DIY Electric Car Forums banner
1 - 6 of 6 Posts

·
Registered
Joined
·
7,937 Posts
Interesting, I hadn't heard about that. Looks like there's no pancake booster thingy, seems fairly compact.
Right - no vacuum assist unit.

I was considering the mechanical booster that's on teslas and a few others (it's a bosch unit I think).
The one used by Tesla (and many other companies, for EV, hybrid, and ICE applications) is the Bosch iBooster. I don't know what Toyota uses.

I don't know enough about it yet to know if I want it. Looks like there's a control module on it which presumably has to be spoofed.

Seen anyone repurpose these yet?
Yes, it has a control unit, but if it's the Bosch you don't need to do anything sophisticated to trick it, at least for basic functionality. If you want the friction brakes to back off in coordination with regenerative braking, you'll need more - Bosch sells an additional electronic module to do that, but although this functionality is normal for even the cheapest EV or hybrid, conversions in general don't have it.

Yes, lots of the Bosch units have been adapted to different vehicles, typically for EV conversions. Here's SuperfastMatt's take:
Inside Tesla's Brake Booster (And How To Use It On Any Car)
 

·
Registered
Joined
·
7,937 Posts
What I meant was, I was fairly well researched on the Bosch unit and that was my plan, but, was asking Remy/anyone if the Prius booster had been reverse engineered yet, since, the Bosch ones are too new to appear in scrap yards yet, and thus will cost me a few hundred dollars
The iBooster is nine years old, but if by "in scrap yards" you mean "in U-pick yards", they wouldn't likely be there... and might not be common in those places before many of us die of old age. ;)
 

·
Registered
Joined
·
7,937 Posts
Well, 2018 or newer Honda Accords. Otherwise I'm buying Tesla parts, and, that's too rich for me.
I don't know when each model started using the iBooster, but there are few other than Tesla that started with the first generation unit, as listed by EVcreate in iBooster donor vehicles. The Malibu, for instance, used the iBooster (in at least some variants) at least as early as 2016. I'm not suggesting that these things are common or cheap in salvage, only that it's not just Tesla, Accord, or nothing.
 

·
Registered
Joined
·
7,937 Posts
I found it interesting that the coolant flows right through the motor. Right inside the A/C port you can see windings with nothing separating them.
I believe that's normal for electrically powered refrigeration systems. The compressor and motor are entirely within the sealed volume, so there is no need for shaft seals (an advantage over an external drive such as a belt from an engine) and the refrigerant can cool the motor. Any common refrigerant is non-conductive, so there's no problem immersing the motor in it.

I know what refridgerant tastes like. It should have occurred to me that if they skipped the yard prep in terms of the battery, they also skipped the yard prep in terms of safely draining the refridgerant. Loosened one line off slowly and listened for the hissing. Nothing happened. Took one line off and got soaked with it, including a mouthful. Blech.
That's bad, but not as bad as it would have been in the chlorofluorocarbon (CFC, e.g. R12) days. More recent refrigerants (hydrofluorocarbons or HFCs such as R134a, and now hydrofluoroolefins - HFO - such as R-1234yf) are not particularly toxic (R134a is even used in small quantities medically), and they're much less harmful environmentally (which is why R12 is banned).

Any refrigerant for this sort of system will be vapour at ambient temperature (since you were not doing this at -30 C); unless there was something such as a check valve or closed port of the compressor blocking the fluid path to keep the refrigerant under pressure, it wouldn't be liquid; even the liquid would flash to vapour quickly, with the associated chilling effect. Did you get a mouthful of lubricant (NipponDenso 11 compressor oil), rather than refrigerant?
 

·
Registered
Joined
·
7,937 Posts
Why are you looking for a steering and brake booster for a little car like that?
Keep it simple!
Power steering and brakes are completely unnecessary on a small car
I didn't have or need power steering on the compact cars that I had until about a decade ago... but they had relatively slow steering. The quick ratio of a typical power-assisted rack is unsuitable for street use without assist.

Drum brakes when used at the front axle are designed to be "self-energizing", so they don't need boost. Very few vehicles have ever been built for street use with front disk brakes and no assist; our Spitfire is like that, but it is very light. Matt's Opel GT has brake assist, as appropriate for its brakes and weight.
 

·
Registered
Joined
·
7,937 Posts
Brake system on your GT - I would be very surprised if you ended up with the same weight distribution as the original car
If I was building it I would build it with two master cylinders and an adjustable balance bar so that I could dial the brakes in to match the actual weight distribution
That would be ideal. While not allowing adjustment, the other approach is to change front or rear brakes to get the right balance.

Isn't that what adjusting a proportioning valve does?
No.
A proportioning valve just crudely throttles rear pressure when incoming fluid pressure exceeds a threshold level (which can be adjustable), to compensate for load transfer from rear to front under braking. Until it triggers, front and rear pressure are the same; after it triggers, the rear pressure is lower.
 
1 - 6 of 6 Posts
Top