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The mkiv Supra Owners Club

Timing


Alex
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I've got a friend to agree to looking at my ignition timing to make sure its running ok on SUL instead of 102octane. Can someone please let me know what sort of timing figures I should be looking for. If its mapped to 102 octane how much should the ignition be retarded by?

 

Cheers

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Oh goody I figured that I could adjust the timing to better suit SUL. Maybe I'm thinking of valve timing? Is there an adjustmant to be made in any other area such as the cams which will affect the timing of the spark etc? and reduce the risk of running lean....

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Alex,

 

I was talking to our ECU calibration guys yesterday. No-one there is aware of anything that says Japanese cars are mapped for anything higher than 95RON. You shouldn't be running lean on SUL (98RON) (if that is what you are worried about).

 

Darren

 

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Hmm.

All the info i've read over the past year indicates that the Jap-spec cars were mapped to at leat 100RON and maybe 102RON.      The ignition timing on Jap-spec cars is advanced (in the timing sense) in comparison to UK cars.   i.e. UK-cars timing is, as stock, retarded to run on lower octane fuel than Jap cars.     Chris Wilson has confirmed this to be the case, and is one of the main reasons why the Jap-spec cars are more torquey than the UK cars (though there are multiple other differences which also have an effect too)

 

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I've read this too, but I think it was in the "myths" section on one of the many importer's websites.

 

My information comes (in part) from the worldwide Emissions regulations booklet published by Delphi systems. I hasten to add that ECU mapping is well away from my area of expertise, but there are plenty of people I can go and talk to about it. To further qualify the case for 95RON, we have a job on right now that will sell into Japan, and that is definitely being calibrated for 95RON.

 

Maybe its different for home-grown cars. Perhaps they have a greater range at the pumps than we do. I can't say for sure. It also may have been different in the past since we are generally talking about 1993 to 1996 cars when we talk about imports. Its certainly 95RON now, to the best of my knowledge.

 

Alex,

 

I was picking up on your other thread where you were talking about going back to a stock ECU. If you are keeping the MINES job, then you could well be right.

 

Darren

 

(Edited by Darren Blake at 4:37 pm on Aug. 1, 2001)

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As for the timing issue don't worry I've now managed to get it through my thick head that I have to adjust the ECU to change the timing. I was thinking that there was a mechanincal way to change it...

 

DOH... don't think I'll ever manage to be an engineer!!

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