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Technical Unos and Super Unleaded fuel

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Technical Unos and Super Unleaded fuel

Ucof

Ucof

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Just got into one of those pointless internet arguements, where you offer your experience and advise, and everyone jumps on you and laughs and says you are wrong.... just for saying your opinion and telling them off your experiences.

Long and the short of it is:

Would a 1ltr Uno feel the benefit of having Super unleaded petrol inside it, rather than just your average standard unleaded?


I filled up with super once and genuinely felt a speed increase. This "other forum" members then all laughed and said the only way an Uno would have a "massive speed increase" would be if you pushed it off a cliff.
The bastards. ;)

Am I tripping, are they c0cks, or is it a mixture of both? :D
 
Unfortunately Ucof, these other people are right. The Uno (other than the turbo I think) doesn't have an anti-knock sensor and doesn't automatically adjust the timing depending on fuel used. Therefore using super unleaded won't make any difference at all. However, there would be less chance that a Uno would 'pink' on higher octane fuel such as super unleaded, but that's the only difference you'd be likely to encounter. Sorry!
 
No need to say sorry!

Im not ashamed to admit I'm wrong! :)
(I won't admit it to them though ;) )

Thanks for letting me know! :D
Im happy paying an extra £1.50 for the placebo ;)
 
I agree with 1986Uno45S (Chas)...

If you have a Turbo, even an old Mk1, with the boost wound up to 1 bar and driven kinda hard, 98 fuel might liberate a bit more power because the ignition timing will end up further advanced thanks to the knock sensor that is fitted.

For the others, no real difference as the ignition system can't adjust itself. You could advance the timing but then it would be hard to start and lose some torque at the low end. Speaking of hard-to-start, I remember fouled plugs when I tried 98 in an Uno 1301cc many years ago.

-Alex
 
1986Uno45S, you are right about super petrol meaning it is less likely to pink.

Ucof it was nice of you to acknowledge my post!

But just so you know, I am still trying to figure why my Uno 45-903, won't start, when cold.
So there is still something to learn.
 
Even the knock sensor on the turbo and i.e. models cant "self tune" or advance the timing to take benefit of higher octane fuel. It is only a safety feature to prevent detonation. (later model cars are better)

If your engine does happen to detonate and the ign is backed of it will make a large difference to the power output. This system is not perfect, and if the engine is detonating (less power) you should be running better fuel full stop. You don't have the option to run it on a lower grade of fuel, that will damage the engine over time.

So talk of your car running better on either fuel is redundant, you should run it on the fuel it requires and leave it at that.
 
rawill said:
So Steve, are you saying we should only run super in our Unos
Click to expand...

Check the Haynes manual as all Unos from certain engine numbers are designed to run on unleaded (some time around 1986 onwards, though I'm not so sure about the 903 ohv engine). Also with the Lampredic ohc and FIRE engines having alloy heads they're already fitted with hardened valve inserts. I've run ALL my Unos on unleaded for tens of thousands of miles with no ill effects, which includes two 1986 1.0 FIRE's and a 1989 1300 SX. :)
 
super unleaded and premium unleaded...... are both unleaded anyway...

You've lost me.
 
Ucof said:
What do you mean, diesel?

;)
Click to expand...

No, I am not talking about Diesel.

At the pump we get both 91 and 95/96 octane petrol which are both unleaded. In some selected places we can buy 100 octane petrol for motor racing purposes, this fuel is still leaded petrol. Similar fuel is used in small aeroplanes, so we can get 100 octane leaded petrol from the Airport.
 
Ucof said:
super unleaded and premium unleaded...... are both unleaded anyway...

You've lost me.
Click to expand...

rawill said:
In NZ all our fuel is unleaded. To get fuel with lead we would have to buy 100 octane racing fuel.
Click to expand...

And above is the biggest misunderstanding (or rather con by the fuel companies) regarding Unleaded. Unleaded fuel STILL HAS LEAD IN IT. Unleaded has LESS lead than the old 4 star and 5 star leaded fuel and replaces some of the lead with other chemicals to reduce detonation. I forget what these chemicals are but I'm fairly certain they're stuff like benzene that is a known carcinogenic.

Lead was supposed to be linked to retardation in children, so with the reduction of lead in fuel how come we still have so many stupid kids? :rolleyes: Oh, and lead levels in children have been going down not because of unleaded fuel but because the old leaded water pipes have been replaced...

*Gets down off soapbox*

:p
 
1986Uno45S said:
. I forget what these chemicals are but I'm fairly certain they're stuff like benzene that is a known carcinogenic.

Lead was supposed to be linked to retardation in children, so with the reduction of lead in fuel how come we still have so many stupid kids? :rolleyes:

*Gets down off soapbox*

:p
Click to expand...

I like the comments above: perhaps because they have stupid parents!

And yes known carcenogenics, toluene and heaps of other nasties, they did a great job of eating up rubber components in fuel systems. I know, we had real issues in Kartsport. Carburettor kits would not last even 1 day initially.
 
Unleaded fuel doesn't contain more than 'naturally occurring' traces of lead - if it did, it would ruin catalytic converters.

The measurable amount of lead in unleaded fuel is less than 1/100th the amount there was in leaded fuel.

Rawill lives in the South Island - I gather the petrol stations down there don't have 98 octane unleaded, then? :p

In the UK, as here, Premium Unleaded is 98 and Super Unleaded is 95, but unlike here, you can't seem to get 91 any more. It's all quite confusing to know which is Premium, and which is Super. It's a bit like buying minced beef at the supermarket here. There's budget mince, mince, quality mince, prime mince, and premium mince (in that order). If in any doubt, you just look at the price :)

There is good unleaded petrol, and bad unleaded petrol. Like most things in life, you probably get what you pay for.

Good unleaded petrol has a low amount of aromatic hydrocarbons (aromatic = compounds that contain 'benzene rings', such as toluene, xylene). There won't be any ethanol. No sulphur, and a certain rate of evaporation that is neither too low nor too high. I think in New Zealand, good unleaded petrol is 98 octane and from Singapore, followed by 91 octane refined in New Zealand.

Bad unleaded petrol has lots of aromatics - hard on rubber, and they produce a lot of soot when burned. The evaporation rate is wrong, so that all the petrol dries out of carburettors and evaporates from petrol tanks, or at the other extreme, engines are hard to start when cold because the fuel won't evaporate easily enough. 95 octane petrol here seems to have some of these problems. Fuel hoses just don't last like they used to.

And then there's the idea of mixing ethanol with the petrol, usually at less than 10%. Lots of countries now do that. I don't know enough about the ill-effects, only that in the USA, Alfa 164 fuel pumps and gauge senders stop working. I don't know why, but it has only happened (to dozens of cars) since ethanol was put in. For example, the low-fuel light comes on after the tank is filled. My guess (and it is only a guess) is that the water content of ethanol leads to tarnishing of the electrical contacts.

-Alex
 
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