[Vwdiesel] Re: Turbo Diesel Exhaust Brake?

Tyler "Casioqv" Backman casioqv at usermail.com
Sat Jul 26 23:53:03 EDT 2003

I think I will try the intake throttle plate method first, as it seems
the cheapest, simplest, and easiest. Hopefully it will provide a
noticeable increase in brake power. When I install my intercooler
(another project) I will install a large throttle body from a gasoline
car (or truck) in the intake pipe just before it goes into the intake
manifold, and it will be connected to a cable which will be activated by
pulling a old style "choke" knob when the engine is as high rpm (I don't
want it to work off the brake pedal, because it might kill the engine if
the transmission is in neutral or the clutch is in, which could result
in dangerous loss of brake assist during a hill decent). A double
benefit of this valve, is that it might provide a stronger vaccum than
the vaccum pump, and allow for decreased braking effort on the factory
brakes. The factory overboost blow off valve will be relocated before
the valve, and prevent damage to the turbo or intercooler from excessive
pressure. As far as an exhaust brake goes, I think I could keep the
pressures from the exhaust brake low enough that it doesn't push the
exhaust valves open (with a large enough orifice in the valve), but
don't want to risk piston to valve contact on my newly rebuilt engine if
I don't get it right the first time, and don't really want to mess with
designing such as valve that can take that kind of heat and pressure
from the exhaust.

1983 Volvo 760TD
1984 Volvo 245D

Roger Brown wrote:
> There are at least 3 types of brakes, the "Jake" brake does alter the valve timing, basically turning the engine into an air
> compressor and shutting off the fuel.  Then there are exhaust brakes that close off the exhaust to raise the back pressure.
> They often require extra strong exhaust valve springs to be installed to keep the back pressure from popping them open.  Then
> some diesels use intake throttle plates to cause the engine to pull a vacuum under braking.
> --
>     Roger

More information about the Vwdiesel mailing list