Race car electrical, what to buy?

[JMortensen]

Ready to start gathering parts for my car, LSx engined autox car, trailer queen, just basic basic electrical. I am a moron when it comes to electricity, so I have a friend who I traded parts to and he has agreed to help in return. Right now though I'm just trying to get parts together.

 

So far I figure I need:

Battery and mount - thinking something small like a PC 680.

Wiring hardness - thinking 8 circuit Painless or similar

Switch panel - saw the Painless was $200+ that seems expensive, have seen other switches from Jegs and Joes which are other options

Kill switch - I think I need the 4 post kind, not sure on this

Battery cables. Need to get something big enough to handle the battery behind the pass seat and fire up the motor without burning up.

 

That's pretty much it. I know there are other options out there for harnesses and batteries, etc, so I'm asking for recommendations. Also was thinking about doing a bulkhead type connector in the firewall and read somewhere that they are a bad idea because in an accident the cable can get pulled out. The suggestion was to just run a long cable through to the engine compartment. Was also considering re-using my 240SX lower rad hose thermostat for fan. I'd rather have the thing come on by itself, and it did work flawlessly for me for years. I gather it's better to have the kill switch within reach of the driver, but then is it better to put it in the middle of the car, or on the A pillar? Feedback on these or any other issues that I am probably totally ignorant of would be appreciated.

[ktm]

So far I figure I need:

Battery and mount - thinking something small like a PC 680.

 

Look into the Deka ETX series. They are the battery manufacturer for Braille (do a Google search on "Braille Deka"). You can pick up a Deka for around $75. I am using the ETX30L and I bought a Braille mount from Summit Racing. Fits like a charm. I mounted the battery right in the middle of the rear deck, slightly forward of the strut towers.

 

Wiring hardness - thinking 8 circuit Painless or similar

 

I would recommend a 12-circuit fuse box. Weight is a non-issue and the 12-circuits gives you more flexibility. I just installed a 12-circuit Painless box in my car. The electric fan circuit is not rated for a fan but rather is wired only to trigger a relay. Seems rather stupid to have a fuse on the relay power line when you have need a fuse on the main power feed to the fan.

 

Kill switch - I think I need the 4 post kind, not sure on this

 

You will need to wire up your kill switch so that it kills all current from both the battery and alternator. I do not know about the road racing sanctioning bodies, but NHRA requires the switch to be accessible from outside the car. I am not "racing" my car and thus mounted my kill switch under the passenger side inspection panel where the battery used to reside.

 

Battery cables. Need to get something big enough to handle the battery behind the pass seat and fire up the motor without burning up.

 

I would recommend 2-ga welding wire. Welding wire contains finer strands and is more flexible. Summit Racing has a great deal on their battery relocation wire. I picked up 12-ft of positive 2-ga cable and 1-ft. of 2-ga negative cable, grommets and clamps for around $70. The terminals are side-mount and come with terminal covers. I'll post a picture later tonight if I remember.

Edited September 14, 2010 by ktm

[johnc]

Kill switch can be inside the car but you must run a cable or a rod from the switch handle to the end of the dash so a corner worker can kill the power without climbing in the car. With all the other stuff you've made Jon, a switch panel is dead nuts easy. You can do something like I did in the ROD:

 

[z2go]

For the wiring harness, check this place out: http://www.autowiringsolutions.com/

 

I ordered from him and I was very happy, especially because every wire is labeled every 6 inches along with the color code. Couldn't be simpler. Plus it's a hell of a lot cheaper than Painless.

[hoov100]

Don't forget a shock sensor that will kill the fuel pump past 2.5 G's or if the car rolls.

[HLS30-08077]

Definately go with the 2 ga wire. I might be able to get it cheaper, let me call "My Supplier" and get back to ya. I might be able to do the side mounts and silicone covers for less as well.

 

Exactly how many circuits do you see yourself having in the Car? Add them up. Single wiper, ignition circuits, fuel pump relay, fans relays, Brake and guage lights, Headlights? etc. If it comes to 8, the 12 might be a better bet and will allow expansion if you add something else.

 

If you add a High amp relay to the alternator power wire, the relay can be controlled by the Master switch. Shutting off the master in the rear of the car will kill power to the relay, killing any power from the alternator as well. I haven't done a race car in a long time so I'm not "UP' on all the new Safety gadgetry.

