What to expect when running 98?

[MaxB]

because the mapping of the ECU favours the higher octane

the trip always the same roads which I use to do alot of for 2 years was Commuting from umutoi(60ks north of palmerston north) to wgtn 210ks each way

I use 98 to extend my tank range. Proven many, many times. It gives me another 80 kms per tank. According to the owners club the optimal octane for my carburettor ZZR is 94 RON. It will run on 91 but likes 95.

I notice one thing about your bike and Dogs' Trumpy. The compression ratios are 12:1. Mine is 11:1. I wonder if that has anything to do with it?

[The Stranger:Me]

It's monday night and I'm bored...
What would be a noticeable difference when I change from 91 to 98 octane?

Stock carbed FZR apart from the can.

5-10% more power AND better fuel economy too. It's a win-win situation.
Run synthetic oil in your engine and WD40 on your chain for even better results.

[Two Smoker]

98 is way better than 91... coz its a higher number... it must be!

[SARGE]

What would be a noticeable difference when I change from 91 to 98 octane?

.

your wallet will become 10% lighter ..

SFA on a stock bike .. get a hi comp big bore and advance the timing to really see anything ..

[vifferman]

Yerp.
You're going to get the most power from your motor running the minimum octane rating recommended for it. You may get cleaner running from 98, as it supposedly has some extra additives that can clean your fuel system. I'm running 98 at the moment (just a couple of tanks full) for that very reason. In the past I've run it to stop the engine pinking when hot (in summer), and when running advanced ignition timing and extra fuelling at high revs/full throttle.
Did I get more power?
Dunno - how often can you run full throttle and 8500+ rpm on the street?

I think there's a lot of confusion with octane rating, because people know that some racebikes (and most dragsters/dragbikes) run higher octane gas. However (but!) that's to stop the engines exploding because they're running sustained hig revs, high compression, and advanced ignition timing. If they could do all that AND run lower octane pump gas, they would.
Octane rating is more or less a number describing resistance to knocking (pre-ignition). If your vehicle isn't set up with a knock sensor and/or some kind of advanced engine management such as VVT, then it can't take advantage of running different octane fuels.

Interestingly (or perhaps not), the vifferbabe's Peugeot isn't particularly high performance (137bhp/2 litre), yet it really does not like running anything other than 98, and knocks like a ....a... knocking sonofabitch.. on anything else.

[StoneY]

My gixxeR (carbed bike) gains about 30kmh a tank on 98 over 91-
My Duc- (EFI bike) gains well over 100kmh in range when using the higher octane

If you do the math- my gixxeR is gaining nothing- utterly nothing- mileage cancelled by price and I can detect no power gain at all that is noticeable

the Duc is a significant saving running on the higher octane and also a measurable power increase-
I cross Mt Wainui daily- at 5,500 rpm in 3rd the Duc does 90kmh up the hill on 91-
On 98 octane I get 100Kmh for the same engine revolutions
I gain over 100km's in range as well if I fill with 98- and seemingly even more from Gull brands Bio Fuel mixture- (50/50 bio and oil) go figure!

Far from a scientific study, but I think like others have said above- high compression motors and EFI are likely to have a more significant differential of performance in regards to octane level of the fuel- carburetted motors dont seem to be AS affected - and that seems logical to me as the fuel mixture of carburetion is less exact

[The Stranger:Me]

I cross Mt Wainui daily- at 5,500 rpm in 3rd the Duc does 90kmh up the hill on 91-
On 98 octane I get 100Kmh for the same engine revolutions

Hmm, you perhaps could have got away with your piss take if not for this gem.

[nallac]

Dunno - how often can you run full throttle and 8500+ rpm on the street?

Ummmmm,lots...thats why my bike guzzles gas....

[Mom]

So, if you have experienced a noticable improvement in performance from moving from 91 to 96, is 98 going to give even more? Not talking about gas/mileage here for the minute, just engine performance. Think mature bike here.

[vifferman]

So, if you have experienced a noticable improvement in performance from moving from 91 to 96, is 98 going to give even more? Not talking about gas/mileage here for the minute, just engine performance. Think mature bike here.

Perhaps. The key thing is the 98 is imported from Perth and is supposedly a better quality witches brew than the 96 swill from the Marsden refinery, which is basically the 91 with added paint brush cleaner. My feelings are somewhat tarnished by the poor performance of the 96 in the wife's car, and the execerable experience I had when I ignored the mechanics at Red Baron and put 95 in my VFR750. It sooted up the tiny wee spockingploog electrodes and ran like an absolute bastid. Never used it in a bike since.

