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51 Buell X1 & 89 Tenere
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Pulled up today and put Ultimate instead of standard unleaded, will it make a difference? I don't notice any difference , but should i water it down with standard unleaded or not bother? Does it heat the valves more?
 

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No worries, it is the same stuff with a bit of marketing-potion added to it. :wink:
Some people even claim to experience miracles after filling their bike up with it, but they probably just kept their nose too close to the filler cap :lol:
 
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babybadger said:
Pulled up today and put Ultimate instead of standard unleaded, will it make a difference? I don't notice any difference , but should i water it down with standard unleaded or not bother? Does it heat the valves more?
I filled up on super plus (ultimate)?? £1.07p litre unleaded the other week. Made the bike a bit vibey, but checked colour of plugs and there was no problem. You dont gain anything with it as timing on the ta doesnt advance like a fuel injected bike would to take advantage of it.
I just run my bike very low and filled up with normal unleaded. A couple of tanks through now of the normal stuff and she is running sweet again.

Paul
 

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24ftlb said:
You dont gain anything with it as timing on the ta doesnt advance like a fuel injected bike would to take advantage of it.
Getting any advantage from higher-octane fuel would be to ignite later, not earlier. I never heard of any fuel injected engine changing the timing to make use of higher-octane's resistence against pre-ignition (pinking). You'd need some magical octane-sensor to do this. There are clever injection (lean-burn) systems that dynamically advance the timing in case the engine starts to pink, but they are triggered by that very event, not the fuel's octane.

Filling up with high octane fuel and changing the timing by force is not a wise option either because the shape of the combustion chamber and cam-shaft timing play a role as well to ensure pink-free running.

You won't get any advantage from a high-octane fuel if your engine is not designed to make use of it. It won't hurt it either, except your wallet ;)
 

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51 Buell X1 & 89 Tenere
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Discussion Starter #5
Thanks folks , I can sleep now. It was a mistake, what with BP's marketing saying 'try me' labelled on the pump, and driving a chipped T5 estate it just came natural until I looked at the the standard unleaded pump in its holster and that sigh of 'Oh F*&^k!' . At least it wasn't diesel!
 

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robelst said:
24ftlb said:
You dont gain anything with it as timing on the ta doesnt advance like a fuel injected bike would to take advantage of it.
Getting any advantage from higher-octane fuel would be to ignite later, not earlier. I never heard of any fuel injected engine changing the timing to make use of higher-octane's resistence against pre-ignition (pinking). You'd need some magical octane-sensor to do this. There are clever injection (lean-burn) systems that dynamically advance the timing in case the engine starts to pink, but they are triggered by that very event, not the fuel's octane.

Filling up with high octane fuel and changing the timing by force is not a wise option either because the shape of the combustion chamber and cam-shaft timing play a role as well to ensure pink-free running.

You won't get any advantage from a high-octane fuel if your engine is not designed to make use of it. It won't hurt it either, except your wallet ;)
Hi, modern performance car* engines are fitted with knock sensors these listen for ignition knock/pinking and alter ignition timing accordingly.

* Not sure if this applies to all modern cars or to FI bikes.

Phil
 

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One of the motoring programmes tested all of these fuels ,Shell Optimax etc,it made no difference to a standard car ,it did however make a difference to the performance of a Suburo Impreza Turbo giving a significant increase in power.
 

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piguglyshandydrinker said:
Hi, modern performance car* engines are fitted with knock sensors these listen for ignition knock/pinking and alter ignition timing accordingly.
Yes, but I don't think there are system that do the opposite (adjusting to higher octane fuel). Again I guess that would be very difficult (if not impossible) to achieve.

On bikes I only know the BMW R1200S(T) have "knock" sensors to enable them to run 95 (where 97 or 98 is recommended) despite 1:12 compression ratio, but maybe it is standard on all FI bikes?
 

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robelst said:
piguglyshandydrinker said:
Hi, modern performance car* engines are fitted with knock sensors these listen for ignition knock/pinking and alter ignition timing accordingly.
Yes, but I don't think there are system that do the opposite (adjusting to higher octane fuel). Again I guess that would be very difficult (if not impossible) to achieve.

On bikes I only know the BMW R1200S(T) have "knock" sensors to enable them to run 95 (where 97 or 98 is recommended) despite 1:12 compression ratio, but maybe it is standard on all FI bikes?
I could be wrong but that's what knock sensors do isn't it?
Allowing the engine to run max ignition advance in any given situation -revs, fuel, engine load etc - without running into preignition...

Phil
 

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piguglyshandydrinker said:
I could be wrong but that's what knock sensors do isn't it?
Allowing the engine to run max ignition advance in any given situation -revs, fuel, engine load etc - without running into preignition...
Yep, you're absolutely right my pig-ugly friend. :lol:

The fitment of a knock sensor allows the engine management to advance the ignition to the detonation borderline, without going into destructive detonation.

This doesn't apply to all cars and bikes with FI though, and indeed you'd only need electronic ignition to do it, not injection. Simple systems (like on early-mid nineties cars, and most bikes) do not have knock sensors and will pink like crazy with poor fuel.

In these engines, the only advantage of the higher-than-standard-spec fuels is their higher calorific values - they produce more energy per kg burnt, so burning the same amount in your cylinder gives you a bigger bang and hence more power.

In Germany, Shell sell an uber-Optimax 100-RON product they call V-Power. I filled up my TL-S for a couple of laps of the Nurburgring with it and it felt great, despite not having knock sensor advance strategy...
 
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