 

I would suggest going with what is safe, recognisable by the safety teams when they inspec your car, and time proven (known to be good parts)

 

I'll check on the power wire stuff and email or write it down here.

Dave

[JMortensen]

Thanks guys, I'll check out the different harness options and the Deka batteries. I've heard plenty of horror stories from Ford owners about the g switch cutting off the fuel pump and I'm going to be running really stiff springs with less than standard rebound valving, so I don't think I'll take that piece of advice.

 

Definately go with the 2 ga wire. I might be able to get it cheaper, let me call "My Supplier" and get back to ya. I might be able to do the side mounts and silicone covers for less as well.

Sounds good, thanks.

 

Exactly how many circuits do you see yourself having in the Car? Add them up. Single wiper, ignition circuits, fuel pump relay, fans relays, Brake and guage lights, Headlights? etc. If it comes to 8, the 12 might be a better bet and will allow expansion if you add something else.

Wiper, ignition, starter, fuel pump, fan, brake lights, whatever electrical gauges... uh... ??? Warning lights maybe??? No headlights, turnsignals, etc.

 

 

If you add a High amp relay to the alternator power wire, the relay can be controlled by the Master switch. Shutting off the master in the rear of the car will kill power to the relay, killing any power from the alternator as well. I haven't done a race car in a long time so I'm not "UP' on all the new Safety gadgetry.

 

I would suggest going with what is safe, recognisable by the safety teams when they inspec your car, and time proven (known to be good parts)

For autox which I will be doing for a while after getting it running, they don't check anything with regards to wiring. I used to run the tech all the time, never ever looked at wiring.

 

I'll check on the power wire stuff and email or write it down here.

Much appreciated Dave. Got a lead on good switches, if I make my own panel?

[JMortensen]

After doing a lot of research I ended up with the PC680 mount. I didn't buy the battery yet because the research told me that storing the battery for a long period of time would likely kill it. Looks like the Deka has about the same reputation, but I found a couple more people complaining about the Deka than I did the Odyssey. I do get the feeling that most people who are having trouble with these are idiots who are using a lightweight battery to run their heavyweight stereo systems, a lot of people seem to have no trouble with either, but you can only go so far on anecdotal internet evidence. At some point you need to just pull the trigger and I went for what I figure to be the more conservative choice.

 

I also bought a Taylor 4 post kill switch. Still need switches, and I'll have to buy a piece of aluminum plate for the gauges, and the harness itself, and gauges if I can't run the old mechanical stuff.

 

Was thinking about oil pressure idiot light, maybe coolant temp too. I had mechanical gauges in the old engine and liked that setup, not sure how to do that with the LS. I did see on LS1tech that you can drill out the oil temp sender and tap it for the mech pressure gauge, maybe it's possible to just run a tee to an idiot light. Not sure if there is room with the carby manifold in place. I have the feeling that the pressure gauge in my truck is less than stellar when it comes to accuracy, and it is the same motor. If it is a problem to run both might just run the mech gauge and skip the idiot light.

 

Am I reading correctly that the Taurus fan draws 60A while running?!? I'm worried that it might kill my battery if it comes on a lot between runs at an autox.

[RB26powered74zcar]

I've been using the same Odyssey PC680 in my Z w/o any problems since 2006. I do use the negative cable disconnect switch I have installed, in between use of the car.

[z-ya]

Making your own harness is really not all that hard. In a race car just keep it simple for things like wipers, gauges, brake lights, etc. Use resetable circuit breakers that are within reach of the driver so that if it trips, you can at least try to reset it without having to get out of your seat. Use heavy duty toggle switches for everything to avoid using relays. For auto-x you probably don't need a battery switch, but I would install one that cuts the battery, and alternator. Located on the outside of the car so corner workers can find it.

 

Are you using a carb with the LSx? If so, ignore below...

 

If you modify the LSx harness correctly, it should be self contained and include all fuse and relays. Reuse as much of the OEM engine harness, fuse block, and or relay panel. Depending on where the relay and fuses required by the ECM were located in the donating vehicle, you may need to add more fuses and or relays.

