Since the rolling road day at Area 52 Motorsport, I discovered that the car was only producing about 12psi or 0.75bar boost when it should be around 1.1bar as standard. So I booked the car into DWR Performance in Chesterfield to get diagnose the fault and remap as and when it was running correctly. Darren at DWR diagnosed a faulty turbo actuator, the ‘top hat’ has rusted through where rainwater has dripped through the bonnet vents down the actuator arm and settled, rusting over time. The actuator is the component that vents excessive boost from the turbo, should it reach the predefined level set by the ECU. Since the actuator had failed in the open position, when tested, it was only holding boost up to around 12psi before opening and venting anything in excess of that amount. This is a common fault with the older Evo’s due to the way the actuator is mounted. Darren removed the radiator and fitted an Evo 8 actuator which does not have the same exposure to rain water due to its orientation.
Coincidentally whilst in for fitting, there was a another Evo on the ramp – a IX that had been brought in by it’s new owner because he got beaten in a straight line by a 1.6 Honda Civic! It turns out he was getting no boost whatsoever! Kinda worrying that he hadn’t realised there was something fundamentally wrong until the Civic zoomed by!
With my new actuator fitted Darren mapped the car on the road with the ECU targeted to 1.5bar which is approximately 22psi. What a difference! The car felt absolutely savage on the way home. I kept accidentally hitting the rev limiter due to how much more quickly the revs climb under boost. The car now pops, bangs and spits flames on the overrun, sounds fantastic, I love it.