Alright, it seems fairly simple enough. But I am curious. I have heard others talk about and how did most of you do it. Just extend the neg and pos to the trunk, or re-wire the routes? Doesn't seem to be much enough on this.

 

anyone?

 

whats the purpose? why would you want to...

 

To make room for something else(possibly CAI) in the engine bay. I think extending it would be the easiest way, I know you can buy some kind of extension. I would also reroute the wires somewhat, no use having it doubled up in the front of the car.

 

yeah if your gonna put in super charger or something, sometimes you need to make room for ****. plus to change the weight load.

 

start with a sfi approved battery box. Moroso makes a plastic one that is vented. 90bucks. Get a battery in the trunk kit that uses 1 or 0 gauge wire. You will need to run a wire from the starter to the junction box by the existing battery tray. Use 8gauge wire at least. This is basically the same wire that goes from the positive side of the battery to the junction block. I drilled a hole in the luggage area and ran the positive up to the passengerside and bolted the negative to the bumper mount bolt.

 

There is a ton of this in the archives. There is also some info on my page.

Miles

------------------
88 427 Camaro
12.18 @ 113mph 1.75 60ft
Currently installing 3.73's into my 9 bolt (YES,it is a 9 bolt & YES they are 3.73's, not 3.70. 4.11's to follow soon )
www.koolmeister.com

 

I personally would not connect the negative battery cable to chassis ground as suggested above. I would run the same size (e.g. 1/0) cable from the battery negative terminal to the engine block as it currently is with a front mounted battery.

Of course, connecting a second wire to chassis ground is fine, I just would not use that as the only connection.

If you just connect ground to the body, how is the current going to pass from the body to the starter? Here are some points that come to mind:

1. There is that small braided ground strap connecting the engine to the body.

2. There is a metal fuel line that electrically connects the engine to the body (at least on my 305 tpi). [EDIT: strike that - it goes to a rubber hose after leaving the engine so it will not conduct electricity].

3. The engine mounting bolts (two). [EDIT: strike this one also - it's electrically isolated with rubber

4. The rear springs will conduct electricity from the axle to the body. So current will have to travel from the engine to the transmission to the drive shaft to the axle to the springs then to the body.

[EDIT: 5. The original battery cable (4 gauge) has a smaller wire (12 gauge on my 91) connected to it which is attached to the fender, so the engine is grounded to the body through these two wires (which was originally connected to the front battery)]

I'm sure the starter would work. I wouldn't even be surprised to hear aftermarket kits that simply connect ground to the body. But if I were wiring my car, it'd have a dedicated wire to the engine block or starter mounting bolt.

The stock negative battery cable which is connected to the block can be connected to the body. This way you'd have 4 gauge wire from the engine block to the body instead of having to go through the little 12 gauge wire. Even so, I'd still use a direct connection. The idea is to keep connections to a minimum. Less connections = less to go wrong. Sure it'll work, but so do coat hangers for antennas.

If I saw Miles images correctly, I saw two 1/0 cables going from the battery to the front. Am I correct in thinking that you ran a ground directly to the engine block?

[This message has been edited by Stuart Moss (edited August 07, 2001).]

 

maybe i should have indicated so, but the starter is not getting a ground only from the bumper connection. There are several other engine to chassis grounds that most motors have (and should be reused where possible) Such as the negative cable from the chassis to the engine. This can be done with the large wire that is made available when the negative cable is no longer attached from the battery terminal to the ground junction block on the fender (or in somecases to the alternator).

I reused my large negative cable to go from the fender to the alternator and it works fine. turned over a 400 with almost 11 to 1 n/p


[This message has been edited by jcb999 (edited August 07, 2001).]

 

If you add a dual SLP cold air box you need to move the battery to the trunk. I used the blue Moroso box, very nice and NHRA legal (i.e. you don't get tossed at the track on tech inspection). I also have a battery cut off behind my license plate (also NHRA required). I ran positive to the starter and a negative to the front sub frame. Then another battery size cable from the front strut tower to the engine via the a/c hold down brace on the passenger side. I also have two braded lines from the back of each head to the firewall.
p.s. the battery in the trunk has been done for years in drag racing for more weight transfer over the rear axle for traction and less weight up front to transfer that weight to the rear wheels easier. Taking off from the line the battery goes from weighing about 25lbs to about 200 lbs!.

------------------
Rob P
89RSconvtZZ4TPI Edelbrock Intake
SLP Dual Cold Air Intake 1 5/8" Headers Semi-Siamesed Runners, IROC
suspension, alum shaft. Numerous mods.
92Z28convt5spd (stock)
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

As mentioned by Rod, you use 2 ground cables. The idea of moving the battery to the rear is to transfer weight. If you want to run a ground cable all the way back up to the front of the car then you're adding more weight that's not required.

The battery just needs a cable that goes to chassis ground. You then make sure there is a similar cable connecting the engine to the chassis. Usually the old negative battery cable is used. Instead of being connected to the battery it's just bolted to the chassis.

