I got my boost and pyro gauges installed today.

My boost gauge doesn't show a constant boost reading, just surge readings. Then when I am cruising it goes back down to zero. Is this normal or do I have a gauge problem or boost leak?

My pyro is installed post turbo. What are the safe temps for shut down and accelerating with this setup.

I'm sorry if I posted this in the wrong area. I am also sorry if there are like 500 posts like this. Thanks for everyone's help.

 

Boost gauge corresponds to the load on the engine; at idle you shouldn't see anything, but cruising down the freeway on flatland should give you around 10 PSI.

Cummins specs our engines for 1250 degree continuous operating temperature. A lot of guys are known to peg the pyro on dyno runs and quarter miles, but that's the best way around to turn your engine into a cash register.

 

Them's pre turbo temps though.

Post turbo temp can be 300 to 500 degrees lower, depending on how worked the engine is or just was.


phox

 

My boost gauge drops down to zero when cruising and only shows boost when accelerating hard. I guess I have a boost leak or the gauge is not installed correctly.

 

So what temps should I go by?

 

Standard is don't exceed 1300 for extended periods, and shut down around 300.

Post turbo, subtract 500 on the top end, 300 on the bottom end, and you should be good to go.


phox

 

How much boost are you seeing when accelerating hard?

Should be topping out around 20 on a stock engine.


phox

 

Highest it got was about 29. Then when I stopped accelerating it dropped back to zero.

 

Ok, so I should shut down around 0 to 50 degrees and not exceed 900 degrees. I cruise at about 500 or 600 right now I beleive. I may be wrong on that.

 

Sounds good, guage works and no leaks.


phox

 

Sounds about right.

Pre turbo, I cruise between 800 and 900.


phox

 

Ok, so it shouldn't show a constant boost reading? I got the truck running 55mph at almost 2000 rpm and it was showing zero. I'm sorry for all the questions. Just want to get this awesome machine going good and right.

I will probably eventually move the pyro probe to pre turbo, but for now it'll stay post.

 

Depends on the terrain of that 55 mph.

Downhill or flat, shouldn't have much boost, uphill you'll see a lot more.


phox

 

I think you got problems with those boost numbers, either a leak, bad gauge, or a blown turbo. Best way to diagnose would be to put that egt gauge pre turbo and let us know what your real numbers are. If they seem high for your stocker, it will be easier to tell if you have sufficient boost or if you've got problems. Just my 2 cents.

 

Will do. I am going to have the probe moved tomorrow. I sure hope it's not a turbo problem. Would I see any other problems if it was the turbo? Turbo sounds good. But I am new to this so I dunno.