorway stations that the rest of us avoid, which have a higher turn-over of fuel so it's in better condition.
I started off thinking "98.6? I'll have some of that, then..." and after a few tanks (not immediately!) the car started to run better - or at least it felt that way. But no there's no noticeable drop in performance when using SUL instead. I have also had a tank of poo optimax, a good tank (from the motorway!) and then poo again - it's quite a noticeable difference to me. I get more detting on the poo tanks than I do with SUL, and about the same on the good tanks.
All a bit variable, then, whereas the usual SUL is identical every time...
I don't like Optimax very much any more (the main switch was when I used some REAL 98RON stuff from Belgium - big difference), but it's the cheapest stuff around here & also my local garage, so...
I started off thinking "98.6? I'll have some of that, then..." and after a few tanks (not immediately!) the car started to run better - or at least it felt that way. But no there's no noticeable drop in performance when using SUL instead. I have also had a tank of poo optimax, a good tank (from the motorway!) and then poo again - it's quite a noticeable difference to me. I get more detting on the poo tanks than I do with SUL, and about the same on the good tanks.
All a bit variable, then, whereas the usual SUL is identical every time...
I don't like Optimax very much any more (the main switch was when I used some REAL 98RON stuff from Belgium - big difference), but it's the cheapest stuff around here & also my local garage, so...
03 July 2002, 05:51 PM
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Optimax in Greece is called V Power. When it came out everyone was saying it is 95 RON but enhanced. I thought it was 98 cos I knew it was another name for Optimax. Every where else V power, or Optimax, was 98. Why was it 95 here in Greece and 98 everywhere else? I thought. Even the advertisements with Ferrari were the same. But a phone call to Shell confirmed it was 95 RON enhanced fuel. I was confused. I even thought maybe Shell had a woman on the phones who didn't know what she was on about. The V power fuel was a little cheaper than 98 RON fuel. I think that is the case in the UK too where Optimax is a little cheaper than 97 RON fuel, so like the UK, I thought our V Power had to be 98 RON. I never used it in my car though cos I wasn't sure
Anyhow to my surprise last week a new V Power came out here in Greece, called V Power racing 99+ and Shell say it is 99.4 RON. It has replaced Shell 98. The other servos, like BP, still provide 98 RON fuel. The V Power racing fuel is almost double the price of the normal 98RON fuel here. 98 RON is 0.50 GBP V power is 0.48 GPP and V Power racing is 0.74 GBP.
I don't know if this info provides any help with the Optimax available in the UK, with all this mix up and performance losses you are experiencing. Maybe your Optimax is also 95 RON with enhancements and maybe you will be getting a higher grade of Optimax soon too.
If anyone comes out here with their Scoob, don't use V power. Make sure you use V Power racing.
Cheers,
Wrexy.
I was confused. I even thought maybe Shell had a woman on the phones who didn't know what she was on about. The V power fuel was a little cheaper than 98 RON fuel. I think that is the case in the UK too where Optimax is a little cheaper than 97 RON fuel, so like the UK, I thought our V Power had to be 98 RON. I never used it in my car though cos I wasn't sureAnyhow to my surprise last week a new V Power came out here in Greece, called V Power racing 99+ and Shell say it is 99.4 RON. It has replaced Shell 98. The other servos, like BP, still provide 98 RON fuel. The V Power racing fuel is almost double the price of the normal 98RON fuel here. 98 RON is 0.50 GBP V power is 0.48 GPP and V Power racing is 0.74 GBP.
I don't know if this info provides any help with the Optimax available in the UK, with all this mix up and performance losses you are experiencing. Maybe your Optimax is also 95 RON with enhancements and maybe you will be getting a higher grade of Optimax soon too.
If anyone comes out here with their Scoob, don't use V power. Make sure you use V Power racing.
Cheers,
Wrexy.
03 July 2002, 07:01 PM
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So? There are people all over the UK using optimax in 100RON wrx's when it might deteriorate back down to 95RON. If shell aren't careful they might be getting their fingers burnt again if these engines go pop!
03 July 2002, 07:26 PM
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i'll never trust shell petrol since the formula shell they sold in the 80's with all the claims for burn valves etc...
saying that we use to run our race car on avgas what power !!!!!!
and have also tried avgas/unleaded 95 50/50 mix to get 99 ron or there abouts,four star/unleaded 95 ron 50/50 mix to get around the same and a tolelene (can't spell it)/unleaded 95 mix all to get just under the rules
saying that we use to run our race car on avgas what power !!!!!!
and have also tried avgas/unleaded 95 50/50 mix to get 99 ron or there abouts,four star/unleaded 95 ron 50/50 mix to get around the same and a tolelene (can't spell it)/unleaded 95 mix all to get just under the rules
04 July 2002, 08:22 AM
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I've just e-mailed Shell with a complaint and asking for some clarification on the matter.
