7-14 psi turbo boost when engine compression brake engaged

Thanks Brett... enough said on this subject.

Guys,

Attacking another's ideas or opinions is fine.

Attacking THEM IS NOT.

Please, let's all remember that and "play nice".

Somebody sounds scared to get real data...

Did your mother not give you permission to learn anything today?

A.. H..., this subject is your third in the last year in the Class A section and most who post in the Class A more often know that a 04 MH can have a 03 engine. I actually saw a 08 Monaco with a 06 engine. I do not have a VGT so your late 02 is off by a year or more. Granted the C brake was an OPTION starting in 2000 on the ISL. Let me repeat... I do not have a VGT... I do not have a C brake. There is nothing wrong with my engine/Jake brake which builds pressure. No I'm not going to take my MH out at your COMMAND and do your dumb tests. You need to stay in the towing and fifth wheel sections that you like so much. I made my judgment of you several posts ago. L&K

Ivylog wrote:
A.. H... What part of "we do not have C brake" do you not understand? Guess we both have the same problem as we both build boost.

F...F... D...A...
Never said I didn't understand.. Simply said you are providing small bits of information and expecting us to read between the lines. Simply put your sig says '04. '04 ISL 400's were equipped with C brakes, actually started in late '02. So either your motor isn't an '04, or an '03 build, or you don't know what you have. I'll reserve judgement.

The OP has an '03 DP so it is likely he has a C brake so that wouldn't put you in the same issues. I have decided you are suffering from a case of RCI, which is probably causing most of the aforementioned issues.

Start actually discussing or stop posting a waste of useless info. Providing just a tiny bit of details would actually make the information useful but that seems to be well beyond you.

If you only build boost on the compression brake then i would say something is awry, but I suspect you will find the boost is there regardless of brake operation or no. One has to to be able to understand and correlate the information presented to them or it's useless. Again I'll reserve judgment.

A.. H... What part of "we do not have C brake" do you not understand? Guess we both have the same problem as we both build boost.

What in either of your posts says you don't have a C Brake? Maybe you should elaborate?! Or are you having fun being a waste of posts? By the bottom of your post, called a sig if you want to talk like you know something, both of you have MY DP's that would have C Brakes with the ISL's you both identified.

Cummins implemented the C brake on the ISL 375/400 around 2002-2003 which means you should have it. It is still a 2 stage Jake brake with added retarding power that comes from building boost to aid the compression release side... makes sense as your seeing boost while braking (thou you seem unwilling to determine if you have boost while not braking).

If you have both have an older enigine that your MY DP then you may have a traditional compression release brake, but it will NOT be the source of your boost while braking.

Stop being argumentative and answer some questions and provide some info, or go away as your not really being helpful just wasting space.

You foul one step further an post your ESN and I'll use my Cummins account to get all the data needed.

Delete

A. H., look at the bottom of my post and the OPs. We do not have C brakes... just two stage Jake brakes. You now rate this :S and there is a BIG difference between a DP and PU.

Ivylog wrote:
"A H" you might want to look at my post on 08/27/15 at 01:24pm... 7th from the top.
I do not put my Allison in N while moving and I did not miss your question nor the edits to your post.

Your still not paying a lot of attention to what I am writing. The ISL 400 uses a C Brake. It is a Combination brake that raises boost with the VGT to enhance the compression release brake. The boost increasing is not a function of the compression brake which is what I have said since my first post. Re-read all of my posts. You keep telling me to look at your post over and over, yet there isn't anything there I haven't addressed. Not sure where your comprehension issue lies.

It sure looks like you are missing something, such as how the different type of brakes work and their effect on the engine/airflow.

Go run those tests and report back.

JetAonly wrote:
A compression brake forces the engine to do work. The air exhausting the engine is hotter than the air entering it by the amount of work done in compressing the air. Adiabetic heating. The turbine continues to extract work from the exhaust gases which produces boost.

Fuel, after all, is just a way to heat air so it expands.

Compression does increase temperature and the rapid pressure drop as the ~500 psi leaves the cylinder will then cool the air and reduce its velocity. Some of the energy is also used to make the nice sound we all either love or hate.

7-15 psi of boost takes a lot of turbine flow to sustain.