Pyro Port On Jake Brake

[HParfitt]

I was reading the info on the Jake brake. I noticed that they say that the jake brake has a port for a pyrometer. Would this port be pre or post turbo? Forgive my ignorance I'm a newbie to diesels.



Jacobs Info:

The Right Size, The Right Features.



A larger-diameter brake housing is designed to match the new low-restriction 4" exhaust system on 2004-1/2 Dodge Ram trucks. A shifter-mounted control switch allows for easy fingertip control of the brake. Plus, the Exhaust Brake by Jacobs includes a drilled and tapped port for installation of an optional pyrometer**, which allows you to monitor exhaust gas temperatures. Of course, the Jacobs Exhaust Brake is available for older Dodge Ram Heavy-Duty models as well (see chart below).

 

[cummins_crewcab]

It would be post since the brake goes on the outlet of the turbo.

 

[wyosteve]

Glad someone started this thread. I'm wanting to know the size of the 'port' for the probe. Is it 1/8 or 1/4 NPT. Getting ready to order gauges and want to get the correct one. Looks like a simple install, just remove the existing bolt/plug and screw in the thermocouple. Thanks in advance.

 

[DJaquez]

The size depents on who mfg's your guages, and who the supplier is. I recently bought a DiPricol EGT from a company and it came with a 1/4 adapter, they acted like I was crazy when I inquired about a 1/8 adapter. They also acted like I was crazy when I said the lighting was bad. Another Dealer helped me to get it squared away. Additionally the instructions they provided had been copied so many times that they were useless to me. When called I was treated like I was an idiot.



Genos Garage ship with both adapters. Depends on the size of hole you want to drill. I chose smalled becuase I can always make it bigger.

 

[wyosteve]

Thanks for the response. The hole is already there and tapped in the Jacobs exh. brake elbow. I plan to order from Genos so if they send both sizes I should be set.

 

[jelag]

Both the PacBrake and Jacobs have a 1/4" npt port infront of the valve on the exhaust brake... . It serves 2 functions... 1 - serves as a test port for testing the exhaust brake's maximum back pressure... . 2 - and can be used for a EGT gauge, post turbo.....

 

[rluft]

Can anyone tell me how to check the back pressure of the brake at idle?

Thanks.

 

[jelag]

Back pressure at idle is very low... . I'm guessing from what I've tested in the 15-20 psi... . There's not enough volumn from the turbo spinning or the expansion of the heated gasses to make it much higher..... you should never exceed 60 psi ..... above that pressure there is a good chance the back pressure will open an exhaust valve at the incorrect time... .



Jim