Ap 98e10 , Interesting Brew .

[discopotato03]

Hi all , in Sydney there are a few servos going under the AP banner and I noticed the 98ULP is claimed to have 10% ethanol content .

I'm curious to know peoples opinions on fuel octane and the different ways that a given fuels octane can be increased and the power potential because of it .

A good friend of mine in the automotive trades for nearly 40 yrs claims that if anything the lower octane fuels are better power developers with the only downside their tendency to detonate in high cylinder temperature/pressure situations .

He says that the higher octane petroleum fuels abilities to resist detonation actually make it harder to light the fire and burn efficiently .

Where I'm coming from with all this is that I suspect AP may be boosting the octane rating of say 95 ULP with ethanol and if that's the case is it possible that their 98E10 may burn better and possibly have a small edge over straight 98ULP - no ethanol .

I'm finding it actually resists detonation better than BP Ultimate in my old dinosaur tech (1986) turbo Subaru and I think it makes my Skyline run smoother as well .

Is anyone game to give this fuel a whirl in a high horsepower roadie ?

BTW it sells for around 1.32/L recently anyway which doesn't appear to be that much different to Ultimate - depending where you get that from .

Opinions ? Cheers A .

[KiwiRS4T]

I and a number of other RB owners over here in NZ have been using Gull "Force 10" for over a year. It is an E10 - 10% ethanol blend. Tuners like it. I think the evidence doesn't support your friend's contention that lower octane fuels can produce more power. Have a look at the E85 thread to see the power people are making with the higher ethanol content!

[scotty nm35]

By volume he is right, you would need more ethanol for the same power but only a little. From my research ethanol has more oxygen in it hence the bigger bang and burns a bit longer in the bore which all equals more torque.

You will notice 98 e10 runs a bit leaner up top if not tuned due to the extra oxygen tricking the o2 sensor, that is the issue for those with factory ecu's.

[JonnoHR31]

A good friend of mine in the automotive trades for nearly 40 yrs claims that if anything the lower octane fuels are better power developers with the only downside their tendency to detonate in high cylinder temperature/pressure situations .

He says that the higher octane petroleum fuels abilities to resist detonation actually make it harder to light the fire and burn efficiently .

Hes mostly correct. If you cannot change the ignition timing at all and it doesnt knock on 91 with that timing then it'd be a complete waste to run 98 as it burns slower and costs more. But due to it burning slower and being more resistant to knock you can run more timing compared to 91 before it knocks, which far outweighs any minute gain you'd have with a faster burning fuel (91) with less timing.

At the end of the day, contrary to popular belief, 99% of standard cars arent worth putting 98 in. The extra cost simply isnt worth the very small gains, if there are any at all. If you have the ability to change the timing then you'll allways make better power/torque with higher octane fuels and possibly better economy too, but its up to the user whether they can justify the cost.

And i doubt the e10 98 would give you the same burn properties of 95 without the knock, as octane ratings are essentially a measure of a fuels resistance to burning and knocking, i'd say it'd essentially perform like 98 but maybe with a tiny bit of the cooling benefit of ethanol, which would make it slightly more knock resistant.

[senilykSkylines]

Hi peoples,

Sorry to bring a post up from the past but I am quite keen on an answer from people with RB's who have used Gull Force 10 which has 10%ethanol. It is the only 98 fuel in Whangarei and I am quite keen to start using it and see if it fixes some of my temperature related pinging. My little intercooler is struggling with a dyno tune I have done. It is fine when the intercooler is cool but if it warms up (it does so quickly), it flat spots because the knock sensor kicks in. I have been running 95 premium of which people think may be my problem.

I am hoping to put off buying a FMIC if I can for now but I am dead sick of the flat spot.

Mods are:

Z32 tuned ecu

3" zorst

K&N panel filter

Walbro fuel pump

Dyno tuned at 168rwkw (auto transmission)