Should be interesting to see what I get back....no doubt something like
"Shell Optimax has been developed in conjunction with Ferrari yadda yadda yadda extensive tests blah blah pulled the wool over the motorists eyes once more......"
Should be interesting to see what I get back....no doubt something like
"Shell Optimax has been developed in conjunction with Ferrari yadda yadda yadda extensive tests blah blah pulled the wool over the motorists eyes once more......"
04 July 2002, 08:39 AM
#22
I've switched from using Optimax to UL + NF Boost, price works out slightly cheaper and it runs Ooh so much better.
I too think Optimax is a bit un-predicatble and also experienced cold start and hesitation problems at low revs.
Not seen it since switching to using NF (50ml per tank)
I too think Optimax is a bit un-predicatble and also experienced cold start and hesitation problems at low revs.
Not seen it since switching to using NF (50ml per tank)
04 July 2002, 11:03 AM
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OK, blub from an 'independant' () chemist:
and...
All cheery stuff.
) chemist:
Why is Optimax so variable?
Age, 'Optimax' has a 'tank life' it degrades quite rapidly as the super hot benzene [xylene] 'loses' it volitility after just 40days in the tank (the one in your car or the one in the ground at you petrol station).
Age, 'Optimax' has a 'tank life' it degrades quite rapidly as the super hot benzene [xylene] 'loses' it volitility after just 40days in the tank (the one in your car or the one in the ground at you petrol station).
From this day, if you use it, then ask the attendent when the last delivery of it was, if he can't answer then get the Manager. I've started doing this lately and they are blissfully unaware of the time thing, and so they answer with a flourish of paperwork and a quizzical look. My rule is simple; look at the docket - it says size of tank 10k ltrs, the discharged amount AT LEAST 90% is needed to keep it at the 97/98 ron, the stuff in the tanker will be 98.
This started from the simple question posed me 'What RON is Optimax' the answer is...enhanced 95ron...this is to avoid prosecution by the Customs and Excise if they perform one of their checks.
...apparently the smallest tank on the forecourt is selected (this bit also explains why it is not available nationally). It is cleaned and sealed with an inert gas awaiting its new load, the inert gas does escape and if the gas is not present the new surface scales into rust, the oxide is bad for the SH Benzene and makes it behave oddly during burning, adn a precipitate (solid) forms...the heating of the solid means that it can perforate the matrix of the cat blowing a hole clean thu it in a few hudred miles.
This started from the simple question posed me 'What RON is Optimax' the answer is...enhanced 95ron...this is to avoid prosecution by the Customs and Excise if they perform one of their checks.
...apparently the smallest tank on the forecourt is selected (this bit also explains why it is not available nationally). It is cleaned and sealed with an inert gas awaiting its new load, the inert gas does escape and if the gas is not present the new surface scales into rust, the oxide is bad for the SH Benzene and makes it behave oddly during burning, adn a precipitate (solid) forms...the heating of the solid means that it can perforate the matrix of the cat blowing a hole clean thu it in a few hudred miles.
04 July 2002, 12:14 PM
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Ditto Tony
A couple of questions then:
To the best of my knowledge, benzene is used extensively in all kinds of unleaded fuel (the basic replacement for lead as I understood it (the fact that it is much more dangerous is beside the point..)) - would the degradation then not occur in any kind of unleaded fuel??
What is the difference between calling a fuel enhanced 95 RON and SUL? Surely all fuel comes from the same source i.e. oil and it is the refining process and the chemicals added that will determine its RON rating? On that basis could you not call all higher octane fuels 'enhanced'?
Chris
A couple of questions then:
To the best of my knowledge, benzene is used extensively in all kinds of unleaded fuel (the basic replacement for lead as I understood it (the fact that it is much more dangerous is beside the point..)) - would the degradation then not occur in any kind of unleaded fuel??
What is the difference between calling a fuel enhanced 95 RON and SUL? Surely all fuel comes from the same source i.e. oil and it is the refining process and the chemicals added that will determine its RON rating? On that basis could you not call all higher octane fuels 'enhanced'?
Chris