Optimax/ Premium Unleaded

Yes.....

Honda HRV 1600 cc. Engine requires Premium Unleaded.

There is a DEFINITE increase in power when using Premium Unleaded, which is what I use all the time.

Sometimes up north, it's not available, so normal unleaded goes in the tank, and you can tell the difference.

My son was trying to explain to me how the differences work, but he was already preaching to the converted.

I would have thought that an XR8 was a big enough ballsy engine to run on anything, and not be fussy like some of the Jap motors, probably why you didn't see any difference.

Bit like the Cleveland 351 I had, bugger would run the same on Standard, Super & ULP!!

Cheers

Wolfie ( Premium )

I do get a few more k`s out of a tank and the power diff is none just stops the pinging(au ute 6 banger with uni-chip)and they tell me never use it in the bike.
So i use other bands pulp.
Cya
Stu

Any increase in performance will only be noticed on an efi computer controlled vehicle, if the computer allows it.

It can take 500-5000km for the ecu to "learn" its required map for the premium fuel.

My HSV VU and VY R8's noticed a performance gain, and got 70km per tnak further on optimax, my 4.5 troopy chugged low rpm in low range like snow better, and did perform better if run for 5+ tankfulls.

Our Nissan 200SX get exactly 10% better fuel consumption on Optimax and pings like buggery if it is filled with normal ULP. 0-100kmh time is reduced marginally on premium but 200kmh comes up a lot quicker. From what I can gather the engine has to be tuned for the higher octane to get the best results.

My 2.6Litre Rodeo gets better economy with PULP and it seems to have a little more power as it revs less at 100km. I use it for trips and various other times.

However at 10c/litre more I don't think it is 10% or so better. So I don't use it all the time.

G'day Jimbo,

as Darren mentioned, it can take 500-5000km for the ecu to "learn" its required map for the premium fuel.

An interesting 'case study' to read from the LCOOL pages on Optimax in a petrol Prado can found at http://www.lcool.org/technical/prado_high_octane_fuel.html.
It describes the timing of spark generation wrt the compression cycle, for the particular engine.

Jeremy.

I found we got a slight increase by using Optimax , and the BP Premium stuff.

We got about 50 to 100k's better per tank. When the price difference is about 10c per litre though , it makes no financial difference.

Hi Jimbo,Ive got a 4.2 efi patrol,I only use plup,Ive found that it inceases both power and Kms,up to about 70 kms around town ,Perth, and on the open road I can get up to 120-130 kms per tank full
regards uppy

I noticed the same thing my GQ (carburettor) on BP Ultimate is using around 16 L/100km vs. around 19L/100km on regular. But the biggest difference is in engine responsiveness.

Lukasz

The difference in economy and power in vehicles tuned for pulp is simple to explain. It has nothing to do with extra density or other crap. It is because modern vehicles are built with knock sensors that retard timing and prevent pinging when using low octane fuel. Higher octane in the fuel allows the engine to run with a more advanced timing that allows more power and better economy. Most cars will run better on pulp but it depends on the original setup of the engine desighn. My 89 Toyota Camry book specifically said to avoid pulp

BP Ultimate 98 makes our work van (2002 Carby 2.0L Mitsubishi Express) run HEAPS better, it actually pulls in second gear instead of just limping along. It stops my EFI 850cc 3 Cyl Daihatsu from pinging but power diff is barley noticable.
My 250cc 4 cylinder Honda CBRR used to only run on BP 98. Even shell or caltex premium fuels would make it idle lumpy and smell of un burnt fuel and a cold morning with anything other than BP 98 octaine meant a flat battery from trying to start it. It just wouldn't go on std premium until the day warmed up. BP, first go every time. It had 4 carbys on it and was a jap import tuned to run on jap fuel.
There is deffinatally a difference. Most of my mates with petrol 4bies run BP 98 because of better performance in dunes etc. Mainly torque.

I generally don't notice a performance increase in the Jack, going from ULP to 98. Over 3 weeks or more of constant use there is a slight economy improvement.

However, the performance decrease is noticeable within a day or two going back from 98 to ULP.

I usually only use ULP or PULP around town, and start using 98 3 to 4 tankfuls before a long trip.

Used Optimax for a while and noticed a slight improvement in performance and consumtion. Couldn't work out whether the extra cost was worth it particularly with the fluctuating prices in Sydney. Gone back to ULP.

This link is worth a look - explains a bit why performance isn't seen straight away (for the Prado anyway)

One of the biggest advantages is the cleaning properties. Continual use reduces or eliminates buildup on the back of inlet valves. I have plenty of experience with BMW engines that are known for extreme buildup on valves, the same engines that have used optimax or ultimate since new or since head overhaul have no buildup at all,in fact look like new. Recently seen 2 examples 1 at 33000km other at 50000km. Was a total sceptic before then, now converted.
Clean inlet = better idle,smoother throttle response,more power+better economy.
Plus the added advantages of no pinging, should equal better engine life.

We had a Merc 230e, old 86 mod and found app 50km better econ per tank on opti, Fairly antique old engine type,would be at home in a chaffcutter and econ was improved. Now use it in the 4.5 80 series, don't know if it improves econ in it, it is always a monster on fuel.

Regards

Greg

I have come to this issue late - Am now trying tu use the new BP 95 octane regularly, should I expect similar improvements to 98 octane over time?