It's no more stressful on your engine than applying power is. Big trucks have been using them for years pulling/slowing much more weight and go for hundreds of thousand miles with good maintenance. That really isn't a fair comparison considering most big diesels top out at 2100 rpm which is far below what our bikes turn, but you get my point. I didn't want this to turn into a pizzing match or anything, just find out if it is possible or not. Yes, I use my brakes too and don't have anything against them, but I also like being in the proper gear at all times which is another reason for downshifting. Makes me cringe everytime I see a guy come to a stop, pull in the clutch and just bang all the gears down at one time instead of one at a time , the way you should.

 

Here is one of THE best sounding diesels ever made ... the old 2-stroke Detroit. I'd love to roll down the mountain like this ... loud and proud!

Pretty damn cool this guy put one in a GMC dually, truck is a little ratty, but I would drive it!

 

I don't see the ACR's lasting all that long if they were used continuously. Whos knows though.

 

Missing one minor detail..

Typical diesels do not have a throttle blade..Air amount in is constant ( a few models do actually run a throttle blade but not many)

The throttle cable effects the amount of fuel supplied not air and fuel

Gas motor do.

When the air keeps getting sucked into the diesel engine it creates a run-on condition.. Air fuel heat compression =combustion

Gas motors have a throttle blade. Once throttle is let off blade closes.. Less air comes into motor.. Same effect as releasing the excess air with a valve.

Posting this quickly so if I missed or skipped something I apologize...

Now If you went with a flapper style exhaust brake......

 

Yep, you brought up a valid point I never thought of. I would still be curious to see if it would do anything or not.

 

Your are confused on how a Jacobs Exhaust Brake works. Opening the ACR will not create back pressure and slow you do you will get less drag.

 

No, and no offense, you're confused or misunderstood me ... I'm talking about a REAL jake, not a wimpy exhaust brake at all. I know the difference between the two and it's a big one, been trucking for half my life.

 

If you let off your throttle on your bike in the right gear for MPH with your RPM up you get your "BWAaaa". If you open your ACR under theses same conditions your bike would not decelerate as fast but should still have the "BWAaa". It would allow you a higher RPM while doing so and not lock up your rear tire. If you just want to **** off the neighborhood, sounds fun. Not sure your stock HD crank would be very fond of it.

 

Yeah, I know ... I already got that BWWWWWaaaaaaa now ... it would just be nice to have a little extra BWAAAAaaaaa along with some extra engine braking, IF possible, BUT I wouldn't want to hack up my wiring or screw anything up trying. Idk if it's even worth trying period until I know exactly how the ACRs work. #1, the ACR plunger/valve inside the combustion chamber is minuscule compared to the size of the exhaust valve which would hamper the retarding effect for starters.

#2, The reason why we currently have engine braking is from a high vacuum condition in the engine from the throttle valve being closed, the pistons are trying to suck in air that isn't there (which Tedwilliams09 reminded me of, that I forgot about) which gives any engine a retarding effect.

#3, This is why the way the ACRs operate is so important ... if they stay open continuously, then you would lose that high vacuum as the pistons comes down on intake because air would be drawn from the ACRs still being open so you would lose THAT retarding effect. BUT, if they actually cycle with engine revolution (like a real Jacobs Engine Brake does) and only opens right before TDC, it would have BOTH retarding effects from high vacuum AND also the loss of pressure downward on the pistons since the compression stroke is exhausted instead ... best of both worlds. The problem there that Ted explained is the volume of air is less with the throttle valve being closed. Like he said, most of your bigger diesels do not have a throttle valve so you get a constant volume of air at all times. Also the same reason a big diesel slowing down without a jake is almost like free-wheeling in neutral, you have no engine vacuum, our bikes have more engine braking than a big diesel does ... unless you turn the jake on, THEN you have engine braking.

#4, Do the ACRs have enough power to push the valves open right before TDC like a jake without the aid of hydraulic press like a jake? If not, what if you opened them just past BDC instead? That way you're still releasing compression without the sudden force of trying to open them right before TDC ... would be more of a gradual loss instead of a quick loss, not sure if the effect would be the same or not as in retarding ability.

Do I NEED to do this? ... no. Do I WANT to? .. yes! ... It's one of those "beat your meat" things you can do without, but would be cool to have. I was hoping someone knowledgeable with the actual workings of the ACRs would chime in here, but no such luck or they just don't GAS about this brainfart of mine, lol. From the sounds of all this, it would probably be easier to plumb a butterfly in the pipe for an exhaust brake instead of trying to turn the ACRs into a real jake, but I want the real deal or nothing. I know there are people smart enough in this forum to help me figure this out, but is it really worth it? ... probably not and will most likely die as another "pipe dream".

 

From the sounds of all this, it would probably be easier to plumb a butterfly in the pipe for an exhaust brake instead of trying to turn the ACRs into a real jake, but I want the real deal or nothing. I know there are people smart enough in this forum to help me figure this out, but is it really worth it? ... probably not and will most likely die as another "pipe dream".[/QUOTE]
The HD ACR doesn't do anything to your valves. It opens to release compression into atmosphere. It's drilled into the combustion chamber like manual ones but is hidden because you don't have to touch it.
Again, the stock HD crankshaft is really not the best thing to be pressing back on. It's a "good enough" part on the motorcycle, and would probably have a premature and catastrophic failure.
Yep best left as a pipe dream.