HUD with RB25

[ninety1two40]

I have a working HUD in my S13, 1991, and used the Dakota Digital speedometer to calibrate my actual speed reading. The problem is.... my HUD doesn't read anything more than 125mph.

In another S13 that I used to own (same year, KA with automatic and HUD) my HUD would read out past 125mph, the highest I ever seen it was 133mph.

Now I know some people might flame me for driving so fast, but this was only a test on an open highway, no cars within sight and in the middle of the day.

Did I max out the dakota digital?
Modified by ninety1two40 at 10:56 PM 5/9/2008

[l0nestar]

You got me wondering on this as well. I need to order one. Have you contacted Dakota Digital about it?

I was just with one of their reps about a week ago

[l0nestar]

P.S. I'm glad you liked my avatar.

[ninety1two40]

I'm going to email them now, and maybe call them next week.

P.S. I'm glad you liked my avatar.

Actually I copied your avatar and have been using it on a local forum here in NY... how'd you know? Anyway, I plan on making my own so it looks a little clearer (better resolution).

[Bwana]

You could always do like I do, my SOHC HUD cluster reads exactly half with the RB trans

[ninety1two40]

Here's the response from a Dakota Digital Tech:

That unit does not have a limit outside of what is being fed into it. It very could be you are reaching a point of saturation on the input that it cannot take anymore or it can no longer correct for the range to have reached.

So I'm going to dig into this a little more, I just bought an osilliscope so I'll try some tests when I get the car running again.

[ninety1two40]

The tech from Dakota Digital forwarded me to one of their engineers and I got his info:

"The input of 134Hz will equal 8k PPM at 60 mph.

What is the actual frequency that is being fed in? The output should becapable up to around 4000 - 5000 Hz so at x2 it should work with inputsup to 2000 Hz.

Also, try switching between OUT1 and OUT2. Some inputs will work witheither one most of the time but only one of them at higher frequencies."

Sooo..... It should work no problem, I'll have to try switching to OUT2.

[l0nestar]

Did switching to OUT2 fix this?

How difficult was the DD speed adapter to install?

[ninety1two40]

Won't be able to try it out for at least ~3 weeks. The car is still getting put back together from my winter rebuild.

The DD was easy to install but it takes time to calibrate it. You only have to interface 3 wires: Ignition power, ground, and cut the speed sensor wire and connect to the input and output of the DD. I used application #6 when setting up the unit, I forgot my course and fine adjustment settings but they will vary slightly for each car's setup (rear diff ratio, wheel/tire size). I used a GPS to calibrate and I am probably +/- 1mph at 60mph.

[l0nestar]

Cool man. I just ordered the adapter and will hopefully have it here by Friday. yay!

[ninety1two40]

Did you install the dakota digital yet?

I got my car back on the road but haven't taken her much past 100. Need some new tires

[l0nestar]

Did you install the dakota digital yet?

I got my car back on the road but haven't taken her much past 100. Need some new tires

Sadly no. I wish I had, but I'm looking for an S14 speed sensor..

[ninety1two40]

Are you going to try and switch the gear or the whole sensor?

[l0nestar]

Hmm.. I forgot about swapping the gears.. I would just need the .. Green? gear from the KA.. I may have a NIB speedo adapter for sale soon..