MoTeC Global Forum

I am wanting to improve boost control on an RB26 Nissan twin turbo engine, it runs the factory style turbo set up, albeit with greater flowing internally wastegated turbos and ported manifolds. In order to get the boost as high as I would like (1.5 bar) I have to run wastegates with 1.2 bar springs in them. I now see that some people are using wastegate actuators on internally gated turbos that have a pressure seal on the rod side of the diaphragm, and two pressure nipples, like an external gate. By using a 4 port solenoid they seem able to run soft gate springs, yet achieve high boost when desired. This gives the ability to map for wet traction without having to run soft springs and hope that at full duty cycle you get enough boost for the dry. Apparently they work off a normal PID output from the ecu, but not sure how, will an M800 run these? Has anyone here got real world experience of these 4 port actuators and twin port actuators for internally gated turbos? Are these dual port wastegate actuators reliable, or do they have seal issues, (as a fixed canister operating a rotating lever will see side shift on the rod where it enters the canister). Are there any control "gotchas"?

A friend who maps another make of ecu e-mailed me as below, citing how he gets around my issues, can an M800 do what he suggests?
Thanks.


"Not used any 4 Port solenoids myself but I tend to if presented with your problem add another Solenoid and drive one nipple with the Phase and other with antiphase of the WGFinalDuty, This works very well.

Unfortunately you cant do this on the Motec after having a quick glance at the Aux Output list. So you are just going to have to get a <censored> "

I don't know why you couldn't mirror your WG output via an aux table on another output, same frequency etc. just flip the polarity, when the WG DC% is 79%, the mirrored aux would be 21%.

Haha, why not simply set the table axis of a second auxiliary output with the duty cycle of the boost control output, then you can pretty much do anything with it.....even make the polarity the oposite so that 79% is 79% but with the signal itself inverted.

What ever the "censored" ECU is I'd put a fair bet that our M800 will do it quite easily......maybe your friend should have a slightly longer look.