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TR4/4A Weight Weenies: Tr4 relo of battery to boot...good idea?

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Willie_P

Willie_P

Jedi Hopeful
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I am setting my tr4 up for "fast road" and AutoX use and have a number of other minor performance mods on the car. I suppose that relocating the battery to the trunk (boot) centered within the spare tire well (I'm not running a spare...don't ask), is better weight distribution than the factory/OEM location under the bonnet.

Pros/Cons, thoughts? Is this really worth the extra effort?

Save me from myself before I perform surgery this coming weekend.

thanks, wp
 
I don't know that it would be worth the effort? It's moderately expensive but likely far easier to simply install a lightweight battery such as one of the Optima line. Meanwhile, if you happened to show up at an autocross with a nearly full tank of gas rather than just enough to run the event, I'd think the weight difference there would be as noticeable as wherever a battery was mounted. I know that was the case back when I was regularly autocrossing my GT6+. I would note, though, that the GT6 tank was behind the rear wheel centerline. Still, I got to the point where I'd do my best to let the tank get down pretty far for a Sunday afternoon autocross...then make sure to fill up soon after running the event so I could get home. ;)
 
I would check the rulebook for the class that you are building for. If it's allowed, go for it. Otherwise, it might put you in a class with much faster cars (than yours). If your club follows SCA rules then the current SCCA GCR General Competition Rules includes a section for Solo 1 autocross by class and car. Do everything that's allowed in your class if you want to compete.
 
As suggested above, I would go for a smaller battery, 380cca is sufficient.
Besides, there is also the extra weight of installing the battery cables from front to back.
 
WP, you could gain a little rear holding by having an extra pair of lever shocks, drain and fill with 40 weight oil. Not recommended for street use, the same goes for the 42 pounds of pressure in the front and 40 in the back.
Have fun.

Wayne
 
I did Solo 1 off and on for seven years and thought about this, but never did it.

On the one hand the battery is mounted rather high up and more rear weight bias might be desirable, particularly if you could move it from side to side depending on whether the course was predominantly left or right tuns.
On the other hand the battery is mounted centrally which reduces the moment of inertia, and you have to consider the extra weight of good thick cables running to the firewall. I did not think it was worth bothering with.
One are people often ignore is driver weight, I got down from 190 lbs to 165 lbs over the course of a few years, almost as good as taking out the spare tire.
Probably worth getting EBC or Repco brake pads, and maybe changing to the finned alloy brake drums from a Datsun 240z, and you definitely want R compound tires. I used 205/50/15, which made the diameter 23 inches instead of 25 inches, a one inch lower centre of gravity and 8% lower gearing for better acceleration.
 
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