My interest was aroused upon reading the SIDC FAQs with regard to resetting the ECU. I rang my local dealer who didn't know what I was talking about. The FAQ article mentions: " or he disconnects the battery for long enough to allow the back up capacitor to drain."

Does anybody know how long the battery should remain disconnected?

After reconnecting ( with super unleaded fuel 98 RON in the tank ) the engine is likely to be cold. Going out and immediately thrashing the engine in order to start the ECU sampling is not going to do the engine much good. Is this just an unavoidable side effect or can anyone offer a better suggestion?

I have a 97 spec car. Has anyone performed this task with a 97 Scooby and noticed a justifiable difference?

Okay, here is the low down and it was done to a 97 spec. Disconnect the battery for half an hour, start engine and let it warm up. Take car out and keep it below 4000rpm, find a long straight and get the car running in 4th gear around 3,3500rpm. Wind the car up to 6500rpm and hold for thirty seconds. Perform the same again. Best time to do this is early morning when the air is nice and cool. The ECU will increase the boost until the knock point is found. I noticed that the throttle response is a lot more lively http://bbs.sidc.co.uk/smile.gif

Is this the same theory that could be applied to a 98MY?

Would it not be better to attend a track day, disconnect the battery for the required time, then blast round the track with 4 people in the car? I also have a '98 and I am quite interested in doing this, my dealer initialised the ecu but since then I've got a bigger (scoobysport) exhaust and 'RamAir' filter. Would this procedure improve the ECU settings? Can I do it using standard unleaded?

Two points.
Firstly, since the reason for disconnecting the battery is to discharge a capacitor in the ECU, can one not shorten the amount of time the battery needs to be disconnected by (after disconnecting the battery of course) shorting the +ve and -ve battery leads together?
Secondly, I tried the ECU reset yesterday, having just filled with 98RON. Not convinced its made the blindest bit of difference.
So, either I did something wrong (what?) or the difference is so slight that I'm inexperienced enough to notice on standard MY98.
6500 rpm in 4th is over 100mph, which is a bit of a problem ;-). Also constant 6500 rpm is not much of an engine load - isn't the point of this to increase boost under load conditions?
Probably more than 2 points there. Sorry.
I'll happily try ECU reset again, if I can better understand what's really going on here.

Tried it on MY98, reset ECU then after warming up went for a blast. Used a long hill and some left foot braking (in 3rd gear).
Noticed an improvment in power from 2500rpm.

When I went back to RON95 the difference was most apparent. Stick to RON98.

Just a thought in the long saga about ECU reset - in particular the rumour that the ECU does not ever advance the timing once retarded - is that filling with 98 RON and going for a blast may improve the car anyway - i.e. WITHOUT reseting the ECU. I'm sceptical about all this anecdotal evidence - the only sure way is to carefully dyno the car before and after - with AND without doing a "reset". I'm beginning to believe that the MY97/98 ECU can advance the timing without a reset. But who knows. I've even written to Unisia Jecs (the manfacturer) - but surprise surprise they haven't replied (yet).

I have done veritably no mileage of late and want to get a second full tank of 98RON in the tank before resetting the ECU. However as Colin said, it would be nice if someone ,with the correct equipment, could really quantify any improvement ( as was done with the ScoobySport Exhaust and Ram-air). Colin, if you publish that address, I would be happy to write to them echoing the same question ( maybe if enough people ask they might respond).