Turbo Whistle on DSE (NON EGR)

aerofabrique said:

With the above in mind could a jake brake or exhaust brake be easily fitted to the P38 (e.g. for use when towing)?

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The back pressure should crack the head nicely. If you are towing a heavy trailer, if the overrun brakes are correctly adjusted there is little extra load on the tow vehicle brakes. If you want a better arrangement, electrically operated trailer brakes are available linked to the tow vehicle brake pedal

jerrytlr said:

Interesting thread.

. I will fit the silencer backwards so it makes the dump valve noise louder rather than quieter.

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If you do this wont the silencer draw air in rather than let it out

I guess nobody spotted his 'April fool' then....

What the ring silencer?

Either a bit tongue in cheek or someone with the mechanical knowledge of a crushed grape.

Well it was a day late.... another failed attempt at humour on my part ;-)

Resuming normal (vaguely serious) mode: I though a Jake Brake works by forcing the exhaust valves to remain closed, on the exhaust stroke, i.e. it is a fairly complex revision of the cylinder head mech. Shouldn't cause the head too much grief as the load is much less than when you are squirting loads of diesel in and causing big explosions, but would be nigh on impossible to retro-fit....

Cheers

Jerry

jerrytlr said:

Well it was a day late.... another failed attempt at humour on my part ;-)

Resuming normal (vaguely serious) mode: I though a Jake Brake works by forcing the exhaust valves to remain closed, on the exhaust stroke, i.e. it is a fairly complex revision of the cylinder head mech. Shouldn't cause the head too much grief as the load is much less than when you are squirting loads of diesel in and causing big explosions, but would be nigh on impossible to retro-fit....

Cheers

Jerry

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Think there maybe a less complexed version that just blocks the exhaust and gives braking that way. Not the true Jake brake but generically know as such. Nice one though.

Errrrrregrrrrrrrrr I must of got vacuume'd in

wammers said:

Think there maybe a less complexed version that just blocks the exhaust and gives braking that way. Not the true Jake brake but generically know as such. Nice one though.

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Too curious and it is lunchtime so I just looked it up - you are right, there is an exhaust block version too Not sure what happens to the exhaust gases when it is activated though, the article I read implied that they are stored, presumably in some kind of compressed air tank?! (the system is silent so avoids the controversy).



Cheers

Jerry

jerrytlr said:

Too curious and it is lunchtime so I just looked it up - you are right, there is an exhaust block version too Not sure what happens to the exhaust gases when it is activated though, the article I read implied that they are stored, presumably in some kind of compressed air tank?! (the system is silent so avoids the controversy).



Cheers

Jerry

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Don't know a lot about them to be honest but think the exhaust block brake is fitted to some Volvos. With throttle shut and exhaust shut the engine will brake on what would be the compression stroke and on what should be the exhaust stroke.

A Jake Brake goes a step further, and actually turns the engine into an air compressor to provide a great deal more braking power. Compressing the air in the cylinder takes power. If the engine's drive shaft is
turning the engine to brake the vehicle, the power used to compress the air is braking power. However, that power is stored in the
cylinder, so if you let it, the compressed air simply pushes the piston back down.
Therefore, you don't really get any braking at all from the compression stroke on an unmodified engine.
A Jake Brake modifies the timing on the exhaust valves so that, when braking is desired, the exhaust valves open right as the piston reaches the top of the compression stroke. The energy gathered in the compressed air is released, so the compression stroke actually provides braking power.
The main advantage of a Jake Brake is that it saves wear on the normal brakes. This is especially important on long downhill stretches.
The principle behind the Jacobs Engine Brake engine retarder is simple. It's a hydraulically operated device that converts a power-producing diesel engine into a power-absorbing retarding mechanism by opening the engine's exhaust valves near the top dead center (TDC) of the
compression stroke. The engine creates a distinctive sound while in operation, but is barely noticeable if OEM-quality exhaust mufflers are maintained on the vehicle.

In a compression release engine braking system for a turbocharged internal combustion engine, excessive stress associated with opening the exhaust valves of the engine near top dead center of engine compression strokes when the engine is turning at high speed is prevented by reducing the intake manifold pressure from what it otherwise would be at that high speed. This is done by retarding the turbocharger so that its speed is less than it otherwise would be at high engine speed. Turbocharger retarding can be accomplished in any of several ways such as by restricting the flow of engine exhaust gas to or from the turbocharger, or by allowing a portion of the exhaust gas to bypass
the turbocharger.

Copy and past skills rather than mechanical knowledge I'm afraid (yes committing forum suicide i know) ... wont be trying it anytime soon seeing as there's no product already on the market for the engine. Food for thought really, perfectly happy with the P38 as is - otherwise wouldnt have brought in the first place.