iBooster Electric Brake Booster

[Chkn]

I've been scouring my ass off and finding this master cylinder has not yeilded anything yet.
There are a literal TON of theses setups for sale by all the usual suspects, but they are pretty generic, no brand name etc.
Scott Drake sells one already configured for a mustang.

Spent some time trying to find more information and I have yielded the same results. Lots of companies selling the same kit but with it branded in their own name.

I did find ZF makes some master cylinders called "Boosted Master Cylinders". But there's not a lot of information related to price, only to send in inquiries.
Boosted Master Cylinders | ZF MICO

The 3rd gen 2010-2015 Prius uses a similar master cylinder. I believe the master cylinder bore is about 7/8" which isn't huge but might work for a smaller weight vehicle. Hydraulically the master cylinder uses a spool valve to increase master cylinder pressure. Only problem is that the master cylinder is bolted to the ABS unit. It looks like they can be separated but then a machined adapter would have to be made to replace the ABS unit and seal off the master. Next time I'm at the junkyard I would like to grab one for cheap and tear it apart.

 

[CarterKraft]

Spent some time trying to find more information and I have yielded the same results. Lots of companies selling the same kit but with it branded in their own name.

I did find ZF makes some master cylinders called "Boosted Master Cylinders". But there's not a lot of information related to price, only to send in inquiries.
Boosted Master Cylinders | ZF MICO

The 3rd gen 2010-2015 Prius uses a similar master cylinder. I believe the master cylinder bore is about 7/8" which isn't huge but might work for a smaller weight vehicle. Hydraulically the master cylinder uses a spool valve to increase master cylinder pressure. Only problem is that the master cylinder is bolted to the ABS unit. It looks like they can be separated but then a machined adapter would have to be made to replace the ABS unit and seal off the master. Next time I'm at the junkyard I would like to grab one for cheap and tear it apart.

Good info, I was hoping to find something like that just to see exactly how it was working.
I was curious about making a hollow hydraulic cylinder to mount between the master cylinder of choice and the pedal assembly. That would allow you to have a really universal system but obviously there is more to it than just a cylinder...

 

[snivilous]

Superduty master update:

I actually ended up going with a plate to rotate the master relative to the booster to get it to package how I wanted. Lots of ways to do that, but I got 3/8" of plate and welded some nuts where the master would clock to, and then the booster side was retained with its normal studs. This is a bit more elegant too than the previous method I outlined earlier.

With the position I clocked the master I had to remove the reservoir which is absolutely huge. It would be really easy to make a new reservoir since a large barbed fitting (I think I had some 1/2" or 5/8" ones that seemed like a perfect fit) can slide right into the rubber grommet on the master feed ports. However as a temporary solution I just flipped the reservoir 180deg and then it cleared the big plug which was my clearance issue. There's a roll pin and two clips (one per side) that hold the reservoir down, and annoyingly the clips are barely off center so don't work if you flip it around. With that said, the reservoir is very firmly held in by the rubber grommet and the plastic barbs going into them. For the time being I just ran a zip tie through the plastic clips that no longer engage anything so the reservoir can't come off vertically.

Onto the good stuff, the brake feel is WAY better. The pushrod off the booster has about 0.75" of motion (out of an available 1.25") before it runs into a wall. I'm not sure what's going on, my wife said the wall would disappear only when we were bleeding the front brakes. In practice you get pretty good braking up to the wall, and then if you really push on it there is more to be had but you really have to shove on it. This is in stark contrast to the car master which had effectively no feel and you could bottom it out very easily.

My brake pedal ratio is around 4:1 currently, braided lines the whole way, no proportioning valve.

Overall it feels a lot better, though I must admit I expected it to be easier to lock up the brakes. The car master would lock the tires up in a discomfortingly easy manner, where as this will also lock them up but requires a lot more effort to do that. The braking zone before lockup feels great, and lockup I wouldn't say is hard, but a kid for example couldn't lock the tires up where as they could with the car master no doubt. I've only done one test drive for ~30 miles, but I like it a lot, and even though it requires a bit more effort than expected to lock up the brakes the flip side is it's a noticeable force increase required to do it so it doesn't sneak up on you. For going fast I like that, for crawling I could see a higher pedal ratio being nice to not have to work so hard, we'll see if I continue that philosophy once I get it out in Sand Hollow.

 

[Gumbybronco]

Superduty master update:

I actually ended up going with a plate to rotate the master relative to the booster to get it to package how I wanted. Lots of ways to do that, but I got 3/8" of plate and welded some nuts where the master would clock to, and then the booster side was retained with its normal studs. This is a bit more elegant too than the previous method I outlined earlier.

