Hellfire
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| posted on 17/10/05 at 08:56 AM |
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Fuel - Optimax/Ultimate
Having been reading a thread regarding the benfits or not of using higher octane fuel. I've done a lot of searching and research on the subject.
I've searched for the previous thread but can't find it!
Results from my research show that the higher octane fuels are superior in both performance and mpg despite certain commentators stating that you
don't benefit unless the engine is tuned. Both fuels are designed to run on standard tune engines - the fuel burns more clean and therefore
improves fuel burn efficiency and hence giving the results predicted.
I personally found a general improvement both in my petrol car and now my deisel car - the engine runs quieter with high octane fuel. Does anyone else
have any similar experiences they would like to share on a public forum to quell the detractors  Popular forums for bikes and cars; that prefer a
fuel state that the fuel is different and not a merely a marketing ploy.
I'm just waiting for an answer back from our Technical Department to hopefully put this myth where it belongs -
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bimbleuk
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| posted on 17/10/05 at 09:08 AM |
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On my turbo'd Corolla I noted the following from comparing fuels.
95 octane fuel = 215BHP
95 octane fuel + octane booster = 225BHP
Optimax = 230BHP
The ecu was having to retard ignition on 95 pump fuel as detonation was detected. The torque curve was also much smoother on the boosted fuels. On the
road this meant the car was more responsive and smoother to drive.
All tested on the same rollers.
I believe the cleaning properties of Optimax are well documented and proven by independant magazine tests.
Justin
[Edited on 17/10/05 by bimbleuk]
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Hellfire
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| posted on 17/10/05 at 09:18 AM |
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Our Technical Dept. has just got back to me - they verify that the higher octane fuel's do improve performance, mpg and emmissions with no
alteration of tuning. This is due to the cleaner characteristic's of the the fuel in question.
Oh BTW - my Technical Department is NGK Spark Plugs (UK).
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TimC
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| posted on 17/10/05 at 09:40 AM |
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Good news - having seen decent benefits on my MX-5, I've never even thought abouot running the Indy on anything but Optimax/Ultimate.
I also read in one of the mags that Tesco are supplying a 99 octane fuel from some of it's sites?!
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donut
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| posted on 17/10/05 at 10:21 AM |
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I noticed today that my local Tesco is selling 99 octane Ultima or optima or whatever it's called but i'm too stingy to buy it!..... mind
you if it does more mpg then perhaps it's not as expensive as it seems.
Andy
When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car.
http://www.flickr.com/photos/andywest1/
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smart51
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| posted on 17/10/05 at 10:29 AM |
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Hellfire, How much better is using high octane fule in a "normal" engine than using "normal" octane fuel? Did your technical
department suggest how much this might be?
I'm interested in this as I will be going to SVA soon and want my carbed R1 to pass emmissions first time. If high octane fuel will make a
difference then I will use it, at least for SVA.
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Peteff
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| posted on 17/10/05 at 11:24 AM |
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Are there differences between manufacturers as well? I had an Escort 1600cvh when unleaded was introduced and as it already had hardened seats I
altered the timing and spark retard valve as in the manual and ran it solely on unleaded. It would pink and splutter like a b@&tard on Texaco fuel
but was fine on any other. I use octane booster in my pinto locost and I know that makes a difference, it pulls a lot cleaner and from lower down the
revs.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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Fozzie
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| posted on 17/10/05 at 11:37 AM |
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Good point.....we have, in our business, been over the years, actively researching this very point.
We have been racing and preparing historics since for ever, but in 1999, it got more serious as in doing the Top Hat series, Gold Cup, Le Mans
Classics, Le Mans Legends etc in 1950's Jaguars. Lead free conversions done to most of the engines BTW. The engines re-built by us.
I am happy to confirm that the cars absolutely flew at Le Mans. We had to use their fuel supplied by the Le Mans circuit, which was 100+ octane. All
of the old cars we have re-built engines for, we insist use Shell Optimax......and in an emergency BP Ultima, the owners of the cars are very happy.
The engines are also very happy....  .
I went on to try out Optimax in my modern tin top, it did not like it, it obviously didn't need such a high octane, it kept pinking.
