Durable 1 'Power Brake' Valve

Mike,

Ahhh, a fresh thread. Ok, have pics below of the install. As the PO or whomever buried the part behind the pair of rotor control thingies (technical aint i ) i needed to remove the rear tire and the cover, but i think in total it took me about 30 minutes to jack up the car, install, and drive away. Note i cover my brakes so crap does not fall on them. Basically loosen hose clamps, remove old part, blow in the new valve and position it so that the way it allows air through goes towards the engine. Tighten clamps and you are done. Simple stuff.

Ok, after about 50 miles of driving various roads from fast corners to slow ones... many properly banked, a few neutral-banked turns, and two moderate turns that are banked a tad bit wrong...

Normal straight line braking seems about the same, if a touch easier but really not overly so (thank G-d). It is less effort though what i did notice is that it seems a bit more responsive on the first 1/4 of pedal movement. NOT touchy, just that is seems to allow for more micro-level control during the first bit of pedal movement. This is especially true coming OFF the pedal (read on).

Stock, when i would release the pedal to ease off braking there was not a whole hell of a lot of 'variable settings' (think a scale of 0 to 100 with 100 being full brake) the lower 1 to 35 are MIA with the stock valve. With the Durable 1 valve, from 34 to 100 you get some nice variety and control ability to balance the car while braking that stock did not quite offer in such a seamless way.

EXAMPLE: Once comfortable i decided to make believe i was 'King Of The Late Brakers' knowing full well i would not make the apex and need to go extra deep into the corner but COULD use the brakes through the turn PROVIDED i kept her balanced. The new valve provided MUCH MORE ability to balance her as i steered through the corner. Even though this leads to a really crappy exit speed versus driving the corner correctly, i feel the new valve allowed a higher exit speed doing the apex wrong than i could have done with the stock valve.

As for 'proper' use, it seems that coming off the brake keeps the car more balanced in general. Please keep in mind i downshift/match revs/more gas then brake (fast sequence), enter turn still braking and keeping her balanced and going as fast as i can, then let off on brake and give her throttle... quickly reaching apex and then full gas to exit corner. It is the part as i let off brake that does not upset the balance of the car so much with the new valve while the stock valve seemed to make the car's balance more twitchy (for lack of a better word).

Hope this makes sense. And yes, i am keeping the new Durable 1 Power Brake valve. And NO, the valve will not improve your braking system, thereby shortening the brake distance. It basically seems to reduce some of the pedal effort yet also provide more brake variables (especially when reducing brake).

Hope this makes sense.
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cool post!

 

Thanks for the great info... I may get one!

By the way, I wonder if yours was relocated way down there because Jeff put those pretty braided stainless steel cover sleeves over all the regular hoses in your beautiful engine compartment...

Isn't it normally here, or is this something else?
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Mike, Your's is in the stock location, or very lose to it. They prefer to be as close to the vacuum soure as possible, be it a OEM valve or this one. That allows the tube to become in effect tad bit more reserviour area.
I came up with the idea out of necessity, as the large cam I was running provided 9 to 10" of vacuum @ idle. I never finished backing out of the sshop. as I knew it would be crazy to go out on the road with brakes like that. Afer adding the valve, I forgot about it until a half hour after coming back. Works fine as a stand alone, or with an extra tank.
Kermit

 

Odds are it was moved by the PO Jeff. As it stands it works fine and as they say "If it aint broke..." tweak it

The STOCK location... that would mean installing it would take about 7 minutes versus my 30.

 

I love little bolt-on gadgets like this.

 

Brake Booster requires 16" of vacuum to operate properly and there is no way this little gizmo increased vacuum from 10" to 16"'s to make up for shortfall in vacuum. So the little story by Kermit is make believe engineering.

This is just another left handed smoke shifter that fits next to the chrome muffler bearings for the water injection system.

I run 400+ lift cams in a 308qv and produce a max of 10" of vacuum which fails to operate the booster at all, the only way to operate the booster was to install a Stainless Steel Brake Corp ( a real company) electric vacuum pump designed to specifically to operate Brake Boosters. For safety I added a summit racing vacuum storage tank.

