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$100 brake upgrade by Phil
Started on: 04-04-2006 08:37 AM
Replies: 419 (53295 views)
Last post by: Kevin87FieroGT on 11-21-2020 07:18 PM
longjonsilver
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Report this Post10-14-2018 08:55 PM Click Here to See the Profile for longjonsilverClick Here to visit longjonsilver's HomePageClick Here to Email longjonsilverSend a Private Message to longjonsilverEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Patrick:

I don't know how else it could've been interpreted. Did you not get the connection between weak legs and the need for a larger power brake booster? It was just a joke, and I thought the picture was perfect.


i guess i can be quite dense at times. Anyway, the correct length of the Fiero rod to cut and thread for my 84 Fiero and for the 95 GMC Sonoma power booster was 5 1/8". i did some welding and now its the correct length and the pedal height is the same as the clutch, and the brake light is off, unless i tap on the brakes and the light comes on immediatly. Just what i want.

Lets do some math (maybe i have weak legs, but hey, i'm getting old and my brain functions fine)
Force=Pressure * Area
lbs force = lbs/in^2 * in^2

the ratio of lbs force new booster/lbs force old booster = Pressure of Vacuum * Area of new booster / Pressure of Vacuum * Area old booster

Since the pressure of the vacuum for both booster is equal, the pressure terms drop out (anything divided by itself is 1)

so we are left with

the ratio of lbs force new booster/lbs force old booster = Area of new booster / area of old booster

Area = Pi * radius ^2 . so Pi divided by Pi drops out ( anything divided by itself is 1) . So we have

the ratio of lbs force new booster/lbs force old booster = Area new booster/ Area of old booster = r^2 new booster/r^2 old booster

Old booster is 9" and new booster is 10 3/4" so R of old booster is 4.5" and R of new booster is 5 3/8"

R^2 of old booster is 20.25 and R^2 of new booster is 28.89

So the ratio of lbs force new booster/lbs force old booster = 28.89/20.25 = 1.427 . But i can't measure that accurately with my equipment so rounding off we get a ratio of 1.4

In other terms the S10 booster is 40% more powerful than the old booster. But you knew that didn't you?

jon

------------------
Astronomy says we will find a coded signal from outer space. Then we'll KNOW that life exists there, for coded signals aren't by chance.

Biology says there are coded genetic signals in every cell, but we KNOW that no intelligence created life.

I'm the original owner of a white ' 84 2M4 purchased Dec 10, 1983 from Pontiac. Always garaged, no rust, 4-wheel drifts are fun!

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Patrick
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Report this Post10-14-2018 09:49 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by longjonsilver:

Lets do some math (maybe i have weak legs, but hey, i'm getting old and my brain functions fine)


I'm 62 and my legs are strong from cycling, yoga and playing hockey... but my math sucks. So I guess we're even.

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longjonsilver
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Report this Post10-16-2018 02:10 PM Click Here to See the Profile for longjonsilverClick Here to visit longjonsilver's HomePageClick Here to Email longjonsilverSend a Private Message to longjonsilverEdit/Delete MessageReply w/QuoteDirect Link to This Post
i've been enjoying my "new" brakes, but one thing that i don't remember anyone else mentioning was the different size vacuum hose between the 84 Fiero and the 95 GMC Sonoma



i had to reuse the Fiero banjo fitting and shorten the hose to fit the larger booster.
Would the smaller diameter Fiero hose (and the longer run from the engine) make the recovery time longer ?

hmmmmmmmmmmmmm

jon
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longjonsilver
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longjonsilver

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duplicate post

[This message has been edited by longjonsilver (edited 10-16-2018).]

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Red98422
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Report this Post10-18-2018 03:21 PM Click Here to See the Profile for Red98422Send a Private Message to Red98422Edit/Delete MessageReply w/QuoteDirect Link to This Post
Are you referring to the little plastic one way valve? If so I just swapped them over from fiero to the s-10 and have seen no ill effects. As for the recovery time, sure it’ll take a little bit longer but not by that much at all, once the booster sees vacuum the likelihood that you will be able to drain it faster than it builds is near non-existent (assuming everything is functioning properly)
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Dennis LaGrua
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Report this Post10-22-2018 05:10 PM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Red98422:

Are you referring to the little plastic one way valve? If so I just swapped them over from fiero to the s-10 and have seen no ill effects. As for the recovery time, sure it’ll take a little bit longer but not by that much at all, once the booster sees vacuum the likelihood that you will be able to drain it faster than it builds is near non-existent (assuming everything is functioning properly)


