Mini Cooper SC

[Icsunonove]

Lauren - if you remove the ABV how does the engine breathe when the SC isn't running ? Apart from its function of controlling max boost under ECU control ( which is disabled by the mod detailed here http://www.mr2sc.com/websites/tech/abvlines.htm ), it opens to bypass the SC when it isn't engaged allowing air to pass straight between the throttle and the inlet manifold.

Correct! Once you blank off the ABV the SC is basically driven by the airflow when the clutch is disengaged. I expect this has a slight detrimental effect on fuel consumption. I was looking at enabling it's bypass function but disabling its overboost function. But since I have learned the SC is engaged so much of the time, can't be bothered now.

[MartG]

I was looking at enabling it's bypass function but disabling its overboost function. But since I have learned the SC is engaged so much of the time, can't be bothered now.

Tom - are you just running it as standard then ? If so you won't be getting the benefit of your big pulley as the ECU will be limiting the boost to about 10psi.

The ABV is normally held open by a spring allowing air to flow directly between the throttle and the inlet manifold, but when the SC engages the manifold pressure increases, and this manifold pressure is applied to the ABV actuator and closes it. The piping between the manifold and the ABV actuator normally goes via an ECU controlled VSV which allows the ECU to cut the pressure and open the ABV when boost reaches a certain pressure. All the mod really does is remove the VSV from the equation by connecting the manifold pipe directly to the actuator so the ECU can no longer open the valve. 5 mins work with a T-piece and you get the full benefit of the added boost - according to my boost gauge I'm getting 0.9bar ( 12.5psi ) on mine.

[Icsunonove]

No Mart, I've blanked mine off. But I was looking at enabling the bypass function and disabling the overboost function. But I didn't bother..

I see peak pressures of just over 13psi on mine.

[Lauren]

Lauren - if you remove the ABV how does the engine breathe when the SC isn't running ? Apart from its function of controlling max boost under ECU control ( which is disabled by the mod detailed here http://www.mr2sc.com/websites/tech/abvlines.htm ), it opens to bypass the SC when it isn't engaged allowing air to pass straight between the throttle and the inlet manifold.

Air just flows through the SC, its no problem at all. The difference is that when the SC locks on the transition between off boost and on boost is more marked.

The way its done on the mr2sc list is frankly crap tbh. When Mark removed his ABV entirely from teh equation he saw another 1psi boost over doing the mod as detailed on that site.

Seriously removing it from teh equation is the only way.

[MartG]

Is it an easy job to remove the ABV ? Do you have ant tech info on how to do it ? ( you may have convinced me )