Unleaded Fuel Issues

[Michael M]

I was very surprised to learn from Peter that 98 unleaded (Super) will be phased out. Of course it has only small market share all over Europe, but the 98 unleaded was the argument of the oil companies to phase out 98 leaded. There are a lot of older cars around needing 98 octanes - leaded or unleaded -, so phasing out means extreme problems for all owners of cars needing 98. Therefore I believe that THR is right. Don't want to be unpolite, but can it be that such rumour has been initiated by certain companies selling additives??

[Peter Mallett]

Well I hope they do keep selling it but my local Fina and Shell garages have stopped it. Maybe I should find a BP garage.

[yelwoci]

Michael M
Thank you very much for your informed input.
I was relying on my Chemical Engineering knowledge of the 80's and was a little rusty.

Its always a pleasure to find soemone who knows their subject.

I think you asked about the French for unleaded, it is 'Sans Plomb'

The problem with Super Unleaded(98) in UK is that only about 50,000L is sold a month throughout the whole country (<1.5% total sales) and volatiles evapourate changing the mix.

With repect to Millers it is a Manganese base which when used as prescribed gives 80mg/L metal, which enhances the knock value of 95 to about 98. It however is 'advertised' especially to FIA for its valve seat protection.

The EPA in the US are starting to get concerned about Manganese as the believe it contributes to Alzheimer's and Parkinson disease.

IanC

[Peter Mallett]

Oilweci,

If you read the other responses I think you'll find that I said that!!!!!

[THR]

an example

we run a 1600 BDA (for sale)
240 BHP
this runs on all types of petrol

the engine was tuned using super
so this works best
however the quality does vary a lot.
if the fuel is left in 4l cans over a week it deteriotes a lot noticable when warming the engine up, its more fluffy.
fresh feul is best
this also goes for 4* and unleaded tho.

the engine runs on leaded best next.
next best thing, but as this is no longer availble its outta the window.

unleaded is also no good as it doesnt go bang enough!

also we noticed the colour and particually smell of super varies. and affects quality

BP ans Shell still sell super

[Michael M]

About Millers manganese stuff: 80 mg/l is 0.08 g/l, last version of leaded had 0.15 g/l, earlier grades 0.4 and even higher. Simple arithmetical calculation, 0.08 g/l manganese = + 3 octane points, so 0.15 = + 6! This is slightly more than 0.15 g/l lead would produce, meaning manganese having better octane response than lead. Sorry guys, but that’s contrary to current state of science!

Only manganese compound known to me producing little octane improvement is
methylcyclopentadienyl manganese tricarbonyl (MMT), which is allowed to be added in quantities of max. 0.008 g Mn / l in most countires. However, it has been reported to increase unburned hydrocarbon emissions and block exhaust catalysts, so it is prohibited e.g. in California. Additionally it is rather expensive, and the equivalent increase of octane figure can be achieved cheaper with components like aromatics and ethers. If even 0.008 g/l has the a.m. negative effects, what about 0.08 then??

What about scavengers? TEL includes ethylene dibromide or dichloride, the hologenates (Br resp. Cl) form halide salts together with the lead, which can be exhausted. Only a small part of the lead is retained in the burning chamber, forming the well-known layer necessary for valve seat protection. If Millers stuff includes no scavengers, the manganese will settle down in the combustion chamber, the longer you use it, the thicker the layer.

As you may know, common alternative to lead as valve seat protector is sodium. Both these metals are rather soft, and exactly this is the reason of their protection property. I’m no metallurgical engineer, but as far I now manganese is a very hard metal, so I cannot see its function.

Phase out of Super 98 unleaded:
Don’t believe majors like Shell will stop it in general, but only for some smaller stations, where they realize turnover is too small.

Yelwoci is right concerning the evaporating volatiles. Part of each gasoline is also a certain amount of C4 hydrocarbons, more common known as butane. This extremely volatile part is needed to create good starting and cold-run properties. As it is a gas, of course part of it evaporates, especially in summer. This has no real influence on the octane rating (butane has approx. 100 RON) and on the ageing process (gum forming), but sometimes when starting and warming-up an engine, as THR found, especially in case of a racing engine.

Of course each gasoline is different from the others. The colour normally has to do with the brand, and the smell with the components. Toluene smells quite different from MTBE e.g.. Also the quality itself differs, e.g. octane rating. The “98” is a required minimum figure, and in case of unleaded oil companies try to stay as low as possible (98.1, 98.2) for economical reasons. High octane ratings for leaded are much cheaper, so leaded 98 sometimes had 99 or even 100 RON. With a normal engine you don’t realize this, but in case of a 240 HP BDA each octane counts.

One can blend his own racing fuel with certain components, but this is illegal for 2 reasons:
(1) Technical rules of FIA and national MSAs are prohibiting this, and
(2) Tax legislation.
Therefore I will not give any details here!

[Peter Mallett]

Well I've just got back from rolling road testing my car. I did this to see if there's any difference with running Unleaded and the additive, compared with running Super Unleaded and no additive. Guess what?

