An Interesting Development

[c3nturi0n]

These engines are quite sensitive to the fuel.

Hi Nick,

I picked up on your comment here and was wondering if you could elaborate slightly for me (mainly for educational purposes ).

Any knock-on effects on the car/engine when using low(/er) octane fuel?

Cheers

[welwynnick]

I picked up on your comment here and was wondering if you could elaborate slightly for me (mainly for educational purposes ).
Any knock-on effects on the car/engine when using low(/er) octane fuel?

I've looked at lots of custom tune dyno charts, and some of them show different results for different fuels. The gains from high octane fuel are usually relatively large. Going by previous experience, this is typical for high compression and/or high boost engines.

The effects of low octane fuels aren't simple. For cruise conditions the ECU will adapt automatically. However, under acceleration the ignition timing is controlled by the map and is not adapted, but the knock sensors will cause the ignition to be retarded immediately if knocking is detected, and will progressively advance it back.

That should keep the engine safe, but if the engine is under heavy load, you really don't want any detonation at all. It's very bad for the engine.

Nick

[cammmy]

Yeah, figured as much. Well, we'll see if the engine has to come out or not. Hopefully by the time that happens, I'll be half way through doing the Lotus And will be able to convince myself that also throwing turbos at the RS is a bad idea X-D

[don0301]

Did I dream that I read somewhere these suck in literally a ton of air per min at 200mph?

[welwynnick]

And you accuse me of talking <beep>?

It's more like a ton of air per hour at 155.

[don0301]

And you accuse me of talking <beep>?

It's more like a ton of air per hour at 155.

It was a joke, you mong....

[welwynnick]

Ah bless, takes me back to the school playground, last time I heard someone say that. How times have changed.

[cammmy]

I'd never heard that before coming back to the UK. In my school playground it would have been "don't be an eeeeeeegg bru"