Hey guys. At high rpm and low speed I see 35 psi boost, but at highway speeds (65+) I see like 22psi and thats with it floored. I think I hear extra hissing. I have the intercooler with the plastic ends. Whats the best way to pressure test everything? Kevin

 

you dont have a boost leak. . .however what you are seeing is the delay of the wastegate opening up.

if you did have a boost leak you would hear a pretty loud hissing and you wouldnt be able to get over 5-8psi floored and the truck would smoke pretty bad.

 

Hey Drew. Well, is what I mean is I usually always hit 35 psi no matter what speed or rpm I`m at. (because of the edge juice) My edge is almost always set at stock, but even if I set it at 1,2, or 3 the boost only goes up to 22psi. I was thinking maybe theres a leak only at higher pressures. I scanned it and have no codes, I just don`t know why the boost is lower then it has been. I have 82k miles. Thanks. Kevin

 

so what your saying is you boost numbers are lower when the edge is turned on???

 

Like drew said usually if you have a boost leak it is very noticable and you will usually hear it and not have any power, black smoke and the like. Not exactly sure on the cummins, but on powerstrokes it is almost always the rubber boots on the connecting parts of the CAC tubes

 

Well, if I`m at a stop and floor it the boost goes up tp 35psi and rpms are around 3k. If I`m on the highway going 70mph and floor it the boost pressure goes to 20, and slowly rises, 21, 22, 23 and thats it. I almost always have the edge set at stock, but the boost fooling is always on. I turned the edge on just to see if the boost would increase and it did not. Power feels ok, its just the boost is low unless I`m at 3k rpms. I could disconnect the edge from the mapp sensor to see what I get. I was thinking ithasa small leak, and when the rpms are high the turbo can overcome the leak, but when the rpms are lower with it floored the pressure can`t build past 22-23psi. Maybe I should disconnect the edge next. I`ve had it on so long,I don`t remember the factory boost pressure. Thanks again. Kevin

 

my 2000 gets 30 psi of boost with the edge on stage 1 about 23 stock thats with brand new lift and injector pumps if that helps !

 

That's not too unusual, really. You have to look at what you're doing....

From a stop, the TC is unloacked and the motor spins up fast and the wastegate can't react as fast as the RPM's are coming up. So even on stock, you can see those numbers jump up into the 30-35 range and then settle back down.

On the highway, when the TC is locked and you're already making a bit of boost pressure, the waste gate has a little time to react and it's limited to around 26-27 psi in stock form.

Once the Edge is turned on, assuming you've manipulated the boost numbers, that is still not too unusual.

In order for the boost numbers to come up quick, the engine RPM has to come up quick from relatively low numbers on each.

From a stand still and up to about 45 or so, if I stand on it I'll bounce off the boost limiter pretty quick. I have mine set for 40 psi to defuel and the alarm goes off at 38 psi.

Now on the highway, unless I get deep into the throttle w/ the T/H mode OFF and the TC unlocks, my boost number don't climb much past the 30 mark.

You're probably just fine. I wouldn't say you have a leak. You'll notice a boost leak REAL FAST. They do not come on subtly. Where ever it happens, you get a VERY loud, POP......HISS!!!

Just ask a 6.0 Powerstroke owner, they are very familiar with that noise.

 

not only that but you have to have the engine under LOAD. i dont think driving unloaded will raise it that much. What we do at work is spray soapy water on all connections. (if you have air to air tester. Its plugs that you use to isolate air to air etc.. to test for leaks. ) also since you say you get 30 psi at idle with pedal down while pedal is down get someone to spray soapy water at air to air connections etc...

 

what baffles me is that you get LOWER boost with the edge juice? is this even possible if anything the edge juice should raise your boost psi