[Mom]

Perhaps. The key thing is the 98 is imported from Perth and is supposedly a better quality witches brew than the 96 swill from the Marsden refinery, which is basically the 91 with added paint brush cleaner. My feelings are somewhat tarnished by the poor performance of the 96 in the wife's car, and the execerable experience I had when I ignored the mechanics at Red Baron and put 95 in my VFR750. It sooted up the tiny wee spockingploog electrodes and ran like an absolute bastid. Never used it in a bike since.

Well you see I also share your opinion of the locally produced "high" octane petrol, it is not as good as the ordinary petrol we used to buy back in the olden days. As a result I have used 91 in all my vehicles for years. Now while I am not very scientific about gas/mileage stats I have for the past couple of months been testing my stupid old bomb of a car (lets call her the rollerskate) distance travelled against fuel purchased. The rollerskate is an early '90's, 2 door Mazda hatch, 1500 cc engine, should run on the smell of an oily rag right? Not so, some fills lucky to get 10 km/ltr. Some fills I can get 15 km/ltr. Nothing different in the way I am driving, same commute each day. I put it down to the petrol, my research continues.

Now my blue lovely has some fuelling issues. Have always used 91 in her and have not really had any issues but...

She runs appallingly when asked to behave out on the open road at hard throttle. Starves for fuel, bogs, runs on 3 cylinders any and all of the above. Makes for a frustrating journey. I have not had the time to pull things apart to have a look and have tended to leave her at home if we are heading out any great distance. I have a proven distance travelled of 200-220 kms before reserve, but this has fallen to 180 or even less.

We went out for a ride last weekend, I took my blue lovely as I was desperate to get out for a ride. For some reason (perhaps fuelled by my rollerskate research) I decided to run 96 in the blue lovely. Now I had 1/2 a tank when I topped her up before we left. Zooming along I was pleasantly surprised to find she did not play up very much at all, slight loss of power at times but nothing like it has been. Refuelled at a g.a.s. station while we were out and spent the rest of my journey actually trying to get her to misbehave. I asked some serious questions of her performance under hard and sustained throttle and she did not skip a beat! Has the higher octance gas made this difference? What if I went 98? I am seriously considering (not really but I have thought about it) buying some Av gas and giving an octane boost to the tank. I work in an aviation company so it is not out of the questin to buy it.

Now all I have to do is see what the gas/mileage figures do. Interesting stuff.

[johan]

I'd be interesting to know the atmospheric changes when you measure the distance of a tank of fuel. (pressure, amb temp, humidity, pressure altitude.)

I'm pretty sure the difference between a good and bad day can easily be 10% in power output. Ask the fly boys...

[MIXONE]

All I know is that all my vehicles get approx 15% more miles from a tank when running 98.Seat of the pants tells me that it is more low end grunt.
As for the Mobil shit I get nothing but grief so I stay well away from it.

[Hahn]

Well you see I also share your opinion of the locally produced "high" octane petrol, it is not as good as the ordinary petrol we used to buy back in the olden days. As a result I have used 91 in all my vehicles for years. Now while I am not very scientific about gas/mileage stats I have for the past couple of months been testing my stupid old bomb of a car (lets call her the rollerskate) distance travelled against fuel purchased. The rollerskate is an early '90's, 2 door Mazda hatch, 1500 cc engine, should run on the smell of an oily rag right? Not so, some fills lucky to get 10 km/ltr. Some fills I can get 15 km/ltr. Nothing different in the way I am driving, same commute each day. I put it down to the petrol, my research continues.

Now my blue lovely has some fuelling issues. Have always used 91 in her and have not really had any issues but...

She runs appallingly when asked to behave out on the open road at hard throttle. Starves for fuel, bogs, runs on 3 cylinders any and all of the above. Makes for a frustrating journey. I have not had the time to pull things apart to have a look and have tended to leave her at home if we are heading out any great distance. I have a proven distance travelled of 200-220 kms before reserve, but this has fallen to 180 or even less.

We went out for a ride last weekend, I took my blue lovely as I was desperate to get out for a ride. For some reason (perhaps fuelled by my rollerskate research) I decided to run 96 in the blue lovely. Now I had 1/2 a tank when I topped her up before we left. Zooming along I was pleasantly surprised to find she did not play up very much at all, slight loss of power at times but nothing like it has been. Refuelled at a g.a.s. station while we were out and spent the rest of my journey actually trying to get her to misbehave. I asked some serious questions of her performance under hard and sustained throttle and she did not skip a beat! Has the higher octance gas made this difference? What if I went 98? I am seriously considering (not really but I have thought about it) buying some Av gas and giving an octane boost to the tank. I work in an aviation company so it is not out of the questin to buy it.

