Octane Booster

[Tinduck Racing]

[Posts removed as requested]


JonB

[Gibbo]

Hi there

At the moment I am running a UK Honda Prelude 4th gen (1992-1996) 2.2Vtec.
It is completely std and at the moment I fill up with STD unleaded fuel.

I've have read most of this thread and have come to the conclusion that if I start filling up with Shell optimax or fuel from Fina/Elf/Total I might see a slight performance increase?

What fuel will be best for my car? If it's Optimax then fine, if it's the stuff Total/Fina/Elf sell then what is it called on the pump? Basically whats gonna give me the best performance and is there any risk of longterm damage?

Or will there be no improvement and therefore I should just stick with bog STD unleaded fuel?

Sorry for all the questions, just wondering if it's worth spending a few extra pence on fuel and what improvement and problems there might be?

Thanks.

[Mycroft]

As far as I am concerned the jury is out on Optimax.

Shells' last foray into an exotic fuel 'Shell Advance' lead to its withdrawal and quite a few claims for new engines, if in a furhter 2 years no-one has claimed that their motor is dead as a result of Optimax then I'll use it, until then it's the T/F/E group for me.

(and a little tolly/xylene for those...special times)

[Mycroft]

Well, some time has past on this matter and a few things have happened here and there regarding this whole subject and for the most part they have been of little or no interest to us here.....however....

In November I read a post from an Engineer from Aston Martin he had noticed over the past year or so that during the strip down and rebuild of the DB7 Supercharged motors and some of the more highly tuned V8's and pepped up 'Old' 6's that there seemed to be a problem with water in these motors, there was rust deposits on the plugs and even on the upper parts of the cylinder liners.

He asked for help as he had performed every conceiveable test he could think of to check for moisture, gaskets...the lot...finally he had returned to him a motor that he had built not long before, it was one of the first motors he had seen with this 'problem'.

This mans qualifications and experience in re-building engines puts him in the top league, he has been flown all over the World to re-build motors for Museums and Collections etc. A man of exceptional skill.

He kindly sent me a Spark Plug from this motor asking if I would kindly check if the brown spots on it were rust and some huge exceptional quality photographs (his hobby) taken with his Hassleblad.

At first glance no doubt about it this engine had a leak, a water leak, not a bad one but bad enough, the odd thing was that apart from the odd hard race and a precautionary strip down and re-build, these motors would run beautifully.

But again that is no surprise as we all know that water can be injected into any engine and in all cases about 0.3% power boost obtained due to the thermal expansion of the water into superheated steam, even better in turbos because of that and the cooling of the charge prior to ignition.
Normally however the explosion and steam never leave a 'deposit'
on anything unless the chamber is 'saturated' and that is a waterway/head gasket failure....none of these motors had this!?!

The plug and photos 'screamed' gasket failure the engines were not using water at all and they ran smoothly, some had been 'cleaned up' and returned just a few weeks later to be found with this 'condition' not one fluid ounce of water missing from the system.

Under a 400× 'scope everything changed....the 'tell-tale' brown rust had become a complex chrystalline structure of great beauty and in polarised light this jewel of a structure flashed and sparkled in a manner that no 'full sized' jewel ever could to the naked eye...I recognised the characteristics immediately.....this was not rust.......this was Manganese.

(Big string section of an orchestra some where behind me goes....Da-daa-Daaaaaaaaa)

I now had a damned good idea as to what was happening.

I immediately made contact with our Engineer, who being a meticulous sort of chap had records of almost every detil of every spin of all the motors he 'owned' as he put it.

As he talked me through each car after about 40 minutes or so (yep, a telephone conversation that could have bored the pants off a frigid nun locked in a fridge in the middle of a frozen lake in the Arctic circle) a pattern emerged, all these cars had run Optimax and Octane boosters which is exactly as I suspected the moment I saw that chrystal structure.

Now I must emphasise that NO DAMAGE had occurred, a few very cautious owners had paid for a couple of very expensive re-builds.

This is why this thread has been revived..because almost all the contributors and many of the readers of this thread I believe are just that cautious and enquiring.

Moral..It may look like rust, it may seem like you are heading for a big bill, but if you use Optimax with a high Manganese Octane Booster then don't have a brown trouser moment, check everything first, perhaps a little less OB?

Regards.

[Alan]

but if you use Optimax with a high Manganese Octane Booster

I have been following this thread over the months since it was raised.
Very interesting Mycroft

In your experience which are the O.B. that have a high Manganese content

Waiting in anticiptation

Best regards Alan

[Mycroft]

Frankly, I don't know!

Now despite the close monitoring of his engines, he is never there when they are filled with fuel/OB and only the info supplied by his customers is available, they may just be putting in the Manufacturers recommendations and a little bit more 'for luck'.

A bit of feedback from Abbey/Gary/Mario/Anyone on this would be interesting.

[Steve W]

SORRY "Mr. Crofters".....

are you saying the manganese is from the OB, or, from the
Optimax ? ?

and,

is this deposition only occuring because of the combined use of
both ?

ie. would it occur if only using either ? ?

(is it a sort of 'over-addition' of additives ?)

"STILL-way-out-of-my-league"-FatS.

[BTW, STILL haven't got/used any Tol yet ! ! SO FAR (~6months)
have been using mostly Optimax and , OB if I couldn't get Opt']

[Mycroft]

Iain or Mycroft 'll do.

From 'which' it is impossible to tell, it appears to happen when both are used in combination, Opt and OB.

[Steve W]

Cheers Iain,

that's probably OK then,
I can't afford to keep using BOTH at once

(I drive like a woos most of the time anyway!)

