Outer Limits 4x4 Board

Is it worth using high octane fuel with 4B's.....I now have a petrol carby setup.........GQ...

what I class as "high octane"

eg: regular unleaded .. 90-92
.......premium unleaded .. 95
.......'high' oct. unleaded .. 98

Do you class as 98 octane pump fuel as high octane?

Thats all I put in my hilux unless there isn't any around

i only use 98

If u have an after market ecu u can program the ecu to utilize the type of fuel u are running to its otimum

I only use the good stuff in all of my vehicles. I get better mileage, little-to-no engine-knock, and it's helped with engine-life. As an example, I am the original owner of my '89 Toyota V6 pickup and it has 409,000 miles on it. Throughout its entire life it's only had maybe a dozen tankfuls of low-grade fuel. The rest has all been high octane fuel. It still has the original (unrebuilt) engine. It purrs like a kitten and still has lots of power.

CapnCrunch wrote:I only use the good stuff in all of my vehicles. I get better mileage, little-to-no engine-knock, and it's helped with engine-life. As an example, I am the original owner of my '89 Toyota V6 pickup and it has 409,000 miles on it. Throughout its entire life it's only had maybe a dozen tankfuls of low-grade fuel. The rest has all been high octane fuel. It still has the original (unrebuilt) engine. It purrs like a kitten and still has lots of power.

That is a lot of K's, good work.
How many K's do you get out of a tank?
Peter.

droopypete wrote:That is a lot of K's, good work.
How many K's do you get out of a tank?
Peter.

For the total mileage: 409,000 miles = 658,221 Km

Per tank: 405 miles = 652 Km

which works out to 27 MPG (or about 11.5 KPL)

CapnCrunch wrote:

droopypete wrote:That is a lot of K's, good work.
How many K's do you get out of a tank?
Peter.

For the total mileage: 409,000 miles = 658,221 Km

Per tank: 405 miles = 652 Km

which works out to 27 MPG (or about 11.5 KPL)

A rough calculation tells me that's a $3500 premium for premium
do you still think it worth it?
For the record I used to use premium (carbed 4cyl ) but when I did the sums, I found it was not worth it in my case, and in my motor bike performance went down hill on premium (this was observed by many fellow riders).
Peter.

How does a carby adjust for the higher octane?

The way u adjust the carby is by selling it and getting yourself a fuel injection system

Ive been using poverty fuel in the 2wd lux for a few weeks and recently using 98 for the last 3 fills, averaged out 70kms more per tank with the 98 so far. The power difference isnt very mindblowing but it feels smoother and more responsive.

Biggest advantage I've had from "high octane" fuels is the reduction in pinging, which can destroy a motor in under 100,000km.

AJFeroza wrote:Biggest advantage I've had from "high octane" fuels is the reduction in pinging, which can destroy a motor in under 100,000km.

bad pinging can destroy a motor in less than a second, my old car a nissan pulsar pinged lightly all its life (280,00km) before I swapped out the motor. I use 95 octane in my 3F cruiser, its running a bit more than stock timing for the gas system so the premium fuel stops any pining, hardly ever use petrol though

cheers

killbill wrote:The way u adjust the carby is by selling it and getting yourself a fuel injection system

That's my point, running high octane fuel on a carby TB42 is pointless

blkmav wrote:

killbill wrote:The way u adjust the carby is by selling it and getting yourself a fuel injection system

That's my point, running high octane fuel on a carby TB42 is pointless

You'll have-to excuse me, .... I've only had diesels in the past, so petrol is a bit of a mystery to me.

Doesn't the engine benifit from cleaner burning etc. etc. regardless of carby/fuel injection...??

If not....why..??

The effect of "cleaner burning" would be so marginal it would be undetectable. The advantage comes with engine management systems that utilise a knock sensor. These will then advance timing and then back fuel out to maximise economy when they detect that higher octane is present. Our Renaultsport Clio was cheaper to run on 98 than on 95.

In a carby car you could really only tune it to run on 98 on a dyno where you could find out how much more timing it will take before pinging. (or time it up.... go for a drive.... have a listen, time it up again... but if it gets real hot you will have to be prepared to back timing out.

98 burns longer than lower octane so if you don't advance the timing there is no performance benefit at all - the extra power is just being wasted.

Having said that, I only ever run 98 and have done for years.

Steve.

You only get a benefit from high octane if the engine can't run properly on low octane.
If it pings on low octane and has to retard the timing to stop it then your fuel economy (and performance) suffer. In that case high octane will let the engine run properly and save you some fuel.

My petrol car (4wd is diesel) can run optimum timing without pinging on low octane so there's no economy benefit to running higher octane.
Octane isn't a quality rating, if your engine isn't high compression or boosted then you're going to gain nothing from the more expensive high octane fuel.