Now all I have to do is see what the gas/mileage figures do. Interesting stuff.

Av gas will see a very noticeable rise in power out of your bike but, isn't recommended... unless you want to burn out piston rings etc etc and only have too rebuild your engine later on. Av gas is also leaded, can your bike handle leaded fuel? From memory, and correct me if wrong lead is used to boost octane up to 130 which regular unleaded can only reach 100 (or 98 at the pump). Even "Low lead AV Gas" still contains lead.

I'd be interesting to know the atmospheric changes when you measure the distance of a tank of fuel. (pressure, amb temp, humidity, pressure altitude.)

I'm pretty sure the difference between a good and bad day can easily be 10% in power output. Ask the fly boys...

They will have some effect on fuel economy (cold winter day/ hot summer day), its all about air density. But for a vehicle down here, the biggest decider would be traffic volume (starting/stopping etc) in your commute.
An engine, more so EFI, will adjust itself for your fuel.
Generally the higher the octane the better power/economy (less fuel needed for same output), but this is only really noticeable on long open road drives or rides. In town you will probably just have a bigger hole in your wallet (maybe even worse economy just because of the way city driving/riding is).

If the bike is running right, probably could do with the carbs having a clean out and a tune up.

Take that with a grain of salt, been a few years since I learned that stuff. Just fixin' planes now, we use AV Tur (kerosene).

[Hahn]

The rollerskate is an early '90's, 2 door Mazda hatch, 1500 cc engine, should run on the smell of an oily rag right? Not so, some fills lucky to get 10 km/ltr. Some fills I can get 15 km/ltr. Nothing different in the way I am driving, same commute each day. I put it down to the petrol, my research continues.

Now my blue lovely has some fuelling issues. Have always used 91 in her and have not really had any issues but...

She runs appallingly when asked to behave out on the open road at hard throttle. Starves for fuel, bogs, runs on 3 cylinders any and all of the above. Makes for a frustrating journey. I have not had the time to pull things apart to have a look and have tended to leave her at home if we are heading out any great distance. I have a proven distance travelled of 200-220 kms before reserve, but this has fallen to 180 or even less.

We went out for a ride last weekend, I took my blue lovely as I was desperate to get out for a ride. For some reason (perhaps fuelled by my rollerskate research) I decided to run 96 in the blue lovely. Now I had 1/2 a tank when I topped her up before we left. Zooming along I was pleasantly surprised to find she did not play up very much at all, slight loss of power at times but nothing like it has been. Refuelled at a g.a.s. station while we were out and spent the rest of my journey actually trying to get her to misbehave. I asked some serious questions of her performance under hard and sustained throttle and she did not skip a beat! Has the higher octance gas made this difference? What if I went 98? I am seriously considering (not really but I have thought about it) buying some Av gas and giving an octane boost to the tank. I work in an aviation company so it is not out of the questin to buy it.

Now all I have to do is see what the gas/mileage figures do. Interesting stuff.

Av gas will see a very noticeable rise in power out of your bike but, isn't recommended... unless you want to burn out piston rings etc etc and only have too rebuild your engine later on. Av gas is also leaded, can your bike handle leaded fuel? From memory, and correct me if wrong lead is used to boost octane up to 130 which regular unleaded can only reach 100 (or 98 at the pump). Even "Low lead AV Gas" still contains lead.

I'd be interesting to know the atmospheric changes when you measure the distance of a tank of fuel. (pressure, amb temp, humidity, pressure altitude.)

I'm pretty sure the difference between a good and bad day can easily be 10% in power output. Ask the fly boys...

They will have some effect on fuel economy (cold winter day/ hot summer day), its all about air density. But for a vehicle down here, the biggest decider would be traffic volume (starting/stopping etc) in your commute.
An engine, more so EFI, will adjust itself for your fuel.
Generally the higher the octane the better power/economy (less fuel needed for same output), but this is only really noticeable on long open road drives or rides. In town you will probably just have a bigger hole in your wallet (maybe even worse economy just because of the way city driving/riding is).

If the bike is running right, probably could do with the carbs having a clean out and a tune up.

Take that with a grain of salt, been a few years since I learned that stuff. Just fixin' planes now, we use AV Tur (kerosene).