 

When I did my RB swap I made the engine wire completely self contained and separate from the stock 240Z electricals. I built this fuse and relay plate which mounts to the ECU:

 

 

The motor will run with a minimum of 4 connections:

 

- Battery +

- Battery -

- Ignition Switch (+12V when ignition is on)

- +12v to fuel pump

 

Additional connections are:

 

- Tach signal

- +12v to fan

- Coolant gauge signal

- Oil pressure gauge signal

 

I suggest thinking it through a bunch of times and drawing a schematic of at least the engine wiring. This is what I drew for me RB swap:

 

 

I would also suggest keeping the LSx wiring separate from the body electrical.

 

Pete

Edited September 29, 2010 by z-ya

[JMortensen]

I realize I could make a harness If I had any clue, but I don't (I should really take an electronics class at the local CC) and I think the easier solution is just to buy the harness and have Dave install it for me. I am running a carb and MSD coil trigger setup, so there are literally 4 wires coming off of the MSD box. I figure there are probably power, ground and switched power, not sure what the 4th is. I'll have to look up what goes where, but wiring for the engine will be really easy.

 

I like the idea of circuit breakers, but I think I'm not going to do that just due to expense. Looking at prefabbed 8 circuit harnesses, and they don't have a circuit breaker option.

 

This?

http://cgi.ebay.com/ebaymotors/8-CIRCUIT-WIRING-HARNESS-KWIK-WIRE-UNIVERSAL-GM-FORD-_W0QQcmdZViewItemQQhashZitem1c0c9ead0aQQitemZ120470809866QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

 

or this?

http://cgi.ebay.com/ebaymotors/Rebel-Wire-8-circuit-wiring-harnesses-1932-Ford-1934-33-_W0QQcmdZViewItemQQhashZitem41532eb59aQQitemZ280568444314

 

I'm thinking about maybe going with the cheaper one, since only the gauges and brake lights will be running full power through the fuse box. Everything else will be on relays.

[z-ya]

I was thinking something like this:

 

http://www.wiringproducts.com/contents/en-us/d62.html

 

And you really don't need relays for circuits less than 20A. Even your Taurus fan probably uses less than 20A. Use simple sealed toggle switches like this one:

 

http://www.wiringproducts.com/contents/en-us/p995.html

 

I have a simple race car schematic I drew up a while ago, let me see if I can find it.

 

Pete

[crazyoctopus]

junkyard 90-95 volvo 24-26 fuse box. all male spade plugs on the wired side. which means that you can use whatever fuse you want and plug in the associated wiring size to it.

 

 

Volvo Fuse Box by crazyoctopus, on Flickr

 

 

Volvo Fuse Box by crazyoctopus, on Flickr

 

junkyard relay box from a nissan, 10 spots and the relays come with an easy to read diagram on top.

 

 

fuse and relay box by crazyoctopus, on Flickr

 

 

fuse and relay box by crazyoctopus, on Flickr

 

chassis diagram for ease of wiring, minor changes are needed for engine components/diagnostics/efi/carbed etc..

 

 

WIRING DIAGRAM rev12 routed by crazyoctopus, on Flickr

 

parts exrpess for $1-$2 switches

 

dpdt http://http://www.parts-express.com/pe/showdetl.cfm?Partnumber=060-087

spst http://http://www.parts-express.com/pe/showdetl.cfm?Partnumber=060-370

 

maybe a bit too much info, but I figured why not add it.

[JMortensen]

With regards to Taurus fan amperage:

http://forums.hybridz.org/index.php/topic/82748-280zx-v8-progress-pics-and-wiring-questions/page__view__findpost__p__807144

Talks about 40A relays being short lived on the Taurus fans.

 

http://forums.hybridz.org/index.php/topic/58262-taurus-fan-slows-at-idle/page__p__532594__hl__%2Btaurus+%2Bfan+%2Bamp__fromsearch__1#entry532594

Pete Paraska says high speed pulls 35A

[ktm]

After doing a lot of research I ended up with the PC680 mount. I didn't buy the battery yet because the research told me that storing the battery for a long period of time would likely kill it. Looks like the Deka has about the same reputation, but I found a couple more people complaining about the Deka than I did the Odyssey. I do get the feeling that most people who are having trouble with these are idiots who are using a lightweight battery to run their heavyweight stereo systems, a lot of people seem to have no trouble with either, but you can only go so far on anecdotal internet evidence. At some point you need to just pull the trigger and I went for what I figure to be the more conservative choice.

