Matthewd5

Question, you make multiple setting changes while it's plugged in?

i always unplug it between changes...

matthew

Twinkydog

One change or function at a time.

Matthewd5

Thats how I do it...

also, in my experience, if your horn doesn't beep twice it means your change didn't take, and in my case it was a simple dip switch reversal.

matthew

Matthewd5

Ok. So I tried tinkering with my AEV Procal programmer

I started with the suggested settings of 35.5"

It was off by just about 10 mph, according to my gps, off meaning the GPS said I was going 10 mph faster

I changed it to 35.75" and the change in mph was barely noticeable, so I changed it to 36.75 hoping for a more tangible result...

Then it went up to the GPS saying I was going almost 15 mph faster than the speedometer

So obviously my Jeep is heavier than thought and I need to start at like 35" or even 34.75" ?

I had read in multiple places that the MTR/K's were one of the tires that was closer to labeled height than the others?

I mean I love the ride on and of road, I just wanted to have a more accurate speedometer

Matthew

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jadmt

measure from the center of the hub to the ground when parked on a flat level surface like a drive way or garage floor and X2 that will get you close. I have found that using a number slightly less then what you get will put you very close.

Matthewd5

thanks for the advice, I measured it a couple of times and came up with somewhere around 35 1/4-35 3/4 inches

but when I started around the size the gps was way off

i know the gps is accurate based on using it our other vehicles...

i didnt initally setup the Procal, I had a shope swap out my factory d30 and d44 with Dynatrac pro rock d44 and d60, they programmed it for the 5:13 gearing and the 37's, but it kept bugging me that the speedometer was off by 5-7 mph

so that is how this whole mini project started.

there was one post from someone with the same tires at the same pressure as what I run, so his numbers were really close to my measurements, but as I said with today's first post it was way off from the GPS said.

I've had people give me the measuring tips earlier in this thread, I started there, and as I posted it wasn't even close to my setup.

i have heavy skid plates, heavy axles, heavy bumpers, winch and a five gallon gas jerry can mounted to my rear bumper/tire carrier, so I'm thinking I need to try going lower tomorrow till it matches the GPS

matthew

Matthewd5

Ok, I started from scratch, reset the Procal to make the Jeep settings factory...

I set my ratio to 5:13 no problem.

I started at 35" and worked my way down, it took me all the way down to a setting of 30" tire size, and even with that it was a couple of mph off, so the true number could be something like 29 1/2" etc.

WTF, these are 37" MTR/K's, has anybody ever had to go this low for the speedometer to be close to accurate?

Matthew

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jadmt

something is not right lol. I have had two procals and both made my speed/trip spot on.

Rebar-7

Try 37 in see what happens..

Matthewd5

Yeah that's a pretty good idea...

now that I reset it, I mean how much smaller can a 37" tire actually get?

when I first got the 37's the shop programmed it for me, it was only off by 7-9 miles per hour at highway speeds...

matthew