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I want to add a universal tach and a vac/boost gauge (not yet purchased) and have a few questions.
1) Where can I get an rpm signal from? (Don't want to use sensor and magnet.
2) Will keeping the motor below boost save fuel or harm anything?
3) Doesn't appear to be much room to mount them anywhere viable; Any ideas?
Why do you need a Tach? Just to have one? On the boost lower boost means less drive pressure which means less fuel is being burnt. Therefore less boost. It will not hurt anything. I would look at an egt gauge and a trans temp as well if you have an auto before a Tach. Much more important as you have a Tach on the dash already. Not sure where to get signal from.
And a pillar or above the mirror gauge pods are available. Riff Raff also has an f650 pod that goes down below the heater controls. Steering wheel pods and I believe the SD have the option if 2 that fits place where the OEM gauge bezel is.
I like the idea of a above mirror mount and thanks for advice on economy. My e450 does not have a tach, never did! Here is why I need one.
I have an after market 200A alternator which produces 36 amps at idle, I made a simple turnbuckle system between gas peddle and floor which will disconnect in literally one second. I have this set to an almost imperceptible rpm increase (by ear) and it now produces 60A cold 80A warm. I would just like to know the rpm both before and after deploying the turnbuckle. PS. turnbuckle is locked so disconnecting it does not change rpm setting.
You might have a tach wire that you can tap into to for a tach signal. The body builders book shows it on the F series trucks. I would imagine it is also included on the E series too. It is a Light Green wire with a White Tracer. Circuit 76 and is located near the parking brake pedal assy.
PS. I am looking at any ways to increase MPG. On the 500 mile drive home from purchasing I was forced to drive 75MPH to keep up with a buddy (in case something went wrong). I got only 9mpg. I appreciate this is a very heavy box truck but I would like to find the most economical speed to drive it at as if and when I go on a long trip with it trip time won't be a concern. I might even consider an after market auto speed control.
Boy ! Good mileage and a box truck? That's gonna be a hard row ta hoe ! Like pushin a sail through the air!! It seems to me that keepin the 7.3 at 2000 rpm and under gonna give you your best mileage . So a tach in that case would be helpfull!!
I have no idea what 2000rpm will be in mph although it does have overdrive.
Some rough approximations from data I found on the web suggests that I MIGHT get 13 mpg at 55 mph. This speed will be enough for me and 13mpg will be more than acceptable. In fact any increase at all would be nice.
The easiest way to add a tach is with an Auxiliary Idle Controller module. You will need the type with the display. The rpms will be in digital format.
Thanks Gregg although I am happy with my turnbuckle control/. How many mpg and at what speed do you get with that trailer shown?
Unknown. I don't have enough data to determine mpg while towing. Unloaded I get around 13mpg if I baby it. With that trailer the mileage is much worse, around 7-8mpg but I then discovered I had a faulty EBP signal. Now it is fixed so I hope to be in the 10mpg range at 65 mph. 4.30 axle ratio, 26k lbs gross.
Thanks Gregg. Another problem with my 9mpg/75mph is that was BEFORE I added a roof full of storage, 21 solar panels and a 100 gallon water tank. Still all of that is mainly drag and with 55 mph ???