Part of making the car faster has involved weight reduction and re-distribution. More on that here:
http://www.mx6.com/forums/2g-mx6-gen...=corner+weight (Corner Weights)
One thing to accomplish both reduction and redistribution was to move the battery to the trunk with a lightweight (9lb) sealed AGM battery.
The grounding cables are all Stinger 3ga cable, di-electric grease applied to the ends, copper lugs crimped on and heat shrink tubing used to prevent any possible corrosion.
First, removing the battery and it's tray. Where the tray bolted is where I chose for the first grounding point. A small amount of paint was removed to facilitate a good contact. This cable was then attached to the top of the trans where the factory wire harness grounds to.
Then to replace the ground wire on the passenger side, again, cut, strip, dip, crimp, shrink and bolt on:
And to provide the alternator it's own ground to avoid any feedback it could cause, this one is bolted to the alt bracket where it attaches to the head:
Of note, after all the ground points were connected I sprayed on clear battery terminal sealer to prevent corrosion.
Next, time to build new cables for the alternator, and run the power cable to the trunk. First was dis-mantling the factory harness from the fuse box to the alt, striping out the old brittle wiring, and using more 4ga cable, copper lugs, and wiring loom wrapped in e-tape for a factory new look. In the far left of the pic you can see where I bolted the alt's ground cable to:
I took the opportunity to replace a LOT of the old crusty factory wiring look, dismantling pretty much everything, and putting new black wiring loom around everything. I was able to simplify things quite a bit, and make it a lot cleaner looking than it was before...still a snake hole of wiring, but better
The Alt cable was run up to the fuse box, a new cable from the main 100A fuse down to the starter where the 0ga cable to the battery also hooks up. Everything you see in the corrugated wiring look is all new. In the process of doing this I was able to throw away about three handfuls of old, crusty, and or just plain un-needed wiring and wiring loom.
Next up, time for the 0ga battery cable. I debated on this for some time, whether to use 4 or 0ga, some people had issues with 4ga...though likely it was installation issues, I figured I'll never need to do it again if I use 0ga
So, I cut a slit in the boot around the steering shaft to run it through...it was about the only place I could find a hole big enough without cutting through the firewall. It was attached directly to the starter, and covered in corrugated loom for abrasion protection.
Of course at this point the interior had to pretty much come out to run the cable, so I took the opportunity to swap out the tan carpet with black. I had previously swapped the tan leather seats for black ones, so time to make everything match. I ran it just behind the pedals and secured with with Zip ties, under the carpet in the crease where the floor meets the exhaust/shifter tunnel, under the front and rear seats to the spot I would be keeping the battery.
Yep, tucked right behind the rear seat. I had considered putting it as far back as I could for maximum weight transfer. However, the further back the weight, the larger it's polar inertia, IE it dynamically weighs more the farther it is from the center of the car's rotation. Since autocross is a highly transitional sport with LOTS of rotation, I wanted to minimize it's inertial effects.
Second, the right rear corner was the lightest, and the LF was the heaviest. Taking the battery weight off the LF and moving some of it to the RR was just what the doctor ordered. After doing this, along with removing the A/C weight was down by 65lbs and weight distribution had IMPROVED by .4%!! Win Win!!
So, Then I needed make sure the battery would stay put. Bring out the plummer tape and self tapping screws. I used some heater hose to pad the battery, cut the power cable to length and fashioned a guard for the power cable, used another stubby chunk of 0ga for a stout ground cable, again wire brushing off some paint for good contact.
**Make sure you're not going to drill into anything with self tapping screws!!** And for corrosion protection I used a spot of Silicone RTV on the screws, and also on the underside of the body where the screws come through.
Worth it? Absolutely. Taking the weight burden off the front tires helped reduce understeer
without increasing oversteer. It's made the car much more neutral and transitions much faster. Overall the car is a LOT more controllable and MUCH funner to drive!
As for starting, it starts, charges and runs just as good as ever. And if there's any doubt about the battery's power, so far it's had NO problems starting the car, even after sitting in 15deg weather for two months straight, still starts right up!
I've been getting a lot of questions about the battery itself, here's some more info on it:
Full product line:
Motorcycle - ATV - Snowmobile - Personal Watercraft - Xtreme Permaseal Batteries - Batteries Plus - Page 1
Another very popular line is Odyssey, here's the battery a lot of people use:
http://www.batteriesplus.com/pc-2896...2-PC545-P.aspx
Here's the battery I used:
http://www.batteriesplus.com/pc-3274...XTAX14-BS.aspx
I chose it over the odyssey because it was rated at at a few more CCA's than the comparable Odyssey battery, and was about $40 less and with the same warranty. I don't particularly like the battery posts on it, but for the performance/price It's worth it.
FWIW, while the little battery has been adequate, if this is for a daily driver it wouldn't hurt to go with something just a bit larger, with more CCA's like these, lots more cca, not much more weight:
http://www.batteriesplus.com/pc-32753-32753-
http://www.batteriesplus.com/pc-3275...AX20HL-BS.aspx
In any instance I'd recommend at LEAST 200cca from the battery.
. Thanks for the pics.
