Drive pressure Gauge

[quadracer37]

if thats the case then thats not good is it? how would that happen?
i recently just put a new turbo on, well a very very low hour turbo. when my head gaskets where leaking and i had it all apart for the studs and new gaskets i found out my turbo was not in good shape so i purchased a used one from Tony B. when i got it from him it was pretty much bare, i had to swap over the waste gate and oil lines from my old turbo. there isnt a whole lot to i dont think i could have messed any of that up..
i have a PPE boost valve and i have my boost gauge plumbed into the wastegate line as well. my boost gauge does not fluactate rapidly at all like the DP gauge does.. if that makes any difference...

 

[kenny]

do your guys drive pressure gauge reading fluctuate quite a bit?
i've got an autometer cobalt 0-60 psi mechanical gauge, and im useing 5ft of coiled 1/4'' copper tubing. gauge is almost impossible to read, when im getting into hard the needle fluctates +- 20 lbs and the needle moves so fast you can hardly see it. (like i'll see a high of 45 or 50 psi, and it will move to as low at 25 or 30 psi, so fast you cant see the needle moving lol)
is this normal for the needle to be fluctating this much? seems like a liquid filled gauge would maybe solve this problem, or is it because im useing a mechanical gauge?

Try adding in a needle valve before the gauge and close it way off (not all the way) to remedy your exhaust pulsing your gauge picks up. Mechanical gauges are a lot more responsive, and will closely mimic these pulses worse than an electrical gauge would.

 

[othrgrl]

if thats the case then thats not good is it? how would that happen?
i recently just put a new turbo on, well a very very low hour turbo. when my head gaskets where leaking and i had it all apart for the studs and new gaskets i found out my turbo was not in good shape so i purchased a used one from Tony B. when i got it from him it was pretty much bare, i had to swap over the waste gate and oil lines from my old turbo. there isnt a whole lot to i dont think i could have messed any of that up..
i have a PPE boost valve and i have my boost gauge plumbed into the wastegate line as well. my boost gauge does not fluactate rapidly at all like the DP gauge does.. if that makes any difference...

I don't think you screwed anything up. I'm not a fan of boost read off the wastegate line though - I like to know what the motor is actually seeing after the intercooler.

Try adding in a needle valve before the gauge and close it way off (not all the way) to remedy your exhaust pulsing your gauge picks up. Mechanical gauges are a lot more responsive, and will closely mimic these pulses worse than an electrical gauge would.

I didn't think of this for some reason but yes each time an exhaust valve opens on that bank there will be a spike in pressure that a mechanical gauge will pick up on, especially if you drilled and tapped the manifold in front of an exhaust port.

 

[quadracer37]

well that probably explains my problem then, it is drilled and top at the very back of the manifold right out of the rear cylinder on driver side. same spot the hold is tapped for already on a BD manifold. so i will go to the hardware store and get a needle valve and put it inline between the copper and plastic tubing and see what that does.

so you drill/tap the turbo housing for the boost reading instead of putting it inline of wastegate?

 

[othrgrl]

so you drill/tap the turbo housing for the boost reading instead of putting it inline of wastegate?

No I drill and tap the intake before it goes to Y-bridge and into the motor. Where the passenger side boost tube hooks to the motor.

 

[TrentNell]

just a FYI when my waste gate opens it actually smooths out my dp gage needle .

 

[Whitetail Addict]

Okay, I know I'm digging up an old post, but is a drive pressure gauge that helpful on a fixed geometry turbo? Didn't find a direct answer when it was asked earlier.

If so what exactly do I need to hook it up...best location, plumbing, best gauge/readout etc?

Looking at it for more of a cylinder psi/tuning aspect.

 

[sweetdiesel]

Okay, I know I'm digging up an old post, but is a drive pressure gauge that helpful on a fixed geometry turbo? Didn't find a direct answer when it was asked earlier.

If so what exactly do I need to hook it up...best location, plumbing, best gauge/readout etc?

Looking at it for more of a cylinder psi/tuning aspect.

Depends on if you tune a lot I would get a gauge that is min double the pressure of the turbo or even tripple

mine comes out of the PS manifold 6" of stainless tubing to a braided hose to the sensor
I use a elctric gaauge from autometer because i like to log the DP instead of trying to watch it

 

[Whitetail Addict]

Cool...thanks Simon.

 

[DuramaxPowered]

Bringing this back to life.......... Where did you guys get the braided stainless hose? I was doing some work on my truck the other day and noticed that the copper line that i have now is kind of loose/wobbly in the fitting and I'd like to just swap the whole setup for one of those sweet stainless ones.

 

[Killerbee]

I have a bunch of -4 and -6 SS braid Teflon line, Aeroquip FWIW. Would love to sell it off.

 

[DuramaxPowered]

So it's standard Aeroquip Braided line?

 

[dmaxvaz]

I dont think teflon lined braided line will last long at 1000*f for long; HOOKED TO THE EXHAUST MANIFOLD

 

[sweetdiesel]

I dont think teflon lined braided line will last long at 1000*f for long; HOOKED TO THE EXHAUST MANIFOLD

X2
I use a 6" piece of SS tubing off the manifold so it doesnt melt the teflon