New booster option for e30 - Bosch iBooster

[hubcapboy]

I took a chance on the Model S booster because it eyeballed to the right size. The Gen 2 booster from the model 3 does NOT have the same firewall pattern. Lars has that documented here:

https://www.evcreate.nl/installing-the-ibooster/

The master cylinder with the ports on "our" side from the Gen2/model 3 also will not fit the Gen 1. If you look at the ears, the two bolts between the master and booster are clocked 90 degrees when comparing the two. (ok... MAYBE it would fit, but the booster would be sideways which doesn't help fitment of the Gen1... it's taller than it is wide)

Lars figured out the RHD/LHD difference as well:

https://www.instagram.com/p/B1DXLYxIj3K/

We're definitely playing catch-up to him here.

I will happily take measurements from anywhere to anywhere. I think it would be useful to have a "silhouette" drawn of the two firewall bolts and the outline of the booster (to scale) so people can print it out to mock up.

Regarding the amount of work to tap for lines on the left... RHD masters are of course very scarce, but to avoid the seat problem and to avoid having adapters stickout out of adapters on the side of the master, facing, drilling, and tapping could make the unfinished side of the master suitable for a banjo bolt. As long as the master cylinder is rebuildable and you can get it apart, that's the kind of thing you can do with a drill press.

That delorean thread is exactly what I stumbled upon, and oudevolvo on that forum is Lars :)

[hoveringuy]

You pretty much covered it. Lots of labor.

I disagree..

Just drill and tap for 3/8-24 and install an adapter to 4.75mm bubble flare.

[nando]

Digging through some EV forums - I found a store that you can buy the connectors, pins, etc - possibly a lot cheaper than sending them from the UK for like $150.
https://store.chiefenterprises.com/1...-Way-Connector

It looks like they have the cover, pedal travel connector, pins, seals, etc. And it seems cheap enough.

http://dmctalk.org/showthread.php?16214-Bosch-iBooster-Retrofit

[nando]

You pretty much covered it. Lots of labor.

The LHD Model 3 MC has the ports on the right side for us, as does the RHD Model S. Probably not worth machining the LHD Model S MC given the costs.

[nando]

One last thought - how different is the E30 master cylinder end from the ones that fit into the iBooster?

[tyeler18]

Can you take a measurement from the inboard most stud on the booster, to the inboard most point on the booster? I think the heads on my LS in my car occupy about where this would bolt to the firewall, but I'd be curious to see how much I'd need to shift it over for it to work.

I applaud you for digging into this more, I've been eyeing this swap since it was mentioned but I have a remote hydroboost in the car so I never pursued it very far. I'd like to ditch the cluster with the remote booster and this is the most ideal way to do so.

[LukeJ]

I’m definitely looking into tapping it on the other side. I don’t have any experience with this kind of machine work, but I expect it would require disassembling the cylinder, facing the casting, drilling and tapping the threads, and cutting the seat for the flare... and then probably re-boring the cylinder to clean up the mess?

Its harder than drilling and tapping for a bolt, certainly.
LukeJ might be the guy to answer that.

You pretty much covered it. Lots of labor.

[nando]

I need to get back to working, but this PDF has a lot of information about the iBoost system in general - the main topic is about sudden acceleration on Teslas and other electric vehicles, which apparently is caused by the iBoost/regen system, but that doesn't apply to us of course. Skip to the appendix and there's an explanation of how the brake force transfer curves work.

This thing is definitely programmable. I'm guessing it has a security key, so you'd have to crack that first. Of course, the programming in the model S could be well perfectly acceptable for the E30. I think if anything, it will feel overboosted, but given the 25mm vs 23mm master cylinder, I'll bet that ends up being a wash.

[nando]

How about the Model 3 booster? Firewall end looks the same? There are way more Model 3 than Model S - should be cheaper/easier to find:


Looks like the Model 3 uses the 2nd gen iBooster.

[nando]

I should have read the above posts first. lol.

yeah, this looks pretty much bolt on. The level switch is probably easy to implement.

Now how about the pedal travel sensor? (edit - had a look - it's built into the booster, no need to mess with it, maybe it just needs power?)



What adapters do we need for the brake lines, or maybe just swap out the ends on the stock E30 lines?

Also, the Model X is pretty similar to the Model S. I'll bet they come with the same booster, although it's heavier so the MC might be different.

[nando]

sure enough:

[nando]

It sure looks to me like that part is dual purpose - the holes are probably milled on one side or the other depending on the application. RHD perhaps?

[moatilliatta]

Anyone check other US electric parts car diagrams for a MC with opposite facing ports?

[hubcapboy]

I’m definitely looking into tapping it on the other side. I don’t have any experience with this kind of machine work, but I expect it would require disassembling the cylinder, facing the casting, drilling and tapping the threads, and cutting the seat for the flare... and then probably re-boring the cylinder to clean up the mess?

Its harder than drilling and tapping for a bolt, certainly.
LukeJ might be the guy to answer that.

[hoveringuy]

How difficult would it be just to tap the correct port size on the blank side and plug the other one?