Aftermarket Tach Install

['76 911S 3.0]

Hi all,

I wanted to share a project I completed over the weekend. I have been having issues with a swinging tach on my 911 for a while now...I contemplated having it rebuild by NHS but opted to go a different route. I purchased a GR4.5-TACH-02-DM from SpeedHut and proceeded to wait a few weeks for the tach to come in.



First impressions, the tach is fantastic looking, matches the original gauges quite well, and they even had the option (not listed on their order form) to add high beam and turn signal indicators on the gauge.

The gauge is slightly smaller than the VDO it replaced but you cannot notice a discernible difference in the overall diameter once installed.

First, I needed a way to mount the tach into the existing hole in the dash, and wanted to use the same mounting as the OE VDO. Drew up a quick adapter ring in SolidWorks and then RP'd the piece.



Once that was done, there are small nubs on the "spin ring" that needed to be filled flush with the adapter ring in order for the original rubber grommet to slide over and seat properly.



Final installation:





Sorry for the poorly lit pictures, I will take more once the sun is in the correct position.

The gauge also features programmable shift lights and can be used with stock distributor ignition or a signal from an ECU (AEM Infinity in my case). I do not have anything with it operating as I am still in the process of wiring my engine and ECU package. I will also post more pictures of the actual assembly a bit later today.

Just thought I would share, I'm really pleased with the results.

[Tippy]

Very clean.

['76 911S 3.0]

Here is how the assembly goes together:

[Elombard]

That is rediculously cool!

I cant believe they can do the TS lights? First thing I thought of when I read your post title.

Ball park price? I would love to have a shift light.

['76 911S 3.0]

Erik,

I paid $220 out the door for the tach, and the adapter cost me material since I have access to a printer here at work. I can't wait to get this thing hooked up and tested!

And the TS and HB indicators are +12v controlled (they can do either +12v or Ground controlled) so hooking those up is as simple as splicing the +12v into the light to the respective wires.

[Elombard]

Nice, thats much more cost effective than I thought it would be. I wonder how I could get an adapter ring with out spending a fortune? I think there are places on the web that will print stuff when you send the file. Have to look into that.

['76 911S 3.0]

I can send you the file for the adapter ring, there are a lot of places online that will print for you.

[JohnJL]

A+ for creativity and thanks for sharing.

The different fonts from the other gauges would bug me tho.

[Taxi!]

Very creative.

['76 911S 3.0]

Originally Posted by JohnJL

A+ for creativity and thanks for sharing.

The different fonts from the other gauges would bug me tho.

John,

You can supply them with a custom font, they will print in any font you desire. I was not aware of this until after I had placed my order. If you know the font of the VDO numerals, they will print them in that font.

[Pato911]

Great solution. For anyone considering 3D printing, a couple good resources are Fusion 360 for design and then upload to makexyz.com for pricing and finding printer. I have used them successfully.

[GWClassics]

Jayson I've PM'd you

[chrisbalich]

this is brilliant.
well done.

['76 911S 3.0]

Originally Posted by GWClassics

Jayson I've PM'd you

Sent you an email with the STL file for printing!

Originally Posted by chrisbalich

this is brilliant.
well done.

Thank you sir! I have since moved on from the SpeedHut tacho and made an adapter for the AEM CD-5 programmable dash utilizing the factory rubber mounting grommet.

[chrisbalich]

Originally Posted by '76 911S 3.0

Sent you an email with the STL file for printing!



Thank you sir! I have since moved on from the SpeedHut tacho and made an adapter for the AEM CD-5 programmable dash utilizing the factory rubber mounting grommet.

did the SpeedHut unit disappoint? or just cramming more info into less space?
TIA

['76 911S 3.0]

Originally Posted by chrisbalich

did the SpeedHut unit disappoint? or just cramming more info into less space?
TIA

The SpeedHut was fantastic, I'm not taking anything away from the quality and usability of the gauge. I opted, as you said, to cram more info into less space.

[Knockdown]

Looking forward to seeing any details of the CD-5 install and operation!

['76 911S 3.0]

Originally Posted by Knockdown

Looking forward to seeing any details of the CD-5 install and operation!

Here are a couple photos of it installed, with the first page on the screen in one of the images. I tried to mimic the OE VDO tach as much as possible, I have additional needle gauges for oil temp, oil pressure, and boost pressure, mimicked the oil pressure warning lamp, generator lamp, gear indicator, and numerical read outs for vehicle speed and lambda. The second page has vastly more info on it that are pertinent to tuning and a good overall image of engine conditions. There are alarms that will appear as text, along with some colored background bars on the second page that will illuminate the channel in red if an alarm condition is triggered. I will get more photos of the other screens when I have some time:

[Knockdown]

Looks nice and really useful for EFI, should be getting my 506 soon.

['76 911S 3.0]

Originally Posted by Knockdown

Looks nice and really useful for EFI, should be getting my 506 soon.

Super useful and 100% reversible.