With the position I clocked the master I had to remove the reservoir which is absolutely huge. It would be really easy to make a new reservoir since a large barbed fitting (I think I had some 1/2" or 5/8" ones that seemed like a perfect fit) can slide right into the rubber grommet on the master feed ports. However as a temporary solution I just flipped the reservoir 180deg and then it cleared the big plug which was my clearance issue. There's a roll pin and two clips (one per side) that hold the reservoir down, and annoyingly the clips are barely off center so don't work if you flip it around. With that said, the reservoir is very firmly held in by the rubber grommet and the plastic barbs going into them. For the time being I just ran a zip tie through the plastic clips that no longer engage anything so the reservoir can't come off vertically.

Onto the good stuff, the brake feel is WAY better. The pushrod off the booster has about 0.75" of motion (out of an available 1.25") before it runs into a wall. I'm not sure what's going on, my wife said the wall would disappear only when we were bleeding the front brakes. In practice you get pretty good braking up to the wall, and then if you really push on it there is more to be had but you really have to shove on it. This is in stark contrast to the car master which had effectively no feel and you could bottom it out very easily.

My brake pedal ratio is around 4:1 currently, braided lines the whole way, no proportioning valve.

Overall it feels a lot better, though I must admit I expected it to be easier to lock up the brakes. The car master would lock the tires up in a discomfortingly easy manner, where as this will also lock them up but requires a lot more effort to do that. The braking zone before lockup feels great, and lockup I wouldn't say is hard, but a kid for example couldn't lock the tires up where as they could with the car master no doubt. I've only done one test drive for ~30 miles, but I like it a lot, and even though it requires a bit more effort than expected to lock up the brakes the flip side is it's a noticeable force increase required to do it so it doesn't sneak up on you. For going fast I like that, for crawling I could see a higher pedal ratio being nice to not have to work so hard, we'll see if I continue that philosophy once I get it out in Sand Hollow.

Thanks for the update.
I look forward to you getting this dialed in. And I’ll likely copy your setup.

 

[CarterKraft]

Spent some time trying to find more information and I have yielded the same results. Lots of companies selling the same kit but with it branded in their own name.

I did find ZF makes some master cylinders called "Boosted Master Cylinders". But there's not a lot of information related to price, only to send in inquiries.
Boosted Master Cylinders | ZF MICO

The 3rd gen 2010-2015 Prius uses a similar master cylinder. I believe the master cylinder bore is about 7/8" which isn't huge but might work for a smaller weight vehicle. Hydraulically the master cylinder uses a spool valve to increase master cylinder pressure. Only problem is that the master cylinder is bolted to the ABS unit. It looks like they can be separated but then a machined adapter would have to be made to replace the ABS unit and seal off the master. Next time I'm at the junkyard I would like to grab one for cheap and tear it apart.

Noticed this setup on a NV3500 Nissan van, seems similar in design with "servo" name call out. 2017-2020 maybe.

 

[fl0w3n]

For going fast I like that, for crawling I could see a higher pedal ratio being nice to not have to work so hard, we'll see if I continue that philosophy once I get it out in Sand Hollow.

if you were only concerned about crawling, you’re saying you’d step up to a higher pedal ratio on the SD master instead of just going back to the car master?

 

[snivilous]

if you were only concerned about crawling, you’re saying you’d step up to a higher pedal ratio on the SD master instead of just going back to the car master?

Yes, possibly. I haven't taken it crawling yet to see if the pedal ratio I have is too low, I was just thinking if you're parked on a steep incline for a couple minutes is the effort required annoyingly high.

I like the SD master a lot more than the car master no doubt, for a small buggy though just crawling it's a toss up. I have a buddies rock lizard in my shop with Toyota axles, I would think the car master on that would be perfect. The super duty brakes are kind of on the border for the car master, it was able to brake but felt like it was on the limit of pushing enough fluid sometimes. But if packaging is a problem, I would be hard pressed to use anything besides the car master since it's so tiny and I ran it for a year without issue.

Also keep in mind I run soft lines the entire way.

 

[HYDRODYNAMIC]

Yes, possibly. I haven't taken it crawling yet to see if the pedal ratio I have is too low, I was just thinking if you're parked on a steep incline for a couple minutes is the effort required annoyingly high.

I like the SD master a lot more than the car master no doubt, for a small buggy though just crawling it's a toss up. I have a buddies rock lizard in my shop with Toyota axles, I would think the car master on that would be perfect. The super duty brakes are kind of on the border for the car master, it was able to brake but felt like it was on the limit of pushing enough fluid sometimes. But if packaging is a problem, I would be hard pressed to use anything besides the car master since it's so tiny and I ran it for a year without issue.

Also keep in mind I run soft lines the entire way.

How is the comparison between the two with no power. Is the SD MC too big for the 4:1 pedal?

 

[snivilous]

How is the comparison between the two with no power. Is the SD MC too big for the 4:1 pedal?

Just pushing on it in the shop I think it'd be hard if not impossible for a normal person to stop/hold the brakes on much of an incline at 4:1

Which makes sense, for a brief time I had a 1.125" Wildwood master at 7 or 8:1 and I didn't like that enough that I went down the ibooster route, so 1.250" at 4:1 gut checks from that of being extremely hard to do.