For my 7 which has a 1978 cross-flow engine, lead free conversion, re-built by me, I use Optimax, it is also a very happy fozzmobile, and runs
beautifully.
So, my experience tells me, that pre-moderns love the higher octane of Optimax, modern technology, does not.
I don't think that I would personally use the cheaper petrols a la Tesco Sainsbury et al, as I am unsure of their country of origin/purity. My
take on it is, that if your engine is of the old variety, you have spent money on the re-build, it makes sense to use the best fuel available. But,
all of the above is only my opinion, and our 'findings' of testing!
Fozzie
[Edited on 17/10/05 by Fozzie]
'Racing is Life!...anything before or after is just waiting'....Steve McQueen
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David Jenkins
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| posted on 17/10/05 at 11:55 AM |
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My x-flow is the same as yours, Fozzie - I feed it Optimax, as ordinary unleaded makes it run on when I turn off the ignition, even if I adjust the
timing.
With Optimax, it runs well with no sign of pinking, even though the ignition was advanced a bit above 'book settings' at a recent rolling
road session.
David
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Fozzie
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| posted on 17/10/05 at 12:14 PM |
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quote:
Originally posted by David Jenkins
My x-flow is the same as yours, Fozzie - I feed it Optimax, as ordinary unleaded makes it run on when I turn off the ignition, even if I adjust the
timing.
With Optimax, it runs well with no sign of pinking, even though the ignition was advanced a bit above 'book settings' at a recent rolling
road session.
David
Absolutely David! exactly my findings with the crossflow!....So....2/2 cross-flow users say.....Optimax!....
ATB Fozzie
'Racing is Life!...anything before or after is just waiting'....Steve McQueen
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mark chandler
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| posted on 17/10/05 at 12:14 PM |
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I had a Rev3 MR2 Turbo, these run an electronic waste gate so boosts until the engine knock sensor backs it off. With optimax it managed 0.4 bar more
which made quite a difference, 240 up to 270 bhp !
Fastest excellerating car I have ever owned, my BEC should trounce it when completed !
Cheers Mark
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jimgiblett
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| posted on 17/10/05 at 12:51 PM |
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I think it depends on the question asked to your technical advisor 
Firstly I believe the original question was whether 95 or 98 octane is best for an R1. With a suggestion that 98 RON will produce more power, mpg and
cleaner emissions.
Please note the info below come from a number of sources and phrase it better than I can :-
Octane rating is a measure of how resistant the petrol is to premature detonation (knocking). Using a fuel with a higher octane lets an engine be run
at a higher compression ratio without having problems with knock (Hence some real advantage for forced induction cars).
In simple terms compression is directly related to power, so engines that "require" higher octane usually deliver more power.
Some high-performance engines are designed to operate with a compression ratio associated with high octane numbers, and thus demand high-octane
petrol. But most major manufacturers design on the basis of the fuel commonly available. High compression engines can be run on lower octane fuel by
retarding the ignition with slight loss of performance.
The goal, then, is to find a fuel with an octane rating that is high enough to prevent knock, but not much higher.
Some people believe that adding a higher octane fuel to their engine will increase its performance or lessen its fuel consumption; this is mostly
false—engines perform best when using fuel with the octane rating they were designed for.
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jambojeef
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| posted on 17/10/05 at 01:03 PM |
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Agree with the above,
Bike engines generally run a higher compression ratio than car engines and so would have been designed to run a higher octane fuel to prevent
detonation. An R1 will almost certainly be best run on 98RON.
In turbocharged cars with electronic boost control, as was mentioned previously, the boost can be increased by the cars ecu until detonation is sensed
by the knock sensor and then the wastegate is actuated. In my Fiat Coupe 20v Turbo this was evident at the Nurburgring filling up with the evil
smelling 105RON stuff they had at the local filling station.
As for the cleaning ability of higher octane fuels I dunno...maybe the addition of higher levels of Benzene to slow the burn has the side effect of
cleaning the fuel system to a greater extent?
In the diesel engine you mention, is it a turbo diesel with electronic boost controller?
Geoff
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smart51
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| posted on 17/10/05 at 01:06 PM |
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High octane goes with high compression, yes but isn't this thread looking at it from a different angle?
