How do I turn up the Jake brake?

[PKozlowski]

Jelag, I really beg to differ on #1. I KNOW you can because I've done it!

I'm not trying to start a war or anthing here.

What we could do is start a new thread and see what people are getting

for temps at high idle. (would be interesting actually)



You have to remember that it's not just the EB being closed off it's that it's

running at 1200 rpms AND on 3 clylinders. Kind of like pulling a hill with the brake on. Yes it Will and Does reach those

temps with the EB on. It's pushing alot more fuel in there vs at regular idle.



I will video and post this for you the next time it goes to 3 cylinder idle.

This morning it was 16 degrees. I started the truck and it went to the high idle

(not 3 clylinder). I let it run for a minute then turned on the EB.

It went to 700 degrees. So if I double the work load of the engine(3 cylinder idle)

yes my EGT is going to climb and alot I might add.

Let me know what yours goes up to the next time it goes to 3 cylinder idle with the EB

on and I'll do the same.



Pete

 

[PKozlowski]

There are several miss nomers mentioned above... .



1 - on cold engine starts and warm up... all the exhaust brake does is back up some of the engine heat... . there is no way any of you on idle or fast idle could see the 1100* mentioned above... there just isn't that much heat produced from the engine at that time... . Are you sure you don't mean 1100 rpm for fast idle and not 100* F.



Jelag

This morning it is 5 degrees outside.

Fired up the truck and it went to the 3 cylinder idle

so I let it run for just a couple of minutes then turned on the EB.



I guess you were right and wrong, it only got up to 978 degrees.



So I guess there is no way any of us will could see 1100 degrees.



I almost did. AGAIN! And you back up my point with almost everything

you said in the post! LOL!



We are dumping some fuel in there when we're high idling

on 3 cyliners and pull the EB on and we're putting even more

in it by the looks of it.

Oh and it could only hold 1000 rpms NOT the 1200 it normally

high idles at(EB off). IF I would have touched the throttle to

bring it up to the 1200 rpms it would have easily went to 1100 degs.



So I actually think you miss nomer is a miss nomer.



Pete

 

[jelag]

Pete



Understand that I enjoy the banter... . it makes us all think and learn... .



I don't have EGT on my trucks to know from actual experience... . My early trucks had the HP turned up and we ran EGT... my current trucks are all stock from that stand point... . All I have to go by is what I've learned watching the engineers at PacBrake run some engines on their dyno's during testing..... and listening to what they have learned... .



What I was trying to say... . is that at idle we shouldn't see that kind of temperature because the engine is doing no work..... on the other hand when it goes into 3 cylinder mode... . to force the engine into doing more work and bring the temperature of the cooling system up... there might be that kind of exhaust temperatures... .



My last thought on this as I read some of these posts is that as the PacBrake and Jacobs do come pre-adjusted for back pressure... . I've read their information and have talked to their engineering... . I can't speak for the others... . but unless you fully understand the operation of an exhaust brake and have the ability to test the back pressure I highly recommend that you not change the butterfly setting... . We test every one we install before we deliver it to the customer... . but understand that if you raise the back pressure above the given specification you run the chance of opening an exhaust valve at the wrong time..... and they can hit the piston... I've never found one too high..... I guess that's good QC... . we do install some inline brakes made to fit 4 or 5 different engines and we are required to set those... they come preset to the lowest number for that series and we raise it as needed for the application based on the engine and valve springs on the exhaust valve...



Hope this helps.....



Jim

 

[PKozlowski]

Ok. I wasn't trying to fight to much.

I just knew what I saw on my gauge.



Dyno testing these things is great but you only get part of the story some times.

ie real wold at -35. It is going to push even more fuel in it LOL!!



I'm almost afraid to know what my back pressure was this morning.

Because if it was down to 1000 rpms vs 1200 it had to be alot.

Sure did warm it up quick.



I know I won't own another truck with out an EB that is for sure.



Pete