M35A2 boost and pryo gauges

[warhorse79]

I purchased a boost and pryo gauge from Hewitt Industries and I'm needing some help for the best locations to install the probes.

 

[m16ty]

For the boost gauge, there's a plug in the intake manifold you can tap into.

For the pyro, you need to drill the exhaust manifold right where it goes into the turbo. Most people say drill it in the back half but I honestly don't think it makes a difference. Drill the manifold with the truck running and it will blow all the shavings out when you break through instead of them falling down into your manifold and turbo.

 

[warhorse79]

I hooked up the boost gauge to the tapped port on top of the intake, is that correct? I notice the truck doesn't make any boost in neutral. At what point should the truck make boost?

 

[Flyingvan911]

It won't make any boost in neutral because the engine isn't really working. When you drive you'll get boost.

 

[61sleepercab]

Think of the turbo as waterwheel powered by the exhaust connected to a fan blowing into the intake. At idle ,little exhaust flow so low boost. When pulling a load is when the boost helps by more air into cylinders for fuel combustion when you really need it.

 

[steelandcanvas]

Put a little grease or cutting wax on the drill bit and tap to help keep the chips in check. If you do a search, you'll find some photos of the correct hole location.

 

[gimpyrobb]

Don't do it in the very center. There is a "rib" there. The exhaust has a front and back chamber.

 

[warhorse79]

Thanks guys, y'all have been a big help!

 

[donnerwetter58]

You can magnetize the drill and tap. The chips attract right to it.
Drill slowly and clean the chips a few times during the process.
While you're there, drill both manifolds. You can add a second thermocouple in the future.