Canuck

I'm sure this has been done to death in the past but my questions are from ignorance regarding the ECU.
I have a MY97 turbo and understand that this is the stoopid ECU that takes ages to learn.

One question is: If it takes so long to relearn if you go from 95RON to 97RON then what happens if you have it set for 97RON and can't find any so that you need to use 95RON; doesn't this take time to relearn the new conditions?

If so then should you only put in the minimum amount until you can fill up with SUL? Guess that's another question ...

Secondly (or is that thirdly), are there any advantages to using 97RON with the ECU taught with 95RON (e.g., fuel economy)?

Finally, is it straightforward to replace the original ECU with a smart one from a late model Scoob?

Cheers in advance,
Canuck

Canuck

Thanks but can anyone else answer my naive questions, please!?

nom

May be a little more info here...
There are unlikely to be any short-term 'performance' benefits from using 1 tank of SUL amongst mainly NUL (possibly better economy), given a slow-learning ECU. But it's better for the engine - short term - to use SUL, especially in hot weather. Except, of course, it will begin to advance the ignition again so worse when you switch back to NUL
Replacing ECU... well, it can be replaced, but not very easily by a later Scoob ECU! The normal choice here would be an aftermarket model.
It's probably a good idea to just stick to the same stuff from the same vendor so the ECU knows what it's getting. Except the fuel quality will vary too

Canuck

Thanks Tom, that clears that up.
Looks like I immediately get significant increase in fuel economy, based on 2 tanks-worth so far, justifying the extra expense as noted here before.
Aftermarket ECU's are something I'll need to think about (re:cost), what I was considering here were scavenging opportunities (to include 4-pot calipers and headlamp adjusters, the latter having bust!).

Cheers
Keith

encoded

When you go DOWN in RON, the ECU learns faster. This is because when using a lower RON than the ECU is used to, the engine can detonate and that is bad news. So when the ECU sees that, it quickly adjusts the timing and/or other factors to prevent detonation. When you start putting higher RON fuels in, the ECU will slowly learn over time and begins adjusting things for higher RON.

About your other points, I don't really know, so I'll just shutup.

e.

[Edited by encoded - 9/12/2002 2:57:13 PM]