dingy

Motor Octane Rating - The motor octane rating, referred to as MON (motor octane number), is the best rating to use when selecting fuel for your race or high compression engine. When testing MON, the fuel is heated to 300° F and the intake air is heated to 100° F. The test engine is a single cylinder 4 cycle engine that is run at 900 rpm. Ignition timing is varied with compression ratio. Engine load is varied during test.

Research Octane Rating - Known as RON (research octane rating). Tested at 600 rpm with a fixed timing of 13° BTDC. The fuel temp is not controlled at all and the intake air temp is varied with barometric pressure. This is done to covert everything to a SAE standard day, which is 60° F, 0% Humidity, and 29.92 inches barometric pressure. The RON should not be used when selecting fuel for a race or high performance engine. The RON will always be higher than the MON.

(R+M)/2 Rating - This is what you get at the gas pumps. It is average of the RON and MON. It is ok to use this for lower compression street motors, but when you get much over 10:1, you should really pay attention to the MON. The closer the RON is to the MON, the more stable the fuel is. This can be very critical when running 7000+ rpm.

The test conditions for the RON procedure are less severe (lower speed, lower inlet temperature) than they are for the MON procedure. Generally, this means that if an engine is detonating at low speed, it needs a fuel with a higher RON, while if the detonation occurs at high speeds, it needs a fuel with more MON


Well according to this the following is pump RON of optimax

Shell Optimax - RON - Typically 98.6 - Guaranteed 98

Shell Optimax - MON - Typically - 87.5 - Guaranteed 86

(98+86) / 2 = 92RON (American PUMP RON only)

I think in the UK the RON is on the pump.

AVgas usually is 109RON with 100MON (for the higher end - Top Speed)

Normal Super has a MON Rating of 86 too.

Therefore at the top end it says to me you are likely to get more det with Optimax.

Toluene then at 114 RON using a 10% mix can work out the following RON RATING for SUL.

10 Gallon Tank.
RON = Average RON (RON+MON)/2
RON of SUL therefore would be (97+86)/2 = 91.5

[(9 x 91.5)+(1 x 114)]/10 = 93.75 pump rating.

If you put that back to UK pump RON you get

(93.5 x2) - 86 = 101 RON
Using 10% Toluene 90% SUL

Using 20%
(96 x 2) -86 = 106 RON

Not sure if the MON rating's increase with the Toluene tho, if not the top end knock may still be there


Maybe this is why You will get det at the top using Optimax, as the ecu sorts out the timing / knock for the Correct RON rating, but the MON rating at the TOP is the same, but the timing is allready advanced...thus causing det at the top.....

The figures are correct, not sure about the last paragraph tho...just makes yer think.

[Edited by dingy - 10/23/2001 4:00:08 PM]

chuckster

So how does Optimax compare with, say, Esso SUL?
All this makes me think is a little knowledge is a dangerous thing
You wouldn't happen to sell octane booster would you?
C
Edit to add, what does NF do to the MON of the fuel? If all it does is increase the RON, therefore making a bigger increase between Ron and MON then haven't you exacerbated the problem?
Makes me think.

[Edited by chuckster - 10/23/2001 4:22:23 PM]

dingy

Chuckster, this is nothing to do with Octane boost, just the petrol.

I used Avgas as on example as its got a HIGH MON rating.
Toluene cause its a high RON.

I am not sure on the MON levels of using any octane boosts at the moment. (research in hand)

I am not sure if Toluene increase's MON.

But Avgas makes yer car runs cooler, Toluene makes the car run cooler, and so does SUL + NF.

Cooler runing points to high MON rating's but as yet i'm not sure

Tis very interesting tho....

Trout...

Maybe this is why You will get det at the top using Optimax, as the ecu sorts out the timing / knock for the Correct RON rating, but the MON rating at the TOP is the same, but the timing is allready advanced...thus causing det at the top.....

Dinghy,

your analysis is interesting and I have no issue with the figures you quote.

However you make a brave statement above - 'you will get det'.

Simply changing to Optimax has enabled me, with no other changes at all, to materially increase the advance in all areas of the map in my ECU. Including, and especially at the top end.

If I use the current map that I have now with Esso SUL for example then I get det, unless I use octane booster.

