Ignition cut-off switch

[superwaxer]

Hi guys,

I'm currently working on a project car that I will be using for club racing next year hopefully if all goes well. So far Ive swapped the engine, prepared the electronics and gave it a paint job. Im trying to do most of the work myself so its a "learn-as-you-go" project. Ive heard that the club I will be joining requires you to have an ignition cut-off switch placed behind the bonnet just down the bottom of the windscreen on that plastic surface (where the whipers sit).

I would like to do this using a smaller switch. In other words, I would like to use this one:



instead of this one:



My main problem is the smaller connecting points on the small switch. Can I connect big battery wires to such small connectors/plates?

Im not an electrician so I dont know if there might be a problem running the current through such a small switch. It has been done before I just dont know where to start.

If anyone has any clue on how to do this, please let me know.

Thanks.

[pimento]

The main concern would be to what the switch is rated at. You can see it there stamped onto the side of the one you want to use, make sure it's rated the same as or higher than the standard ones and you should be ok. I'd also suggest you contact the club and make sure they don't have a size requirement for the cut-off switch.. it'd suck to have to rip it back out again, yes?

[superwaxer]

Originally Posted by pimento

The main concern would be to what the switch is rated at. You can see it there stamped onto the side of the one you want to use, make sure it's rated the same as or higher than the standard ones and you should be ok. I'd also suggest you contact the club and make sure they don't have a size requirement for the cut-off switch.. it'd suck to have to rip it back out again, yes?

Yes it will. What do you mean by "the standard ones"?

[pimento]

Well, the ones that everyone else use. The big red ones. That's what people'd normally use, yes?

[superwaxer]

Originally Posted by pimento

Well, the ones that everyone else use. The big red ones. That's what people'd normally use, yes?

Cool thanks that makes perfect sense Ill check it out. Do you put the switch between the main battery cables or something else like the cable running to the coil?

[pimento]

I've no idea, I've never raced.. I imagine you just cut the positive feed from the battery... as long as that kills everything. You'll need to make sure the fuel pump, the coil and.. pretty much everything is killed by it I guess.

[2ndclasscitizen]

The big red ones are used for a very good reason. What do you think will be easier for the marshalls to see when you're upside down in the gravel, the little one, or the big red one?

[superwaxer]

Originally Posted by 2ndclasscitizen

The big red ones are used for a very good reason. What do you think will be easier for the marshalls to see when you're upside down in the gravel, the little one, or the big red one?

Lol yeah I know! Most of the racers that use the small switches (like me hopefully) have a big ass blue and red ignition sticker on the bonnet pointing to the switch.

[clutch-monkey]

Originally Posted by superwaxer

Lol yeah I know! Most of the racers that use the small switches (like me hopefully) have a big ass blue and red ignition sticker on the bonnet pointing to the switch.

is this what you mean? the one in the cabin is a little hard to see at first
edit: and don't leave the actual switch out when you park it somewhere

[superwaxer]

Originally Posted by clutch-monkey

is this what you mean? the one in the cabin is a little hard to see at first
edit: and don't leave the actual switch out when you park it somewhere

Yes thats exactly what I mean. If its a switch I dont have to worry about parking it somewhere!

[Matra et Alpine]

Contacts on a small switch are too small to be realiable.
LARGE current flows from the battery on starting and good chance you'll weld a throw switch closed
There are reasons why race/rally regs require the "standard switch".
Small switch like the one you want to use are normal on the iginition circuit -- whcih is low current -- NOT the main battery.
Also, re comment earlier about marshalls ..... BIG RED KNOB is easier to turn than tiny little switch - especially if suited up in fireproof gloves !!
If you dont' want the big red bit showing during nevery day use, then do as the Porsech did. That red wire loop is connected to the red switch under the bonnet. You pull on the wire and it rotates the switch !

[clutch-monkey]

Originally Posted by Matra et Alpine

If you dont' want the big red bit showing during nevery day use, then do as the Porsech did. That red wire loop is connected to the red switch under the bonnet. You pull on the wire and it rotates the switch !

advantage is that you can fold the wire loop away when not in use, as you say
the switch in the cabin has a large red arrow next to it too (it's fixed to the underside of the rollcage across the front).
but i thought that's the actual ignition switch and the one on the bonnet is a battery isolator if that sounds right?

[superwaxer]

Originally Posted by clutch-monkey

advantage is that you can fold the wire loop away when not in use, as you say
the switch in the cabin has a large red arrow next to it too (it's fixed to the underside of the rollcage across the front).
but i thought that's the actual ignition switch and the one on the bonnet is a battery isolator if that sounds right?

Yes thats exactly what I thought too

[superwaxer]

Originally Posted by Matra et Alpine

Contacts on a small switch are too small to be realiable.
LARGE current flows from the battery on starting and good chance you'll weld a throw switch closed
There are reasons why race/rally regs require the "standard switch".
Small switch like the one you want to use are normal on the iginition circuit -- whcih is low current -- NOT the main battery.
Also, re comment earlier about marshalls ..... BIG RED KNOB is easier to turn than tiny little switch - especially if suited up in fireproof gloves !!
If you dont' want the big red bit showing during nevery day use, then do as the Porsech did. That red wire loop is connected to the red switch under the bonnet. You pull on the wire and it rotates the switch !

Thanks for that it helps alot. The only thing is, I have seen soooo many race cars with small cut-off switches - why would they do that if it doesnt work?

[LeonOfTheDead]

probably because they think it's cooler, beside being unsafe. stick with the standard one with the "clutch-layout"