Vario 814 da exhaust brake
- Thread starter ianc
- Start date
Neil
Observer
Hi Ian
I know it's on a slightly larger scale but when I engage mine you can definitely feel it , it really does retard. I would assume that yours isn't working correctly. I know that the butterfly valve needs to nearly shut. It must have a very small opening when shut and the size if this opening is critical. If it's too much it has no effect.
I would start here.
Must chat soon
Neil
I know it's on a slightly larger scale but when I engage mine you can definitely feel it , it really does retard. I would assume that yours isn't working correctly. I know that the butterfly valve needs to nearly shut. It must have a very small opening when shut and the size if this opening is critical. If it's too much it has no effect.
I would start here.
Must chat soon
Neil
Squiddlydiddly
New member
Is the same for me Ian. I have a floor mounted foot switch on my 814DA 1999 and when I hit it I can hear air and engaging but there is no brake retardation I can feel. Having said that, I have not really tested it over 2k revs or a really long downhill run.
I haven't gone any deeper into this but would like to have the exhaust working because I know at some point I'll be facing some serious mountain road downhill work and would like to know I have backup!
Cheers
Steve
I haven't gone any deeper into this but would like to have the exhaust working because I know at some point I'll be facing some serious mountain road downhill work and would like to know I have backup!
Cheers
Steve
I'm currently in the Pyrenees and defo need the exhaust braking to work. And it does when the engine is reving like Feck (Irish technical term). Don't ask ow I know, but lets just say that a Vario 814DA can cope with a 1 in 3 downhill.
Neil - perhaps the exhaust brake is less effective because mine is a little girley 4 cylinder!
BTW - Mine has a "Posh" stalk at the steering to activate it.
Neil - perhaps the exhaust brake is less effective because mine is a little girley 4 cylinder!
BTW - Mine has a "Posh" stalk at the steering to activate it.
Neil
Observer
Enjoy your adventure Ian, and we will catch up soon. Maybe at AO 16 in Stratford in September
My engine brake is a button in the the floor . it is pneumatic and I think it probably shuts the exhaust down by about 90% maybe more. When the flap is rotated it only leaves the slightest gap for the gases to get through.
What is also important that when operated it instantly shuts off the fuel supply to the pump ( mechanical ) this ensures that there no combustion taking place and that it is only using the air drawn in naturally by engine rotation. The accelerator pedal goes solid and wont move . Strangely after prolonged use , maybe 15 minutes the engine temperature comes down as there is no combustion .
I also did many european mountain ranges this year, Pyrenees, Alps, Dolomites etc . using the exhaust brake is fantastic but very slow. It takes about the same time to go up the passes as it does to go down.
When operated ,the vehicle just doesn't go any faster on the down hill.
It's Bloomin noisy though.
Neil
My engine brake is a button in the the floor . it is pneumatic and I think it probably shuts the exhaust down by about 90% maybe more. When the flap is rotated it only leaves the slightest gap for the gases to get through.
What is also important that when operated it instantly shuts off the fuel supply to the pump ( mechanical ) this ensures that there no combustion taking place and that it is only using the air drawn in naturally by engine rotation. The accelerator pedal goes solid and wont move . Strangely after prolonged use , maybe 15 minutes the engine temperature comes down as there is no combustion .
I also did many european mountain ranges this year, Pyrenees, Alps, Dolomites etc . using the exhaust brake is fantastic but very slow. It takes about the same time to go up the passes as it does to go down.
When operated ,the vehicle just doesn't go any faster on the down hill.
It's Bloomin noisy though.
Neil
We're doing portions of this: http://www.vibraction.org/road-books/espagne-portugal/road-book-5/
Mine too - but the there is a separate button to turn this feature off
part time nomad
Adventurer
For the exhaust brake to work correctly, when you are going down hill, you need to be in the gear you would be to get up it!
that means that it will be "revving like feck" (I am familiar with the terminology) also the larger the engine size the more efficient, I will often drive a truck for hundreds of miles and only touch the foot brake a couple of times.
