Digital Gauges and accuracy

[Archive]

Finished changing over my guages this weekend to the SPAs. Where on my old analog gauges, by the time I got off the Interstate and into a stop, the analog gauges indicated I was at about 250 deg. With the new digital gauges, the EGT (pre turbo) stays above 300 until I let it idle for a couple minutes. Then it cools to 286 fairly quickly and will drop slowly from there to 260. It will only go below 300 if idled. I'm confident the gauge is accurate because I checked at installation with a digital thermometer and read what the gauge read after installation. My running temps are consistent with what my analog gauges were reading which is about 650 running down the highway with 5/6 lbs of boost. All of this is to say, watch your cool down time and temps. I think I've been running on the edge of not cooling down enough. My analog gauges would show just over 200 after a good run and some slow running through the gears before stopping. I don't think the digital is necessarily more accurate but leaves less to interpretation.

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2001 HO 6 spd 2500, 4. 10 LSD, Towing Package, Electric Brakes, EGT/Boost Gauges, Running Boards, Fog Lights, Real Backup Lights

 

[Archive]

If everyone will forgive the reminder, I have the same truck, also with SPA guages, and also live in the South. Only difference, POST turbo mounting instead of pre. So here's the reminder: Post turbo temps drop slower than reported by Alan; in the morning, I have some downhill as I get close to work and I can usually arrive and shut down (=300) with less than one minute of idling in the mornings. But during the afternoon with temps in the high 90's, it generally takes me 3 or more minutes to get to the nice cool temps that Alan is reporting, and I've never had the patience to get down to 260. I suspect the "300" number has enough built in margin to cover the pre-turbo mounting choice, but, if you want to protect your turbo to the max you might want to go a hair lower than 300 before shutting down.

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2001 ETH, QC, LWB, 4WD, 3. 54, SPA Pyro & Boost, Leer Cab-high shell, Rear ARB locker

 

[Archive]

Does anyone with the SPA gauges see a minus reading on the boost gauge at idle or when off the pedal on downhill grades? Mine sits between -01 and -02 at idle and -01 to 00 on downhill grades. Is this normal or is there some calibration I have missed?

Thanks,
Ed

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1999 QC SLT 4x4 LB 2500 Cummins, 6 speed, HD.

 

[Archive]

Ed,
I see -01 with the truck at idle at times. There's a post on this somewhere. (about a month ago) I was told that it reads a vacuum.
I believe this to be correct. What I've done is to hold down the red button and start the truck to achieve a 00 reading at idle. Sometimes it will still show -01 but after driving a little, it will go to 00.

Steve

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Intentionally Left Blank for the Dodge Web Nazis

 

[Archive]

I have had the SPA in my truck for almost the longest of anyone (but perhaps MCrossley who mounted his faster)

My experience mirrored MCrossley in that the original temp sensor was too thin and broke off. My replacement (larger) sensor arrived promptly and has been no problem since.

The pressure sensor is mounted to the manifold fitting near the firewall. That sensor has been suffering from some accuracy issues which seems to be related to the wiring harness. When I suspect the sensor accuracy, I stop and wiggle the plug. That solves the problem for a time. SPA had told me to mount the sensor away from the engine and use tubing to link the sensor to the engine. I will try that eventually, the tubing kit I bought from IISPRO is kicking around in the truck somewhere.

When I crank up the HOT Edge with my DDI's, my 1250 warning light(via SPA setpoint) comes on pretty quickly. When I push the truck it takes time to cool below 300 before shutdown. Mounted in the manifold pre-turbo.

I am motivated to get the shutdown module completed for the SPA which MCrossley and I started on several months ago. Unfortunatly I simply do not have the time to do it.

David
(from a hotel in So. California)
http://www.joes-pond.com

 

[Archive]

Steve,

Thanks for the info. I guess the vacuum theory makes sense since the turbo is not turning much at idle.

Thanks,
Ed

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1999 QC SLT 4x4 LB 2500 Cummins, 6 speed, HD.