Save your money.

 

Have you tested it? Do you know?

I'm not taking any sides, but I really wish every tech thread that involves Kermit's stuff didn't turn into a mudfest. Steven posted his observations, that's all.

 

Something seems different in my system. FYI: i used my mouth to blow through the stock unit and it was fairly hard to get air through it though did flow in one direction. The Durable 1 unit was much easier to blow through with much less resistance.

 

Tillman

My response was factual on vacuum required to operate a booster and was NOT directed at Steve's post it was directed at Kermits "story".

I actually think Steve's post was just fine and have no beefs with his opinion.

When a manufacture of a product chimes in to a post with a story that has no basis in fact and is solely done to sell that product then there lies the problem.

And by the way there is no way a device in a vacuum line can increase the vacuum an engine produces. That is common knowledge! If there was I am sure Kermit would be a very rich man.

This is "splitfire plugs" for Brake Boosters.

Steve,

The reason that is...is that the valve has less tension but then your orginal one is 20 + years old and have built up a resistance from corosion .... IT does not increase vacuum as that is made by the engine...it only releases it to the booster.

 

Of course that's true.

But how about this? These aren't real or Ferrari-relatable numbers and I'm no engineer, but the theory of it seems intuitively plausible, unless the actual engineering physics aren't intuitive. Here's what I mean: If some hypothetical engine produces 20 inches of vacuum, and it takes 10 inches of vacuum to just open an inline valve, doesn't that leave just 10 inches of volume for any downline devices? So if you reduce the requirements of the first valve to 5 inches as a trigger threshold it would then leave 15 inches vacuum for downline devices? Or are the engineering physics such that regardless of the first valve trigger threshold, the ENTIRE amount of vacuum is available to downline devices once the first valve is open?

*******************

I'm editing this thread but leaving my original question above even though it shows my ignorance and I now know the answer (I went down the hall and asked one of our physics guys). In the hypothetical case above, ONCE THE VALVE IS OPEN, the FULL amount of vacuum created by the engine is available to all the devices down the line. The valve doesn't "use up" part of the available vacuum.

So maybe the Durable 1 valve does have a lower trigger threshold, but it doesn't increase ANYTHING at the brake booster... it may just allow the vacuum to get there sooner at lower revs/initial vacuum.

I was just trying to understand how it works and whether it does (or even COULD) provide any benefit over the stock valve.

 

Agreed there is no way the part can increase vacuum. You are also probably right that the original part here has aged and, perhaps, has clogged thereby causing it to not work correctly and allowing less air through (but has not suffered a total failure). Still... the Durable 1 unit may have less resistance than a perfectly working stock unit so....

With that said, the new Durable 1 unit may have fixed the clogged stock part. Lemme look up what a stock OEM unit costs. Hmm... cant seem to find it in the Spare Parts manual (CAT N. 361/85). Anyone? Anyone?

EDIT: Found the part: #128435 NON RETURN VALVE
Unit price: £12.30
Quantity required: 1
This part supersedes: 101538, 680956

EDIT #2: The part is NLA from Ferrari UK and Dennis McCann does not have it either. The plot thickens

 

I believe you have the "gist' of it.
I tested the OEM valve from that 308, and it took 4.5" of vacuum to open it. Without tearing it apart, I am still quite sure that it is a simple ball and spring check valve very much like the PCV valve common on cars. The new valve is a sliding type, that due to it's light weight is easily operated by the movement of air, and does not need vacuum to pull against a spring. The motor was producing 9 to 10" of vacuum @ idle. So if it too 4.5" to open the valve, the remaining 4.5" is what actually gets down to the booster. Simple.
Another advantage I have found is that due to the lightness of the valve (weight @ .7 Grams), it reacts to the natural pulses in the induction system, opening at the vacuum part of the pulse,and closing quickly as it turns to the pressure part. This helps preserve available vacuum in that situation, while the heavier ball type has too much mass to move quickly enough to achieve this. Gauges do not usually show this as they are dampened thru a metering oriface, so that the reading is more easily taken whithout the needle fluctuating as it follows the pulses. So in short, a gauge shows an average, not the pulses which constantly fluctuate between pressure and vacuum
HTH
Kermit

 

Am not an engineer, but am making a guess.