On the Merc 1617 as Nick says it has an air operated cylinder that shuts of the exhaust after the turbo, that builds up a back pressure in the cylinders so it restricts the piston movement and slows the truck. it also is connected to the throttle linkage and shuts the fuel off, all done mechanically and quite efficient.
with Ian`s 814 the same as mine, it is done in a similar style but electronically through the ECU, as with most ECU based trucks you have a few option`s with it....automatic-comes on in throttle off, but regulated by the revs. brake assist- comes on while braking. manual- use on stalk switch when required. off!
As you say Ian they are not so good as the big trucks but are a help.
They can be so good on the older & big trucks, that their use on the "Mont Blonc" is banned at night, because they reverberate through the mountains so loud that it wakes all the inhabitants!
If you want a truly efficient system to retro fit, the best is an electronic retarder fitted in the drive line Telma and Webasto do them, they are so good that I have worked on trucks and coaches fitted with them that the normal brakes have seized up! through lack of use.
If money and weight were not an issue it would be a must, they are also progressive in use and can bring you to a stop.
Upshot Ian have it revving like feck to make it work.
that means that it will be "revving like feck" (I am familiar with the terminology) also the larger the engine size the more efficient, I will often drive a truck for hundreds of miles and only touch the foot brake a couple of times.
On the Merc 1617 as Nick says it has an air operated cylinder that shuts of the exhaust after the turbo, that builds up a back pressure in the cylinders so it restricts the piston movement and slows the truck. it also is connected to the throttle linkage and shuts the fuel off, all done mechanically and quite efficient.
with Ian`s 814 the same as mine, it is done in a similar style but electronically through the ECU, as with most ECU based trucks you have a few option`s with it....automatic-comes on in throttle off, but regulated by the revs. brake assist- comes on while braking. manual- use on stalk switch when required. off!
As you say Ian they are not so good as the big trucks but are a help.
They can be so good on the older & big trucks, that their use on the "Mont Blonc" is banned at night, because they reverberate through the mountains so loud that it wakes all the inhabitants!
If you want a truly efficient system to retro fit, the best is an electronic retarder fitted in the drive line Telma and Webasto do them, they are so good that I have worked on trucks and coaches fitted with them that the normal brakes have seized up! through lack of use.
If money and weight were not an issue it would be a must, they are also progressive in use and can bring you to a stop.
Upshot Ian have it revving like feck to make it work.
Excellent explanation. Going down the hill in the same gear as you use going up I have not heard in years. That truly applies to any vehicle. Using the engine HP to slow you down with the exhaust brake or at best to maintain the engine braking is expected. Remembering that diesels don't make vacuum. A jake brake is an expensive option but will pay off in brake service savings over time. That is if an engine retarder can be installed on the engine application.
Dragonsmaug
New member
I have an 814DA and decided to test mine as it did not seem to be as effective as it used to be, To test it I swapped the electrical connector on the air valve in the chassis somewhere just in front of the RHD passenger seat, I plugged in the connector for the transfer box and used the switch to change to low ratio and the exhaust brake plston appeared to extend fully and the butterfly valve in the manifold closed. With the engine running at tick over there was a loud hissing and some small leakage from the butterfly shaft. My conclusion is that the butterfly valve is ineffective may be burnt. A pig of a job to fix so we go down hills at a speed where normal engine braking does the job. Just setting of for South Africa
Regards
Chris
Regards
Chris
Exhaust brake does exactly that, restricts exhaust flow.
Engine retarder is very different and if not used properly can stall the engine. Its also an expensive option if its available for that engine. The higher the engine rpm, the more braking. Use at low engine rpm is hard on the valves.
Engine retarder is very different and if not used properly can stall the engine. Its also an expensive option if its available for that engine. The higher the engine rpm, the more braking. Use at low engine rpm is hard on the valves.