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Ken Block’s Group A Cossie Boost Control

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I’ve watched the quick video that mentions how this set up works, but is there any in depth info to how this is plumbed? What sort of situation this set up would be advantageous (high boost/low boost?, large boost spread?, high accuracy of boost control?, etc)? And any other links to some more reading about this set up and it’s implementation within an ecu (running on a pwm channel or an injector driver)?

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The "Air Injectors" seem to just be a left over from the 80's when there werent any other readily available solenoid valves that gave good response. It was made popular in the cosworth sierra's that used a Pi/pectel board in the weber ecu and it just seems to have hung around in that fraternity. Pectel call it phase/antiphase wastegate control and give you two tables so you can control the two valves separately - but every map I have ever seen using this system has always had them just set up as exact inverse of each other anyway - so effectively achieving exactly the same effect as a 4 port mac valve or two 3 ports plumbed opposite. If set up right I suspect it may give you some extra flexibility compared to a more traditional set up but it seems to be rarely done.

I have only seen the strategy in English ecu's Cosworth/Pectel and Life racing.

I have been thinking through a project car - what i want out of it, things i want to learn, things i want to build, things i want to do with it.

My thought is a FWD drag car. Which with things like boost by gear, and really low boost pressures at launch with relatively high boost pressures at the big end, there is potential for a pretty large boost spread driving a fairly light wastegate spring and the need for pretty accurate boost control for the boost by gear to be able to tune for the traction conditions at the track is a must.

I like to tinker and i like to build things, sometimes for the hell of it. But the main goal of my project car is personal learning. Would a set-up like this be something worth pursuing with those goals in mind or would a 4 port be a more sensible option and put my time in some other area?

My plan is to run an ECUmasters EMU Black with a PMU16, so I'm not even sure I could have that strategy you mention with it.

For the high powered drag racing stuff the more modern approach seems to be dual solenoid dome pressure control - often using bottled CO2. The idea with this method is you are only trying to control the small dome volume inside the wastegate chamber so it is much more predictable and controllable compared to trying to control the manifold pressure which is highly dynamic and has significant latency due to the volume. You can get usually get more stable control of boost pressure during dynamic situations such as 2 step, launch etc.

Unfortunately I dont think the EMU can do either the phase/antiphase control or CO2 dome pressure control so you will likely have to stick with the conventional approach anyhow.

Hi Matt,

You may find this useful: https://d28lcup14p4e72.cloudfront.net/178729/3977821/MQ12Di%20Wastegate%20Control%20Application%20Note.pdf

This is an overview of the wastegate control options in the ECU that the aforementioned Cossie runs.

As said above, running 2 3-ports in Phase/Antiphase is very similar to running 1x 4-port, however you have a little more control as you can modify the duty transfer function per valve.

Leave the EcuMaster and switch to an ECU with considerably more control. Cosworth/Pectel SQ6 isnt massive money, the boost control / knock control is miles ahead as well as the rest of the product.