The Durable 1 valve has less resistance and therefore lets even small amounts of air pressure through. Said 'newly available' air pressure assists in allowing the brake booster to operate at smaller increments. Therefore the lower end of the braking scale is enhanced (more flexible) and the speed of initial brake reaction would be increased due to the vale being more sensitive. In audiophile terms, you are achieving more microdymanics and have also increased the slope of the initial rise and fall times.

Hope that makes sense??????????



Wow, it never ceases to amaze me the sheer knowledge i learn from others here. It is like getting a great education for virtually free.

Kudos to Rob for Fchat (Rob has had a bad week, he deserves a few ).

 

Rutlands had them about 2 months ago when I checked...

 

THERE'S the engineering mis-information! See my post above. From a physics and engineering point of view, it does not "use up" the initial trigger threshold of vacuum... once it opens the FULL vacuum gets down to the booster.

 

No, you had it right the first time.

It is a check valve with a cracking pressure of say 5 psi. That means that the only time the valve will be open is when there is a 5 psi differential pressure. That is the force required to hold the valve off the seat and the valve will close when the pressure is less than 5. The 5 psi isn't "used up", it is still in the manifold, but the brake boost will never see it. If you substitute a 2 psi valve, 3 more psi will make it to the brake booster.

To the vacuum. Big cams will cause the engine to idle at a lower vacuum pressure, oftern to low for the brakes. But that doesn't mean the brakes won't work, because even with big cams, a very high vacuum is generated when the engine is decelerating. Using a check valve and if necessary adding a large reservoir usually solve the problem. Of course with very large cams sometimes the only option is to just add a vacuum pump, but most "streetable" cam and engine set-ups don't require going that far.

 

I personally *like* what you're saying, but it conflicts with a degreed physicist here that I had asked. I'm just trying to figure out reality.

 

Did a lookup. There seems to be a lot of stuff about check valves. Wish i could find Professor ARD Thorley's "Fluid Transients in Pipeline System" paper. Wow this is getting geeky.

Montreal F1 practice session live on TV in 4 minutes. Be back later

 

I would have to disagree with some of what is being said here. I had the Valve tested by an independant, and it does increase the amount of vacuum at the brake booster compared to stock valves. On the stock valve topic, the unit I first replaced when I started was in good working order, and as to the amount of effort to open it, this was very close to the other 6 OEM Ferrari valves that I tested. One took as little as 3.5" and one needed 5.5" of vacuum to unseat or open, but the point is they all take a pressure differential to perform.
While I do not have a degree in physics, and in that I cannot qoute the necessary books to back it, I tested it in other means.
The valve showed consistantly more vacuum at the booster when plumbed into an individual runner than into a common, or plenum type enviornment. This is how I came to the conclusion that the valve had opened during the vacuum, or lower pressure portion of the pulse. Perhps there is another explanaton, if so, I would like to know what it is. The vacuum gauge is still going to show what it did I would think, as I repeated the test to make sure I was correct.
If it would assist in understanding this matter, and validating what I have experienced the first time, I would offer a unit, free of charge, to an F-chat member that is running a larger than stock cam, and has problems with the low vacuum in the booster. I would suggest that the individual be mutually agreed upon to in order to help insure a valid test and opinion. Sound fair?

 

Where are those "independent test results"?

What seems lost in all this is the simple fact that if the engine produces 10"'s of vacuum then that is all there is....no in line valve is to the booster is going to produce more then what is supplied to it. It is nothing more then a switch it does not produce vacuum. if it opeartes at a lower threshold so be it.

