I've been told by a previous classic WRX owner, that if you run your tank really low, disconnect the battery for 3-4 hours then feel up with V-Power or Tescos 99, and the ECU will reset itself for that petrol and you'll gain an extra 10bhp, now if thats true I'm doing it, but I'm not sure?

Can someone tell me if this guy is talking rubbish!

Thanks

 

Not sure...i run my car on tesco's 99 and can tell i do have a litle extra "umph" .....worth a try i'd say

 

Disconnecting the battery will drain the capacitors in the ecu before you do that though make sure you have enough of the petrol you use in the tank after however long you want to leave the battery disconnected.Then go for a drive (normal road speeds) don't just stick to 30mph go for a blast on a dual carriageway (no need to redline the car) and the ecu should have adjusted itself (the early ecus retard ignition more easily than they advance ignition) but tbh gaining 10 bhp is bollox imo.

do a search on here for saxonfield for an alternative way to reset the ecu

 

well if ure car is running weak or limp mode from using poor quality fuel roughly 7psi/0.5bar then adding quality fuel and resetting the ecu will do the trick... here's my experience
1995 STi V2 no cats only mod.

using 93 octane fuel, boost gauge reads 7psi = 99kw ATW
using 102 octane fuel, boost gauge reads 12-13psi = 146kw ATW

Hope this shed some light?
S

 

Yes. Basically rubbish.

Resetting the ECU will put it back to factory settings and it will adjust to the fuel you are running, within reason. Basically you want the best fuel you can get for a JDM car that has not been altered to run on 95 RON.
What model /year. JDM or UK?
Leaving the battery disconnected will reset the ECU in time but I have no idea how long it takes. It would be better to do a proper ECU reset.
Someone may post a link.

Obviously for the best result from a better fuel than you have been running it is best to fill up when you are nearly empty so you get as near to 100% new fuel as possible. Shell V-Power is good and if yours is a JDM car, that is the least you should be running.