New booster option for e30 - Bosch iBooster

[hubcapboy]

The i3 and x3 masters looks like they have a smaller diameter "plug" on the interface into the booster. They certainly aren't the same shape (there's a side-shot of mine separated on the first page).

I haven't taken my pedal linkage apart or taken a good look at it. We're going to need to lengthen it, if anyone wants to take a look at how best to do that.

I'm also curious what the Tesla hard line flares look like if you unscrew one. I think they're M12 ISO double flares (not bubble flares). I ordered the wrong adapters the first time.

If I was stuck with a LHD master and didn't think I'd have room for the ports on the engine-side, I think I'd try attaching to the reservoir ports and mounting it upside down. This is a similar idea:



There shouldn't be any pressure there other than the head from the remote reservoirs, and as long as they're mounted above the master the cylinder won't know which way up it is.

This would put your outlets on the fender side and your reservoir connection on the bottom. It would actually give you *even more* room because the next closest interference if you're doing something crazy like ITB's is probably the reservoir tank. It would also open up your shopping options to any ibooster master with the right diameters, because the shape of the reservoir is no longer important.

You could even use the Chevrolet Bolt master, which is super goofy and at 45 deg rotation:

https://www.ebay.com/itm/2016-2017-C...gAAOSwUORd~Q2b

(before you get too excited about that whole thing being $83 with the booster and everything... that one's different at the firewall, although it does suggest that sourcing a replacement "booster" out of the middle of your RHD assembly is going to be cheap going forward.

[nando]

RHD Model S booster in. Anything you folks wanted as far as measurements?

Looks clean, nice score on the RHD master cylinder. Mine will be here within the hour (LHD though). Can't wait to mess with it. :)

[nando]

The X3/X4 MC looks promising as well:
https://www.ebay.com/itm/2011-2015-B...3/143761928740

I can get both an i3 *and* X3 MC for less than the cost of shipping a RHD Model S MC from Australia.. so I might just go for it. Brand new X3/X4 MCs are like $100, and I'll bet the Model S reservoir will fit. if it works you guys can thank me later :p

[Bored]

RHD Model S booster in. Anything you folks wanted as far as measurements?

[hubcapboy]

Tough to say without getting one in hand, but looking at the photos did make me think that threading the reservoir bungs and remote-mounting the reservoir could be an option... then you could just run the master cylinder inverted as well.

[nando]

I'm convinced that somewhere, there exists another MC that's not necessarily Tesla, fits the same bolt pattern as the gen 1 ibooster, and has a bore suitable to the E30 with the ports on the correct side.

For one, these kinds of parts don't get made in a vacuum. Tesla buys from suppliers like everyone else - suppliers who want to save as much capital on tooling and designs as possible.

So the same reason this bolts into the same firewall pattern as the E30 (and every BMW since the dawn of time, apparently), there must be more than one MC that bolts to the ibooster.

Anyway, just wasting time on a google image search, I think the i3 MC is a potential candidate - and, it's cheap. Thoughts? Part # 34336858911

https://ebay.us/DGb7Yh

[Trevbot]

It's far more hazardous to the safety of other road users to cobble together hydroboost systems from junkyard parts, use outright dangerous chase bays single circuit master cylinders, or build iffy looking unengineered remote booster setups, than it is to install a twin or tandem cylinder manual brake setup with more pedal travel which can still lock the brakes on dry pavement without undue effort.

This solution is not a hydroboost, has dual circuits, was engineered by bosch to mount directly to the firewall on an identical flange to the E30, and retains factory ABS. All the reasons you have listed are exactly why we are pursuing this.

Also, some things are not adequately protected from water intrusion in all orientations, something further to look into is to sure to make sure it is well sealed in the inverted position and shielded if it is not.

If you read the whole thread you would know it is used in the "inverted" orientation in a RHD model. Actually its on the first page.

[hubcapboy]

Hi.

So, I don’t want to start a fight. We’ve just already had one item that wasn’t a brake booster posted here. Maybe I should have said “he” instead of “you.” I imagine that more than one person other than you might be reading my reply, so I just thought I’d clarify a huge reason why this is an advantage over manual braking: no increase in pedal travel.

Im really, really, sorry that I rounded to 3. It’s actually not 2.7 either if you’d like to go back up and edit again. We could just keep adding digits if you want.

https://www.r3vlimited.com/board/forum/general-forums/members-rides/the-project-forum/368510-1991-diamantschwarz-318is-slicktop-231hp-na-m42?p=9943204#post9943204

Since we’re being so precise, it’s unclear why you think I’d say “it was mentioned in exactly one thread” if it hadn’t been mentioned in exactly one thread.

[nando]

If you've got so much water under the hood that the brake booster is getting soaked.. I think you have bigger problems than worrying about the brake booster.