Thanks anyway, FatS.

[Peter]

Iain,

I think you've solved a longstanding mystery for me. When I took my stock turbos off my car to replace them, both wastegate chambers (?) were covered in what I took to be rust. This caused some head scratching as my car never has used any water so, in consultation with the experts, we concluded that as the car had been standing for a couple of weeks prior, this was the result of condensation and nothing to worry about.

The main reason for me never really accepting this was why were the turbines also covered in rust being that they are ceramic? For the past year or so prior to this change, I religiously used Optimax and OB. I no longer use OB except on track days... I've still got them if you want a scaping?

Peter.

[Blow Dog]

For what it's worth, I've stopped using Optimax.
Had a tank full of it in the car for over 2 weeks a while ago, car really wasn't happy in it's running for a few days. Also notice excessive det with Optimax.
Texaco Super now with OB, runs much better.

Cem

[Mycroft]

Peter.

No, been there, solved the mystery.

I'm pleased to have it further confirmed on here.

[GTR-NUTTER]

sorry if i sound daft but what should you use then , and is optimax worth it

[ctrlaltdelboy]

Hey Mycroft

do me a favour and tell me your 'preferred' recipe

I have 25L of toluene and 500ml of Isopropyl alcohol in my garage
how much iso should I mix with the tol and then how much of the resulting mix would you recommend to mix with super u/l or optimax?

cheers in anticipation - I'll let you know how it goes.

ps car is Honda NSX 3.0 VTEC normally aspirated, compression ratio = 10.5:1, low cam profile up to 5k rpm then switches to high cam until 8k rpm, I'm running a hi flow air intake with cold air induction, performance headers & exhaust and hi flow cats. around 300HP at the flywheel.

[InsBro]

Some points they have answered, they will be glad to answer any questions!

From a website
"Why is Optimax so variable?

Age, 'Optimax' has a 'tank life' it degrades quite rapidly as the super hot
benzene '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 so 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.

Shell Say

"I will reiterate:

'Shell Optimax is 98 RON min, it is a completely new uniquely formulated fuel in which the high octane comes from refinery blending components not octane boosting additives. It also contains a top tier detergent additive which has the ability to clean away the deposits left behind in the airways of the engine by other fuels.

All Petrol, including Optimax, is manufactured to a specification which correlates to a storage stability of 2 years when stored under correct conditions. We do not, however, recommend that it is stored for a period of more than 6 months due to the seasonal variations of the fuel. The RON of Optimax would not decrease over the period of time that the fuel remains in the tank of the vehicle or the retail site, and is only likely to decrease by 0.5 RON max under very extreme conditions.'

The comments regarding benzene are irrelevant since benzene is not particularly volatile, and it is typically only present in quantities of 0.5%v/v or less in fact the specification for all grades of petrol is 1% max.

Optimax is 98 RON min, typically around 98.6. It is NOT an enhanced 95 RON fuel, it is a uniquely formulated fuel in which the increased octane comes from high octane refinery streams not an additive."

Another
"It also scrubs the tank, and this may well be what ****ed Adis' cats, his
explanation of events fits the dirty tank scenario, 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, there is a precipitate (solid) formed and
this is what I think got Adis cat in trouble, 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."

Shell

"When a tank on a forecourt becomes available for Optimax it is drained and refilled in quick succession (if it is a diesel tank it may require testing for licensing purposes and this will be the only situation where nitrogen (or any gas) would be introduced). The tanks at our retail sites are manufactured from coated steel and therefore occurrence of rust is very unlikely. And again, the benzene issue becomes irrelevant on two counts."

Another

"Manganese is essential for Optimax to work (see my paper of Oct. 2000,
LSOC) I have found only traces of Toluene in Opt. for the most part it is
Xylene and Benzene."

Shell
"There is no manganese in Optimax. Manganese is often used in octane boosting additives, however Optimax is a uniquely formulated fuel where the increased octane comes from refinery streams alone.

Again, the maximum benzene spec for all UK petrols is 1%, Optimax is typically 0.5% or less."

Another

"Optimax is high (very high) in Iso-parafins."


Shell

"Probably quite true - iso paraffins are generally high in octane."

Another

"Any 'metal' (if its compound is 'soft') will assist the valves and to some
extent the detonation. However some metals will cause the valves to rotate
to quickly (performance road cars valves rotate at around 1/2RPM, saloon
cars 1RPM) causing valve wear, this what caused all the trouble with Shells
last foray into the hi-performance fuels, that had to be withdrawn as the
claims against them were getting 'out of hand' I like what Optimax does, but
I am always aware that their last effort screwed cars over a 2year period, I
hate to feel like a long term test 'guinea-pig'. To some extent I feel that
way about all the OBs'."

Shell

"Optimax contains no metal compounds.

The fuel you remember was Formula Shell. Formula Shell contained a spark aider additive which was the cause of exhaust valve problems in a small minority of cars running on leaded petrol only. Shell Optimax is a completely different petrol formulation since it is an unleaded petrol and it does not contain the spark aider additive contained in Formula Shell.
We have extensive engine test data showing that this unique high octane, clean burning petrol, with its market leading additive performance will enhance engine performance, improving responsiveness and giving superior acceleration. This has also been rigorously tested and benchmarked against other petrols currently available in the UK."

Helen Scholey
Technical Manager - Automotive Fuels
Shell U.K. Oil Products Limited
Rowlandsway House, Rowlandsway, Manchester M22 5SB, United Kingdom

I am just awaiting confirmation I can publish the email address then you can send your own questions.

Jeremy