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WIRING - Race Car
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Author:  rodrocket [ Mon Jul 02, 2007 6:12 am ]
Post subject:  WIRING - Race Car

greetings all

just after some thoughts or advice here

i am about to completly rewire my car & thought i would get others thoughts & ideas before i jump in the deep end

the car is a Race Only deal & will never see the street

the switch panel that i plan on useing is a Painless 6 Switch Panel

the items that i will need to power are as follows:

Water Pump - CVR

Fan

Fuel Pump - Magna Fuel 4450

Trans Brake

Line Loc

Tail Light

Ignition

16 Volt Booster Box

Dash Lights

Inhibitor Switch

C02 Solonide Switch

i belive that i should run relays on the Water Pump, Fan & 2 on the Fuel Pump

i have an isolator for the rear & would like thoughts on weather to keep it as an Isolator or use it to completly shut the car down

i also have an extra starter button in the engine bay to enable me to crank the engine when doing valve clearance adjustments

as well as running the main power cable from the batteries that are mounted in the rear up to the starter i will also run the earth cable with it as i have a large earth cable mounting point inside were the igniton ect sits on a seperate plate thats retained with dzus fastners

i would be interested to hear anybody's thoughts on this & anything else they may recomend

regards
rod

Author:  DCarr [ Mon Jul 02, 2007 4:22 pm ]
Post subject: 

First I'm going to recomend Kens thoughts on running relays, just run a heavier gauge wire instead and you'll have one less thing to go wrong. I never ran relays except to ground out my Magneto. Then the last time I wired my car I added relays just because everyone did, but never got to use them because I sold the car before I got the wiring finished and installed.

Are you planning on running two pairs of cables from the batteries up to the front of the car or just run the batteries in parallel and run one pair of cables up front ?

I would run the switches as follows

Water Pump

Fan

Fuel Pump

Ignition

Starter

Tail Lights / Dash Lights

And then seperate and appropriate switches for the:

Line Lock , On Shifter

Trans Brake, On steering wheel

C02 Solonoid Switch, for shifter I assume and run it off of an RPM switch box ?

Inhibitor switch ???

Author:  Margaritaman [ Mon Jul 02, 2007 5:05 pm ]
Post subject: 

If you choose to not run relays I would make for darn sure you have a heavy duty switch that is capable of handling the said accessory's amperage consumption/output + 20%.  Those PAINLESS switches in that panel aren't designed to be ran without relays.  Doing so is only asking for eventual trouble IMO.  That fuel pump pulls 13A, electric fan even more, and the switches last time I looked at mine are 10A.  
A relay removes the high current flow from the switch (little switch) and runs it through the relay (big switch) which is designed for 30A.  Run 15A through a 10A switch and it's only time before it either has terminal meltdown or refuses to turn on/off at all, not to mention you won't get full power to the accessory which on something like a fuel pump can't be good.
Increasing the wire gauge will help deliver the full amount of juice to the said accessory but once it hits that switch you're back to square one.
Think of a relay as the BIG SWITCH and the dash switch is the LITTLE SWITCH.  The little switch turns on the big switch, kind of like foreplay!  =;

Agree or disagree?

Author:  oobob [ Mon Jul 02, 2007 5:13 pm ]
Post subject: 

Try 1 of these panels and you'll throw rocks at painless stuff.
Take 1/2 the time and is twice as neat.
http://www.jegs.com/webapp/wcs/stores/s ... 3_-1_10405


Mark

Author:  DCarr [ Mon Jul 02, 2007 5:48 pm ]
Post subject: 

MM ... I was probably running 20 amp. switches they could've been 10a or 15a as far as I know ( doubt it though ), I just dont remember as that part of the car was done many many years ago. But I do know that once I got good switches w/ metal throws I never had another problem.  The only switch or electrical problem I had was with the cheap switches w/ plastic throws and those the " toggle " would break or the lever would break off.

I was running a Mitsibitchy dual fan w/ 14 ga. wire and never had a problem with it. Same with the Moroso Water Pump drive, I dont know how they compare to the electric water pumps as far as amps pulled but there again never had an issue.

On the fuel pump, that is a lot of amps but this is a Track Only car so its not like it will be on for an 30 min. straight, and realistically no more than 10 min. at a time for the most part. I started off with 2 Holley Blues ( 2 seperate power supplies ), then dropped down to one and then to a BG280 all with 14 ga. wire and it was like that for 16 yrs. with the first 6 years being street driven, not much but it was taken out most weekends.

