Hello all, as I have only had my 1990 300ZXTT for a couple of weeks now I have been experimenting with different Fuels. I.E. standard unleaded and Shell Optimax. Inside the fuel flap it's got a sticker with 98 RON on it which is why I have tried Optimax (bloody expensive) I was wondering if anyone could tell me what they usually fill up with and if it makes a difference?

Cheers

 

Glenn

 

P.S. My car has just developed an intermittent miss fire could this be down to the petrol???

My car did the same when I first put Optimax in it.

 

You should really be using Optimax. Most of us on here do. I would never use anything else.

You want to get the Octane level as close to the Japanese petrol as possible which is around the 100 mark.

Optimax has an octane level of 98.

 

A few people here also put Octane boost in there tank ever couple of fill ups. It's about £6 from Halfords. This is not essential but it does help performance.

 

The mis-fire may be caused by a sudden change of petrol. The previous owner was probably using normal unleaded from Tesco or something. You may be able to get rid of the mis fire by resetting the ECU. You can do this by disconnecting the negative battery terminal for about 30 mins.

 

Your car may seem a little out of shape when you reconnect the battery again, but don't worry it will correct itself. It's just the ECU learning to talk to the engine again.

 

Hope this helps. Let us know how you get on.

Thanks Stuart, I will have a go at doing that. The bloke who had it before me didn't seem to know much about the car so you are probably right about the Tesco fuel.

 

Glenn

Used to have horrendous misfires on mine too.

 

Try running super unleaded with an octane booster like Millers.

 

Currently mine runs on super with two bottles of Millers (only viable if you've de-catted your zorst) :D

Thanks Adam, I noticed you are near Chester, I am in Northwich are you anywhere near me?

 

Glenn

By the way Glenn , whereabouts in cheshire are you from?

Kingsmead estate near Northwich Adam.

Where are you??

oops bit slow with the old typing skills there.

 

I'm just outside of Chester.

 

My Zed is poorly sick at the moment but I should be getting it back around christmas (just in time to bankrupt me with a f**kin 6-7k bill!!:( )

Blimey, what's wrong with it?

I actually live in the rural idyll (it says here - read tiny village) of Elton .Its about 5 miles out of Chester , 5 miles from Ellesmere port and 15 miles from Warrington .

 

so now you know:)

Yep, I know where that is, not far from me.

Snapped cam pulley leading to piston/valve interface!!!:(

 

It's an engine out job so I thought while it was there forged pistons , hybrid roller bearing turbo's , metal head gaskets etc etc might be a good idea:D :D :D

 

 

basically I only want to pay 2k labour once , so while its out I'm doing everything , complete engine rebuild to try and make it as bombproof as possible.

 

'course the 450-500bhp has nothing to do with it:D :D

NICE!!!! Let me know when you get it back.

Normal unleaded in Japan is 98RON and Super is 100 or more I think, so that is why it says use 98 RON. It should be OK with normal unleaded but I use Optimax virtually all the time. I dont when I cant find a Shell station.

 

I found that the car ran a lot better with Optimax which is only 2-3p a litre more when Super Unleaded is about 10p a litre more. With Optimax I also found my MPG go up slightly which really cancels out the extra money spent on it.

 

Also higher RON petrol is needed if you have a modified car so to prevent detination.

 

Stuart

Same theme, slightly different subject. I read a report on Optimax. They ran 3 cars, an M3, XJR and something normal I think. Checked all 3 with a camera down the plug hole etc, tested for speed and MPG. All cars were faster, more mpg. Jag a lot cleaner inside, M3 was spotless in the first place so no difference. Conclusion was it works.

Goin' to confuse the issue here as I have just looked under my flap ( oooh er missis ) and found a sticker saying 95 octane. :confused:

 

This must be because mine is a UK model. Do I presume that Uk and Imports are set up differently.

Mine doesn't really seem to benefit from super unleaded in any noticable way and I did use a full tank. Goin to fill up next with Optimax and see if we have any different results.:cool:

everybody goes on about optimax being the best, but they only guarantee 95 ron, so you might as well use super:cool: :cool:

Originally posted by ukmark

everybody goes on about optimax being the best, but they only guarantee 95 ron, so you might as well use super:cool: :cool:

I beg to differ. Can you show us where you get that information?

http://www.shell.com/home/Framework?siteId=uk-en&FC1=&FC2=&FC4=&FC5=&FC3=/uk-en/html/iwgen/shell_for_motorists/fuels/questions_answered_0312_0921.html#7

according to the website and an email i have recieved from there customer service department it is 98 RON in UK systems?

I use Optimax on a JAP ecu and it makes a noticable difference on my car.

i was told by some motorsport company , when i asked about the best fuel , they said might as well use super , instead of optimax ask it is not an guaranteed 98 ron . not even shell will guarantee that it is , they may say it is, but they wont guarantee it , . i have not put this down to start a arguement, i am just saying what i was told.:p :p

Quoting from Shell's website (the link which Warren put up) :

 

What is the Octane level of Shell Optimax?

 

Shell Optimax has the highest octane specification of any petrol in the UK. It is greater than 98 Research Octane Number (RON).

 

They may not use the word 'promise' but I think they'd struggle to defend themselves if it wasn't !

 

No two cars are exactly the same and your best bet is to try it - if you notice the difference and value that difference then use it.

 

When I had my ECU mapped, I filled up with normal unleaded before the rolling road session. This meant that once it was mapped to that, I could then use super (it was pre-optimax days - I'm very old) to add a further margin of safety.

your are probably right ,but as i said, this is what i was told.

Optimax guarentee 98RON at the pump while Super say 98RON during refining.

 

Where is Nelson to tell us how good Shell products are when you need him ;)

who cares , as i said THIS IS WHAT I WAS TOLD .. SO STOP HAVING A DIG AT WHAT I PUT. I WAS TOLD IT !

Originally posted by ukmark

who cares , as i said THIS IS WHAT I WAS TOLD .. SO STOP HAVING A DIG AT WHAT I PUT. I WAS TOLD IT !

I dont think its having a dig, i think you need to back up your statement?> Like Hairy says, Shell would have a horrid time Stateing something like that on the web? or in there Advertising of the product withouth being able to back it up?

 

Who were the "motrosport company" that told you this?>

if its not guarantee it aint 98 and they can not promise, but who gives a shit ,coz i dont, supers fine and easier to get and happy chrismas all :D :D :D

I use ordinary unleaded, and haven't noticed any problems. Maybe it's only if youve mod. the output.

Tanzx