What is even more interesting, which cannot be explained by MON/RON numbers is that with Optimax, the addition of Octane Booster such as Millars makes no difference to the ability to increase advance/avoid det. Whereas with Esso SUL, adding Millars enables more advance/better det protection.

This experience is similar to that had by another experienced engine mapper.

So the only conclusion I can draw is that Optimax has a composition that does not benefit from the use of octane boosters, but is itself a good fuel.

Good for Shell, not good for Octane Booster salesman.

Trout

Hanslow

I know this has probably been covered, but what exactly is detonation and how do you know if it is happening? What are the symptoms, or can it only be detected with specialist sensors?

Just curious

Shaun

Trout,

Can you get better advance with SUL+OB than by Optimax alone??

dingy

Trout, i know what you mean regarding my comments "you will get det".

Should say, "we got det using Optimax" - i guess.

These are just interesting figures thats all.

I have mailed, Millers and Silkolene Regarding MON ratings and NF are in the process of getting some results to me.

So i will post what we recieve..I have also got a mate at BP looking into this for me (research Dept - hey Alex )

Might explain a few bits and bobs.

All interesting tho.

SL2

I'm going to give optimax another go. Last time i tried it i seem to lose a bit of power, like it was running on unleaded.

How are imprezas on 95 unleaded(i see as standard they run on it). You guys seem to run your cars on SUL etc. On a standard turbo is there any gain in using SUL. I'm looking for a new car at the mo and would like to use 95 if i could. My RS turbo is set up for SUL and ive had a few times when i was low on fuel and couldnt fill up with SUL. Had to fill up with unleaded and keep the revs low.

Trout...

Shaun,

my experience with Optimax is that it 'feels' better than SUL + Millars.

With Esso SUL and 1 bottle of Millars I can run about the same map that I get with Optimax on it's own. And as I said, Optimax must already contain some form of booster as further Millars makes not much difference. If anything it does not run quite as clean.

Is there a long term cost of running a fuel that cleans as a it sweeps, well only time will tell. It took me four tanks of Optimax to get the full benefit.

Dingy,

thinking about the MON/RON issue - clearly I have had a different experience to Craigs car. A though crossed my mind - is it possible that Craig has an issue with control of heat. This may show up as det if your prognosis regarding RON/MON is having an impact.

Trout

CraigH

If I'm running more Boost than you David I guess that is one area that is possible....

It "kind of" makes sense as I hadn't thought about the MON rating, but with Optimax it only dets at higher revs and higher boost - with Esso SUL and NF it doesn't??

I'm not a Chemist - I can just see what's happening - Optimax does (with OB), Esso SUL doesn't (with OB)

Maybe Optimax is just cheap fuel that's maxed out with Octane Booster already! Kidding

Trout...

Craig,

you're last comment could well be true! It is strange that Optimax does not seem to tolerate octane booster tho'.

Regarding boost - the posts I have seen state det problems at 1.3bar, so no you are not running more boost than me at that level. I am running considerably more

And before anyone comments - I have been running these levels of boost for nearly 20,000 miles with no problem, on track and on the road.

Interesting that we have had opposite experiences - my own experience is being mirrored with some other Link tuners. Could it be an ECU issue - I hear that you are rethinking your ECU strategy.

Also, have you tried Optimax on it's own - Shell claim a different approach to fuel composition and maybe Optimax and NF simply don't mix. As I said I am happier with plain Optimax over SUL + OB. Just a thought.

Cheers,

Trout

[Edited by Trout - 10/23/2001 9:50:24 PM]

CraigH

David,

I think the 1.3 should read 1.8.............

You running more than that?

Gary Foster

Lol @ Craig

chuckster

Another thing to remember is booster only has incremental benefits as octane rises. 1 bottle of millers added to 97 ron is good for say 2 extra ron, but 2 bottles doesn't = 101 and 3 = 103 IIRC.
Therefore as Optimax is already 98.6 (IE SUL + 1.6) then addition of Millers is going to only raise octane a smaller amount.
Other than that the additives in Optimax may already be doing the job Millers does with regard to more efficient combustion, so again adding Millers has little effect.
My Audi S4 and 22B (Both static mapped for > 97ron) both 'feel' much better on Optimax, and the knocklink is very quiet on the 22B with Optimax no booster, at least as quiet as Esso SUL + Millers.
Chuck
Edit 'cos I can't add

[Edited by chuckster - 10/24/2001 10:50:16 AM]

Trout...

