schwank

Posted this over at the NASA forums, but it also seemed relevant given some discussions going on here, so I'll post it for anyone interested and for the archives.

Inspired by the posts we've had here regarding data acquisition, I decided to go all out and do a full hardwire of my Traqmate system. Not just power, but also RPM. This is required for computing the actual gear being used (the next version of traqmate software will do this for you). I purchased the unit back in March and have done perhaps half a dozen days covering the two existing layouts here in Portland - with and without the festival curves chicane.

Up to this point I was using the unit with the portable battery pack, and had it mounted on the rear deck using the velcro included with the kit. Velcro you say? Yep... this is some serious stuff though... it is actually difficult to get the velcro undone, so I wasn't too worried about it going flying. The antenna is magnetic so it sticks to the deck as well with a great view of the sky out the hatch glass. I still run the center console surround so I have been zip tying the display into the former radio slot during run sessions.

One of my criteria is that the unit can be removed from the car entirely. I don't want to leave $1000 just sitting there, and the car is often parked in my driveway while I work on other cars in the garage. So without further ado, here is how I went about a little bit better install.

The GPS does most of the work, and I will still leave the antenna on the rear deck. However I decided to move the sensor unit as well as finally wire in the RPM channel. Though the process differs for newer cars with electronic ignition, for all of our old 944's to capture RPM data we need a signal from the negative terminal of the coil. The instructions call for 20 gauge wire but most 20 gauge is not well shielded. I opted for 16 gauge wire with a ring terminal and then wrapped it in some high temp oil resistant heat sheathing. I ran the wire through the windshield solvent line hole and then through the small rubber grommet in the firewall used for the windshield radio antenna wire. Once inside the car the line runs over the glove box area and into the center console. This signal line is terminated at a spade connector so that I can disconnect and remove the unit.




Next up I need power. The instructions recommend not using the batteries with RPM inputs. I think it would work but that battery life would be reduced. If used by NASA for verification I am sure it would last a full session for the purposes of testing a car using only the battery pack. But, I've had my batteries die once on me, so I want power, and preferably constant power. After searching a bit I realized that the interior dome light was powered full time. I don't have that installed anymore, so I dug those wires out from under the dash and sure enough, constant juice. The stock wires were long enough to reach across the dash and out to the center console, so I didn't need to do any special wiring under the dash. I cut the stock spade connectors and replaced them with new ones as with the RPM signal wire.



Finally, I wanted a bit better mounting setup, but still something I could take out of the car relatively easily. Since the car is mostly driven on track, I don't run the armrest part. I had an old busted armrest hinge tray laying around, and it seemed a perfect mounting for the sensor unit. A couple quick holes with the drill, and a little trimming with some end cutters, and I have holes for wiring pass through. Again I used the supplied mega-velcro underneath, but for added protection I ran 2 zip ties through the tray to firmly secure the sensor unit. Made the two wiring tails for power (using the supplied wire) and the RPM signal, and wired everything up.







A quick power on test, and voila!, we have power to the unit full-time. Turn the key and fire her up, and the Input Settings show a pretty stable ~950rpm idle. I'll log full data for my sessions tomorrow at PIR, and make those files available to anyone interested. You can download the TraqView software free and play around with anyone's data files.

For NASA verification purposes, I think it would be easy to build the unit as a standalone piece and move it from car to car. Batteries should suffice for quick checks of gearing, but if permanent power is needed the ciggy lighter or other source could be used. A small wire could be placed through the passenger window, under the hood and up to the coil for RPM. In this way it would be possible to get an idea of gear ratios from the speed and RPM, and know if stock/legal ratios were being used.

So that's all there is to it. I don't think it will be in the way at all as I don't rest my arm down there while driving on track. But I made zero new holes or modifications to the car, so it will be easy to move if it seems to be an issue. Any questions? Fire away!

David 23

Nice install. I just used mine the first time yesterday, with only a very temporary install. While my 993 interior and electrics are different, some of your ideas will help my install. I also need to make it easy to switch back and forth to my wife's MINI. I need to do a little investigation on where to tap into the RPM output for the 993. I found it pretty impossible to even glance at the display while on track, so I just want to make it easy to reach for the controls.

trackjunky

Looks similar to mine except I used the lead from the cigarette lighter. This power quits when I turn off the key. Which adapter did you purchase from Traqmate to hook up the RPM data?

schwank

If you look in the photos the small grey adapter is the part that is used to hook up RPM. It is called the Track Tach and can be found on the traqmate website. My complete kit came with this adapter already. from looking at their install instructions it appears there may be two versions of this piece, one having more digital connections that the other.

I decided to go for constant power in case I forget to shut the unit down before turning the ignition off.