Hi fellow Z riders...ive had my 300zx tt for 4 months now and i use 97 or 98 octane fuel in my Z....and thinking of using 99 octane which is being sold at my local tesco garage, :hyper:

 

i now that jap sports cars can take higher levels but whats the best level for Z cars? :dance:

well most import 300's are programmed to burn something like 92 octane because at the time they were made, this was the standard fuel. so if you start using higher octane it will do a bit but if the ecu is re mapped it will be a lot more efficient.

So by that am i right to think higher octain fuel will be ok in a UK TT without having to remap the engine?

 

carl

i've been running mine on tesco 99 now for about 3 weeks and it's great. Noticable improved fuel ecconomy but mine has been re-mapped. I thought that Japanese fuel was around 100 octane and "unles you put an octane higher than 95 in it will knock and go into safety boost" - Thats what my workshop manual says anyhow.

higher the better (and advised)

OPTIMAX :bow:

 

and no need for any alterations use straight from the tin

99 tesco mate !! can notice the difference easily over even optimax !!

Mine runs better on Sainsburys 97 than Optimax????better economy and performance.

Explain that????

There was a test in one of the jap mags which said optimax although has a lesser octaine rating gave you better performance and fuel economy.

There was a test in one of the jap mags which said optimax although has a lesser octaine rating gave you better performance and fuel economy.

lol...wonder who that was sponsered by :D

 

Deffo Tesco 99ron :bow:

Forget rip off Optimax :xxx:

 

I have used it for about just under a year now.

Have covered thousands of miles and it is definately better on mileage.

And it is definately better on power for my setup.

I use a central20 chip ;)

HTH

Try and get whatever fuel you use as fresh as possible i.e. use a busy garage that regularly refills its pumps. Petrol has a low shelf life and old fuel will effect performance.

 

I've used BP Ultimate from a garage that clearly had little demand for the expensive stuff and my NA ran like crap. On the flip side my local ASDA only sells 95RON but the car seems to love it! Not sure i'd risk 95 in a turbo though.

 

:smw:

Both Top Gear and 5th gear tested these so called higher rating octane petrols, ranging from Optimax, BP Ultimate and Tesco 99 ron and none of them gave a whiff of performance increase or helped with detonation any more so than normal super unleaded. They all ran the same but obviously these higher rated petrols are more expensive just stick to your usual super unleaded and save yourself some money !!! ;) If you think they are helping its all in your mind !

Both Top Gear and 5th gear tested these so called higher rating octane petrols, ranging from Optimax, BP Ultimate and Tesco 99 ron and none of them gave a whiff of performance increase or helped with detonation any more so than normal super unleaded. They all ran the same but obviously these higher rated petrols are more expensive just stick to your usual super unleaded and save yourself some money !!! ;) If you think they are helping its all in your mind !

 

actually thats not true

 

they did a test on optimax, bp ultimate and supermarket fuel on three cars:- a 81bhp clio, a 172bhp golf gti and a subaru impreza with 235bhp. They connected each up to a power/tourqe machine a did six runs for power increase only, each time resetting the ecu. Here are the results;

 

Clio- supermarket 81

BPU 81

Optimax 81

 

Golf-supermarket 172

BPU 174

Optimax 177

 

Impreza-supermarket 235

BPU 247

Optimax 249

 

so as the power increases in the car, so does the performance of optimax;)

actually, around theses parts tesco 99 is cheaper than all the other super unleaded and optimax supliers at 99.9p/lt

LOL!! I wonder how much is in our heads on these fuels! prob only makes like 0.1% difference!! :D

 

i generally use 99 tesco or Optimax, Tesco is a higher RON but the car seems to feel a little better on Optimax.

just remember it's not the power advantage you buy the fuel for, it's its resistance to detonation! There may be negligible power advantage of 99 over 95 ron but when you floor it the risk of damage is lower!

just remember it's not the power advantage you buy the fuel for, it's its resistance to detonation! There may be negligible power advantage of 99 over 95 ron but when you floor it the risk of damage is lower!

What he said.

 

Would have to be a huge jump in octane before you noticed any real power difference at the wheels. If i remember rightly even Avgas (aircraft fuel for pistons) is only 110 RON. Its more about avoiding Det and the additives to keep things lean than just octane=power

just remember it's not the power advantage you buy the fuel for, it's its resistance to detonation! There may be negligible power advantage of 99 over 95 ron but when you floor it the risk of damage is lower!

 

Sorry for sounding dumb, but do u mean 99 Octane is more ressitant or less.. and which is better??

 

(I've always been using tesco99).

 

snx.

higher octane is MORE resistant to Det

yup, & doesnt increase power!! thats down to the quality of the fuel, not the RON.

It might have already been said but a summary of the known facts is good:-

 

1. When the Z was designed and launched the higher octane fuel now readily available in japan was not so prevalent.

2. Most chipped jap cars will have been chipped assuming higher octane fuel than UK's typical 95RON unleaded

3. Higher octane generally = better det protection (but there is an exception) Optimax seems to significantly out-punch its weight as it is only 98RON but allows for significant increases in ignition advance before detonation occurs compared to other higher octane rated fuels.

 

On the basis of the evidence i have seen my personal pecking order for fuel is:-

1. Optimax 98RON

2. BP ultimate 97

3. Tesco 99

 

When using anything other than optimax i add octane booster for piece of mind. I am running a (mine's ECU)

 

To add to the mix BP supposedly has 102RON available in a few locations as a race / trackday fuel. As we progress as a nation maybe higher RON fuels is the trend anyway

the highest octane fuel in Canada is 94 (petro canada)

usually gaz station offer 91 as Premium fuel :rofl:

I think the lowest is 87

the highest octane fuel in Canada is 94 (petro canada)

usually gaz station offer 91 as Premium fuel :rofl:

I think the lowest is 87

 

I think you'll find yours (& the USA) is worked out differently to ours though

i use normal 95 92.9p a litre tesco fuel, but the 99ron at tescos up here (north east0 is only 97.9P so i think i'll try it for a few weeks and see how it goes.

us and uk octane is worked out differently, although i was driving a 5.7l v8 suburban this time last year and paying ALOT less for gas out there, but 87 octane did make me laugh

U.S is MON

Uk is RON,

 

The benefits ARE noticable...plus lower ontane fuel can be false economy as higher octane fuel tends to offer better MPG

the highest octane fuel in Canada is 94 (petro canada)

usually gaz station offer 91 as Premium fuel :rofl:

I think the lowest is 87

 

 

The octain units in Canada are mesured in AKI (Anti Knock Index) Where as in the UK the units of octain are measured in RON (Research Octain Number)

 

Basically a 91 AKI octain here in Canada is the equivilent of 97 RON in the UK.

 

Just to confuse you the US use MON (motor octain Number) and also PON

 

I spoke a the development engineer at Shell just to clarify a few things, I was a bit concerned bringing my Z over to Canada and which fuel to use. Although the numbers seem lower the fuel is actuall refined to a higher standard out here, and the highest option of 94 AKI is equivelent to 100 RON

 

Not sure why they dont all just use the same system!!!

 

Also the RON system was developed back in the second word war when fighter planes were suffering with detonation and basically crashing. They needed to regulate and control the fuel so engines could perform and be reliable. The method of testing is still the same and by modern standards very cude with low tolerances, which is why the Yanks use the MON/PON system tested on modern engines and using up to date technology. The AKI is a further extension with very tight tolerances between grades.

 

Andy