Now that the cold has set in, it’s time to turn to the winter projects for the car. Of course, the garage is cold, so I’m having a hard time getting up the motivation to really work on it. There’s a lot to do though, if I want to improve the performance of the car by the spring. Here’s a list of some of the planned “improvements”:
- Replace the broken fender support and fender – Still waiting for these parts from Westfield – it’s only been a couple of months you know, these things take time…
- New Exhaust – 2.5″ turbo-back – The current exhaust has several sharp bends and other restrictions after the turbine, as well as being a bit smaller than I would prefer. I’ve purchased a welding rig to learn how to weld my own exhaust. Probably not the easiest first welding project I could have picked, but it’s the one I’ve got.
- Get the boot box lineX’d, and install the boot box lid – I purchased a boot box lid with the kit, but haven’t installed it yet, since I’m still making adjustments to the rear end.
- Repair the rear left light cluster – something I forgot to post on was the fact that my wiring bundle in the rear left wheel well came loose from its (not well secured) mount, and the wires rubbed against the tire, which rubbed through the sheathing and broke the ground.
- Get rid of the Serial cable for my ECU – Since this is a project car, I’ll be tinkering with the ECU for a while, adjusting settings and getting dyno tunes occasionally to improve power/response etc. However, the serial port on the ECU is in an awkward location, and having a cable dangling inside detracts from the overall aesthetics.
- Shroud the radiator – primarily a hot-weather improvement to reduce engine temps. The nose has lots of paths for lazy air to take around the radiator. Since this also means that the air will bypass the intake charge intercooler, this reduces the overall efficiency of all my cooling components.
First up: replace the serial cable for the ECU
Since the garage is cold, and little electronics projects can be done next to the fire in relative comfort, I decided to tackle this first (I know, I’m a wuss).
I looked around a bit before deciding that my best bet is to use a bluetooth–>serial converter, since I could then connect wirelessly to the ECU from almost any laptop. I found plenty of BT->Serial converters on Amazon, Newegg etc. but they were all at least $60, and as much as $100 for something decent, and far bulkier than I wanted to have hanging off my ECU. Plus, where’s the fun in buying something off Amazon? So, I bought an HC-05-D Serial–>Bluetooth module from ebay, since it had exactly what I needed, seems to have a good reliability record, and was substantially less expensive than the commercial alternatives. Unfortunately, the module needs a regulated 5V power supply. To provide this, I disassembled an old car cell-phone charger to obtain a DC-DC converter circuit based on an MC34063 chip.
Unfortunately, the circuit was designed to output 6V instead of 5V, since this was an old non-USB-standard charger. I used this online calculator to figure out that all I needed to do was replace two resistors with 1k and 3k Ohm and voila! now I had a stable, regulated 5V power supply, designed for 12V car power input.
I installed both PCBs into a small project box, and now I have a functioning BT–>Serial convertor for a total of about $30 in parts. Haven’t actually hooked it up to the ECU yet, that’s for this weekend, but I’ve been able to set up the module with a custom device name (“BRG7″ of course!), and a custom PIN. I’ll post and update if it works when I get to test it.
