New drive, boost, and pyro gauges

[dordtrecht5]

Bought some different gauges from Kennedy Diesel. They are Hewitt Industries. Dual boost is for boost and drive pressure and the pyrometer. That is the first time I have checked drive pressure (eeek!).

This picture is cruising at 72mph. Green needle is drive and red is boost on top gauge.


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[Slammed2007Lbz]

Those gauges are really nice! But i thought 1-1 drive pressure was really good? It looks like you are about 1-1 i have heard some guys running 3-1

 

[rgullett83]

I like

 

[dordtrecht5]

Thanks.

Well, that is just at cruising speed. Very little throttle input, load, etc. If you saw what it was at WOT, lol.

It peaked at 80lbs for an instant when the tires lit and maintained about 70lbs with a hair over 30lbs boost. It's 2:1 driving normal acceleration in town. Drive pressure needle stays busy in town with all of the shifting gears.


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[TeaBagger2006]

I saw 75 drive and 35 boost on mine. What size is that guage? 2 1/16?

 

[dordtrecht5]

Yes, your standard 2 1/16.

Maybe someone could help me with a problem though. I would like to get the lights on the gauges to the dimmer switch. The instructions just tell me to go to the accy. I'm not sure I like it with the gauges lit like that.

Which wire do you tap into on an 06 for the dimmer?


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[Burn Down]

I'm not sure which wire on your 06'? I just used my test light and found a wire that dimmed with the dial and used it for my gauges...

 

[Houser04lly]

x2 on that

 

[Harbin_22]

Mine was an orange wire behind the dimmer. Not sure if it is the same though. My boost/drive is around 58#/70ish#. On my biggest tune. That is a neat idea having them combined

 

[crazycrew]

How much was that gauge if yo dont mind me asking? You can PM me if you'd like

 

[dordtrecht5]

Mine was an orange wire behind the dimmer. Not sure if it is the same though. My boost/drive is around 58#/70ish#. On my biggest tune. That is a neat idea having them combined

Nice! Thanks for the heads up on the wire.

Thanks for the suggestion about the dimmer from the other guys as well. I never thought about using a test light to find it. I was kind of in a hurry and was getting frustrated with the s.s. fitting on the drive at the manifold.

I really like these gauges.


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[dordtrecht5]

How much was that gauge if yo dont mind me asking? You can PM me if you'd like

$90. John is very fair on his prices. It comes with two 8' nylon tubes and (2)1/8 NPT 90°, (2)1/4MPT-1/8NPT, and (2) 1/8 NPT (3/16 tube fitting).

The only thing that it doesn't come with is copper tubing and a stainless compression for exhaust manifold. It was a PITA finding that part were I was in SW Kansas. I went to an oil well shop to finally get what I needed.


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[[email protected]]

im new to duramaxs and im trying to learn all i can what is the drive pressure and y should you watch it? thanks!

 

[dordtrecht5]

Drive pressure is the amount of air that is pushing itself into the turbine housing on a turbo. Boost pressure is just the opposite, it is the amount of air coming out of the compressor housing into the engine. Ideally you want these two numbers to be 1:1. The higher the drive pressure, the less efficient the turbo is working and the more likely failure to happen to the engine and/or turbo.

The way drive pressure is measured is by tapping into the exhaust manifold and using a pressure gauge. Copper tubing at the manifold, coiling it at 5'-6', attaching a nylon tube to it and then nylon to the pressure gauge.

So, to put it as simply as possible; your monitoring both sides of the turbo: turbine (driven by the exhaust), and boost ( created by the compressor side of the turbo, which is spun by the turbine).

Hope that makes sense to you and helps.

In addition to all this, on a stock turbo (what I have) it is virtually impossible to have any high performance out of the turbo without high drive pressures. Tuning plays a key role in drive pressure, but so does picking the right turbo for the application. With my turbo, I could help it out with another turbo, compounding the amount of air coming out of the compressor and into the engine. In this application the drive pressure would likely be about the same, depending on how it's tuned, but I would be creating more boost. I would be getting the ideal ratio closer.

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[[email protected]]

thanks i get it now! so if you have a large laggy turbo drive pressure would be high till it lits?

 

[dordtrecht5]

I have never seen drive pressure on a big single, so I can't speak concerning them. It is usually the smaller turbine housings that have higher, out of ratio drive pressures. The reason is because the turbine blades don't have enough area to move exhaust


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[RoboF16]

Nice stuff.
I've been wondering what drive pressure stock turbos generate, thanks for posting. I changed all of my stuff at once and didn't get to do the before and after check.

WRT to the drive pressure gauge, I highly recommend a compressed air type filter with a condensation cup. I was shocked how much soot and water collects in the bowl, not pretty.
Also I reversed the spring on the bowl drain such that it defaults shut and has to be drained manually. Too noisy otherwise – ticking noise at low boost, etc.

 

[dordtrecht5]

Is that a brass compression into the manifold?

Before I put the compression in I checked the melting temp of brass. I decided to go with stainless. As I mentioned before, it was a PITA to find the fitting.

I like your setup. Looks nice!


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[RoboF16]

Before I put the compression in I checked the melting temp of brass

I was worried about that too but every post I found was using brass with no issues and so far so good for me.

 

[dordtrecht5]

Robo, what do you see for drive with those manifolds and the 4094 you have listed in your sig? I'm curious to know what the differences are with that along with tuning.