Without a doubt you are correct in that its in his best interest to run a heavy duty switch. And if those switchs are only rated at 10 amps and he doesnt swap them out then he is going to have to run relays.

And I should've mentioned that if he does decide to use relays to use Sams idea and wire up a small lite up to it that is visable from the drivers posistion that stays on when the relay is powered up and goes out if the relay goes bad. That would've helped me out a couple of times w/ my Magneto Relay !!

Author:  Beretta [ Mon Jul 02, 2007 8:37 pm ]
Post subject: 

Margaritaman wrote:
If you choose to not run relays I would make for darn sure you have a heavy duty switch that is capable of handling the said accessory's amperage consumption/output + 20%.  Those PAINLESS switches in that panel aren't designed to be ran without relays.  Doing so is only asking for eventual trouble IMO.  That fuel pump pulls 13A, electric fan even more, and the switches last time I looked at mine are 10A.  
A relay removes the high current flow from the switch (little switch) and runs it through the relay (big switch) which is designed for 30A.  Run 15A through a 10A switch and it's only time before it either has terminal meltdown or refuses to turn on/off at all, not to mention you won't get full power to the accessory which on something like a fuel pump can't be good.
Increasing the wire gauge will help deliver the full amount of juice to the said accessory but once it hits that switch you're back to square one.
Think of a relay as the BIG SWITCH and the dash switch is the LITTLE SWITCH.  The little switch turns on the big switch, kind of like foreplay!  =;

Agree or disagree?





I agree with you Jeff.......I used a relay on everything on the Beretta... =;

Author:  gearhead1011 [ Mon Jul 02, 2007 10:25 pm ]
Post subject: 

I don't think you need relays  if you use a quality switch. My panel has 20 amp circuit breakers below each switch so if you exceed the circuit capacity  it'll pop the breaker. It's never happened on mine.  A fuel pump relay isn't a bad idea just because of how close to the battery it is.  I do use relays to convert 12v circuits to ground circuits.  Ain't that right Barry? =;

Author:  rodrocket [ Tue Jul 03, 2007 4:44 am ]
Post subject: 

Thanks guys

Appreciate your reply’s here

I have already ordered the 6 Switch Painless panel so I will make do with it


I was planing on wiring the circuits as follows

Starter Button: wired in parallel with the extra starter button under the hood this circuit will need to run through the inhibitor switch (neutral safety switch)

Ignition Switch: will power all the circuits up & give the ignition power

Fuel Pump: this switch will run through 2 relays as per the Magna Fuel wiring instructions

Water Pump / Fan:  this is a two way switch were you can have just the water pump on or water pump & fan, I am thinking of running 1 relay to the Water Pump & 1 relay to the Fan

Accessory Switch 1: will be used for Dash Lights (4 globes in the gauges) & will also power the taillight

Accessory Switch 2: I was thinking of using this to isolate power from the Line Loc, Co2 Shift, and Data Logger


Wiring the car this way I would only be using 4 relays, 2 on the Fuel Pump, 1 on the Water Pump & 1 on the Fan

What are your thoughts on this?

I am also trying to decide what is better for an isolator on the rear of the car, would you wire it as a battery isolator or use it as a complete Shutdown switch were by if you were to turn it off whilst the engine was running it would kill the alternator & shut the car down

I already have the Moroso 74102,  300 Amp Battery Disconnect Switch

Thanks again

Regards
Rod

Author:  DCarr [ Tue Jul 03, 2007 11:51 am ]
Post subject: 

rodrocket wrote:
I am also trying to decide what is better for an isolator on the rear of the car, would you wire it as a battery isolator or use it as a complete Shutdown switch were by if you were to turn it off whilst the engine was running it would kill the alternator & shut the car down

I already have the Moroso 74102,  300 Amp Battery Disconnect Switch
]


I would wire it so it shuts off all power along with the engine. And that is the correct switch for running an alternator. You'll run the main Alt. wire to the switch instead of to the battery ( or ?? )

And thanks for the explanation of the " inhibitor switch "

Author:  rodrocket [ Wed Jul 04, 2007 5:17 am ]
Post subject: 

thanks Duane

that one thing that i was tossing up

as i have all the gear to do it as you have said i think its worth doing

would you run a relay on that circuit or let the cables carry the load

regards
rod

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