best fuel - engine smoothness at idle & acceleration

[vsv6dude]

Hi

Without having done a tuneup, or without use of an injector cleaner etc Which fuel (98, 95, 91 Ron) gave an immediate noticeable improvement to your vehicles engine smoothness at idle & acceleration ?

I understand that it can be affected by fuel quality and vehicle maintenance etc but this is just for members that have noticed improvements just by using a specific fuel. Not talking a fuel economy.

Thanks VSV6dude

[aaronevolution]

You wouldn't notice any difference until you went through 2 or 3 full tanks. Or atleast that's what I noticed in my old VR. Better throttle response.

[vsv6dude]

Which grade of fuel was that ?

[aaronevolution]

Woops I forgot the important bit. I was using 95 from United, then I changed to 98 V Power at shell.

[Dum*P*ster]

Woops I forgot the important bit. I was using 95 from United, then I changed to 98 V Power at shell.

I use V.. wagon seems like to it, and idles very normal for a ecotec ;p

[wortus]

It will also depend if your engine is standard or not. I've tried E10, 91 and 95 in my VY Ecotech which is standard, no mods to the car at all and it seems to idle the same on all 3 and the throttle response is about the same as well. I ran about half a dozen tank fulls of Vortex 95 and have gone back to 91 mostly as one of the local garages still has it.
I know you didn't ask but economy on 91 and 95 was also about the same, it uses more E10 though. if it was specifically tuned to suit the 95 it may be a different story but a standard Ecotech assuming everything is working propery doesn't need high octane fuel.

[James39]

You wouldn't notice any difference until you went through 2 or 3 full tanks. Or atleast that's what I noticed in my old VR. Better throttle response.

I agree, most people keep on switching fuels then say there is no difference.

[wraith]

Don't use 95 from United it's an ethanol blend. I have and will always use BP Ultimate 98 octane. That + tune is good.

[pjdm1980]

BP Ultimate for me as well, was suggested and tuned for it by APS.

[aaronevolution]

Don't use 95 from United it's an ethanol blend. I have and will always use BP Ultimate 98 octane. That + tune is good.

Yeah I was only using it because i was a cheap bastard haha. Now it's 98 or nothing

[vsv6dude]

I have been using a mix of 50% Shell Vpower 98 ron and 50% of Shell 91 ron to make a "95 ron" seems to work OK.

[wraith]

I have been using a mix of 50% Shell Vpower 98 ron and 50% of Shell 91 ron to make a "95 ron" seems to work OK.

Yeahhhh doesn't work like that...... Vpower is crap.

[wana s' charge stock vt]

my cars really boarder line with mod's(more boost), being untuned, and pinging, ect, and noticed it was the best/least pinging on bp's 98 fuel.... but stopped using it cause the closest bp to me was charging 18cents more than the 91 fuel the scammers, every other servo only charges 12-14cents more..(i could buy a lolly pop for that sort of coin )

[WogBoyz]

BP Ultimate for me as well, was suggested and tuned for it by APS.

Also use Ultimate, my old v6 didnt like v power ran shit on it, eventually got it tuned on bp 98 and my ss has been tuned on bp 98 too, wouldnt use nethin else

[RX25SE]

a standard Ecotech assuming everything is working propery doesn't need high octane fuel.

Agreed.

An Ecotech is a fairly simple engine with a basic management system. I have never seen a worthwile improvement using other than 91RON fuel.
If you want to run a higher octane fuel, get a tune to suit.


Mine actually leaked fuel through the injectors (after a clean and flow test!) with 98RON fuel and used to start in the mornings with a missfire.
Went back to 91RON and the problem went away.

[VSSS_5L]

Maybe it was just a placebo effect. But i reckon my vr v6 auto went harder on bp 98.

[aaronevolution]

Maybe it was just a placebo effect. But i reckon my vr v6 auto went harder on bp 98.

Same. My VR and VY V6 autos liked 98.

[SUSS8]

My car didn't like v power for some reason. Use to feel very sluggish with bp ultimate. Now I use caltex 95, runs better and doesn't feel sluggish or anything and I get a better fuel economy I've noticed

[Jesterarts]

I don't think cars without a performance engine will see much difference between a Premium 95 and Premium 98.

You will noticed a difference between say your standard 91RON Unleaded and a premium and it's good for the engine, so if you can afford it, then run premium.

I only use BP Ultimate98 in my car, but that's because it's tuned for it.