[Michael M]

Peter, you still owe me the information which octane rating the engine officially needs!

[Peter Mallett]

Not sure what you mean by "officially needs" Michael. If you mean what was the engine designed for then I would say 98 octane four star. In fact my engine ran on Super Unleaded last year and as I left you all yesterday with a guessing game I suppose its only fair to tell you that running unleaded and the additive is producing the same power as super unleaded without additive.

[Peter Mallett]

Michael.

I was talking about my RACING CAR which is a V6 Capri with 11.5:1 cr. The wholre power curve is exactly the same and all the other statistics (Co etc.) are also identical.

Now. The MGB was running on 4 star leaded until this year. Whilst running on that petrol it would "diesel" (or run on) when switching off. That doesn't happen now. Also the mid range power has increased significantly without any noticable effect on running temperatures and no ignition adjustment.

Your statements assume that a loss of power is acceptable. I am saying that it is unacceptable for a racing car. You must admit that your theory of lower octane only works if you retard the timing to avoid knocking. That in turn ruins performance.

As my engine is a highly tuned racing engine all the arguments about running with lower octane and backing off the ignition are perhaps not appropriate.

[Michael M]

Peter, „officially needs“ means that somewhere in your owner’s manual the manufacturer should inform about the required gasoline quality resp. octane rating.
It seems that you did not know this exactly, so it may well be that 95 or even 92 could be sufficient. Again, without this knowledge a rating of the additive is not possible.

Of course the engine is producing the same power, because octane rating has
n o t h i n g to do with power output. As this subject obviously creates misunderstandings, let me explain again.

Example 1:
An engine is designed for a minimum octane rating of 91. If you use regular gasoline, such engine will run without any problems, producing the power output it is designed for. If you now use 95 or even 98 octanes, nothing at all will change. The power output will be exactly the same, because it is based on the mechanical constellation of the engine, and not on the fuel.

Example 2:
You change the mechanical data of this engine, e.g. increase compression ratio by using a thinner cylinder head gasket. Effect of this mechanical adjustment will be higher power output. If you now still use regular (91 RON), the increased power will be recognized, but most probably the engine will „knock“ at certain stages (high revs, accelleration out of low revs). If the increase of compression was only moderately, you can avoid the knocking effect by adjusting the inginition a few degrees earlier, but then of course you will loose again the additional power you achieved before.
If you now change the fuel to 95 or 98 – depending on how much you increased compression - , and adjust the ignition to original data, the power increase is back again, but without the knock problems.

So high octane ratings only i n d i r e c t l y have influence on the power output. Using high octane fuels has no effect at all on the power, you have to change the mechanical specification of an engine to use the advantages of higher octanes. On the other side, if an engine n e e d s high octanes, but is fed with lower octane fuel, there is no reduction in power, and if is driven moderately, even the knock effect does not show off.

If your test with 95 + additive shows no difference to 98 plain, it is obvious for me that the engine needs only 95. In order to answer this question you should do the same test again, this time with 95 plain. The power output will be the same, that’s no question, but interesting would be whether there are some knock effects or not. Important is that such driving test is caried out under comparable conditions. Highly interested to learn the result!



[This message has been edited by Michael M (edited 28 February 2000).]

[Michael M]

I researched a little, found out that compression ratio of early 4cyl MG-B was between 8.0:1 and 8.8:1, later models most probably have even less (US legislation). If these figures are correct, I believe 95 RON is sufficient, may be even 91/92 is workable. Peter, if you cannot find this item in your literature, please let me know more details of your car, so that we can try to find out.


[This message has been edited by Michael M (edited 28 February 2000).]

[Michael M]

Sorry Peter, I thought you are talking about your MG-B.
Of course loss of power is not acceptable for a racing car, that’s no question.
I stated this clearly in my earlier posting, saying „but in case of a 240 HP BDA each octane counts”.

I also never said that loss of power is acceptable – also not for a road car -, but if the octane rating of available fuel is not sufficient, it’s better to loose some power by retarding the timing than to damage the engine.

“You must admit that your theory of lower octane only works if you retard the timing to avoid knocking. That in turn ruins performance”, that’s exactly what I said, only in other words (“If the increase of compression was only moderately, you can avoid the knocking effect by adjusting the inginition a few degrees earlier, but then of course you will loose again the additional power you achieved before!”).

I know that my English is not the best, but up to now I thought it is at least understandable, sorry if that is not the case.

What is 4 star leaded? Is it 98 octanes resp. the old leaded premium? If yes I cannot understand the diesel effect when switching off. This normally only happens when ignition is adjusted totally incorrect, or if the fuel is extremely low-octane (< 90).

I really don’t doubt your experiences with the MG-B and the Capri, although I do not understand them, as physical rules are put out of force (general rules, not my rules!).

[Peter Mallett]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Michael M:
I also never said that loss of power is acceptable – also not for a road car -, but if the octane rating of available fuel is not sufficient, it’s better to loose some power by retarding the timing than to damage the engine.<HR></BLOCKQUOTE>

Yes whilst you are absolutely right I think the question was originally posed to highlight the problem with the loss of leaded petrol and the lack of performance from unleaded.