470k's to a tank of 10%ethanol regular
520k's to a tank of regular
670k's to a tank of premium
730k's to a tank of 10% ethanol premium

chikoroll_ wrote:470k's to a tank of 10%ethanol regular
520k's to a tank of regular
670k's to a tank of premium
730k's to a tank of 10% ethanol premium

Sorry Chiko please don't take this too personally (it is laced with a bit of humor ), but my bullshit detector just went "full scale", I would have to question your testing standards, either that or you are the creative director in charge of the Optimax advertising campaign .
Peter.

PS, do you have a Hyclone fitted?

Premium will give the best result in high compression or forced induction engine engines, in a carby GQ I'd suggest power timing it on the dyno, generally on premium you can add 3-5 degrees of timing that will increase performance and economy. If you are putting it in a stock engine with 8.5:1 comp dont expect too much, if your engine has 10:1 comp or more you will realize the benefit moreso.

Joel

lol wtf is a hyclone?

my jack is very tempermental
it hates regular, and especially regular ethanol, worst i have had is 380k's for 80 litres

premium and premium ethanol is brilliant though

the measurements i just posted are all highway k's, wasn't gonna bother about to/from work, it is pathetic (17-23L/100k's) (5km hilly trip) so for that i just use the cheap junk

chikoroll_ wrote:470k's to a tank of 10%ethanol regular
520k's to a tank of regular
670k's to a tank of premium
730k's to a tank of 10% ethanol premium

You might have your timing a bit high, i believe alcohol is slower burning than premium, and this may explain your better ecnomy with premium ethanol, if u retarded your timing u migt get better economy on std..
you should be able to run std economically up to 9.5/1 static compression, its when u go over that where u will find benifits in premium.. (high compression motor may be untuneable on std)
VE will alson effect your actual compression, so if you have an diffrent cam, head work bigger carb ect, to improve your VE at higher revs, you will need to get your dissy regraphed, for more total timing at high revs. (and less at idle ect)

in my opinion (and im no engineer) regular with ethanol is a joke as the alcohol will still be burning long after the unleaded is burnt up so your basically just watering uour fuel down by 10% u cant tune for boath.

bring on the 100% ethanol i say....

I don't know about petrol 4B's, but my 2.4D luxie doesn't seem to care what flavour of unleaded goes in as 5% of her fuel load.. Any unleaded gives her more bang and better fuel economy

now my mini, and my BMW K100RT starship (that's a bike..) were both designed for leaded fuel, so get a little upset (and piggish) if I try and run them on anything less than 98 octane fuel - I always keep a bottle of octane booster in the boot (It's cheap enough to do when both have 20Lt tanks )

--DG

I use 98 octane in my LT1 - its the only fuel(other than gas) to run it on. 98 octane has a higher RON rating than the highest octane in the states

i just use the regular BP in the GU. i have tried both but didnt really notice much difference in economy.... after all its a patrol, economy and patrol dont really sound right in the same sentence
i have noticed a bit more power with the BP ultimate.

in the bike i only use ultimate since brand new

legsx1 wrote:I use 98 octane in my LT1 - its the only fuel(other than gas) to run it on. 98 octane has a higher RON rating than the highest octane in the states

But not as much higher than we tend to believe.

The US calculate their octane differently, they don't use the RON method. (can't recall the way they do it, but it has an averaging effect- the calculation is actually written on the pump) so their 91 is miles better than our 91.

I do agree though, I think that our 98 comes up about 95 in their system so we are still better off.

Steve.

Gwagensteve wrote: But not as much higher than we tend to believe.

The US calculate their octane differently, they don't use the RON method. (can't recall the way they do it, but it has an averaging effect- the calculation is actually written on the pump) so their 91 is miles better than our 91.

RON vs MON?

Yup - Mean octane - I seem to recall a photo of a pump with the little equation on it somewhere.

Steve.

Gwagensteve wrote:Yup - Mean octane - I seem to recall a photo of a pump with the little equation on it somewhere.

Steve.

Actually "Motor Octane Number" vs "Research Octane Number".

90Mav wrote:

chikoroll_ wrote:470k's to a tank of 10%ethanol regular
520k's to a tank of regular
670k's to a tank of premium
730k's to a tank of 10% ethanol premium

You might have your timing a bit high, i believe alcohol is slower burning than premium, and this may explain your better ecnomy with premium ethanol, if u retarded your timing u migt get better economy on std..
you should be able to run std economically up to 9.5/1 static compression, its when u go over that where u will find benifits in premium.. (high compression motor may be untuneable on std)
VE will alson effect your actual compression, so if you have an diffrent cam, head work bigger carb ect, to improve your VE at higher revs, you will need to get your dissy regraphed, for more total timing at high revs. (and less at idle ect)

in my opinion (and im no engineer) regular with ethanol is a joke as the alcohol will still be burning long after the unleaded is burnt up so your basically just watering uour fuel down by 10% u cant tune for boath.

bring on the 100% ethanol i say....

don't have a turbo... motor is completely stock standard - 3.5L, late '98 model