Cheap Boost Gage - PeachParts Mercedes-Benz Forum

Dan Stokes · #1 05-15-2015, 09:43 PM

I needed another boost gage to read exhaust manifold pressure in Mutt and for some reason I thought to look at Harbor Freight. Sure enough they had them, with multi-colored light display (that I'm not using). Anyhow, it was like $17 or something. Evidently they bought a boatload of them for cheap. Anyhow, it seems to work OK - though I can't vouch for the multi-colored lights.

Dan

DeliveryValve · #2 05-15-2015, 09:51 PM

Any pics of the setup? Also what type of line you used to the exhaust manifold?

tbomachines · #3 05-15-2015, 09:56 PM

I did the same, super easy, tapped the vacuum line off of the intake manifold and plumbed it through the firewall. 3 wires were ground, 12v and constant

Sent from an abacus

tjts1 · #4 05-15-2015, 09:56 PM

Wouldn't an EGT gauge be more handy?

The problem with most of the boost gauges on the market is they also include a vacuum section which is kind of useless on a diesel.

Simpler=Better · #5 05-15-2015, 10:23 PM

The super cheap it to get a $5 tire pressure dial gauge (which typically has a 1/8NPT fitting) and hook that up

Auber instruments sells ~$75 EGT gauge setups, FYI

Dan Stokes · #6 05-15-2015, 10:55 PM

I already posted a pic of the set-up in another thread so I can't repost it - sorry. Darn if I can remember the name of the thread but I didn't originate that thread. Basically I used a loop of copper line off the exhaust manifold to dissipate the heat before connecting to the provided plastic line. For a boost gage the provided line would be fine.

Anyhow, I have an Auber EGT and a boost gage in the dash. The extra boost gage was to calculate the pressure ratio to help diagnose the boost issue with the race truck. I'll remove it now that we know that's OK. Must have EGT and boost pressure in a race truck!

I just thought some of you folks might like a cheap alternative - and readily available for many of us.

Dan

vstech · #7 05-15-2015, 10:59 PM

I've got the same gauge in my truck, and TD124

m1tch · #8 05-16-2015, 04:03 AM

I just bought a basic one on the bay of E, make sure you go for a mechanical one (eg the vacuum/boost goes directly into the back) - the stepper motor ones can give incorrect readings if there are any electric issues.

tjts1 · #9 05-16-2015, 04:47 AM

I have this EGT gauge and sensor in the 300D. It fits perfectly in the ashtray.

http://www.ebay.com/itm/EGT-Gauge-Red-LED-for-Exhaust-Temperature-Sensors-with-Weld-Bund-Combo-Kit-C-/251958514377?pt=LH_DefaultDomain_2&hash=item3aa9e5d2c9&vxp=mtr
I had to get a separate NPT to metric adaptor to attach it to the manifold.

funola · #10 05-16-2015, 11:32 AM

Quote:

Originally Posted by tjts1

I have this EGT gauge and sensor in the 300D. It fits perfectly in the ashtray.

EGT Gauge Red LED for Exhaust Temperature Sensors with Weld Bund Combo Kit C | eBay
I had to get a separate NPT to metric adaptor to attach it to the manifold.

NPT to metric adapter?

Per their specs below, the threads are 1/8 NPT on the probe and weld bung. Is that a mistake and the threads are actually metric?

Specifications

EGT Probe

Probe Material : Stainless Steel 304

Probe Diameter : 5mm (0.2”)

Probe Length : L1 80mm (3.15”) L2 30mm (1.18”)

Threads : 1/8” NPT Adjustable Compression Fittings

Cable Length : 2m (6.6’)

Cable Insulation : Fiberglass braiding with stainless steel overbraiding

Type : Ungrounded

Connector : Spade connector

Temperature Range : -200 ~ 1250 degree Celcius (-150 ~ 2300 F)

EGT Gauge :

Display Range : -200 ~ 1250 Celcius

Display Type : 4 Digit LED (Red)

Dimensions : 79W x 43L x 25D mm (3.1" x 1.7" x 1")

Panel Cut : 74 x 40mm (2.9" x 1.6")

Accuracy : +/- 1%

Power : 12VDC

Weld Bund with Plug

Material : Stainless Steel

Threads : 1/8” NPT

Outer Diameter : 0.5" (12mm)

Length : 0.6" (15mm)

tjts1 · #11 05-16-2015, 12:53 PM

Quote:

NPT to metric adapter?

Per their specs below, the threads are 1/8 NPT on the probe and weld bung. Is that a mistake and the threads are actually metric?

Didn't use the weld bung. The hole in the manifold is metric.

http://www.ebay.com/itm/291463706244
With the adapter its all bolt in.

funola · #12 05-16-2015, 03:41 PM

Quote:

Originally Posted by tjts1

Didn't use the weld bung. The hole in the manifold is metric.

Metric Gauge Adapter M10x1 Male x 1 8 Female NPT Male to Female Brass Union | eBay
With the adapter its all bolt in.

M10 x 1 is very close to 1/8 NPT. I have screwed a Tee adapter with male 1/8 NPT threads into the oil pressure port on a VW cyl head that is M10 x 1 with lots of teflon tape (the thick gas/ yellow stuff) and it's been fine for 4 years now with no leaks.

tjts1 · #13 05-16-2015, 04:30 PM

Not sure lots of Teflon tape is a good idea on a part that will see close to 1000f on a regular basis.

Zacharias · #14 05-16-2015, 04:30 PM

Quote:

Originally Posted by tjts1

I have this EGT gauge and sensor in the 300D. It fits perfectly in the ashtray. I had to get a separate NPT to metric adaptor to attach it to the manifold.

Can you change the colour of the readout? I would find red 'moving' numbers irritating at night. If that display fills the ashtray area it's pretty big....

Edit: DOH. You mean it fits into the ashtray, right?

tjts1 · #15 05-16-2015, 06:30 PM

Quote:

Originally Posted by Zacharias

Can you change the colour of the readout? I would find red 'moving' numbers irritating at night. If that display fills the ashtray area it's pretty big....

Edit: DOH. You mean it fits into the ashtray, right?

No, can't change the color or brightness but I've seen blue and yellow versions on ebay. I though the display might be annoying at night too but it wasn't too bright especially in the low position outside my normal line of sight. Its about the same brightness as my center console turned to max.

The wire from the sensor was long enough to go all the way to the ash tray through the AC pipe hole in the firewall.