The best boost controller for a Motec ecu

[Wolf_Tm250]

Hello Mates,

given that many of you know well the Motec ecu,
i'd like to know if you prefer, and why, to let the ecu to control the boost, via stock turbo vsv, or if it's better to use a separate boost controller, for example a blitz id3.
Thank you

[fivebob]

Provided you are prepared to spend some time playing with the settings in the Motec then, IMO, it's the best option for boost control. However using the stock VSV is not the ideal solution, especially if you want to run high boost. This is because it is a two port solenoid and can only be used as a bleed valve. Either after the wastegate actuator, in the case of the stock turbo, or off the line going to the actuator for an aftermarket actuator or external wastegate.

Using this type of boost control means that the maximum boost is determined by the flow through the VSV. This is ideal from the manufacturers point of view as it can limit the maximum boost even of the valve fails in the open position, but is no good if you want to increase the boost. You could drill it out for more flow but this leaves the other problem of the bleed off design, which is that the wastegate will still partially open before the desired boost level is reached, this delays the spool up of the turbo.

A better solution is to get a three port solenoid, which has a bleed port to allow the wastegate to shut when the valve closes. This is placed it between the turbo and the wastegate like most aftermarket controllers. You can do the same with the Motec by using a Delco (GM) boost control solenoid. This is a far cheaper option than an aftermarket Boost controller, especially if you source it from a GM parts supplier, rather than through Motec. Cost is approx $US35+shipping provided you can find a parts supplier that will ship outside the US. Part #'s are;

1997152 Three Port Solenoid (for a GMC Cyclone)
12102747 Connector

I haven't tried to order one from the US before as I couldn't find a supplier that would ship to NZ, but a quick search on the net comes up with http://www.trademotion.com/partlocator/ ... eid=213815 as a possible source, at least they don't specifically say that they don't ship outside the US.

[Wolf_Tm250]

Hi fivebob !

As usual I've to thank you for your definite replies....

Let me clarify a bit, sorry if I haven't done before:

I have an external wastegate and as I suppose, the stock 2 way solenoid valve can only be used as a bleed valve, and not as a relief valve.

Scenario is that I already own a Blitz id3, so what I'm asking is if it's really better how Motec control the boost in comparison to "external" ebc like id3.

Moreover, sitting somewhere I have an A'pex 3 way solenoid valve, the one of the Power fc's boost control kit...

Thank you !

[fivebob]

IMO the Motec Boost control is probably the better choice. However it's not easy to set up to give stable boost control, as ,unlike the new generation of aftermarket controllers, it has no "learning" function. You have to try quite a few combinations of the settings to get it working correctly, and if you drive through large changes of altitude it can become less accurate, though most boost controllers have this problem.

The Blitz iD3 will allow you to do speed dependent boost control with the power meter, so it's slighty better than the average boost controller. However the Motec will also do this as well as allowing restriction of the boost when the engine is cold, or when the intake/engine/exhaust gas temp is too high. With the addition of a variable resistance switch it will also allow for in car boost control, or that compenstaion can be used to alter boost levels when using water injection.

[Wolf_Tm250]

IMO the Motec Boost control is probably the better choice. However it's not easy to set up to give stable boost control, as ,unlike the new generation of aftermarket controllers, it has no "learning" function. You have to try quite a few combinations of the settings to get it working correctly, and if you drive through large changes of altitude it can become less accurate, though most boost controllers have this problem.

The Blitz iD3 will allow you to do speed dependent boost control with the power meter, so it's slighty better than the average boost controller. However the Motec will also do this as well as allowing restriction of the boost when the engine is cold, or when the intake/engine/exhaust gas temp is too high. With the addition of a variable resistance switch it will also allow for in car boost control, or that compenstaion can be used to alter boost levels when using water injection.

Ok, I perfectly understood what you mean, and given that you didn't mention, spool up velocity must be the same in the two systems.

Thank you.