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It is a pretty engine, hopefully this year it will be a running engine

Today I got looking at my proportion valve and kind of realized/remembered what I had done. The valve drops the pressure to the rears be 57% and as a starting point the adjuster was full out so that offset began at 150psi. as a comparison, the 348 valve knees at about 400psi and is about a 50% reduction. so rear braking was at a minimum which I'm sure I did as a known safe starting point but if the valve is installed it is always working so the master cylinders really need to match so I ordered a second 5/8". I also found EMPI makes a 50% reduction valve for the dune buggy market that seems a better match than the 57% valve I have so I ordered one and will replace that as well.

I couldn't find any graphs for the new valve and I don't have brake line pressure sensors of really anything to measure the valve with so the right setting will be kind of a guess and involve a lot of slamming on the brakes in different conditions but such is life. Wilwood has a very nice map of theirs of course. and below is a 348 curve from the manual overlaid with the wilwood data Sean D whipped up as he's doing a similar project on a 348...the offset is a valve the 348 has so ignore that but you can see slope difference which is what propted me to order the EMPI valve

I had four gauges, 2000 psi that I made bleeder adapters for. If I had a brake issue on a car, I would screw the gauge in the brake bleeder and push the pedal. It gave me the pressure at each wheel. Maybe a set up like that will get you close in the shop before driving and sliding into something unwanted.

_________________
Wade Williams
Master Ferrari Tech
Restoration Tech
Engine Machinist
Fabricator
Racecar Driver

I was having a meltal melt-down today and got tired of guessing and did some actual math.  I calculated axle load as a function of braking G force, then the axle forces to go with, then converted to system pressure, put a 10% reduction on the rear axle to know the front locks first, then optimized with just mastercylinder/balance bar, then added a proportioning valve and re-optimized, then a 2nd valve, then a 3rd.  The 3 valve system uses non-standard valve ratios so really just to see.  The graph goes to 1.5G so slicks but I let the line cross the safe line after about 1.25G that I figured DOT race tires might give.  

Its kind of an assumption on my part that matching the curves is a good thing as it should give shorter stopping distances in suboptimal conditions and also I thing should keep the car better balance coming off the brakes into turns.

Well damn. That is why I have some crap gauges screwed into bleeders and you have math skills. I would have no idea how to calculate all that stuff. But that is why I just turn wrenches.

So, after all the math, what are you planning to bolt on the car

_________________
Wade Williams
Master Ferrari Tech
Restoration Tech
Engine Machinist
Fabricator
Racecar Driver

Design is what you think you want, actually measuring is what you have, both are pretty important.

For starters, leaving it exactly as was is ok, as is just installing 2 5/8 masters. The new 50%valve was a poor choice, at least on its own.

I looks like the best option is go 5/8 front, 3/4 rear on the masters, then set the balance bar about 1/8"toward the front master. Then use the new 50%valve set to about 500psi knee, and the old 57% valve set to knee at about 600 psi. But I still want to play with the number tosee what happens as things change, pad friction in particular so it's safe with various pads as that changes system pressure and that means the optimal valve set points move

Then the question is how to measure to know if the setup is right? I'll need to think about that.

So much to catch up on. Good luck with all of it. The broaching and the fabrication on the cover are fantastic.

I played some more and fixed a couple not quite right calculations. It looks like 5/8 and 0.7 masters are about perfect then the 50% valve then a 57% valve, and a 3rd 57% if I'm in the mood for perfection, but it does seem like if I can have 13 MAP sensors I should be able to have 3 proportioning valves . The pad cf messes with the valve setup because they work on pressure and pad cf changes system pressure.....so the spread sheet tells me where to set everything for what pad cf number.

Now I need to decide if I need to add transducers and log brakes or just buy a couple gauges to do the setup....I need to go back there the ECU setup info, its been a while and I'm not sure what all is still available and what extra wiring I ran or if I would need a CAN expander or some such.

On the Trans Am race car and the Ferrari GT car we run brake pressure gauges. The newer cars have that in the electronic dash.
I like to have a gauge set in the middle if the dash so at a glance I can see where the bias is set. I then dial the bar back and forth to get what I want.

One of my drivers told me that he really wanted more rear brake but the gauges show it is a nice balance. He decided to dial in more rear anyway and at the next corner, backed it in the wall. I think the gauge was correct.

I am sure you can dig up another couple channels and get brake pressure on the data log.

_________________
Wade Williams
Master Ferrari Tech
Restoration Tech
Engine Machinist
Fabricator
Racecar Driver

It looks like AN21 and AN22 are available. Light gray is what AEM used them for and I try to follow when I can going back to when I wasn't sure my program would would correctly and thinking I could reload theirs....I now know only they can load their firmware but it was a good thought.


And I have 3 2-conductor shield wires. 1 I want to safe for a front CAN line but I could use the others 2 and send 5V and ecu gnd up 1 and the 2 brake pressure signals back in the other. I have 3 unshielded wires too but I like to keep analog signals in shield wires anytime I can and I have them sitting. There is a 4th, I think 3 wire under the dash on the by the steering wheel planned for steering angle.

Anyway, it looks like front and rear brake pressure transducers are a go and I'm kind of eying accelerometers but I thing I'll hold that thought until the car is actually driving and just use a phone app to setup the brakes for now.

I thought this weekend was brakes......but brakes can wait since the head shims/rings arrived a week early and they look marvelous!


The pin holes were a little tight


but now fit. I hadn't ordered the orings knowing thinking there was time, but did last night when I got the shipping notice for the shims and they will be here tomorrow so I can assemble and get it on leak test Saturday maybe