View Full Version : To speedo or not to speedo?

01-15-2013, 03:10 PM
So I'm reconfiguring the gauges in my zb21, making a new laser etched billet plate. I plan to do a 4.5" tach with 4 other smaller gauges. My question is this. Gps speedo is a no brainier but about $400 for gauge and receiver. What gps speedo do I carry with me everywhere? My iPhone, and it's a free app. And it will always be with me in the boat playing the tunes. So then I ask: speedo gauge or iPhone?


01-15-2013, 03:45 PM
Neither, guess your speed and add 10 like most do. :jestera:

01-15-2013, 03:49 PM
I always felt the speedo was for the passengers to see how fast they are going. i had a speedo in the last two boats and the pickup was kicked up so neither worked. i guess if i had a gps speedo i might like it . i always used my handheld gps to track speed

I guess it would depend on how balanced the dash plate looked too

01-15-2013, 04:43 PM
Just a crazy idea...

What if in place of the GPS speedo you cut out a tiny space in the dash and put a vertical iPhone dock that comes out of the dashboard there? (those docks are cheap so even if the connectors change again they are easy to replace) then just put your iPhone there and it charges while displaying the speed. I suppose you'll have to have the brightness turned all the way up on a sunny day and you'll need an app that displays the speed in large black font with a white background in order to be read if the sun is glaring on it.

If anyone wants to build on the idea go ahead :biggrin:

01-15-2013, 07:30 PM
Or traditional speedo, as a form of backup...mine seems remarkably accurate, within 1 mph.

But I'd definitely put SOME speedo in, even GPS, just for resale if nothing else.

01-15-2013, 07:42 PM
I still have my old traditional speedometer if you are interested in doing what Ghost said for backup.
If you need it, send me a PM.

01-15-2013, 08:00 PM
Mattyboy, either the pickup is up, clogged or broken, so traditional speedos never work. Hence GPS is the way to go. And exactly on the iphone mount. Already have the mount and extra power port. SO, for balance I plan to do a monster tach in the center surrounded by 2 gauges on either side. The free app displays a white number only in full screen on a black background. If I care about speed, well then I can look. Otherwise the vitals of temp, rpm, and oil pressure are in full view. I actually drive by rpm most of the time.

Thanks fellas. Should be awesome. If you guys end up liking the panels and billet, my buddy owns a shop in Hackensack, NJ that does custom laser dash panels for all kinds of applications. I'll post photos when done.


01-15-2013, 08:12 PM

yes I have the pickup kicked up on purpose so the speedo doesn't work , never had any real luck with the pitot style always seem to bust a pickup, or crack the tubing letting water in. haven't found a gps style gauge that looks period correct for my older hornet, plus I have an analog clock to tell me how fast I am going :? LOL

what do you like? and how do you invision the dash with two large gauges or one large one?

01-15-2013, 09:28 PM
My Blackberry with Speedometer v4.0.4 is pretty accurate for a couple of bucks.

01-16-2013, 10:38 AM
So just like a lot of older race cars, and even like the mini cooper today, I plan to put a monster 4.5" tach in the center with 2 gauges on either style. I'm laser cutting the panel out of red anodized billet aluminum and will also cut the donzi letters and Z logo into it as well. I'll do all the other panels at the same time too.

I'm liking the autometer carbon fiber series.
Not vintage gauges by any means but the boat is an 80s model which is suitable for retro-modding.
Those with a Livorsi wheel should make a nice cockpit.

Let the shopping commence!

01-16-2013, 12:22 PM
Mattyboy, I'm not sure what your gauges look like so it's probably a long shot, but I know that the Livorsi II special edition has a retro look.

They're worth a look at.

01-16-2013, 01:13 PM
yembo, I also went with the Auto Meter gauges, and I wanted a speedo.


Dreamer Dave
01-16-2013, 02:31 PM
Looks good
Is that 75MPH (GPS) just before impact? :smile:

01-16-2013, 03:03 PM

Actually it was 70 MPH before impact, but that is a whole different thread.

Yeah, I don't know why it is showing 75. maybe I took the photo before I had the panel wired, couldn't say.


01-16-2013, 05:04 PM
Ken, great looking dash. I don't mean to jump into someone else thread (please forgive my rudeness) but when the new gauges went in did you have to rewire everything to get the new look hooked up? Always confused me just how that was done one these boats? When I put a new gauge package in my outboard I ended up rewiring the entire boat, lots of work.

Thanks and again sorry.

01-17-2013, 06:59 AM
Offset, the wiring was easier than I thought. I removed the old gauges one at a time and hooked them back into the harness once they removed from the dash Once the new gauges were installed, I followed the original harness design making sure I had the correct terminals wired up. New harnesses were made,because of more gauges, but they were spliced into the original wire when necessary. The water pressure hose and wire for the oil temp sender were pulled along the gunnel into the engine compartment, that was easier with another person , and installed the oil temp sending unit in the oil filter housing

I did have to add 2 bus bars I think for the dash lights as they were pigtails and not terminal posts.

As I said, it went much easier than I thought, but I did use a awful lot of zip-tys. My next project is to clean up the wiring under the dash.

Just take your time and don't attempt if you are color blind.



01-18-2013, 09:43 AM
No hijack complaints here. That's good info for the gauge install. I plan to do the same thing but since I'm removing the panels, I'll take each gauge out one at a time and label the wires. Im doing all of the switches too.

Can't see all the photos on mobile but looking forward to seeing the dash on real comp.


01-18-2013, 10:03 AM
Here is a shot of the switch panel.

The white rubber cover for the circuit breaker has been changed to black.


01-18-2013, 12:14 PM
Speedos? We don't need no STINKIN speedos!

joseph m. hahnl
01-18-2013, 07:17 PM
speedo's essential for adjusting slip :drive:

It also can alert you of a problem with the drive , motor, or prop :propeller:

01-18-2013, 07:51 PM
I always feel uncomfortable wearing mine. :cool:
Sorry. I couldn't resist

01-19-2013, 01:09 AM
Oh brother!!!!

01-20-2013, 04:32 PM
this may be of some help

from the LGDCC Library Merc Electrical Manual (http://www.lgdonziclassic.net/pdfs/merc.pdf)

also it may pay to get a new harness depending on what condition yours is in


01-21-2013, 07:54 AM
Also make sure if you buy new gauges you buy the matching senders

Let me know if you need a hand with the wiring

01-21-2013, 10:29 PM
I did the same thing for my 2+3 last summer. I opted not to add a speedo; you know when you're hauling the mail! :biggrin.:

I'll try to find an installed pic. I welded stainless threaded studs I had made to the back side of the dash so I could use straps to go across the back and have an install with no visable hardware. It worked like a charm.


01-23-2013, 11:52 AM
I did the same thing for my 2+3 last summer. I opted not to add a speedo; you know when you're hauling the mail! :biggrin.:

I'll try to find an installed pic. I welded stainless threaded studs I had made to the back side of the dash so I could use straps to go across the back and have an install with no visable hardware. It worked like a charm.


That looks great and nice option to delete the hardware! I was looking for some nice stainless or anodized Allen hardware but the strapping is a good idea. Problem being in my zb21 is that the dash is closed on the bottom...I think. I'll check but I might just use the same hardware locations.

Ordered the gauges and wheel. Should be here Monday.