Turbo Boost guage

[peterbylt]

I plan on installing a Boost pressure gauge in my MCI 96A3, 8V92TA all mechanical engine.

Would the Plug that I circled in red in the Picture be the correct place to tap in the line I would run up front to the Gauge?

I plan on installing about a foot of copper tube, and then switching over to ¼ inch plastic tube running the remaining 35 or 40 feet to the dashboard.

Peter   

[plyonsMC9]

I had earlier posted a question about those using any AI for troubleshooting.  In the interests of answering Peter's question, and trying out AI, I pushed this question up to ChatGPT5.  https://chatgpt.com/

I would first say take everything with caution.  But it looks like some/all may be helpful.  Even feedback on the picture from Peter.

If not interested in anything from AI - please skip this!

Else, here it is, and hope it helps, 


You said:
where do I mount the sensor for a turbo boost gauge in a 1989 MCI 96A3 bus?
ChatGPT said:

To mount a turbo boost gauge sensor (also called a pressure sender or MAP sensor) on a 1989 MCI 96A3 bus, you'll need to tap into the intake manifold pressure after the turbocharger but before the intake valves. This will give you an accurate reading of boost pressure. Here's where and how to do it:
✅ Sensor Mount Location:

1. Intake Manifold (Best Option):

    Look for a vacuum or boost reference port on the intake manifold.

    If none exist, you can drill and tap a 1/8" NPT fitting into the manifold.

    Use a brass barb fitting or threaded sensor port depending on your gauge setup.

2. Charge Air Piping (Alternative Option):

    Tap into the charge air pipe between the turbocharger outlet and the intake manifold.

    Be aware: readings here may not be as accurate due to pressure drop across the intercooler (if equipped).

⚠️ Important Tips:

    The Detroit Diesel 6V92TA engine (most common in MCI 96A3) usually has a boost reference port on or near the intake manifold already.

    Use steel or brass fittings rated for pressure if modifying or tapping.

    Route the sensor or hose away from heat sources (like exhaust manifolds or turbo).

🛠️ Tools & Materials Needed:

    1/8" NPT tap & drill bit (if tapping)

    Boost gauge sensor or MAP sensor

    Hose/fittings (if using mechanical gauge)

    Thread sealant (for any fittings)

Would you like help identifying a specific port on a photo or diagram of your engine? If you can provide one, I can point out the best place to mount the sensor.


You said:
<<< Phil - PlyonsMC9 attached the picture Peter attached >>>>

ChatGPT said:

Thanks for the photo — that helps a lot.

You're looking at the Detroit Diesel 6V92TA engine, and the image clearly shows the turbocharger, exhaust housing, and part of the intake manifold. The area you circled in red is on the intake side of the blower, right where we want to focus for boost pressure.
✅ Boost Sensor Mounting Location:

Yes — the area you circled is a good candidate for tapping into boost pressure.

This section is on the blower housing (above the roots blower, under the turbo), and post-turbo, so it's where manifold pressure builds. On many 6V92 engines, that casting has a flat boss or plug specifically for pressure fittings or sensors. If yours isn't already drilled and tapped, that's exactly where you'd do it.
🛠️ To Install the Sensor Here:

    Inspect the circled boss area closely — some engines have it already tapped and plugged with a pipe plug.

        If plugged: Remove and install a boost hose barb or sensor fitting.

        If solid: Drill and tap it (usually 1/8" NPT is common).

    Use a right-angle adapter if clearance is tight.

    Route the wiring or boost line cleanly away from the turbo/exhaust heat. Use heat shielding if necessary.

⚠️ A Few Warnings:

    Be cautious while drilling/tapping near the blower — don't let metal shavings fall in if the engine is assembled.

    If uncomfortable drilling/tapping, have a diesel or turbo shop do it — one wrong move and you're into a major casting.

Would you like a diagram or sketch showing exactly how to install the sensor and route it from there?
You said:
yes
ChatGPT said:

Phil note:  etc., etc., etc,. continues.. 

[luvrbus]

Yep that where can install it, check it may have another plug on the opposite side,you will need more than foot of copper or steel to get  the DOT tubing away from the heat or it melts,I don't use copper I use steel brake line tubing cheap and easy to work with,DD never used copper tubing anywhere on those engine.That area with the hot housing for the turbo gets hot with the 8 to 900 degrees exhaust spinning the turbo,You won't see high turbo boost reading on the engine so don't worry about it they are happy at 5 to 10 lbs for normal driving and maybe 20 lbs under a hard pull

[peterbylt]

Just the info I needed.

Thank You for the responses.

I will be getting most of the parts needed today.

I will take the suggestion and use at least 3 foot steel brake line.

Is there a favorite boost gauge everyone uses?

Peter

[luvrbus]

There is a big assortment I  used the VDO  2in  30 psi you don't need anything over 30 PSI they are easier to read than a 60 PSI gauge, there is lot of cheaper Chinese made gauges but they don't last long ,Most of the better boost gauges are 1/8th in ,I use 1/4 in  and reduce it on the gauge the distance on a bus the 1/4 inch reads faster that the 1/8th line

[Iceni John]

That's exactly where I used to have a Cold Start ether injection nozzle previously fitted, but that's now gone.   I used half of a 10-foot roll of 1/4" copper tube before joining it to 1/4" DOT air line to the gauge.   I have a VDO 150-052 30PSI boost gauge (made in India), but the DayGlo orange paint on the needle has now completely faded to white!   The most pressure I've ever seen was 26PSI, but mostly it maxes out at about 23 or 24 PSI.   When climbing long 6% grades in hot weather I keep boost to no more that 18PSI, and doing that with a 3/4 throttle in 3rd gear keeps the coolant at about 200F.

John

[luvrbus]

All the VDO gauges I have are made in Germany,I guess the Germans found a cheaper source of manufacturing

[peterbylt]

This looks like the one to get.

https://www.summitracing.com/parts/vdo-150052?srsltid=AfmBOooG0m_0vLlQ0pq24DiDxeDHnlHlgJgx8a8O-Wro6Fs7Sh_8P0ab5Ww

Peter