Foxbody battery relocation vs weight balance| Grassroots Motorsports forum |

ReverendDexter UltraDork
3/28/12 8:49 a.m.

K, so I just ordered a battery relocation kit (I know, how ungrassroots of me )

Now, the stock location for the battery is the absolute worst place Ford could have put it - as far forward and high up on the driver's side as it would go and still be in the engine bay.

Now, the engineer in me is of two minds as to where to relocate the battery. On one hand, for overall weight balance, it seems the best place for the battery would be at the back of the passenger side of the trunk. This is the popular place to put it, and the obvious place if you're drag racing. However, considering this is an AX car and not a straightline pony, I'm thinking that mounting it on the floor of the passenger side of the car where the rear seat was would be better for polar inertia and cross-weights, as well as have less positive cable length up to the starter selenoid (better for overall weight and resistance).

Now, either will be leaps and bounds better than the stock location, but is one of these positions better-est for a conecrusher like my Mustang convertible?

JohnyHachi6 Reader
3/28/12 8:56 a.m.

If you have adjustable spring perches, then the cross-weights are a non-issue and I'd be inclined to move the battery further back to help with your front-rear balance.

ReverendDexter UltraDork
3/28/12 8:59 a.m.

No adjustability in my ride height currently. I'm saving up for coil-overs on the front (saving up as when I do it, I'm also doing new A-arms and a K-member), but I have no plans to replace my LCAs with weight-jacker arms at this point.

JohnyHachi6 Reader
3/28/12 8:59 a.m.

Good GRM article with some recommendations here:

LINK

ReverendDexter UltraDork
3/28/12 9:08 a.m.

Yeah, looking through that article just makes me more uncertain about running the battery in the trunk - by having the majority of weight over the driver's side front and passenger side-rear, I'm really screwing with that cross-weight.

81cpcamaro Reader
3/28/12 9:19 a.m.

I would move it further back, Fox Mustangs have quite a front weight bias so anything to offset it is good. You can put it right behind the rear axle, or put it where the right rear passenger seat bottom would be, if you don't have a rear seat.

ReverendDexter UltraDork
3/28/12 11:08 a.m.

81cpcamaro wrote: I would move it further back, Fox Mustangs have quite a front weight bias so anything to offset it is good. You can put it right behind the rear axle, or put it where the right rear passenger seat bottom would be, if you don't have a rear seat.

Heh, those are the two places I'm debating between. I'm just not sure what's going to have a better net effect; the better front:rear weight balance but increased polar inertia from adding weight to the rear overhang, or the reduced polar inertia but added wedging from having the increased percentage of weight on my LF/RR cross.