Ignition/Start Switch amps

[70chall440]

In building a 73 Cuda road race/street car, I am installing a push start button (the column has been replaced with a tilt column w/o key); I have been looking at all of the push to start buttons and systems out there. I am not concerned with the RFID versions or the more modern car style (I have several versions of these in hand, but not real impressed with them). To get a "nice" keyless entry system, cost is high (~$700), there are cheaper versions but the imperative word is "cheap".

All this said, I am running a master power switch along with a push button and other switch for accessories, etc (think race car). What I am wondering is how much amperage a starter switch needs to be rated for. I have a number of them in hand ranging from the Moroso style (50amp) to a more modern version that is 10am. What I am trying to do is get a "start engine" button verses the rubber type (which will work, just would rather have something more ascetically pleasing.

So, the ask here is how much amperage flows through the start button/switch. I know I can (am most likely will) use a relay, but thought there are some smart people on here that might have some insight.

[DocMel]

Like your avatar.  I was in 1/75th, the 5th SFG and the 3rd SFG.

Starter switches are almost always wired somewhere with a relay.   The relay reduces the high amount of amps that goes thru the starter circuit when the starter is engaged 

Imagine this: Ever have a motorcycle?  Ok, the small little starter switch mounted on the handlebars has super small gauge wires leading to it.  If it didn't have a starter relay to reduce the amount of amps going thru it when the starter was engaged, it would heat up, smoke and melt in about one second.

On your Cuda its the same deal:  You have that small little black box  (your relay) mounted near the battery on the drivers inner fender well.  It serves the same purpose.  It keeps your small gauge wires at your ign switch (and harness) from frying when the starter is engaged

The starter draws the highest amp load on its associated wire harness when engaged, hence the relay   

To answer your question, any switch you use, without a relay somewhere, is going to get hot, really quick.  Here is an example.  Lets say I wanted to start my car by just jumping with a very large gauge cable directly to the starter.  That cable will get very hot, very very quick.   

So to answer:  I really don't know how many amps (with a relay) would go thru any starter switch,  but Ill guess its not more than say 20-30 amps, solely because I haven't seen any fuses or fusable links rated at more than 30 amps

So running any switch, or button, without some sort of relay, would be a non-starter in my book (Pun intended).   Not saying thats your plan, but some folks don't know the purpose of a relay

Good luck

[70chall440]

Thanks on the avatar; I was with 1st SFG and retired out of there in 04.

as dumb as this is going to sound, I knew that... I was just trying to get my head around why some of these switches are 50amp, others are 10, etc. Obviously the car has a starter relay under the hood, but the switch issue got me wondering if I should be using yet another relay (like a Bosch 5 pin) or something.

[laramie]

Forgive me if I misunderstand your prior comments... but why not use the relay that is already there?  Just rewire the start wire to run to the starter button rather than the ignition?

[dodj]

The stock starter relay probably takes less than an amp. I've never measured,but your 10 amp start sw. will do fine.
And yes, you will use a relay- initial starter current is over 100amps.

SFG?

[70chall440]

Thanks all; I realize that the starting system needs a relay, however I was concerned that the amperage between the relay and the switch was higher than 10 amps for some reason.

SFG = Special Forces Group, supposed to be SFG(A) actually = Special Forces Group (Airborne)