I bought a Citroen ibooster GEN2 and have some questions

[jrbe]

I meant it more as a lazy adjustment to make some random stack up of brake pedal to master cylinder parts work vs shimming things up / adjusting it properly so it gets it's full range.
I'd be very surprised if the booster was the short straw in travel.

I don't mean to sound harsh but I don't trust a YouTube video for info. I take sourceless info with a 55 gallon drum of salt.

It irritates me how partially-discovered all this stuff is.

We're using parts out of their original design. Some of this stuff is likely broken down in troubleshooting manuals but might need to be adapted. Some is locked down OEM for safety.

This is speculation but there might be an expected travel to pressure map for the OEM application that likely doesn't match it's new usage. If it's adjusting the boost on the fly it might need this expected travel to pressure to do it's thing quickly and smoothly.

[MattsAwesomeStuff]

I don't mean to sound harsh but I don't trust a YouTube video for info. I take sourceless info with a 55 gallon drum of salt.

Well, the guy spent 7 months reverse engineering the iBooster CAN protocol and sells brake-by wire kits with his own replacement controller.

I think he probably understands more about the iBooster than anyone except those who designed it.

[jrbe]

I've seen Seb's work on this previously. The can bus reverse engineering side is impressive but the whole might be missing some critical things. I don't mean it as a knock, just that it isn't fully worked out yet from my point of view.

The backstop recommendation was mentioned for the remote brake request potentiometer. Sounds like it was just for testing out of the car with missing back pressure from the system so it doesn't error out and stop working was the gist of it.

It's very odd to me that excessive travel would cause a no brake assist error / shutdown mode. I can't imagine a scenario where Bosch saw this as acceptable. If it's hitting it's travel limit it should only stop pushing harder at that point, not go out of service. If there was a brake failure you don't want a second failure on top of it. I'd say there's something wrong or missing that allowed / allows this to happen.

This splits into 2, one for mechanically pushing on the pedal, and potentiometer request brake travel.

Mechanical pushing - Again, I can't imagine it going into shutdown from full pedal travel. It's a dangerous choice to just have the booster shut down.

Potentiometer requested travel - the booster may be sending warning info on the travel limit, motor overload, etc. that the requesting controller should be accounting for. Asking for more after this limit may put it in an ignore the potentiometer / travel request mode. This is of course a guess of what's going wrong to trigger this. But it makes 0 sense that now that self drive has put the booster in an error mode then hands the controls back to the driver but without brake assist. Still seems odd that Bosch would be ok with this shutdown / error mode and is very dangerous.

Sounds to me like something is very wrong here. I wouldn't use it until I had worked out what it is.

[AMP3R]

Today I discovered that the master cylinder is preloaded about 1 mm by default without any power being applied to the ibooster. So it means that preloading the push rod isn't a bad idea. It has a little free play which is needed for the calibration of the travel sensor.

[MattsAwesomeStuff]

Today I discovered that the master cylinder is preloaded about 1 mm by default without any power being applied to the ibooster. So it means that preloading the push rod isn't a bad idea. It has a little free play which is needed for the calibration of the travel sensor.

That would be excellent info to add to the wiki.

[jrbe]

Today I discovered that the master cylinder is preloaded about 1 mm by default without any power being applied to the ibooster. So it means that preloading the push rod isn't a bad idea. It has a little free play which is needed for the calibration of the travel sensor.

Is this a part of the code in the booster, a recommended mechanical spec, or an error?

You have to be careful preloading a brake master cylinder. At some travel point it blocks the port to the brake fluid reservoir. This means as the brakes / fluid heat up the system builds pressure when there should be none and the brakes drag.

Bosch making the ibooster and the brake master cylinder means they know exactly what their tolerances are and how much they can safely preload the brake master cylinder. Adding more to this might put it past the reservoir port.

[AMP3R]

Is this a part of the code in the booster, a recommended mechanical spec, or an error?

You have to be careful preloading a brake master cylinder. At some travel point it blocks the port to the brake fluid reservoir. This means as the brakes / fluid heat up the system builds pressure when there should be none and the brakes drag.

Bosch making the ibooster and the brake master cylinder means they know exactly what their tolerances are and how much they can safely preload the brake master cylinder. Adding more to this might put it past the reservoir port.

I know a guy (Filip Kossakowski) who is an engineer at Bosch automotive in Poland. He was developing and testing ibooster gen2. I think the best way to know info about preloading is to ask him. I'll try again.

[MattsAwesomeStuff]

I know a guy (Filip Kossakowski) who is an engineer at Bosch automotive in Poland. He was developing and testing ibooster gen2. I think the best way to know info about preloading is to ask him. I'll try again.

... I would absolutely abusively take advantage of this relationship. Kidnap and interrogate him

So many questions.

[AMP3R]

... I would absolutely abusively take advantage of this relationship. Kidnap and interrogate him

So many questions.

If someone has linkedin please contact him. I don't have access to private messages there. https://pl.linkedin.com/in/filip-kossakowski-6270a6153

[woutvanschaik]

What have you wired up, please show us? did you wire the 4 pin position sensor?

eventually got it working. seems that the wiring of the toyota is a bit different. it also has a different connector compared to other gen2 iboosters. the wiring should be the same as other gen2 iboosters, except the sensor. sensor should be wired as follows:
main connector pin 2 --> position sensor pin 3
main connector pin 8 --> position sensor pin 1
main connector pin 22 --> position sensor pin 4
main connector pin 23 --> position sensor pin 2

[MattsAwesomeStuff]

eventually got it working. seems that the wiring of the toyota is a bit different.

Please make sure this ends up in the wiki!

[AMP3R]

I was tired of struggling with PSA software and, in order not to suffer, I bought another iBooster from the 2022 Tesla M3. I plugged it in and there was complete silence! No clicking every 5 seconds! And as a bonus I got the opportunity to do an adaptive cruise if desired. At PSA this is still done by the ESP.

In short, this topic is no longer relevant to me. I’ll assemble one ibooster from the two and it can be screwed onto the car.