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| $100 brake upgrade (Page 42/43) |
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wftb
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JAN 27, 04:44 PM
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pmbrunelle
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JAN 27, 06:56 PM
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I am wondering why the 65 mph stop took a shorter distance with the big booster.
I'm thinking that with the big booster, your leg (and the booster) are reaching the maximum braking force in less time than with the stock booster.
Less time spent near 65 mph during initial brake application would lead to shorter stopping distance.
At 2:30 in the video, with the stock booster, there are no tire squealing sounds (as with the big booster at 3:16), so it seems like maybe you weren't pushing on the brake pedal hard enough with the stock booster.[This message has been edited by pmbrunelle (edited 01-27-2020).]
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liv4God
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JAN 28, 02:30 AM
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| quote | Originally posted by pmbrunelle:
I am wondering why the 65 mph stop took a shorter distance with the big booster.
I'm thinking that with the big booster, your leg (and the booster) are reaching the maximum braking force in less time than with the stock booster.
Less time spent near 65 mph during initial brake application would lead to shorter stopping distance.
At 2:30 in the video, with the stock booster, there are no tire squealing sounds (as with the big booster at 3:16), so it seems like maybe you weren't pushing on the brake pedal hard enough with the stock booster.
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Locking the wheels and sliding actually makes stopping distance longer. My goal in the test was to push the brakes as hard as I could and modulate it when necessary to avoid locking up and get the shortest stopping distance. With the stock booster I could hold it full pressure the hole time until the last bit and then let up slightly at the end. Thus being easy to avoid locking up and maximize the braking performance. The big booster locked up easier so it was harder to avoid locking up. This decreased the effectiveness of the big booster and is the primary reason that both boosters had the same stopping distance in the 35mph test. If a driver could do a better job modulating the bigger booster to avoid locking up it should stop even faster. That being the concept behind antilock brakes. (also avoids losing control in a slide) The function of the bigger booster is giving more force into the master cylinder. When added to my foot's force that becomes a force great enough to lock the wheels faster than when with the stock booster. That's why it helps decrease the speed better at first, but also leads to locking up faster than before even with the same amount of force from the driver's foot.
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liv4God
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JAN 28, 02:33 AM
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That would have been perfect! Any other ways to adjust bias?
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cvxjet
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JAN 28, 12:38 PM
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In reading the beginning of this thread, Phil stated that he removed the 12" Vette discs because he didn't want to carry a 16" spare wheel up front. Somewhere I read that a Fiero guy came up with a fix for this situation; The spares from certain Subarus (Around 1996)use a 16" wheel...they will fit over a 12" brake setup. The hub hole in the middle needs to be routed out slightly and the wheel/tire fits in the spare well NOT taking up any excess room. Tire size is 115/70-16....This allows you to have 12" discs and a normal spare.
As an added note, I have my battery mounted up front and the tire fits over it and locks in place as normal.
 [This message has been edited by cvxjet (edited 01-28-2020).]
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Tony Kania
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JAN 28, 03:45 PM
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wftb
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JAN 28, 09:44 PM
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I use a Willwood 260-11179 pressure reducing valve on my front brake circuit in conjunction with a stock prop valve that is disabled by removing the rubber valve that is part of the threaded in spring assembly. So the prop valve in my car only acts as a fluid junction.
Removing the rubber valve gives an approximate 50/50 split to front and rear wheels. Doing this mod alone will not result in improved braking.The rears will still do very little and the fronts will still lock up prematurely. I know this because I tested my car with the stock prop valve disabled.
The problem is that you need to increase the pressure to the rear brake circuit. Hooking the Willwood valve to the rear circuit will only give you the ability to reduce pressure to the rears, the opposite of what needs to be done.
So with the prop valve disabled I put the the Willwood valve on the front circuit and I have it setup so that the rears have more braking force but still do not lock up in a panic stop. The fronts will lock up in a panic stop but not until you are going fairly slow around 10 mph.
So I am happy with my setup. It is what you would call a static setup in that the pressure front to rear increases at the same % no matter how hard you push the pedal. There is no auto proportioning going on. So far I have not had any reason to change the setting of the Willwood valve. My car is not winter driven.
I am not saying that people should go out and replicate what I have done. In fact I do not recomend it at all. I just provide this as information only.
The Thread where I have described what I have done and lots of discussion about the prop valve problem is here:
http://www.fiero.nl/forum/Forum2/HTML/109173.html
What started me down this path was once I put on a lebarron brake kit front and rear , the braking improved but I ended up with right front lockup. Too annoying for words.------------------
86 GT built 2.2 ecotec turbo
rear SLA suspension
QA1 coilovers on tube arms
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liv4God
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FEB 05, 01:29 AM
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Thanks for the ideas on the proportioning valves. The biggest issue seems to be the disparity between the brake line coupling sizes. I think I can make it work, trying to decide which option is the best. Using adapters or refitting the lines with the necessary couplers. [This message has been edited by liv4God (edited 02-05-2020).]
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PePe-LePu_For_2
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NOV 20, 04:37 PM
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Gents, can anyone tell me what the correct length is for the booster to master cylinder push rod when the S10 booster is used? [This message has been edited by PePe-LePu_For_2 (edited 11-20-2020).]
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Kevin87FieroGT
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NOV 21, 07:18 PM
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Reuse your current push rod that is between the booster and master.
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