I put in my 735i assembly in yesterday. My car is a non-abs and my friend who is a mechanic said to tee the rear line together with one of the fronts (teeing the two fronts together would have required much more brake line work, which I'm not equipped to deal with, not the least of the reasons being the fact that there is far less room for the mess back there due to the longer booster). I asked him about the bias valve under the stock MC, if I should keep it, he said don't bother...
I completely disagree. I didn't tell him because I'm sure for all of his clients, they don't see a difference. But ok here's my reasoning. Someone correct me if I'm wrong. I studied the stock setup and the way it was done is this: the front port is split in two and one half goes straight to the left front I believe (one of the fronts). So that gets 25% of the force. Then the rear port and one of the fronts, goes into the bias cylinder. The narrow end of it, goes to the other front, and the big end, goes to the rear. So to me, this says that BMW designed this system to split the effort evenly (or at least evenly amongst the front, and then whatever bias to the rear). Judging by the size of the bias valve it makes sense - it looks like 50% of the overall force goes to the rear (or whatever the split is BMW decided on with the valve), and the remainder 25% to the other front. So I've basically kept the system the same, the only difference being that the front port, instead of having 2 holes in the MC, it comes out of one hole, and splits right after. This way, the bias should stay even and each wheel will get the same share left to right.
The way I see it, simply teeing one of the fronts to the rear, effectively gives 3 wheels half of the braking power, and one front the other half. I'm sure it'll "work" but this car is for the track. I can imagine flying into a slow corner, jamming the brakes, and one front wheel doing barely anything and the other locking up... not good.
By the way, to guys who have said you can get the tee at any brake shop, you can eat my ass. I spent a day calling everyone, a few brake specialty supply shops had tees but they were all SAE threads. Finally I remembered that the rear of the E30 has a tee, looked up the p/n and I managed to get the only one in Canada (not even one in the warehouse) 50km away. The p/n is 34341111435
Final result (crappy cell phone pics but the idea's there). This is the first time I've done anything like this and it feels solid (I know the bias valve isn't bolted down but it's supported by 4 metal lines, sure feels solid, it's gotta be good enough...?). All the bends were tight and not easy to get this way so I know it doesn't look uber professional but none of the lines rub or anything... I think it'll work but I'd appreciate it if someone experienced can tell me if you see something dangerous I did:
The other thing I got done:
EDIT: LMAO, I uploaded the wrong pic but I'm not deleting it, it's too funny of a fuckup. I initially posted this instead of the pic above:
I completely disagree. I didn't tell him because I'm sure for all of his clients, they don't see a difference. But ok here's my reasoning. Someone correct me if I'm wrong. I studied the stock setup and the way it was done is this: the front port is split in two and one half goes straight to the left front I believe (one of the fronts). So that gets 25% of the force. Then the rear port and one of the fronts, goes into the bias cylinder. The narrow end of it, goes to the other front, and the big end, goes to the rear. So to me, this says that BMW designed this system to split the effort evenly (or at least evenly amongst the front, and then whatever bias to the rear). Judging by the size of the bias valve it makes sense - it looks like 50% of the overall force goes to the rear (or whatever the split is BMW decided on with the valve), and the remainder 25% to the other front. So I've basically kept the system the same, the only difference being that the front port, instead of having 2 holes in the MC, it comes out of one hole, and splits right after. This way, the bias should stay even and each wheel will get the same share left to right.
The way I see it, simply teeing one of the fronts to the rear, effectively gives 3 wheels half of the braking power, and one front the other half. I'm sure it'll "work" but this car is for the track. I can imagine flying into a slow corner, jamming the brakes, and one front wheel doing barely anything and the other locking up... not good.
By the way, to guys who have said you can get the tee at any brake shop, you can eat my ass. I spent a day calling everyone, a few brake specialty supply shops had tees but they were all SAE threads. Finally I remembered that the rear of the E30 has a tee, looked up the p/n and I managed to get the only one in Canada (not even one in the warehouse) 50km away. The p/n is 34341111435
Final result (crappy cell phone pics but the idea's there). This is the first time I've done anything like this and it feels solid (I know the bias valve isn't bolted down but it's supported by 4 metal lines, sure feels solid, it's gotta be good enough...?). All the bends were tight and not easy to get this way so I know it doesn't look uber professional but none of the lines rub or anything... I think it'll work but I'd appreciate it if someone experienced can tell me if you see something dangerous I did:
The other thing I got done:
EDIT: LMAO, I uploaded the wrong pic but I'm not deleting it, it's too funny of a fuckup. I initially posted this instead of the pic above:
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