Is this the best way to install a tachometer on a 1998 Cobra?

[tmoneyballin]

My friend and I are going to hook up tach's on our Cobra's this weekend - his a 96, mine a 98. These are the instructions I got for 96-98 Cobra's. Is this the easiest and most accurate way? I know the factory tach is off so I want to make sure going through the instrument panel is the best way - My friend that did it on my old 96 Saleen years ago tapped into the computer on the passenger side floor if I recall...SEVERAL years ago...so it's a little foggy....The wires for the tachometer are short too, so I wouldn't have enough wire to run it anywhere but the instrument panel without getting more wire. Let me know if these instructions are my best bet and any tips that are helpful would be GREATLY appreciated. Advice like both of our wires/setup/etc are the same or not, which wires to look out for, etc...

Here are the instructions I got off of another website:

http://www.corral.net/index.php?option=com_content&task=view&id=111&Itemid=26
Pick where you want to mount the tach (I used the A-Pillar).

Remove the screws (2) holding on the instrument panel bezel. Remove the light switch then remove the bezel.

Remove the screws (4) that hold the instrument panel in place. The instrument panel is now free to be tilted forward (Bottom first).

Remove the 2 electrical connectors from the Instrument panel. The connectors have a push tab and will disconnect easily once this tab has been pushed.

The left connector is CN1, the right is CN2.

Feed the wires from your tach into opening behind instrument cluster.

You will be connecting to CN2.

Connect your Tach Signal Input to pin 8 on CN2. This is circuit 11 (Instrument cluster Tach Signal Input) in the Ford schematics and is feed from the EEC-V Pin 48 Electronic Diagnostic Signal (Circuit 659).

Pin 4 on CN2 can be used to supply +12VDC to your tach. This circuit is ignition switched and fuesd.

Pin 5 on CN2 can be used to provide 0-+12VDC to your tach light feed. This circuit is feed through the light switch dimmer circuit. It is fused.

Connect your Tach to ground. I used the existing ground screw on the fuse panel for this.

Reverse steps to re-connect your insturment panel. Re-assemble your dash and enjoy your tach.

Let me know what you guys think from experience!

 

[tmoneyballin]

Is this the best way??? I want to make sure I get the "actual" rpm level, which if I understand correctly the stock gauge just positions the needle higher automatically, but the wire going to that gauge is accurate...is this true?

 

[Dragstr05]

I dont have any experience to back it up, but I do believe my tach is right, as I hit the rev limiter right at 6200 - 6250 where it should be.

 

[tmoneyballin]

No Ford intentionally makes your tach read 300-400 rpms higher than it really is - so you think you are in the "danger" zone before you actually get there. That's the main reason people add Tachometer's is to get accurate readings, but also shift at your peak RPM range - when the light goes off(which you manually set depending on your set up.)you shift because you are making less power and damaging your engine past that point(if you know where your car makes the most horsepower).

It is even more relevant for Cobra's because they rev a lot quicker and are more efficient in higher RPM's so you don't want to shift at 6,700 when you really need to shift at 7,000 - your stock tach will say you are at 7,000 but you really are at 6,700 if you had an aftermarket tach hooked up.