Different fuels burn at different speeds and different fuel compositions burn more completely (cleanly) under different conditions. Given this, if
you run optimax / ultimate in an engine that is happy on 95 RON fuel, will the use of certain higher profile fuels burn more cleanly or
efficiently?
I can imagine a scenario where a "good" fuel burns ideally in my engine as it is, giving lower HC and particulate levels than a
"cheap" fuel that doesn't fully burn under the same conditions. Theoretically, the fully burnt fuel may release slightly
more power for the same quantity of charge. This may lead to slightly better MPG as you don't have tp put your foot down as far to get
the required power to maintian your speed. I can imagine this and I can imagine an expert running a series of experiments and proving it. Is the
improvement 0.05%, 0.5% or 5%?
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Hellfire
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| posted on 17/10/05 at 03:17 PM |
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Technically - all engines differ.
Increases of lead in fuel aid's lubricity but reduces the speed of burn. Therefore, the time it takes to burn the fuel occasionally overlaps
with valve opening and let's unburned fuel into the exhaust system, so loosing 'some' power - higher octane fuels increase the speed
of burn thereby increasing the efficiency. Therefore higher revving engine's will especially benefit from this improvement. There have been no
conclusive test's with NGK to state this as fact due to the first statement... and research into this would give very erratic results.
One 'off the cuff' statement came when asked about temperature ranges - the cleaner higher octane fuel makes a big difference when the
engine is cold. The spark plug is out of it's normal working operating temperature and carbon deposits form on the electrode so causing an
amount of fouling. This is burned off as soon as the range is reached... from NGK's point of view this should be the only time a benefit would
be seen.
Very popular opinions state Optimax is better than Ultimate - this is possibly due to the 1 unit higher RON value. Preach all you like about
fuel's but the general populous is for higher octane fuels.
The spark plug is ignored as one part which doesn't normally fail. But today's pre and post TDC spark systems (Fireblade for instance)
take there toll... renew regularly with NGK Spark Plugs the OEM's choice!
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jimgiblett
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| posted on 17/10/05 at 05:51 PM |
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quote:
Originally posted by jambojeef
Agree with the above,
Bike engines generally run a higher compression ratio than car engines and so would have been designed to run a higher octane fuel to prevent
detonation. An R1 will almost certainly be best run on 98RON.
Geoff
Higher compression yes. Will run better on 98. No, not unless the timing is advanced. If the engine was manufactured for 98 it would knock on
lower grade fuels and as the R1 manual says normal pump gas in its service manual that means petrol down to around 90 would be okay. Mr Yamaha would
be getting lots of warranty claims from riders who have put lower octane fuel in their bike.
If you want to take advantage of 98 octane fuel with a R1 get an ignition advancer else you are wasting your money.
ps my R1 passed SVA with Tesco 95 with very low emissions no problem.
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Marcus
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| posted on 17/10/05 at 08:11 PM |
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My good old 1700 crossflow had a hiccup going down to South of France - I have a 20 litre tank and had to stop every 130 miles to fill up. Halfway
down France it was dark and I was tired so I filled up the car as usual. The fuel seemed to last forever, I'd only used just over half a tank,
and the odo. read 122 miles!! I was a bit freaked out 'cos I thought I'd get stuck in the middle of nowhere so I filled up again anyway.
Seemed I'd put optimax in instead of 'super' unleaded.
I'm definitely a convert now!
Marcus
Marcus
Because kits are for girls!!
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Hellfire
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| posted on 17/10/05 at 10:24 PM |
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quote:
Originally posted by jimgiblett
Higher compression yes. Will run better on 98. No, not unless the timing is advanced. If the engine was manufactured for 98 it would knock on lower
grade fuels and as the R1 manual says normal pump gas in its service manual that means petrol down to around 90 would be okay. Mr Yamaha would be
getting lots of warranty claims from riders who have put lower octane fuel in their bike.
If you want to take advantage of 98 octane fuel with a R1 get an ignition advancer else you are wasting your money.
ps my R1 passed SVA with Tesco 95 with very low emissions no problem.