On my 87GT, I also had to swap the old check valve to the new brake booster as well. I used the Tuff Stuff booster with the Rodney Dickman end. Actually two screw on ends come with the Tuff Stuff (Hurst) booster but they are too short. They could be extended with a long nut and a small length of threaded rod but I thought that keeping only one attachment point was beneficial. BTW by tightening with some Red Locktite on the threads I cannot see the end coming off. If I was that worried I would tack with mig welds there. Best brake upgrade ever.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
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liv4God
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Report this Post01-26-2020 12:44 PM Click Here to See the Profile for liv4GodSend a Private Message to liv4GodEdit/Delete MessageReply w/QuoteDirect Link to This Post
I've put together a before and after test comparison video for anyone who is wondering what affect the big brake booster actually has on their Fiero:

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Tony Kania
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Report this Post01-26-2020 02:59 PM Click Here to See the Profile for Tony KaniaSend a Private Message to Tony KaniaEdit/Delete MessageReply w/QuoteDirect Link to This Post
Cool review.
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wftb
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Report this Post01-26-2020 05:01 PM Click Here to See the Profile for wftbClick Here to Email wftbSend a Private Message to wftbEdit/Delete MessageReply w/QuoteDirect Link to This Post
That is a great video. Funny the Motor Week guys got the rears to lock up on a stock Fiero, I have never seen that happen. Nice to see a video that clearly shows the kind of results a mod can give you.

------------------
86 GT built 2.2 ecotec turbo
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liv4God
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Report this Post01-27-2020 03:05 PM Click Here to See the Profile for liv4GodSend a Private Message to liv4GodEdit/Delete MessageReply w/QuoteDirect Link to This Post
Thanks for the positive words guys!
I would like to find a way to adjust my brake bias to add a little more in the back. I think it could stop even faster if the bigger back tires are pulling their weight.

[This message has been edited by liv4God (edited 01-27-2020).]

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Report this Post01-27-2020 04:44 PM Click Here to See the Profile for wftbClick Here to Email wftbSend a Private Message to wftbEdit/Delete MessageReply w/QuoteDirect Link to This Post
http://www.fiero.nl/forum/Forum4/HTML/064690.html

Unfortunately no one is making this handy little gadget anymore.
http://www.fiero.nl/forum/Forum2/HTML/109173.html

This thread explains why and how the prop valve works the way it does.

------------------
86 GT built 2.2 ecotec turbo
rear SLA suspension
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Report this Post01-27-2020 06:56 PM Click Here to See the Profile for pmbrunelleClick Here to Email pmbrunelleSend a Private Message to pmbrunelleEdit/Delete MessageReply w/QuoteDirect Link to This Post
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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Report this Post01-28-2020 02:30 AM Click Here to See the Profile for liv4GodSend a Private Message to liv4GodEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
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.



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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Report this Post01-28-2020 02:33 AM Click Here to See the Profile for liv4GodSend a Private Message to liv4GodEdit/Delete MessageReply w/QuoteDirect Link to This Post

liv4God

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quote
Originally posted by wftb:

http://www.fiero.nl/forum/Forum4/HTML/064690.html

Unfortunately no one is making this handy little gadget anymore.
http://www.fiero.nl/forum/Forum2/HTML/109173.html

This thread explains why and how the prop valve works the way it does.



That would have been perfect! Any other ways to adjust bias?
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cvxjet
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Report this Post01-28-2020 12:38 PM Click Here to See the Profile for cvxjetClick Here to Email cvxjetSend a Private Message to cvxjetEdit/Delete MessageReply w/QuoteDirect Link to This Post
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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Report this Post01-28-2020 03:45 PM Click Here to See the Profile for Tony KaniaSend a Private Message to Tony KaniaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by liv4God:


That would have been perfect! Any other ways to adjust bias?



A proportioning block with adjustment... https://www.summitracing.co...roportioning%20valve
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wftb
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Report this Post01-28-2020 09:44 PM Click Here to See the Profile for wftbClick Here to Email wftbSend a Private Message to wftbEdit/Delete MessageReply w/QuoteDirect Link to This Post
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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Report this Post02-05-2020 01:29 AM Click Here to See the Profile for liv4GodSend a Private Message to liv4GodEdit/Delete MessageReply w/QuoteDirect Link to This Post
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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Report this Post11-20-2020 04:37 PM Click Here to See the Profile for PePe-LePu_For_2Send a Private Message to PePe-LePu_For_2Edit/Delete MessageReply w/QuoteDirect Link to This Post
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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Report this Post11-21-2020 07:18 PM Click Here to See the Profile for Kevin87FieroGTSend a Private Message to Kevin87FieroGTEdit/Delete MessageReply w/QuoteDirect Link to This Post
Reuse your current push rod that is between the booster and master.
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