If I'm in a tight spot runnig out of fuel, my next best choice is a Caltex.

Shell is very much at the bottom of my list of places to fill up.

[Brett_jjj]

I will use any of the three main 98 octane fuels,either caltex's vortex 98, BP ultimate, or shell's V power. I mainly use shell V power because their price for 98 octane fuel is slightly better than others, and it seems to be more consistant as far as how it runs. I find that these fuels all pretty much run the same though. I have noticed that around here the BP ultimate can cause the car to run a bit poorly sometimes, I dont know why this happens,and it doesnt matter which BP servo around here I buy it from. One minute it runs like it should,and the next time you fill up it doesnt. The caltex vortex 98 isnt too bad either, and I use it a fair bit too.
I have sort of done a bit of experimenting with all 3 of these fuels with the tech 1 connected to monitor whats going on with the ignition timing and knock counts and knock retard etc,Ive also tried a lot of different ignition timing settings in the tune,and Ive found all these fuels are very similar in how they perform,especially from around half throttle right up to to full load/full throttle conditions,which is where the 98 fuels really come into their own over the lower octane fuels.
Also where you buy your fuel from can make a difference,because as fuel ages,it looses some of its power generating properties,so if the fuel has been sitting in the servo's underground fuel tanks for a few weeks,it will start to go off and will not perform as good as fresh fuel will. Living up here in the country,I find this can happen a fair bit at the quieter or no name type servos or corner stores that also sell petrol etc.Its always best to use the busier main brandname servos..

[wortus]

If an unmodified Ecotech with a standard tune had a high number of "knocks" then I'd be checking the components of the engine which if not working properly increase the octane requirement of the fuel. Things like the EGR valve for example as the introduction of exhaust gas lowers the octane requirement of the engine.

[FATMOE]

I only use BP 98 Ultimate and nothing else in my VY SS. It won't take any other fuel from anywhere else as the nozzle won't fit lolllllll haha BP ftw lol

[Brett_jjj]

If an unmodified Ecotech with a standard tune had a high number of "knocks" then I'd be checking the components of the engine which if not working properly increase the octane requirement of the fuel. Things like the EGR valve for example as the introduction of exhaust gas lowers the octane requirement of the engine.

These knocks arent acually mechanical knocking sounds caused by component/mechanical failure,but are caused by pre detonation (or pinging or knocking),which can occur when an engine is under heavy load conditions and is running on a lower octane fuel,the fuel/air mix will pre fire or pre detonate by itself without the spark plug firing it,and this happens before the piston is at its proper firing point in the compression stroke,which is usually anywhere from 4 -10 degrees BTDC ..It can also be caused from other things,but these dont really come into play that much if the engine is in good mechanical condition.These knocks are measured by the ECU via the knock sensors in the engine block, and if/when they reach a certain level,the ECU will retard the ignition timing until the knocking had stopped being detected,then it will advance the ignition timing again and so on.This all happens thousands of times a second too.
The higher the octane rating of the fuel is,the less an engine will ping under load,and with todays engines,this means that the ECU can advance the timing more before it detects knock and drops the ignition timing back.And the more advance you can run in the ignition timing,(to a point) under load, the better the engine will run,both power and economy wise.This is mainly why we get such good milage and low emmissions from these engines when compared to a non ECU controlled engine.
Also I dont think the VS ecotec has exhaust recirculation.Im sure it was introduced with the VT,so I havent had a chance to "have a play" with the tune etc on them,so I cant really comment on the effects of EGR on these engines.

[RX25SE]

Pinging= (pre-ignition) Ignition of fuel before the set ignition point. Low octane fuel may auto-ignite due to the heat generated by compression, carbon buildup or because the ignition timing is too advanced.

Knocking= (detonation) When the fuel is ignited but burns violently and uncontrolled, causing several flame fronts to be generated. When these flame fronts collide with each other, thay create a 'knocking sound'. In normal combustion there is one flame front that radiates out from the spark plug.

The knock detection in the PCM is 'tuned' to the particular frequency that detonation or pinging generates.

[shadetreemechanic]

Well in my car I notice 91 runs crappy on some days. A few weeks ago it ran so crap (pinging on light throttle) I stopped and bought 20L of 98 and straight away she loved it...btw it's on stock tune with no mods.

I reckon fuel quality varies wildly especially with the 91, it should be phased out anyway. My recommendation is 95 if you boot it like me every so often