Premium unleaded 95/98 for Jazz?

[garbage]

Thinking of just running my 08 Jazz on regular unleaded. Does anyone here run their 08/09 Jazz on 95 or 98? Is there any noticeable power/economy benefits?

[BiLL|z0r]

I ran my 05 on regular but since BP has gone E10 for all stations the economy has gone terrible so I'm now running 95/98 so I'm going the other way. On the other hand there is hardly any premium in SE Qld currently so it's basically get what petrol you can find.

[borad]

I don't run premium, but I do confirm E10 is terrible efficiency, and therefore value, wise.

[rossw]

I've been using 91 octane unleaded in my Jazz with no problems. Unless the ECU gives you more ignition advance using 95/98 there is no advantage in using it.

95/98 octane DOES NOT clean your engine better than 91

95/98 octane DOES NOT burn more efficiently than 91

95/98 octane DOES NOT contain more energy than 91

95/98 octane DOES allow more ignition advance without detonating than 91, IF the ECU can allow for this.

95/98 IS more profitable for the oil companies, which is why they promote them the way they do and call it "premium" unleaded ("If you're not using Shelltex premium plus, you're not looking after your car"). There's nothing "premium" about it at all, but because of the connotations of the word people expect premium unleaded to work better, therefore their seat of the pants dyno tells them their car IS running better, whether it really is or not.

If your engine is designed for 95/98 octane fuel (most european cars) you will see economy and performance benefits from using it (and you might have to use it to avoid damaging your engine).

In the case of the Honda Jazz, it is designed for 91 octane. Depending on how the ECU checks for detonation and adjusts the ignition timing, you may or may not see better fuel consumption with the standard engine. You would then need to allow for the greater cost of 95/98 to see if you are ahead or not.

If you use a device to alter the temp input on the ECU or something, you might get more advance and be able to get more power/better fuel consumption using 95/98 octane fuel.

The only really certain way to check is to use an OBD reader to measure ignition advance under load using different fuel types. If you then see more advance going up the same hill at the same speed in the same gear using 95/98 octane fuel, then you will see a benefit.

As far as E10 goes, it actually does contain less energy per litre by about 3%. therefore your fuel consumption goes up by that much. I don't use it unless there is no other choice or the price difference is greater than 3%. When petrol was around 1.50 per litre, the $0.03 saving made no sense at all. Now that it's around a dollar a litre, well it doesn't matter which one you use (in a Jazz).

My local Caltex is substituting regular unleaded for E10 right now due to short supply, so I can get unleaded for E10 price :).

The only time I choose E10 over unleaded is if I'm filling up a rental car before returning it. I save the $0.03/litre, and the next person gets the poorer fuel consumption.:angel:

[dyljoy]

haha, good point indeed, rossw

[BiLL|z0r]

The only time I choose E10 over unleaded is if I'm filling up a rental car before returning it. I save the $0.03/litre, and the next person gets the poorer fuel consumption.:angel:

HAHA, I do that too.

As I said, I only use premium now since E10 is the only regular fuel BP sell now and they don't discount by 3c/ltr unlike the other servo's (unless you get the Ecocard but I have enough cards).

[rossw]

HAHA, I do that too.

As I said, I only use premium now since E10 is the only regular fuel BP sell now and they don't discount by 3c/ltr unlike the other servo's (unless you get the Ecocard but I have enough cards).

My Jazz is leased, so I have cards for Caltex and BP. I get a discount with Caltex so I usually use them. Haven't actually tried BP yet.

[BiLL|z0r]

I'm not sure about your area but BP fuels come from the Caltex refinary here in SE Qld anyway. I just get 5% BP so use it. It was quite the discount when fuel was much higher.

[rossw]

Hate to burst your bubble but the Jazz/Fit ECU DOES advance the timing depending on octane. I was a believer like you that it makes no difference but recently a member on the other fit site did a nice comparison using a scan gauge and driving the same course using first 87 octane then the same circuit using 95 octane at several speeds (the highest in the states must be the same as OZ 98). He waited a few days between to make sure the 87 was used up and it was running on 95.

The results clearly shows that the ECU DOES advance the ignition timing based on the knock sensor reaction. The difference was average of 2 degrees more advance most of the time and up to 4 degrees under certain circumstances and although it sounds like a small difference 2-4 degrees is enough that you should feel the difference in the seat of your pants.

He did a nice job and took pains to perform both tests in the same conditions and multiple times with both octanes of fuel and since that experiment I have begun to use 95 in my Jazz.

You can run 87 with no problems but if you can afford it and want to take every advantage you can for performance using a higher octane WILL help

Well I'm glad to hear that. What you describe is exactly the test I said would be needed to demonstrate what I said would need to be the case before higher octane fuel made any difference.

Now it depends on what the price gap is as to whether it is worth it - from a purely economic point of view, of course. If you are after every last bit of performance, then 95 or more is the go.

I suppose it's also true then, that there is little point spending money on engine mods, exhaust, intake, etc, etc if you then go and run the thing on regular unleaded or E10.

