A cautionary tale for anyone disconnecting the electrics in the hope of improved performance:

I have a Type R version 5. The only relevant mod is a Scoobysport rear box.

The car has done 34,000 miles, strictly on Super unleaded. Never noticed detting on 98, but when Super was reduced to 97 RON I heard faint tinkling on full boost, so immediately started using octane booster and have always used 97 + booster since. Initially Silkolene pro-boost, then Millers. I had a Knocklink fitted at Scoobymania last year for peace of mind and the engine appeared to be free of detting - in fact Mike Tuckwood remarked that it was a quiet engine.

Last week I had a new clutch and centre section exhaust fitted. The starter was removed, so the battery was disconnected for about 4 hours. I guess this reset the ECU. The next day I gave the car a quick blast (after warming up on a run first, of course). To my amazement, the thing seemed to have more torque than ever and as the boost hit peak at about 4,000 rpm the Knocklink lit up like a Christmas tree! I could hear faint rattling and backed off immediately.

Since then I've driven cautiously and increased performance gradually. After 200 miles I can now use full throttle with little activity from the Knocklink. Strangely, performance is as good as ever and not noticeably short of when it was detting.

I've read about the ECU reset on UK cars and can see how it can improve performance. Just be careful if you try it with an STI - especially a version 5 or 6.

Anyone else had a similar experience?

Keith

 

This is pretty normal behaviour, the ecu "reset" puts back its defaults, that means defaults suitable for Jap spec fuel (102 actane) in the case of any STi. the version 5 ecu will learn pretty quickly but ... an STi will always tend to suffer like this after a reset, UK cars can benefit but STi's on UK fuel only get hurt. 97 ron plus double millers would probably have kept it quiet in the short term but it still needs to see the det to adjust down. Taking it steady and gradually boosting it over a distance of say 30 miles usually starts the adjustmnet process well on its way, gradual boost increase will allow mild det and hence the ecu will gradually adjust down. Without booster it will normally never get there as it runs out of adjustnment though.

 

Bob,
I am running 97MY UK spec with SUL+Millers (cat friendly). I went through the process of ECU reset as illustrated on MRT homepage, but haven't really noticed that much improvement. I am currently toying with the idea of flushing out the Boost solenoid + hoses just to make sure I'm boost correctly.
Any ideas on what should be happening or any other recommendations or is this normal? I must admit, I was expecting some better gains than this......

Cheers Bob,
Jacko...