OK, LOL, however all the other posts did say 1.3 was where det occured.

And of course I am running 1.8....yet!

Trout

Mike Tuckwood

A little knowledge is a dangerous thing, this is like looking at the tip of an iceberg, then claiming that Ice will float above the surface of water.

I have sent a full range of NF octane boost from my stock, Millers Octane + & CVL, (via Millers technical department), for some "proper" testing by ITS.

ITS are the FIA testing laboratory.

I already have some results available for differing ranges/mixtures of fuels with Millers additives/avgas Etc but will have compiled a more accurate and full assesment and results when testing has been done (approximately 2-3 weeks).

There are so many elements/variables to consider, such as avgas in aeroplane engines; aero engines only see up to around 4000rpm (apparently) and altitude helps reduce det..... Etc. Etc.


Mike.

[Edited by Mike Tuckwood - 10/24/2001 4:52:04 PM]

Danny Fisher

Whilst being REALLY BUSY here at work, I found this. I hope this just adds to the confusion...

It is common to hear racers talk to one another about the octane rating of the fuel they are using. It also seems that the "more is better" law seems to be the common conception. So what do those octane numbers really mean? Where do they come from? Is more better? What about Avgas?
Basically the octane number of a given fuel is a rating that determines its ability to resist detonation. Detonation (pinging) is a very bad thing that, at best, will rob you of some horsepower. At worst, it will quickly destroy an engine.
The octane number is measured on a large, single cylinder, variable compression, test engine. The compression can be varied by turning a crank which raises and lowers the cylinder head. This engine also has provisions to carefully control the speed at which it runs, the intake temperature, etc. The variables are set according to the type of test being run, the test fuel is added, and the cylinder head is lowered until the engine begins to detonate. When the detonation point is found, you simply read a scale that registers the height of the cylinder head. This number is the octane rating for the fuel being tested under those conditions.
The conditions of the test (engine speed, intake temperature, etc.) vary depending on the type of test being performed. Here in the United States, the common ratings for car gasoline are the "Research Octane Number" (RON) and the "Motor Octane Number" (MON). The rating on the pump is the average of these two, also called the Anti-knock index (AKI).
The test conditions for the RON procedure are less severe (lower speed, lower inlet temperature) than they are for the MON procedure. Generally, this means that if an engine is detonating at low speed, it needs a fuel with a higher RON, while if the detonation occurs at high speeds, it needs a fuel with more MON.
Back in the 60's, gas stations used to advertise only the higher RON numbers. That is why 100 to 104 octane fuel was common! We can all learn a lesson from this by finding out when shopping for fuel what procedure was used. I have seen some of the racing fuels advertise "110 octane" fuel, only to find out they were advertising only the RON numbers or using some non-standard rating procedure. (Buyer beware!)
Is more octane better? Yes and no. If your engine is tuned properly and detonating, yes. However, if your engine is tuned for maximum power and does not exhibit any signs of pinging or detonation, the answer is "no". More octane will not give you any more power....
More octane is only a benefit if, for example, your engine can make more power by advancing the timing slightly. But perhaps that slight advance causes detonation. Situations like this call for more octane.
Largely "unadvertised" specifications such as the distillation curve (a measure of the amount of fuel that is vaporised at a given temperature) can be more important that octane numbers in determining how well a given fuel burns in your engine. (this is because the gasoline must be vaporised before it can burn)
Avgas. Avgas uses yet another set of conditions for the octane tests! The numbers cannot be compared directly to the test used for "car" gasoline's! The test procedures call for quite a bit less demanding conditions than either the RON or MON tests. Avgas 100/130 does have both RON and MON ratings of about 100 when tested using those procedures... but that does not tell the whole story.
Avgas is formulated to burn efficiently at high altitudes. The temperature at altitude is generally quite cold. And aeroplane engines are generally run at near constant rpm. These factors allow Avgas to not need as high an "octane quality"... What this means is while the RON and MON numbers may be impressively high, Avgas is much more prone to detonation under hard acceleration than "car" gas.
One other important factor for aircraft is weight. Avgas weighs about 5.8 to 5.9 pounds per gallon versus 6.1 to 6.2 pounds per gallon for "car" gas. This reduction in density means that you must run richer jetting when switching from "car" gas to Avgas. Not a great feature when fuel consumption is restricted.
More octane is not always better... and Avgas is not really a cheaper substitute for racing fuel. (Although it can and has been used quite successfully.)
Fuel selection is somewhat of a "trial and error" procedure. The numbers on the pump and in the advertisements do not tell the complete story. All brands do not perform the same even though the octane ratings may be identical. Unfortunately, some of the characteristics that make one fuel perform better than another are never published (such as the distillation curve). This is why you may get better performance from one brand, or even from a fuel with a lower octane rating!
The bottom line is that higher octane numbers do not guarantee more power. They are only a small (and perhaps not too important) part of the performance picture.


