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The mkiv Supra Owners Club

unleaded???


ulysees

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how much damage if any will i be doing to the engine if i run it on premium unleaded, i have tried them all and it seems to like premium but i was told not to use it, my car is a 93 import n/a any help would be great

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do you mean super unleaded or normal?

in japan they use 100 ron fuel so you wil be running it on way less than its used to or made for.

but since youve got an n/a it doesnt matter too much but id be carefull,i use super all the time plus its better fuel anyway

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do you mean super unleaded or normal?

in japan they use 100 ron fuel so you wil be running it on way less than its used to or made for.

but since youve got an n/a it doesnt matter too much but id be carefull,i use super all the time plus its better fuel anyway

 

 

 

yes i mean normal

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one of the reasons i ask is that its pinking under load at low revs so i tried all sorts of unleaded to see if it would cure it but no luck, but it did like premium so i will stick to that if its not going to do any damage

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If your chopping and changing fuels often you might not feel the difference between them instantly.

 

The general consensus is that it will take a good two or three tank fulls before the engine will perform any different.

 

I use Tesco 99 ron in mine and it loves it, I dabbled in V-power for a while as well as BP Ultimate and the Tesco stuff seemed just as good as the others but was much cheaper.

 

I try to steer clear of 95 ron fuel though as the engines were designed for higher octane stuff than that. (afaik)

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I have taken this from http://mkiv.supras.org.nz/

 

In general the better the fuel the less chance of "pinking" (detonation).

 

Fuel types - 96 & 98 RON? Will Supra run on these? Additives?

Coming out of Japan, the Supra is happiest with 100RON fuel. The stock computer handles 98RON fuel (eg Shell Optimax, BP Ultra etc) quite well, and will tolerate 96RON (normal) premium, but forget normal (91RON) unleaded.

 

If the car was fitted with an aftermarket ECU while it was still in Japan, it will almost certainly have been programmed to take advantage of the 100RON fuel over there (ie boost increased, timing advanced to the max), which means that it will just ping & detonate itself to death when it’s brought down here. Avoid unless you’ve got a stock ECU handy.

 

Of all the octane boosters on the market, the only one that I’ve found that actually seems to work is R104+ (black bottle). Keep a bottle or 2 handy in the boot, & add half a bottle to a full tank of fuel when you’re out in the country somewhere & can’t find premium unleaded. Using these once in a while is okay, but according to the tech articles on http://www.mkiv.com, long-term use will leave red/orange deposits on the valves.

 

New Zealand now has two suppliers of 98 octane fuel (BP Ultimate and Mobil 8000). Basically the higher the octane the better with turboed cars so use the highest octane fuel you can. Gull is looking into bringing out a fuel with 5% methanol in it which should be good octane, but no specifications are available yet.

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I run my on either V-Power or BP ultimate.

 

Once filled up on normal shell and the car seemed to develop a high idle problem (once warm) of 1000 to 1250 Rpm.

 

May just of been a coincidence and bad timing.....

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I also believe that the stock ECU "learns" the fuel and the best way/mix of using, reseting it means it will re-learn what fuel you put it and decide how to best cope.

 

Please correct my statement if wrong.... think I got it right. :)

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