Brake bias with Wilwood BBK from Arizona Z
I am slowly getting the kinks worked out of my track car (2004 350Z Enthusiast), and the next one to tackle is the brake bias. The PO put Wilwood 6 pot up front (5960/5961) and Wilwood 4 pot rear (9703). The ABS module is bypassed. I don't know (yet) if the factory proportioning valve is still installed but I suspect it is. As you can tell, I am new to aftermarket brake kits and the brake hacks for 350Zs - I'd appreciate some help.
The rear brakes lock up a good bit before the front. I'd like to adjust that. Wilwood has a couple adjustable proportioning valves with different threads - I don't know which I need for the factory fittings. I also would like to do a plug and play of some sort, and figure it might be easy since the brake lines are all right there under the hood where they bypass the ABS module. Thoughts? |
https://cimg4.ibsrv.net/gimg/my350z....788618cd80.jpg
ABS bypass I'm thinking I can insert a prop valve right before the splitter block. I think those fittings are 10mm x 1 - correct? |
And where can I find a gender bender? I will need a male to male adapter fitting...........
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A proportioning valve is pretty much a must. From the factory it’s built into that ABS block you bypassed |
Originally Posted by terrasmak
(Post 10970428)
A proportioning valve is pretty much a must. From the factory it’s built into that ABS block you bypassed So if the bias is built into the ABS module, I've got no bias right now except pad and rotor size. I need a prop valve and I really like the thot of it being easily accessible, right at the splitter. Where can I get the male to male adapter? Or even a very short brake line? |
Looks like Pegasus racing has M10x1 to -3AN adapters; I can add a female -3AN coupling and get there. But somebody surely SOMEONE has a male to male inverted concave flare M10x1 adapter?????
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Originally Posted by TheRedZed
(Post 10970461)
and I really like the thot of it being easily accessible, right at the splitter.
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Im not clear which one you need from your description...but here are both:
Male-Male: https://www.merlinmotorsport.co.uk/p...m10x1-bbu-hu22 https://www.carbuildersolutions.com/...ad-brake-union Female-Female: https://shop.advanceautoparts.com/p/...FdBRhgod0MYOQw |
It isn't easy to describe, I had to draw it at the parts store. The fittings you linked (thank you, btw!) aren't it, they have a convex nipple (pointing out), this app needs need concave.
Think of it this way - in the pic above, I need to install the prop valve between the tee and the line coming from the master cyl. The line from the MC will screw into the prop valve inlet just fine. But the prop valve outlet has a female thread connection with a convex nipple inside that inserts into the mating flare (which is concave). That is also the same connection as the tee. So I need male M10x1 threads with a concave flare, on both sides. I went thru several bins and a catalog at the parts stores, no luck. What I did find at the parts store is an 8" pre-fab'd flared brake line ass'y with the M10x1 fittings. It should work, but I'd rather have a solid adapter if there is one. |
I would just make a short fitting...you just need a single flare brake line connection for each side. iirc it uses a single flare...
https://cimg9.ibsrv.net/gimg/my350z....359a89dbe8.jpg |
The 8" line ass'y I bought has a double flare. The Nissan hard line pictures I've seen look like double flare but I can't tell for sure. If Nissan is indeed single flare is there any reason the double flare tube won't work still?
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I've read that you should never use a single flare for brake lines: http://www.fedhillusa.com/?page=flare
Look at the 7th picture. I've also found several references to Nissan using double flares on their factory brake lines. Problem is Wilwood calls theirs a bubble flare on the prop valve. If it really is a true bubble flare (DIN) it won't work. Devil is in the details........... |
Just research what it is and match it. The devil is having the right tools for the job...
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Well I consider asking others on the forum who may have already done this part of the due diligence research. I find it hard to believe I'm the only one here who ever needed to do this, and I don't happen to have a brake flare kit that does double flares and bubble flares. Yet......
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Can someone confirm which line coming off the master cylinder is for the rear brakes? I assume the master cylinder has a primary and a secondary, and the one marked "S" is the secondary, aka for the rear brakes.
So is the circuit coming off the "S" tap for the rear brakes? |
Ended up tracing the brake lines. For anyone else who cares to know, the line with the smaller hex nut on the master cyl, across from the "S", is the rear brake line.
I bought a set of used brake lines off Ebay, a bubble flare kit and some M10x1 bubble flare nuts. The Wilwood prop valve has M10x1 with bubble flares, and the 350Z has M10x1 nuts with a double flare (45° SAE). I straightened out the kink and cut the rear brake line that runs between the master cyl and the ABS module (or in my case, the tee). I also removed about an inch. It lines up pretty well - I'll install and bleed tomorrow. In the picture it is laying like it would installed, in the first picture of this thread, the tee on the right. https://cimg7.ibsrv.net/gimg/my350z....e96e5002ea.jpg |
Good job hoss.
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Tried out the new bias this morning. Cloudy conditions, smooth cool pavement, summer street tires. The Prop valve instructions from Wilwood says 57% minimum gets thru to the rear. So I started there and added rear brake until the rears locked up before the fronts. Then I backed it back down until I got the fronts to lock first again. Ends up it isn't far from the minimum rear brake setting on the prop valve. Makes me wonder why anyone would upgrade the rear.......?
When I get on the track, I expect the grippier tires will mean more weight transfer to the front and I'll be adjusting the prop valve all the way down on the minimum stop for the rear brakes. Overall big improvement in balance of braking, |
Youll likely have to calibrate the settings in wet conditions also.
The rears brakes are sized appropriately (albeit conservatively) for their heat requirements, and bias is set accordingly. But your point is valid. The Conti 370zs ran BBK front w/OEM Brembo rears in their racing, as do many others. |
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