Dan

dingy

Mike whats yer full range of NF, as yer can only get 2 in this country from US..

CraigH

Quote from Blade:

"some motherf***er is always trying to iceskate uphill"

CraigH

Mike,

Thought you said a little while back that NF didn't work?

ski

According to DIN Standards The RON and MON should be

Regular 95 RON 85 MON

Super Plus 98 RON 88 MON

that should include Optimax

ski

dingy

Shell says its garaunteed 86 MON.



and only Garaunteed 98 RON.

dba

will someone speak in English? Is Optimax a good petrol or not ffs!!??

dingy

Well the millers increases the MON level By 1 and the RON by 1.2 using recommended dossage.

Pro Boost increases RON at 1.5% fuel by 1.2 RON, still waiting for the MON Rating.

Still waiting on the NF results on MON

Mike Tuckwood

I'm setting up a lecture by the head of the technical department at Millers Oils.

I have REAMS of information on this now, which makes quite obvious how complicated this area is.

dingy, your figures are innacurate, Millers Octane + clearly states (and tests) at RON increase of 2 or more. (No daft measuring cup malarky either)

97 RON test fuel with correct mixture level gave 99.5 RON. (tested by ITS).

Octane Boosters
Theer are a number of them on the market now, the most common ones:-

Toluene (Methyl Benzene) 42%, 35% in 2005
MTBE (Methyl Tertiary Butyl Ether) being banned in USA from 2002 Maybe Europe also?
Ferrocene (Dicyclopentadienyl Iron)
MMT (Methylcyclopentadienyl Manganese Tricarbonyl) Used in USA & Canada for 25 years
Lead (Tera Ethyl Lead)

Flame Front Control

TEL (Lead) provides this, as does MMT.

The rest of the info goes into depth stating how the formation of Peroxides in the burn process can be (and should be) avoided, and how flame front controllers (FFC's) act as a mirror, 'reflecting back' random flames. Random flames cause metallic pinking.


Complicated Eh?


Mike.

carl

Make your own octane booster. See http://au.geocities.com/ozbrick850/e...taneboost.html but read the disclaimers.

Also note that on a karting site I found the following statement: (original article can be found at http://www.foxvalleykart.com/html/fuel3.html

dingy

Mike, you are funny.

These figures are from millers, would you like me to post the email....

please give me some credit

[Edited by dingy - 10/26/2001 2:16:48 PM]

dingy

Oh these figure was with optimax.

Mike Tuckwood

Funny yes, but also accurate, I'm quoting figures from ITS (via Millers).

Perhaps your figure are not up to date or you are misinterpreting them.

(Should I fax you the details)?


Mike

dingy

----- Original Message -----
From: "Peter Woodward" <webmaster@millersoils.co.uk>
To: <dingy@happyland.co.uk>
Sent: Thursday, October 25, 2001 5:48 AM
Subject: Re: Feedback Form from Website


> Starting with Shell Optimax - 98.3 RON/87.2 MON we get 99.5 RON/88.2 MON.
>
> With Over-treatment we have 100.8/89.2
>
>
> Graham Lord - Millers Oils Ltd
> ----- Original Message -----
> From: <dingy@happyland.co.uk>
> To: <webmaster@millersoils.co.uk>
> Sent: 23 October 2001 16:49
> Subject: Feedback Form from Website
>
>
> > Millers Oils Customer Feedback for: Technical Queries
> >
> > From: Steve Carlin
> > Email: dingy@happyland.co.uk
> >
> > Products: Millers Octane Boost
> >
> > Comments: What does this increase the MON rating of Super unleaded to.
> >
> >
>
>

Dates are there mate.

Fax it over then

01159586633 along with the knockbench test apparatus