It would be interesting to see back to back dyno runs to see how much power difference there is. (no longer trying to prove or not prove anything, just curious - 90+kW out of 1.5 litres naturally aspirated? :cool:)

There's an idea for a magazine article if ever I saw one. Has anyone tried it?

[040501912]

lol.. let seee.. my dyno day .. i wouldn be surprise if i only get less then 80 kw on the wheels LOL !!!

the engine is 88 kw.. on fly .. wheels would be 70 kw ish =.=...
its not all about power of the engine.. is how well the driver and how good is the set up of the car in the given track...

I did some hill runs and was going against 180sx 200 hp car (well quiet modified) i'm keeping up with him on every corners in or out.. until the long straight :( when his power kicks in..

Modifying performance on jazz would just be pointless... for me.. because is a economic car.. how mater i modify it it wouldn't get 150 hp on wheels... (could but may be BIG BUDGET)

swap engine would be nice :p

Aniiwaaaay..

if you can afford 98 why not?
i fill up the jazz 98 all the time since day 1
it get me about
Full tank to 0 km on the reading fill up 38 litters of fuel
+/- 560 km good driving (tested it when going down south of Perth constant 80-110)
+/- 500 city mix with freeway good driving
+/- 480 city drive stop and go
+/- 400 heavy footed spirited driving

car is 7500 km in 4 months
run in first 1000 km easy drive no more than 3000
1000 - 2000 - no more than 5000
3000 tried running on mountain runs and gymkhana days (started to revving up the engine WOOOT)

stock engine, no mods or wat so ever for performance.

i would say 98 is better in efficiency and power delivery compare 91 octane.

ECU is tuned to 91 but its still be better if you run 98
remember is factory tune ecu.. not all the car running from the product line is the same as another car that have L15 engine even though is the same ecu tune.

Engine A may no be as powerful as engine B or vice versa given its L15 or L13..

complete fuel burning = efficiency n higher k's lol!...

[dyljoy]

I will go for 98, but if it out of stock, normal unleaded instead, just like today. hoho

[040501912]

tell us the different from 91 to 98 .. :p

i bet u got more responsive and less bogged when u take off lol

needs about 3 full tank of 98 to clear out ur 91 octane ;)

[rossw]

lol.. let seee.. my dyno day .. i wouldn be surprise if i only get less then 80 kw on the wheels LOL !!!

the engine is 88 kw.. on fly .. wheels would be 70 kw ish =.=...
its not all about power of the engine.. is how well the driver and how good is the set up of the car in the given track...

I did some hill runs and was going against 180sx 200 hp car (well quiet modified) i'm keeping up with him on every corners in or out.. until the long straight :( when his power kicks in..

Modifying performance on jazz would just be pointless... for me.. because is a economic car.. how mater i modify it it wouldn't get 150 hp on wheels... (could but may be BIG BUDGET)

swap engine would be nice :p

Aniiwaaaay..

if you can afford 98 why not?
i fill up the jazz 98 all the time since day 1
it get me about
Full tank to 0 km on the reading fill up 38 litters of fuel
+/- 560 km good driving (tested it when going down south of Perth constant 80-110)
+/- 500 city mix with freeway good driving
+/- 480 city drive stop and go
+/- 400 heavy footed spirited driving

car is 7500 km in 4 months
run in first 1000 km easy drive no more than 3000
1000 - 2000 - no more than 5000
3000 tried running on mountain runs and gymkhana days (started to revving up the engine WOOOT)

stock engine, no mods or wat so ever for performance.

i would say 98 is better in efficiency and power delivery compare 91 octane.

ECU is tuned to 91 but its still be better if you run 98
remember is factory tune ecu.. not all the car running from the product line is the same as another car that have L15 engine even though is the same ecu tune.

Engine A may no be as powerful as engine B or vice versa given its L15 or L13..

complete fuel burning = efficiency n higher k's lol!...

Heh I was referring to flywheel kW. I was guessing a 2-3 kW gain at the fly wheel for using 98, which is how much it would need to be for you to notice.

It would be interesting and instructive to see two tests:

1. Back to back dyno testing of unleaded vs premium unleaded in the same car.

2. Back to back blind comparison testing - person drives car without knowing which fuel is which and has to pick - Good one for Mythbusters perhaps?

I have used 91 since day one and have no problems with bogging down or driveability.

The price difference is more than 13c /litre. You would need around a 13% saving in fuel consumption or better to be ahead, and you cannot compare different cars/drivers. I would need to be showing 5.3l/100km or better on my average consumption gauge to make it worthwhile ( I know it's not that accurate, but it should be at least consistent, making it useful for rough comparison) The difference is probably more like airconditioning on vs air conditioning off.

Check out Autospeed.com.au where they have a simple mod using a resistor that tricks your ECU into thinking it is running colder, and therefore advances the ignition further. They tried it on a Honda Insight and got some performance gains. If you are already using 98 octane exclusively, it's worth a look - cheapest performance mod you'll ever make, but listen out for knocking and adjust accordingly. Don't forget to take it out when you get it serviced or bye-bye warranty!

If 98 isn't always available, put a bypass switch on it for when you have to run regular unleaded.

