I'm not sure what the difference is between 2 & 4 pole kill switch.

I just want to make sure I'm getting one that's legal for track use.

Which one is most people running? regular $30-40 jegs/summit unit?

 

T1 makes a sold state style switch that seems to be popular. They say it's NHRA legal.

http://www.t1racedevelopment.com/cat...ery-cutoff-kit

You'd have to look it up to be sure.

 

just use a 2 pole switch , its legal and cheap, i bought mine moroso 2 pole switch from jegs .

 

Explain why cheap should be a deciding factor here? You buy cheap, you get Taiwan crap that will fail with moderate load on it. A dual-pole switch to carry ~175A+ on crank is not something to buy because you find it for a cheap price.

The solid state is the preferred option as there are no moving parts, and will eliminate lengthy runs of cable - resulting in decreased weight, and more likely than not eliminating excessive voltage drop issues due to using 'cheap' audiostore wire to run an average of 16'.

 

first of all moroso products are made in america and also the 2 pole switch has a surge amp rating of 2000 amps and a continuous amps rating of 300 amps. people have been using moroso 2 pole switches for years in drag racing and still in use,just because something new and better came out dosent mean that old technology dosent work

 

1) Moroso makes quality parts, I will agree with that. However their parts being 'Made in the USA' vs repackaging of another manufacturer's parts (switch) are not the same thing. I am not saying Moroso sells/supplies a subpar switch, just pointing out the obvious. They very well may be re-selling a quality Cole Hersee switch, but I would assume every other DIY-racing supplier (Summit, Jegs, Quickcar, Painless, etc) may not.

2) 'If it ain't broke don't fix it' - I get it. BUT - it's not about something new replacing functionality of something old. It's about efficiency to obtain the same result. There is always a smarter way to do anything.

In my opinion, ~$125 difference between the two is negligible compared to the associated benefits.

 

Use a solid state relay. Anything else can chatter with vibration.... meaning that your power source will cut in and out intermittently. If that's cool to you, then cheap out.

 

Simple 12v solenoid does the exact same thing.

Those take years to fail. I also see solenoids in really rough condition not cut in and out at all. Driving down a track won't cause it to cut out.

If you think anything solid state relays or rectifiers dont fail you're wrong.

I see rectifiers fail all the time.

 

I've seen a few of the solenoids fail where I have yet to see a SS relay fail. No moving components is a SS relay and they can handle serious amps.

 

ive changed a few failed solid states on fairly new aircrafts. everything fails at one point

 

yes I know about solid state (silicon) electronics. They will fail eventually.


Chiner solenoids fail faster then American made solenoids. I use solenoids daily that get used maybe a thousand times a day. On,off,on,off,on,off.
On lift pumps from 12-72 volts. Im talking 3 shifts a day. They last For about 5 years. The cheap aftermarket ones not so long.

You guys run your cars maybe what 30 times a year? 50 at most?

Its over kill for a car. looks nice tho.

 

Sure it may do 'the exact same thing', but the solenoids I'm assuming you are referring to are not rated for the current. Yes they will handle the draw of the car running, but not the starter.

You're right, everything can fail at some point. I have had one solid state fail, and watched numerous solenoids and even high current rated switches crap out.

If the benefits and the potential inherited issues of the other don't just 'click' for anyone looking for direction in what option is more suitable, well then it would make sense - 9/10 are more concerned about how their front end, vinyl wrap, and shaved bay are going to look.

 

300 amps at 100 percenty duty cycle

If you buy a solenoid from a vendor that buys them from china but marks them up you wouldn't know the difference.

This is where the bad rep is coming from.

Those solid state switches you guys are buying have a huge mark up on them too.

I can get some to whoever wants to try them. They maybe cost 20 bucks. ( talking solenoids)

 

300A @ 100% DC is junk. Trust me. Do you know anything about inrush current? Do you know that when a motor starts current is roughly 20 times higher than operating current? That and vibration is what kills the solenoids. You don't have that issue with a SS relay, at least not the Littlefuse relays that I recommend to others.

 

How much current can our little power cables handle?

What are they like 6 gauge? 4 gauge? I forget...

On top of that only 12v?

 

Did you know diesel motors run the same solenoids without issue?

7 liter high compression motors don't have problems with them

 

Big issue that I see with solid state in this application is when they fail, they fail closed. With no secondary protection, it could be bad news.

Per nhra you only need to "cut electrical function," which is shutting the car off. Cut main/ecm power and its taken care of. Hit switch, engine stops and cant restart, done. No need to run the battery, starter or alt through the switch unless its more convienent.

 

Markup is nothing new, everything has a markup - why should this be a deciding factor when choosing an efficient means for a safety component?

6AWG in a decent cable will carry ~90A continuous, 4AWG ~120A. These are estimated average over 4-5'. Now a solenoid is not what the OP was asking about, he was referencing the standard 'heavy-duty' switches; as per tech would need to be mounted on the rear most point of the vehicle. So, you're going to tell me it's a worthwhile trade to add ~15' of heavy gauge from front-mounted battery to switch and then forward again? (keep in mind most would source junk cable from an audio spot - throwing the above current ratings out the window). The solenoids you're mentioning, when purchased correctly are a great alternative - but again not what the OP asked about.

4AWG to starter +, 6AWG to vehicle + is more than enough for most dedicated track cars (ECU, Ignition, (2) Fuel Pumps, Waterpump, Fan, Cabin/Dash, and Lamp).

PaulVR6 - And what happens in the event the car was wired by DIY'er Joe with fuel pumps on a switch, and not triggered by the ECU? Driver crashes, is dazed, someone shuts the 'kill switch' you're mentioning which removes power from the ECU, while the pumps are still flowing. Kaboom. If the car smacks up, the motor will likely stall - who the hell cares if the switch will prevent it from restarting?

This is safety - not let's do it as cheap as possible because it should work. I don't feel safe in half the cars I climb into while I'm just wiring them - life is more valuable than saving a buck.

 

Whoops didn't notice he was trying to use a switch.

I was mentioning markup meaning cheap china made products get marked up by certain vendors, then people think they are good quality because of the price. Then the product fails and the whole idea gets a bad rep.

But I thought op was going to run a solenoid, Also the solenoid could be mounted anywhere inline with the existing power cable and all that is needed to be ran is a 18 gauge switched ground to the solenoid to the rear of the car.

I thought this was a common thing, this is what I did on my track car.

my paint skillz suck but like this

Charlie if youre interested in running a setup like this shoot me a pm ill tell you where to pick one up at

 

you guys are so busy arguing about where the switch is made, that you missed the original point, you need at least a four pole if you are running an alternator, battery needs to cut off, alternator needs to cut off. Other circuit needs to interrupt field current to the alternator.

 

Nobodys arguing, guy.

Just discussing alternate methods to achieve the same results.

 

well back on topic anyway, I know on some Honda alternators there is more then one circuit that needs to be interrupted or voltage feedback will continue to cause the field to be powered

 

Look at my circuit I made for the solenoid, guy..

It cuts all positive voltage to the enitre circuit.

 

if the alternator is turning, you still have voltage coming from the alternator, and if you cut off the battery without turning off the alternator, it looses the stabilizing effect of the battery and you end up with a huge voltage spike, the engine will continue to run as you've only cut off halve of the voltage sources

 

here's one from flaming river that kills both the battery and alternator, says 150 amp continuous and 2000 amp surge http://www.flamingriver.com/index.ph...5/s0001/FR1013