Well I'm sorry Jim but you have totally contradicted yourself within three paragraphs. If Mr Yamaha made his engine to suit down to 90 Octane
then running it on 95 would have no effect... conversley 98 Octane in a 95 Octane designed bike would also have no effect! Consumers who have bought
from other regions of the world (Czech Republik for instance) complain about the lack of performance when using cheap fuel's. RON does make a
difference...
It does... and judging by the few replies on here most people seem very happy with it making claims of improved efficiency however it is delivered
whether it be more mpg or performance.
No fuel has guaranteed consistancy therefore engine manufacturers build in allowances for fuel, the difference between 90 and 98 RON should fall into
those tolerances whereby reasonably small gains can be made without retuning.
If you want the ULTIMATE gain from a 98 RON fuel - obviously a retune is in order, on that I can agree. To say "you are wasting your
money" by putting in higher octanes is a very general comment and could be construde as incorrect as it is obviously not what the vast majority
are saying.
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David Jenkins
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| posted on 18/10/05 at 07:49 AM |
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My gut feeling - based on no known science - is that Optimax is the only fuel that effectively replaces good old leaded 4-star in my x-flow Locost.
There is no reason why I should need a higher octane, as the compression ratio remains the same, and I used to run with the standard timing. The main
difference now is that I shift more fuel through the engine (bigger carb, better filter) and let the exhaust out a bit quicker (better manifold &
exhaust).
I have no experience with super unleaded, as it's hard to find round my way, neither have I tried the BP stuff - anyone know how this compares
to Optimax?
rgds,
David
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jimgiblett
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| posted on 18/10/05 at 09:37 AM |
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quote:
Originally posted by Hellfire
Well I'm sorry Jim but you have totally contradicted yourself within three paragraphs. If Mr Yamaha made his engine to suit down to 90 Octane
then running it on 95 would have no effect... conversley 98 Octane in a 95 Octane designed bike would also have no effect!
Contradicted... How??
My exact point which seems fairly clear is that higher octane fuels do no damage but give no gain. However, conversely running too low an octane will
cause detonation and damage. Yamaha R1 is designed to run on standard pump gas. Which is exactly where the whole thread started ie. fueling an engine
with a higher octane fuel than it is designed for is a waste of money.
Paying extra for no effect is by definition a waste of money. Your words not mine.
[Edited on 18/10/05 by jimgiblett]
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smart51
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| posted on 18/10/05 at 10:43 AM |
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quote:
Originally posted by jimgiblett
Contradicted... How??
Your earler post could be read that and engine designed for 98 ron cannot be run on 95 without causing damage. The R1 is designed to run on 95 and so
is OK to run on 90. It is just a slight ambiguity, that's all.
The sum of this thread seems to be that whilst high compression and suitable spark timing is needed to get the most out of high octane fuel, the
cleanlyness of optimax / ultimate has benefits over ordinary fuel, even in an engine that is designed to run on your normal 95. It is the difference
between "beter" and "the most better it can possibly be".
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jimgiblett
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| posted on 18/10/05 at 02:08 PM |
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quote:
Originally posted by smart51
[ It is the difference between "beter" and "the most better it can possibly be".
Yes, and octane selected should match that for which the engine was designed. Getting close to this is better. Being spot on is best it can be.
Deviation from this optimum by definition is negative.
If air fuel ratio is at its optimum you wouldnt add fuel to get more power. Like wise if the octane of the fuel was at its optimum you wouldnt
increase it.
Ambiguity... pah only if you try and find it
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Syd Bridge
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| posted on 18/10/05 at 03:45 PM |
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Fozzie..That fuel supplied at LeMans is a loooooong way from normal pump fuel! And a lot closer to 100 octane avgas than they would have you
believe!!!
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smart51
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| posted on 18/10/05 at 05:23 PM |
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quote:
Originally posted by jimgiblett
Deviation from this optimum by definition is negative.
No, it can sometimes just be "not any more positive"
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jimgiblett
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| posted on 19/10/05 at 03:30 PM |
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quote:
Originally posted by smart51
[No, it can sometimes just be "not any more positive"
And that must be worth paying the extra pump price for !
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