ECU and RON

[Scuzi]

My car is normally run on Optimax but now that I've been in Ireland for the past two weeks, I've been running the car on 95RON as SUL is scarce and Optimax isn't sold here. I've been told that the ECU changes the timing to suit the higher RON but once you use a lower RON fuel, the ECU defaults back to 'safer' settings therefore losing you a bit of performance. I've also been told that if you then put in 98RON again, it can take a while for the ECU to change its settings back to those required for best performance.

I'll be going to the OcUK Rolling Road on 1st July and want the engine putting out full power so how many tanks would I need to run through the car to get the ECU back to its best settings? I'm in economy mode at the minute so every penny counts, 95 RON is all I can afford

Car is a '53 Seat Toledo 20VT

 

[Matt82]

fill it back up with 98ron and then disconnect the battery for 30 mins, ought to do the trick

 

[merlin]

Quite a few cars have the ECU fused - so you just pull the fuse and give it 5 minutes.

Otherwise as said, it's onto disconnecting the battery.