Thread: TD5 waste gate actuator operation

..... factory setting being about 14 threads visible on the actuator rod i believe.

I'm asking because in the past like many on the forum i tinkered around with increasing boost by shortening the actuator rod. It's a crude solution but it worked somewhat...anyway I have now moved to a manual boost controller (ball and spring type with boost bleed vent) and have returned the wastegate actuator rod back to factory setting. However its occurred to me that because an amount of boost air is continuously vented from the MBC this lowers the boost pressure available to the wastegate actuator relative to the actual turbo boost pressure determined by the MBC adjustment. Because of this wastegate activation will be delayed which i dont think is desirable as it's a safety valve is it not? I'm thinking that i need to lengthen the actuator rod to lower the pressure required for wastegate actuation so that it will function to protect the engine from unsafe boost levels.

Or am i overthinking this ...?

Way over thinking it...

And adjusting the rod isn’t crude the MBC is crude - just a bleed screw

Once you’re set it then becomes redundant.

Thanks Toombie..... once the MBC is set the wastegate is redundant - is that what you're saying?

Once the MBC is set you’ll likely never use it again.

Originally Posted by onebob

... I have now moved to a manual boost controller (ball and spring type with boost bleed vent) and have returned the wastegate actuator rod back to factory setting. ...

The active boost control managed by the ECU through the wastegate modulator is way more efficient than any kind of manual control, if that didnt work well for you(provided the modulator is good) you might have a management or air/boost flow issue which IMO will not be fixed with a manual boost controller

Originally Posted by sierrafery

The active boost control managed by the ECU through the wastegate modulator is way more efficient than any kind of manual control, if that didnt work well for you(provided the modulator is good) you might have a management or air/boost flow issue which IMO will not be fixed with a manual boost controller

Hi SF, i've got not problems that I'm aware of, I'm just being cautious and following your advice for wastegate setting from a past post of yours where MBCs were being discussed...

I have been running a BAS boost box and VDO boost gauge for many years now and are happy with the TD5 performance ..... and with the MBC the boost gauge response is quite different ie almost no lag and boost rise seems quicker but i might just be imagining it

Where did you pick up the boost for the gauge?

The WGM modulator works better IF the stock boost levels are retained.

The stock engine maps have a target boost map which is compared against current boost to generate an error signal that is used in controller code which uses a bias amount and the accumulated error to determine the WGM Duty Cycle.

If you wind up the boost, the measured boost is higher than the target boost and the WGM controller works to reduce boost by decreasing the duty cycle allowing more boost pressure to reach the waste gate.

So winding up the boost by adjusting the arm reduces the effectiveness of the WGM with the result that the partial opening at pressures below the boost level set by the actuator still occurs.

Using a MBC or EBC is actually a better solution (for the moment at least). Because the MBC is preventing boost pressure reaching the actuator until the MBC set pressure is reached it eliminates the problem of "early opening" that winding up the arm introduces.
I'd suggest that this difference is the main reason why people report smoother boost build-up and better spool when they reset the arm to stock and add a external controller.

It's early days at the moment but I've posted some information on the basics of the WGM maps on my site.
I'm currently running with the error accumulating part of the WGM controller code disabled to get a better feel for how the bias component works. I've also been doing some "debugging" with a guy from Chelyabinsk who is tuning D2's for himself and his father. He has since been able to get boost up to 1.56bar with the stock actuator adjustment and no additional controllers and was planning on testing to higher boost levels when he emailed last week.

Even when we get the WGM controller sorted out it is something that will need to be tuned the turbo, remap and boost level to operate well. Basically its going to be the same sort of tuning process used by HALTEC or MOTEC for the boost controller components of their ECU's.

But for "simple and easy" a ball and screw MBC is going to be "less crude" than just winding up the rod.

Should add that the old type of "duration" remaps that were sold by BAS, Alive and Td5Inside until very recently (last 6 months or so) interact as described above. The newer remaps which are more inline with standard load based TdI tuning practises interact differently with the target boost map and can cause boost to overshoot. Until the WGM maps are altered to deal with this an external boost controller is preferable to the WGM.