Spike16 wrote:i use permium as its suposidely better for the engine, (makes me feel like im raggin it less) and the nc is so cheep to run im not worried about the extra 60p per tank other standard

my bikes restricted to 33bhp for the while so im not bothered about the performance increase, I can still have my mate on his full power nc in the corners every time (as long as i know the road)

your having a laugh!!!!

you obvioulsy aint trying hard enough , 70 miles to a tank is normal for me :D

ouch, mine does at least 100 before i hit the reserve, then again i am restricted at the moment, that probably helps a bit

the jetting isnt changed for a 33bhp kit, so you will still be using the same amount of fuel.

i just ride flat out, but thats why i love it :D :D

the jetting isnt changed for a 33bhp kit, so you will still be using the same amount of fuel.

The kit restricts the amount of air entering the engine, have I got that right?

In which case, less air will draw less fuel through the jets so that the fuel/air mixture remains the same as an unrestricted engine.

So less air = less fuel.

I think.

yeah you could be right, but all i know is when i had mine in, it did absolutely stink of petrol out the exhaust, ran fine though.
but now i have them out, the mpg hasn't changed but the petrol smell is not there anymore (just smells like a normal exhaust)

I notice no difference at all in power / economy no matter what type of fuel I use. Provided the bike is running properly all modern petrols burn really really cleanly, and considering the VFR's 20 years old now I really think these modern fuels are wasted on the engine.

The only bike that i've ever noticed a difference on is my 87 XBR500 and thats using proper leaded 4 star as opposed to 95 Unleaded, idles smoother and has more lower-end grunt. Could probably have it dynoed with normal unleaded in but buying 4* reminds me of days gone by :)

90 miles to a tank! thats 22mpg, terrible haha! Mind you one guy I was chatting to at a bikers meet the other week was telling me his CBR954 RR3 was doing 60 miles to a tank round the Nürburgring, which is about 16mpg :/

Here I was thinking 32 was bad out of my VFR750!

Druid

I notice no difference at all in power / economy no matter what type of fuel I use. Provided the bike is running properly all modern petrols burn really really cleanly, and considering the VFR's 20 years old now I really think these modern fuels are wasted on the engine.

The octane rating is different though, and that's where the extra power comes from. And the detergents in the premium fuel keep the fuel system clean. Those are the benefits, and it's irrelevant how old your engine is as to whether they're real benefits or not.

Have you done any experiments with fuel type versus mpg? I have, and over the last 6 months I have enough data to be sure of the results.

(Most of the riding I do is on dual carriageways, but around 15% is around town).

I average 50mpg on my NC31 using the cheaper 95 RON fuel, but 55mpg using 97-99 RON fuel (with added detergents!)

That's a 10% increase in mpg, costing around 5% more at the pump, so there's a "real world" difference of an extra £1 in my pocket every time I fill up. I reckon that's about £8 a month saving, or £96 a year, give or take. (Annual mileage is around 8k).

:D

alexibrow wrote:

I notice no difference at all in power / economy no matter what type of fuel I use. Provided the bike is running properly all modern petrols burn really really cleanly, and considering the VFR's 20 years old now I really think these modern fuels are wasted on the engine.

The octane rating is different though, and that's where the extra power comes from. :D

Extra power comes from extra air into the motor. The higher octane allows you to run higher compression rations which is a way of getting more air into it.

Higher octane fuel on it's own at the same compression as std is not likely to blow your socks off and I would guess it does onthing for power from the bang.

If it does lower internal friction, or does cause a more complete burn then yes...but the octane rating on it's own does nowt but let you squeeze more in if you want to..

rock on..the mental effect of the higher octane are more difficult to measure

higher octane fuel is more stable and burns slower than lower octane fuel, consequently it requires more ignition advance than lower octane fuel would in the same engine and as a result can actually give less power.

it all depends what the engine in question is setup for, and all the 400's in stock trim are setup for normal unleaded, so there's little point using super high octane fuel unless you have raised the compression or advanced the ignition timing to the point where normal unleaded is causing detonation/pinking.