Thread: TD5 Boost Limit Box group buy

What boost will this unit allow before the engine limits boost?

Originally Posted by Slunnie

What boost will this unit allow before the engine limits boost?

The box will allow you to run any boost you require,althow i only recomend 17.5-18psi max as there are other limiting factors on the TD5 engine that will cause problems if more than that is run continuously.


Regards Pete

Originally Posted by B-A-S

The box will allow you to run any boost you require,althow i only recomend 17.5-18psi max as there are other limiting factors on the TD5 engine that will cause problems if more than that is run continuously.


Regards Pete

As the TD5 in the D2 already allows about 19psi due to the ecu controlling the boost modulator, how can this device be of any benefit on such a vehicle?

The D2 running the modulator allows a combined atmospheric and charge pressure of upto 242Kpa to be seen in the inlet manifold for no more than 400ms before it gives limp boost and fuel cut which is 10Kpa and 20Mg of fuel at the same time as running a base maf reading of 100Kpa which is actualy atmospheric pressure.

BUT it ONLY allows this if controled/made by its self in certian scenarios it does not run this pressure all the time and does not allow it to be mechanicly done by a third party.

So yes you can run more boost than standard with mechanical adjustments but the side effects that happen are more than most think.

Regards Pete

Originally Posted by B-A-S

The D2 running the modulator allows a combined atmospheric and charge pressure of upto 242Kpa to be seen in the inlet manifold for no more than 400ms before it gives limp boost and fuel cut which is 10Kpa and 20Mg of fuel at the same time as running a base maf reading of 100Kpa which is actualy atmospheric pressure.

BUT it ONLY allows this if controled/made by its self in certian scenarios it does not run this pressure all the time and does not allow it to be mechanicly done by a third party.

So yes you can run more boost than standard with mechanical adjustments but the side effects that happen are more than most think.

Regards Pete

I can definitely verify that statement. After a new fuel map was loaded my car (Disco TD5 Auto) actually had less get up and go than standard.

Would appear that the increase boost of the new fuel map was triggering this "self detune" point. I was recording around the 240kpa quite quickly then performance was very flat at best. After lengthening the waste gate control rod it’s back around 225-230 and now goes unbelievably well, so mechanical adjustments will make it worse once that magical point is crossed. My understanding is that The Boost Box modifies the signal returned to the ECU from the sensor essentially forcing the ECU into thinking there is still not enough boost.

I originally shortened the waste gate control rod after reading some misguided advice on this forum – how much trouble and time did that waste!

And before someone asks - I am NOT associated in any way with Pete (B-A-S) or Mike (Tombie2), I’m just one very satisfied (overpowered) TD5 customer.

Regards Craig

Originally Posted by B-A-S

The D2 running the modulator allows a combined atmospheric and charge pressure of upto 242Kpa to be seen in the inlet manifold for no more than 400ms before it gives limp boost and fuel cut which is 10Kpa and 20Mg of fuel at the same time as running a base maf reading of 100Kpa which is actualy atmospheric pressure.

BUT it ONLY allows this if controled/made by its self in certian scenarios it does not run this pressure all the time and does not allow it to be mechanicly done by a third party.

So yes you can run more boost than standard with mechanical adjustments but the side effects that happen are more than most think.

Regards Pete

I'm referring to the factory setup where the wastegate actuator is meant to be set to 1 bar when operated directly by the turbo's boost pressure, yet the ecm allows up to approx 19psi, albeit under controlled circumstances.

Originally Posted by Graeme

I'm referring to the factory setup where the wastegate actuator is meant to be set to 1 bar when operated directly by the turbo's boost pressure, yet the ecm allows up to approx 19psi, albeit under controlled circumstances.

I fully apreciate what you are stating and it possibile from logging data from the ecu you may see some of this information but belive me side effects will be present.

I prefer not to get into a forum debate on the electronics of this car as it will take me ages to type out and explane the running stratgies of this car and the reasons for them etc etc.

All i can say in short, is what i already have and the box works and does what is says on the tin.


Some info on the standard modulator for reference if any one is intrested

The turbo wastegate modulator allows the pressure required to open the wastegate valve to be alterd so boost pressure can be controled as it desires.

This actuator requires a PWM signal from the ecu to operate correctly.
The valve operates at a fequency of less than 50Hz.

Vsat(A21 to GND) Isink=0.40A max 0.19V
Current trip level (assuming load variation of -+10% min 2.6-12A
+ve Clamp voltage@Isink=10mA (Drive Off) Max Vbatt+1.5
-Ve Clamp Isink= -10mA -1.5V


Regards Pete

ive been running one of pete's units for over 12months now and i can report no dramas what so ever, extremely easy to fit also.

works really well with the IC and upgrade.

cheers phil