[040501912]

1. Back to back dyno testing of unleaded vs premium unleaded in the same car.

2. Back to back blind comparison testing - person drives car without knowing which fuel is which and has to pick - Good one for Mythbusters perhaps?



good one! lol i like this idea...

the chip are just to trick but not tune the ecu.. is better off getting a piggy back and tune it for fuel consumption not for power.. i think thats safer and better rather then putting some random chip that dont know what it do to the ecu and how the ecu reacts

91, 95, 98 is all about user preference really.. not saying 91 is bad but if you can put extra 10-13 cent a litre it wont be hurting .. in total it would just be extra 3-5 dollars :p thats ur COFFEE money...

well thats the way i think .. LOL!!!

[FitRS]

How much are you guys filling up each week or every week and a half?

[040501912]

i travel about 500 km a week or abit fill up about 35-38 littres

about $40-48 full tank of bp ultimate.. dependes on the fuel price as well
BP ultimate in perth about 108 c - 118 c
normal unleaded 95c-108c

[dyljoy]

Just filled up mine last night, last tank use shell's Vpower(98), done 393km with 35L which combine hwy km and most of city km(AVG 8.9L/100km). i don't why Vpower ran less than the normal 91 I filled b4(AVG 8.3L/100km), coz I ran similiar rd condition as well. and I filled new tank up by 35L noraml unleaded last night due to Vprower out of stock, and it costs me $31.XX.

PS:always using Shell btw

[rossw]

good one! lol i like this idea...

the chip are just to trick but not tune the ecu.. is better off getting a piggy back and tune it for fuel consumption not for power.. i think thats safer and better rather then putting some random chip that dont know what it do to the ecu and how the ecu reacts

91, 95, 98 is all about user preference really.. not saying 91 is bad but if you can put extra 10-13 cent a litre it wont be hurting .. in total it would just be extra 3-5 dollars :p thats ur COFFEE money...

well thats the way i think .. LOL!!!

See with me it's my internal Scotsman telling me to keep my coffee money and save it for a WRX or maybe a holiday and spend as little as possible on getting from A to B in the meantime. That way I keep my 5 bucks and not BP or Caltex (hey, they don't need it...) I still get to where I'm going, and my car's warranty is fine because I'm meeting the manufacturer's specs.

Now if you care about those extra couple of kW, well using 95 or 98 octane is as cheap a performance mod as you'll get... Or you could sell the Jazz and get a VW Polo GTi or Fiesta XR4 or a Ralliart Colt instead for even more performance gain.:cool:

[dyljoy]

Ya, I bought my jazz for cheap petrol not expect it can bring any performance, if I would like to do so, I will pick true performance aspect car.

[040501912]

yeep yeep ..

the jazz just for daily driving cheap fuel only .. getting from point a to b and its one of my baby.. that's why i treat it the best and pampered it lol...

its way way slower than my old car which i sold it. lots of power - waste of fuel just for driving around.. not practical for daily

My turboed accord 280 km - bp 98 full tank .. =.= fill up at least 40-45 litters every time lol... just doesn't make sense even tough is fast enough to make high 13's and kept up and beat wrx or skyline, just cant afford to pay the fuel :(

point is if you love your car.. you treat it the best you can lol..
if you want a faster car get a real car! dont drive honda AHAHAHA... (well thats what mos people says)

[rossw]

yeep yeep ..

point is if you love your car.. you treat it the best you can lol..

I love my car. I wash it regularly, maintain it properly, and treat it well, but I put in the tank what the manufacturer recommends. It won't thank me or last longer or be more reliable for putting in the more expensive stuff.

It's not like buying your GF (or BF) a $30 bunch of flowers instead of a $10 bunch, or dinner at Doyles instead of McDonalds. Your car will not reward you similarly...:angel:

[4thGenExi]

Speaking of premiun fuel - has Brisbane restocked on BP Ultimate yet?

[BiLL|z0r]

Not that I know of. The fuel companies seem to be keeping it quiet in the media, hardly heard a thing.

[Shia'J]

at the moment i'm paying $35 for a full tank each week on 98

[fundies]

Been running Mobil premium in the 06 VTI CVT Jazz for a couple of months now, and it is definitely more responsive to drive running high octane. I also noticed that the car was pinging slightly on hot days, with the airconditioner on driving up hills using regular unleaded.
I haven't bothered to see if it's getting better economy, the nicer driving experience alone is reason to keep using it.

[ahmondjai]

I've tried the different fuels from Shell(unleaded, V-Power & V-Power 100), Caltex(unleaded, Vortex 95 & Vortex 98), BP(unleaded & Ultimate) and Mobil (2000, 6000 & 8000) on both CVT Jazz and 08 Civic Vti, not a significant power gain but enough for you to notice it. Whether it's only psychological or actually happening, without proper dyno results, can be hard to justify, but as mentioned from others, it does turn out with much lesser pings or virtually eliminated in the FD (only with Vortex 98 while others such as Shell and BP still pings a bit, lesser than with normal unleaded).

P.S. still no Vortex 98 in BNE.....