98 octane fuels?

[KEN]

I am running all my cars,and my Suzuki 1400 Intruda on the BP Ultimate 98 Octane and thay run a lot "sharper" and smoother an it. What are your views and experences??

[Sleepr]

I been running my hornet 250 on 98 too, it seems to be running fine. I am yet to run it on 95 and see what the difference is like.

[Coldrider]

My understanding is higher octane fuels are slower burning, so as to stop pre-detonation under higher compression.
I can't tell any difference on my ZX between 91 & 95, 98 i haven't tried, but would have to be tuned for it to get any benefit, as it makes ample power anyway, I won't be bothering.

[Mr Merde]

I have been running my Suzuki 1200 on 98 for about 6 months now.

It may be me and my perceptions but I seem to be getting better milage to the tankful by abiout 50km.

possibly the fact that I seem to be running less revs top get a certain speed.

Worth the few extra cents, IMHO, for this.

[vifferman]

We try to run the cars (two Peugeots and a Fiat, all EFI) on 98 when we can, and the VFR (also EFI) at least every other fill, with 91 on the other fills.

Now I'm running a PCII map on the VFR with ignition advance, I need to run 98 so it doesn't explode.

Even before the map, the VFR seems to run better on 98, as it pinks a bit taking off when it gets hot (especially when the tank's getting low, as the fuel pump's in the tank, and warms up without much fuel to cool it). But in the winter, the 98 takes a bit more cranking to start, due to the slower burning, so I use 91 a bit more.

[Delphinus]

What is classed as high compression?
Like is 12.5 : 1?

[Brian d marge]

Its not slower burnning , all the same speed ( 30 odd ft/sec ) 98 has glue in it which makes the flame edge more stable , ( less likely to fall apart under heat and pressure )

All Jap vehicles are designed for 91

Interested in the sharper smoother comment ,, ,, What other factors were there ,,when this happened ? was it raining? damp ...

Stephen

Sorry this is a pre coffee post

[scumdog]

What is classed as high compression?
Like is 12.5 : 1?

Yep, that would be high.

My F100 is 11:1 and pinks even on 98.

Funilly enough it didn't do so on the old 'leaded' Super.

[scumdog]

I
possibly the fact that I seem to be running less revs top get a certain speed.
.

Can't be done - unless your clutch is slipping same revs = same speed.

Maybe you might have less of a throttle opening, that's quite plausible.

[Delphinus]

Yep, that would be high.

My F100 is 11:1 and pinks even on 98.

Funilly enough it didn't do so on the old 'leaded' Super.

I've been running my Triumph on 91 and seems fine so far.. Will give 98 a try.

[Mr Merde]

....
Maybe you might have less of a throttle opening, that's quite plausible.

Thats what I meant. sorry busy day, fat fingers and slow brain.

[jrandom]

My F100 is 11:1 and pinks even on 98.

The factory spec compression ration on the FXR150 engine is 10.7:1. I found that 98 octane in summer made a noticeable difference to the way my one ran.

[fireball]

The factory spec compression ration on the FXR150 engine is 10.7:1. I found that 98 octane in summer made a noticeable difference to the way my one ran.

i noticed my FXR runs better on 98 in summer but starting in winter is alot harder so i drop to 95 in winter very tempted to run it on racing gas just for a giggle im sure that will clean the cobwebs out

[scumdog]

i noticed my FXR runs better on 98 in summer but starting in winter is alot harder so i drop to 95 in winter very tempted to run it on racing gas just for a giggle im sure that will clean the cobwebs out

Put my F100 on race/av gas and hoo-boy does it run well! Can advance the timing another 2-3 degrees and still doesn't pink (much)
Even idles smoother (well, as smooth as the cam will let it)

[fireball]

Put my F100 on race/av gas and hoo-boy does it run well! Can advance the timing another 2-3 degrees and still doesn't pink (much)
Even idles smoother (well, as smooth as the cam will let it)

im amused tho i can get top speed **blush** of 130 red lining of course on 95 octane but the 98 puts my top speed **more blushing** at 140
not that i speed or anything im a legal rider