------------------
Follow my racing progress on Stephen's racing page
and check out the race car

87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block

Best ET on a time slip: 11.242 altitude corrected to 10.89
Best MPH on a time slip: 121.52 altitude corrected to 125.89
Altitude corrected rear wheel HP: 497.9
Best 60 foot: 1.546

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

 

I'm so lost and confused now, haha

 

Anyone have any pix?

 

Use a dry cell battery if your planning on doing this

 

A dry cell battery still needs to be put in an NHRA approved vented box if you wish to pass a tech inspection because the battery is still inside the drivers compartment. NHRA does not distinguish what battery is sealed and what are not so all batteries are considered non sealed.

There's also a lot more involved than just running battery cables. Since the car is the ground you need to run a positive cable from the starter to the back of the car. You also need to install a master kill switch at the rear of the car.

It must be wired into the positive side of the battery and kill all electrical components including the engine when switched off. The switch cannot be keyed or made of plastic. Off must be clearly marked. If setup in a push/pull style, push is the off position.

Pics of the setup are on Miles's site www.koolmeister.com however how to wire the kill switch to kill the engine requires a bit more work. You need to install a relay somewhere so that the alternator is disconnected when the kill switch is turned off or it will keep the engine running.

 

I think just putting a masterswitch on the positive from the batter will not kill the motor when the switch is thrown. Won't the motor continue to run from the alternator? I think 12 volts also has to be removed from the alternator when the master is thrown.

 

Optima is a completely sealed/maintenance free AGM (Absorged Glass Mat) [this is better than gel cells] battery that I have mounted in the trunk area on the rise between the rear well and spare tire area. I bolted the battery to a 1/4" aluminum plate using holes on the battery's lower base. The battery sits in the open - no enclosure needed/wanted. I've had it for three years and am very satisfied with it. If I had the time I would have mounted it in the storage area on the driver's side, but I didn't have time to fabricate the mounting brackets/welding. It would have been a tight fit had I put it there. The spare tire area has some amplifiers occupying the space so that option was out.

I have the Optima Yellow top deep discharge battery to power my sound system, again, no reason to have it in an enclosure (no racing regulations). There is no reason to vent it because it doesn't produce any (hydrogen) gas as long as the charge voltage remains < 15 volts. No gas also means no corrosion to worry about.

There is also no liquid to spill (AGM technology) so even if you shoot a bullet through the case no liquid will come out.

Their web site is http://www.optimabatteries.com/ .

http://www.dcbattery.com/optima2.html has some additional information on them.

[This message has been edited by Stuart Moss (edited August 07, 2001).]

 

i have the same battery as stuart mounted in one of those cheap Summit boxes. the only thing worth money in that kit was the wire. Anyway, we dont have a tech inspection at the local dragway, so for me, it doesn't matter. Oh yeah no cut off switch for it either.

On a side note, it does suck when i want to take the car to a different track. Ive gotten away with it once (they didn't notice it was back there). but the other two times ive had to move it back up front (you have no idea how big of a pain that is when the starter and headers are scolding hot. For this reason, im plaaning on doing it the correct way over the winter.


EDIT: one more thing, i didn't run a ground cable from the battery to the front. I just grounded it to the chassis. Its been like that for about a year and i haven't had any problems with it yet....

Eric

-----------------
My 1986 Z28
GM350, T-5, 3.23's, lots of go fast goodies, 4th gen Firebird interior etc...
85 IROC w/ 1364 miles!

You'll always find what you've lost in the last place you look

R.I.P Dale Earnhardt

[This message has been edited by zupmanZ28 (edited August 07, 2001).]

 

I also highly recommend that battery.

 

I moved mine into a home-made fully welded box with a sealed top but never put a kill switch in. Running the ground to the front is not needed, and will add alot of weight with all that heavy guage wire. You could pick up some welding cable and copper crimp lug ends (Don't use those cheap silver lugs with the plastic band around the collar, they snap)

I did add extra ground straps from the heads and from the starter to the framerail for good measure though.

 

Wiring it up with a relay will fix this problem.

------------------
1989 IROC-Z 5.7L
NOS 5151 150HP kit
ProBuilt 700R4, PI Vigilante 2800 stall lockup
Baer Brakes 12" Sport System

 

Yes, I ran the negative (1/0)directly to the engine block. I wouldn't do it any other way or use any smaller cable. The few extra pounds is well worth the extra reliability on the street to me.

Miles

------------------
88 427 Camaro
12.18 @ 113mph 1.75 60ft
Currently installing 3.73's into my 9 bolt (YES,it is a 9 bolt & YES they are 3.73's, not 3.70. 4.11's to follow soon )
www.koolmeister.com

 

Good job Mr. Miles.

Electronic designers/engineers/buffs know that, from an electrical standpoint, the preferred (not to be confused with "only") method of making an electrical connection is the direct route. This becomes more important as the load (amperage) increases.

The added weight (minus the stock 4 and 12 gauge cable which would not be needed) is negligible.