hydro boost with 24v swap.

[flyboyx]

i was wondering around my local pick a part and came across a 635i. i know the hydraulic brake system is more complicated than simply using a vacuum booster, but i see advantages. i wonder why almost no one uses this system on their e30s? anyway, i spent 40 bucks on the entire thing, so i figured at least i will have the over size master cylinder out of the deal if i never use any of it.



there are a few barriers to using this syst in an e30. the hoses from the 6 series are not compatible, but i have parts cars up the ying. i am hoping that i can use some of those. the problem is the pressure lines. the returns are no big deal. they can all be replaced with new hoses on the hose barbs.

locating the componets could be a slight problem. the acumulator( the black round bulb thing) could be located under the master cylinder but a bracket would need to be welded to the inner fender to hold it in position.

the resevior is about twice as long as the standard one. it would fit fine on the motor arm bracket. i don't know if it can be mounted that low, since the booster would be above this location.

i have not read much about this swap, but there are a few negatives on the forums. the biggest being that it is complicated to hook up. to this i say it would just be a matter of coming up with pressure hoses that will work.

i think the hydro brakes will be more powerful than the e21 booster that everyone uses. i have read to the effect that you can loose feel or lock the brakes up easier with this syst. i have abs, so i can't imagine wheel lock being an issue.

here is the size difference between the e30 mc and the e24.



here is a comparison of the end that goes through the firewall. the hydro is about three eights inch shorter, but i can take that out with the clevis adjustment.



i am going to be running the setup on the right below. i'm not confident my e21 booster will handle thes adequately.

[Ray Smoodiver]

Pay massive attention to how the hoses are routed, and where the restrictors are, you'll have to replicate them exactly in the E30 as they were in the E24.

It's a fine system, and I plan on using it mated to Movit fronts and rears with my Euro S50 swap.

Ian Haynes is the man to talk to (as usual) about using this booster with a DOHC swap, but i'm sure he'll be more than happy to help.

[flyboyx]

Pay massive attention to how the hoses are routed, and where the restrictors are, you'll have to replicate them exactly in the E30 as they were in the E24.

It's a fine system, and I plan on using it mated to Movit fronts and rears with my Euro S50 swap.

Ian Haynes is the man to talk to (as usual) about using this booster with a DOHC swap, but i'm sure he'll be more than happy to help.

i taped the ends of the hoses and labeled them before i took it apart. took a couple of photos too. there were no restrictions in the hoses as far as i can tell. i am pretty sure that i am going to have to do something with the restriction in the brake line going to the rears.

i would love to talk to this guy ian haynes. does he post on this forum or the other one?

[Charlie]

i wonder why almost no one uses this system on their e30s?

As you stated in your post, complexity. On a Euro S50 swap with its very limited clearance, it begins to make sense, on US LHD swaps, it doesn't. An E21 booster is almost plug & play once you mod the fork. You can keep your MC and everything else. Also, as you mentioned, cost. Yes, you can find junkyard 20+ year old HW for 40 bucks, but spec that stuff out new. Personally, I'm not a huge fan of reusing old crap when it comes to things like brakes.

-Charlie

[Kerrath]

A lot of things people do don't make sense and it doesn't have to. Why do you have an e30 when you could have something better for the same amount you put into your e30? Because you want to, not because it makes sense.

Besides that, he explained that he wants the extra braking power of the hydraulic system which you would've known if you'd read.

to op:
I originally wanted one of these, but when it didn't readily make itself available, I ended up with an iX booster. Works ok.

Good luck with this, I want to know how it turns out.

[flyboyx]

As you stated in your post, complexity. On a Euro S50 swap with its very limited clearance, it begins to make sense, on US LHD swaps, it doesn't. An E21 booster is almost plug & play once you mod the fork. You can keep your MC and everything else. Also, as you mentioned, cost. Yes, you can find junkyard 20+ year old HW for 40 bucks, but spec that stuff out new. Personally, I'm not a huge fan of reusing old crap when it comes to things like brakes.



-Charlie

well i see your point of view about the parts being 20 years old. the truth is, though, even if the hydraulic system failed, you still have manual backup just like the vacuum assisted booster. there is a rod that runs all the way though to the master cylinder from the brake pedal. basically, doing the same thing with hydraulic pressure instead of air. my daily driver diesel pickup has hydro boost. the system is really awesome.

A lot of things people do don't make sense and it doesn't have to. Why do you have an e30 when you could have something better for the same amount you put into your e30? Because you want to, not because it makes sense.

Besides that, he explained that he wants the extra braking power of the hydraulic system which you would've known if you'd read.

to op:
I originally wanted one of these, but when it didn't readily make itself available, I ended up with an iX booster. Works ok.

Good luck with this, I want to know how it turns out.

kerrath, thank you for your encouragement. i still don't know if i am going to use these parts on my car, but i am considering it. there is space, though just barely. the accumulator will fit under the booster. the reservoir can be either mounted on the s52's engine mount arm or located in about the same place the standard e30 ps reservoir is mounted.

the biggest barrier would be the hoses. i have about a dozen hoses that i pulled off of my various parts cars and not one of them will work on the e30 as it is from the factory. however, after examining the pressure hoses closely, i have come to the conclusion i can grind off the fitting crimp and remove the hose from the barbed ends. that way i can make my own custom hoses with the stock ends. i am thinking to douple clamp each end of the pressure lines to make sure they don't blow off under a load. it looks very doable in my opinion.