<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>
I know that my English is not the best, but up to now I thought it is at least understandable, sorry if that is not the case.<HR></BLOCKQUOTE>

Your English is fine. Don't apologise its superior to my Dutch, German or any other language you care to mention.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>
What is 4 star leaded? Is it 98 octanes resp. the old leaded premium? If yes I cannot understand the diesel effect when switching off. This normally only happens when ignition is adjusted totally incorrect, or if the fuel is extremely low-octane (&lt; 90).<HR></BLOCKQUOTE>

The old four star was supposed to be 98 octane but it was degraded over the years. A modern engine can cope because it automatically changes the timing with every firing of the engine. Old cars don't have this ability.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>
I really don’t doubt your experiences with the MG-B and the Capri, although I do not understand them, as physical rules are put out of force (general rules, not my rules!).<HR></BLOCKQUOTE>

Maybe we're talking chemistry when physics would be more appropriate?

[Michael M]

Leaded v/s unleaded:
Here on the continent the withdrawal of leaded was never a problem of octane rating, because besides the Euro Super with 95 RON most stattions also offer the unleaded Super Plus with 98 RON, so no lack of performance at all. I understand that in the UK it's the same, 98 leaded phased out, but super unleaded offered as substitute. So principally only the valve seat problem evident.

Physics v/s chemistry:
Sorry, but octane rating and engine performance is pure physics. May be result of chemistry (blending components, addtives), but nevertheless in it's effect only physics.

[Invader]

BLATANT SPAM!!!! I have an account with Burlen Fuel Systems and can supply stuff at amazing discounts....roll up, roll up get yer SU kit here...also Weber products and Lucas and Bosch K & N and JR and......ouch, whaddya mean your gonna move this post to the classified forum.

[Bluebottle]

Apparantly, the last lot of leaded in the U.K. was sold sometime around October last year- it took quite some time for the oil companies to change the signs etc so we were unknowingly using the cursed L.R.P.(spit!!) for a few weeks, which could go some way to explaning the sudden onset of knocking and loss of power in our Granada, not to mention the carb problem!
We are now using unleaded with a potasium based additive in all our cars (1984 2.3 Granada, Vincent Hurricane with a 1500 Spitfire engine and a Dutton with a 1300 Xflow) They all seem to be quite happy with the stuff.
I heard a rumour that a small oil company has been granted a licence to sell leaded 4-star in the U.K. anyone know anything about this?

[THR]

There is a list on approved petrol stations that can sell 4*
dont have it tho!

theres a petrol station in Great Torrington that sells it tho.

[Peter Mallett]

That's what I'm saying. However I have hardened seats in my engine so I could run S/ul. I am somewhat sceptical about the "stale" S/ul issue but having had the seed planted I am also worried that I may blow up what is an extremelty expensive component.

[Tony Harman]

Phew !!! what a posting this has turned out to be, think I need a rest after reading all that.
Anyway for the UK based racers... according to the MSA leaded fuel (4*) can still be sold in the UK if you have the appropriate license. They say that all circuits that have pumps will sell leaded 4* fuel this season - but at what price I wonder ?
Last year I ran my Kent FF1600 on a 50/50 mix leaded to super unleaded. This year I was thinking of using 100% super UL but from what your saying Peter I may be better off with Premium plus the Millers VSL ?

[Graham De Looze]

Hi Micheal,
Lots of companies sell octane booster,one even calls its product Octane Booster.I believe these products are usually Toluene or Acetone based.why do people not use industrial methanol as fuel it is really cheap or do you get told off for not paying the road duty.Or is there another reason.
graham

[Michael M]

Graham, good question.
The only pro of MeOH is its high octane rating, but there are lot of contras.
The calorific value of MeOH is about half that of gasoline (or petrol, as you say in the UK), that means for same production of energy double quantity is needed. As you can see from my profile, I’m trader in chemicals, and I traded MeOh and also Gasoline for more than 20 years now. MeOH was always cheaper than gasoline, but never – except today – below 50 % gasoline. Another hurdle is the mineral oil tax which is due on volume (at least in most European countries), so it also has to be doubled. Use of MeOH (and other chemicals like Toluene, MTBE, etc) without paying the corresponding tax is illegal. In chemical business you have to prove the final destination of any tank truck of „fuel substituting chemicals“, and these files are controlled by authorities. There are also a couple of technical problems. MeOH is poisonous, and it is hygroscopic (collects water from the air). Main problem is the fact that it is a pure chemical, meaning it has a fixed boiling point (abt. 80°C). Gasoline is a hydrocarbon mixture, with no boiling point but a boiling range which starts at abt. 30°C and goes as high as 215°C. Advantage is that the fuel is carburated constantly at all temperatures, it has good cold-starting properties, but also works properly in extreme heat.
As you may know motor industry is working on MeOH as fuel since years already, but instead of combustion engines running on MeOH latest developments go more into direction fuel cell (MeOH to Hydrogen).