If a booster needs 16"'s of vacuum to operate and the engine only produces 10"'s no silly in line check valve is going to magically create the missing 6"'s of vacuum.
Kermits "story" is a Story no matter how much it's been tested by independents. There is no mathamatical formula that can create vacuum that does not exist in the 1st place.

 

I'll offer to test it -- impartially. I'll get my mechanic to help with a vacuum gauge before and after, or however seems appropriate and I'll report the seat-of-pants impressions. However, I have the stock usa QV engine, though upgraded brakes (big Brembo kit). I would expect that if I get the similar results to Steven and indeed like the difference in feel (presuming there is a difference to be felt), it would be good reprentative feedback for other potential purchasers. Of course, you take your chances -- it there's no noticeable difference, I'd report that too.

Matt, look for an email from me.

Mike

 

Well, I am a degreed mechanical engineer and designing this kind of thing is what I do for a living.

It's a force balance problem. On one side you have a spring pushing the valve closed. On the otherside you pressure trying to push the valve open. Lets say it is a 5 psi check vavle, that means a 5 psi pressure is require to generate enough force to push the spring back and lift the valve off it's seat and allow flow. If the pressure is ever less than 5 psi, the spring will push the valve closed. If there is more than 5psi the valve will try to open further, but there must allows by at least 5 psi or the spring will win and the valve will close.

I guess it would be possible to design the valve such that after it opens and air is flowing, the viscosity of the moving fluid could hold the valve open at a pressure below the valves cracking pressure, but I’ve never seen one.

 

If Mark Eb wants to check it out (I've always been impressed with his knowledge and the supercharger work he's accomplished) he'd be a great guy to do it, presuming he hasn't already done something funky to his stock brake booster.

 

Sloan, Mike, and all,

Now i am feeling bad about posting my results but i will say no matter what others are saying it seems to have made a difference in the 308 here, ESPECIALLY when i let off the brake during turns AND the ability to have better micro control of the brakes. Will gladly send the old valve for testing to whomever as, frankly, i don't want to use it (why step backwards?).

While i am an audiophile magazine editor/reviewer for many years (see my little side of the web http:/www.EnjoyTheMusic.com), if the unit sycked i would have sent it back to Kermit... as my 'job' is not as a car parts reviewer so i have no obligation to write a review no matter the outcome.

The Durable 1 unit, no matter what it actually does scientifically, allowed the non-modified engine yet modified brakes (Brembo slotted rotor package front with DS1100 pads, stock rear calipers with DS3000 pads and Girodisc slotted rotors) perform to my liking better over the stock unit. Sure we can argue over the science behind it, yet my experience tells me it made a positive difference that i really enjoy AND should help on track days AND during my <cough> normal drives

My apologies if this has now turned into something of a debate. Sloan, seriously dude, get one and feel the difference for yourself. i realize you use less grippy pads so it may be a bit more subtle as the car here has a more aggressive setup. It would be great to read someone elses impressions, but frankly i am not the type who needs 'validation.' Never been a 'follower' type in life, maybe it is the Leo is me...

My race/car mechanics thinks i am wacko to put all sorta of money in the 308 here (Kinesis rims, Brembo brakes, Nick's suspension system, etc)... you guys know all the effort and $$,$$$ (literally) in the car here. A measly $80 is throw away funds for me... Hell, my cigar or custom blend cappucciono habit per WEEK is...

My apologies for starting to rant. i'll shut up now

Enjoy the Music (Roger Waters "Amused To Death" on limited edition vinyl right now),

Steven R. Rochlin

"When the sleigh is heavy
And the timber wolves are getting bold
You look at your companions
And test the water of their friendship with your toe
And they significantly edge
Closer to the gold
Each man has his price Bob
And yours was pretty low

Now history is short
The sun is just a minor star
The poor man sells his kidneys in some colonial bazaar
Ce sera sera
Is that your new Ferrari car
Nice, but I think I'll wait for the F50

You don't have to be a Jew
To disapprove of murder
Tears burn my eyes
Moslem or Christian, Mullah or Pope
Preacher or poet, who was it wrote
Give any one species too much rope
And they'll fyck it up..."