Hi

Does anyone know what is the spring in the standard E8 MR actuator rated at, ie the minimum boost I can realistically expect to see without bleeding air with the solenoids?

I'm experimenting with the boost at the moment and have been trying to get rid of the taper. Since I don't have a wideband fitted yet, I'm trying to hit and maintain a lower boost level than standard to keep things safe.

To this end, I put the "desired load" right down to 11.9 throughout the rev-range. In this configuration, I still get a peak boost @ approx 4000 RPM of 19 PSI (read from zietronix map sensor) and then it tapers away to 14 PSI by 6500. With the load this low I was suprised to see 19 PSI. I'm now thinking that the spring in the actuator might be causing that?

My next experiment is to zero down the wastegate duty tables. This should mean that the boost is controlled purely by the spring in the actuator - with no bleed-off - right?

If I still get a peak & taper then it's correct to assume that these are characteristics of the wastegate spring rather than any software maps - right?

And so effectivly the taper could be eliminated by ramping the wastegate duty upwards with revs to counter the natural taper?

Cheers & thanks in advance,
Boon

 

By ramping up to max (with the right restrictors) on the stock actuator you should be able to hold 20+ PSI to red line, especially in higher gears.

Actuator is about 10 or 11 PSI, with exhaust mine creeps to 14-15 PSI at red line.

 

These cars stock, run obnoxiously rich on WOT under full boost, you don't have to worry about running too lean at all with the stock turbo, etc.

All you can do to "maybe" help with the taper on a full stock setup is to make all your "Boost Desired Engine Load" values (all 3 maps) 159.4; change the Boost Control Load Offset to say 80 or 90.

the cells in your "Max Wastegate Duty" are probably already at 100% for all cells, if not set them to 100% up to 5000rpm and then set from 5500 to 7000 to max which is 127.5.

If the car still tapers it's a biproduct of the turbo hose coming off of the turbo manifold allowing to much air to get to the wastegate actuator at higher rpms & the Boost Control Solenoid not allowing enough air to vent off... this is a hardware boost limit that Mitsubishi engineered into the car.

As you mentioned you will have to change out the wastegate actuator if you want to keep the boost hoses and BCS stock.