 

My research regarding reliability was similar, though I filtered the whining idiots. I figured the same as you. These are, for all intensive purposes, repackaged ATV/motorcycle batteries.

 

I was looking at using the Lincoln Mark VIII fan at one point, but it is too thick at 5-in. for the L-series. It is the "new" Taurus fan. It pulls around 33 to 40 amps continuous, but over 100 amps on start-up!

 

I still recommend the 12-circuit fuse box. I do not know if this car will ever see the street at some time in the future, but the incremental cost difference is well worth it for the added flexibility.

 

Wiring is not that hard. I taught myself everything and it is not very hard once you do it once or twice. Since Dave is local that is an option, but you may want to give it a go yourself at first.

 

I agree with z-ya that if you do attempt it yourself, think it through a few times and understand how you want to route your circuits. I built my own harnesses as well and used a Painless 12-circuit fuse panel and a generic 8 circuit panel.

 

If this is a pure track vehicle, the manually reseting circuit breakers are a good idea. They are not expensive (cheaper than a fuse box) and you would ideally have a circuit breaker for each major circuit (ECU is on a circuit all by itself, followed by coils and fuel injectors, pump, fan, etc.). Ron Tyler and Hughdogz both have a very slick circuit breaker panel that is compact and attaches to the kick panel area. Check Hughdogz build thread for photos.

 

The one (potentially big) problem I see with circuit breakers is the power feed. On a fuse box, you have one main 10 ga feed that provides power to the fuse box. With circuit breakers you need to run a main feed to each circuit unless you had a distribution bar/point.

Edited September 29, 2010 by ktm

[z-ya]

Found this schematic on the web. Looks like it would do the trick. No relays and you could replace the fuses with circuit breakers.

 

http://cranston-racing.com/images/POWER-1A.pdf

 

The Taurus fan seems overkill. Yo just have to go real fast Jon

 

Seriously, I'm using a aftermarket 14" fan in my race car and it is more than sufficient to keep it cool on the grid. It draws around 12A.

 

Pete

Edited September 30, 2010 by z-ya

[JMortensen]

Found this schematic on the web. Looks like it would do the trick. No relays and you could replace the fuses with circuit breakers.

 

http://cranston-raci...es/POWER-1A.pdf

 

The Taurus fan seems overkill. Yo just have to go real fast Jon

 

Seriously, I'm using a aftermarket 14" fan in my race car and it is more than sufficient to keep it cool on the grid. It draws around 12A.

Thanks for that schematic Pete. Aren't relays a good idea? I"m thinking of how slow my wipers were, and how dim my lights were without relays. I know I've replaced some burned out relays and even taken some apart and sanded the contacts to make them work, so I know there are some potential failures there, but I thought it was a good idea to avoid having the full current going through the switch.

 

I have the Taurus fan already. Bought it with a radiator as an afterthought, but for a good price. I'd just as soon use it if it won't kill the battery if it comes on while I'm gridded up and waiting for the next run.

[hoov100]

I'm on the opposite of the relay spectrum, I like using relays on everything practical, but use the ground to control it. I have burned out too many switches and set to many cars on fire to go back to using switches alone to hold the current. Also be sure to hook up an alternator kill switch on that 4 post battery disconnect and don't forget the ford solenoid.

[CarJway]

Battery and mount - thinking something small like a PC 680.

 

I currently have this in my car, and I have had it in the car since Jan 2010. I haven't driven the car for more than 2 miles, and only started the car about 7 times, and always starts right up. I don't unplug the negative wire or anything. So, I have had good luck with keeping the battery outside, and unmonitored.

[z-ya]

Yes, relays are a good idea. But, they add a lot more complexity to the wiring, and add more components to fail. And, they add a lot more cost (weight too). If you buy good quality switches that can handle the current in the circuit they are switching, then you should not have issues. Also, always put the circuit protection between the battery and the switch in case the switch does short.

 

Next year I plan on doing some vintage races along with the time trials I usually do. The EFI has to go to run in C Production. I am switching to Mikunis so that I don't have to run with some crazy fast IMSA GTU cars. I've got a lot of wiring in the car, including at least 4 relays. I plan on completely rewiring the car for simplicity and ease of service when at the track.

 

To me, the only reason to have relays is if you are controlling pumps, fans, etc. with an ECU. Otherwise you are just adding another switch to a switch (if you know what I mean).

 

Pete