BTW: scrounging through my scrap metals pile I discovered a 4" bore cylinder liner for a Kohler engine. Wall thickness of 0.120 looks about right for exhaust brake body? Pretty easy to rig the butterfly and neck it all down to fit my 3" out pipe, and use above linkage and a spring with a bayonet switch actuator? 'Always broke' is the real mother of invention for me.....plus I'm a natural born cheapskate near as I can tell.

 

Make shore you replace the ex springs before you put that ex-brakes setup on! then you will need to check back pressure, if the ex brake is to good your going to hold the valve open evan with the higher pressuer springs. If the valve hit the piston.......game over!!!

 

Thanks, Flash, but I'm going to build a D-celerator type, in the exhaust piping after the turbo outlet. It's simpler/cheaper, plus I'm not bright enough to engineer a Jacob's type...

 

Maybe i don't understand the whay you sytem words?
dus it block off most of the air exiting the turbo?

 

I've looked at those and I understand the wastegate type access but where to they get the pressure signal from to open the actuator? The actuator is just like a wastegate actuator right? spring holds it closed and enough pressure builds it opens? So obviously you would need your reference line from between the brake and engine but wouldn't the hot gasses melt the actuator?

 

Near as I can tell it's a simple exhaust restriction in the pipe, under the truck. I haven't discovered the exact theory of why it works, but a butterfly valve in the exhaust pipe to block exhaust flow somehow causes deceleration. It requires a housing [the Kohler cylinder liner] and a butterfly valve inside that hosuing, and an actuator, normally a ram pushing a bellcrank outside the exhaust pipe. There's fancy ways to actuate, but for me I may use a cable-pull actuator or a simple pushbutton controlled 12V solenoid, if the solenoid has enough ooomph with lever advantage to close the valve. It's been mentioned in these forums that the effect is like the old trick of stuffing a potato up somebody's [car/truck] exhaust: no-go-no-mo.

It's also similar to the Pac-Brake exhaust brake.

 

All exhaust brakes, with the exception of the original "jake brakes", are basically a butterfly valve in the exhaust. There's just 2 designes on how to limit the backpressure.

The first, easiest and cheapest is to just have what looks like a 3/8" bleed hole in the butterfly so at high rpms it works fine but the lower the rpms the less braking effect you have because the hole bleeds too much pressure off.

The 2nd type I now see is the same basic butterfly valve but without the bleed hole. Instead it has a wastegate to bypass pressure around the valve at a certain backpressure. So when backpressure gets to ~60psi it opens so this design has much more braking power at lower rpms than the 1st design. This design looks a little more complicated and more expensive but would definately have more braking power.

What would be cool is a variable controller so you could change how much braking power you have, instead of just on/off. maybe like a linear actuator or a stepper motor? Then you could encorporate something to monitor backpressure and just crack the valve open enough to bleed just enough pressure to maintain your maximum ~60psi backpressure when you want maximum braking.

 

the pac-brake uses a small electric compresser(12v) to actuate the ex-brake.
The jacob's ex-brake brakes uses vac. to actuate and both us a hevy spring to keep them open!

If you build to much back pressuer you will over come the spring pressure and the valve will not close all the way......Bam, by by eng!!

Jacob's make a "eng brake" for the big truck that is a diff idea all to gether.

 

The 2nd type I now see is the same basic butterfly valve but without the bleed hole. Instead it has a wastegate to bypass pressure around the valve at a certain backpressure. So when backpressure gets to ~60psi it opens so this design has much more braking power at lower rpms than the 1st design. This design looks a little more complicated and more expensive but would definately be more expensive.



Thanks apwatson50 I didn't no that had any thing diff the the valve,plate type!!

 

I don't think that would work quite the way your saying. Because if you push on one side of the butterfly valve is going to try to keep it closed while pushing on the other side is going to try to open it. Now the area is the same on either side of the pivot point so these forces will cancel eachother out. I get what your saying about a big spring keeping the valve open and then vacuum/air pressure closes it. So I think its all about how big the bleed hole in the plate is as to how much back pressure you create.

Aaron

 

the bleed hole size is vary much corect!!!!!!! but the butterfly is put in the hosing off set so the air is always trying to push it open.......kinda like the butterflys on a gas carb eng. the spring pulls it back but the off set help it to close allso....unless it wide open!....Just some trivea

Edit only the gas on's offset is opisit to close the valve

 

OK that makes sense. I've never had a chance to look at one real close. This is some good info!!

Aaron

 

So then its just a matter of figuring out just how much pressure/vacuum is needed to shut the valve but will still allow the back pressure to open it back up at less than ~60psi.

 

Here is a good explination of how an exaust brake works, even if it is from THEM.
I wish there was a easy to lock up the converter on a A727 or I would have one.
Jim

http://www.bankspower.com/tech_howexhaustbrakeworks.cfm

 

Thank Jim lane!!!
re reading thru this thread I was running around my head how to best explan the theory of the brake and well ........