Calm down dude.. but thanks for the informative post. I think everyone here knows how manual brakes work. My first car had manual brakes from the factory - I'll just say, no fucking thanks.

[varg]

It was mentioned in exactly one thread, but it didn’t sound like they’d installed it yet (and they had a gen2).

No. There have been other mentions of other electric boosters in other threads and gross misunderstandings of the equipment and its installation. Last time I saw them come up I had to point out that what was being discussed was not a booster at all. Luckily you know what you're talking about.

You’ve linked a manual pedal box... the reason the bores are so small is to give you mechanical advantage for braking. Changing the pivot point and lever length on the brake pedal can do the same thing.

Why yes, it is a manual pedal box. I'm glad you pointed that out to me I didn't know that furthermore, nobody suggested going straight to 14mm from stock size just pointed out that there's a massive range of sizes available which make pedal effort an easily remedied problem. It isn't necessary to try and "triple" (going from 23 to 14mm would be a 2.7x change, not 3x), it is only necessary to bring brake force down to a level that is streetable to the driver(s) of the vehicle. I am more than aware of the intricacies of how a braking system works are and have corrected others here and called out chase bays for misrepresenting their single circuit master cylinder kit. Unfortunately they continue to do so...

While they are not for everyone, there is nothing wrong with manual brakes in modified street cars as long as they are done correctly, and I assure you that having driven in a pinch with a failed check valve and disconnected line that it isn't remotely necessary to try and triple the hydraulic advantage unless you're trying to configure your engine swapped E30 for that 5th percentile of women from that 1970 NBS study on brake force, a difference of less than 2x is necessary. Nor does an increase in pedal travel in an unboosted car have quite as dramatic an effect as you imply. It's far more hazardous to the safety of other road users to cobble together hydroboost systems from junkyard parts, use outright dangerous chase bays single circuit master cylinders, or build iffy looking unengineered remote booster setups, than it is to install a twin or tandem cylinder manual brake setup with more pedal travel which can still lock the brakes on dry pavement without undue effort. I hope you get the electronics side of it working correctly and that it's simple to configure, but there is always this cheap, safe and effective option for all kinds of swaps.

Also, some things are not adequately protected from water intrusion in all orientations, something further to look into is to sure to make sure it is well sealed in the inverted position and shielded if it is not.

[hubcapboy]

I haven't seen any swaps on r3v that use this, but it seems like a reasonable alternative to these more complex booster solutions that keep popping up and not actually being pursued. https://www.compbrake.com/product/bm...ylinder-kit-b/ bore sizes down to 14mm are available in this style of AP racing master cylinder, so there is no doubt that you could easily get pedal force down to a reasonable level.

It was mentioned in exactly one thread, but it didn’t sound like they’d installed it yet (and they had a gen2).

You’ve linked a manual pedal box... the reason the bores are so small is to give you mechanical advantage for braking. Changing the pivot point and lever length on the brake pedal can do the same thing.

The disadvantage of a manual brake system is you get the power by adding pedal travel. Stepping down from a 23mm master to a 14mm will give your roughly three times the braking power, but at the expense of three times the pedal travel.

The new opportunity here with the Bosch electric booster is that it will clear *any* 24v intake manifold, retains power brakes, retains the dual-circuit brake system (a safety feature where the front and rear brakes are on completely separate circuits in case you blow a brake hose), retains factory ABS (which the forward located e34 booster deletes it) and doesn’t require any firewall modification.

[varg]

I haven't seen any swaps on r3v that use this, but it seems like a reasonable alternative to these more complex booster solutions that keep popping up and not actually being pursued. https://www.compbrake.com/product/bm...ylinder-kit-b/ bore sizes down to 14mm are available in this style of AP racing master cylinder, so there is no doubt that you could easily get pedal force down to a reasonable level.

[hubcapboy]

Unless the MC is rebuildable, drilling isn’t an option. I have a spare MC I’ll try and disassemble to see what’s going on inside, but if you have to drill into the bite it’ll have to be rehoned to clean it up... and if you don’t you’ll still have to have it totally disassembled to clean after drilling.

[nando]

yeah, I suppose I could always pick up a RHD MC later. I was thinking the idea of drilling and tapping the left hand side wouldn't be so difficult - just need a brass fitting with the right female end for the E30 lines. It doesn't look like it would clear the 3-stage installed on the right side, although I could still put it in right now as it would clear the M20 manifold by a mile.

[hubcapboy]

hoveringuy means he was pushing the pedal on mine in the driveway.

https://www.ebay.com/itm/331605500736

These guys appear to make the right adapter. I have a set and will be testing them soon (but with a RHD master because of my intake manifold).

I have no idea what condition the calipers are in on my parts car... I don’t know if it’s worth plumbing it’s up other than to check the adapter.

Honestly if my parts car wasn’t blocking my driver in the garage I probably would have installed it on the driver (the head gasket would hold up for a trip around the block).