Kill switch

Kill switch

Postby RacingFrog » Tue Jan 06, 2015 10:27 pm

The current rules state:
"5. GENERAL
AA. Kill Switch
1. Switch to cut off / isolate battery power throughout the car, obviously
marked with standard lightning bolt symbol and off position is clearly
marked. "

The way the kill switch is currently wired in Lincoln's STI, it just cuts the battery which means that once the car is started and is running from the alternator, the kill switch doesn't kill anything until you turn the ignition key off. This seems pretty useless to me and in the Vette the kill switch kills both the battery and the ignition so that the worker can actually switch the car off by turning the switch.

Given that the car has passed even Mt Washington's tech, I guess it's not required for a kill switch to actually kill the ignition?
Is this something that we want to specify in the rules and is that something that tech is willing to check?
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Re: Kill switch

Postby walterclark » Tue Jan 06, 2015 11:07 pm

It IS supposed to kill the engine as well as isolate the battery. I assumed everyone knew that by now, especially if they are running a P class car.

We do not check every switch, but we do check some of them at random or if we think there may be an issue. If we did check every one of the things we require in each and every car we would have to start tech on Thursday or begin running after noon Saturday. We assume competitors are smart enough to do some things like this correctly, since it is their own best interest.

Since it was Don and I at Mt Washington a s well as at every hillclimb doing tech I assume your are taking shots at our sloppy work. If it were me I would just fix it and keep my mouth shut.

Guess who is not going to be making any more special trips to someone's pit to tech their car because they need a special lift and it is inconvenient to bring it with them to tech.
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Re: Kill switch

Postby RacingFrog » Wed Jan 07, 2015 12:12 am

walterclark wrote:Since it was Don and I at Mt Washington a s well as at every hillclimb doing tech I assume your are taking shots at our sloppy work. If it were me I would just fix it and keep my mouth shut.

Guess who is not going to be making any more special trips to someone's pit to tech their car because they need a special lift and it is inconvenient to bring it with them to tech.


I am sorry, I didn't attend Mt Washington and didn't know who was doing tech. I heard that some people were doing safety modifications to their car for Mt Washington so I assumed there were stricter rules, it wasn't my intention to blame or point fingers to anyone.

When I was researching how to wire the kill switch in my Vette, there was a debate on the Vette forums how to kill the ignition and it looks like some racing series only require to isolate battery power but not kill the ignition (which I don't get but that's the way it is). So to summarize, I think that our rules are not clearer since they only mention to cut off / isolate battery power which does not require cutting the power coming from the alternator. I am not blaming anyone, I am just trying to clarify and possibly improve the current rule. I thought it was also important that tech weigh in on this issue as you are the ones with the knowledge and experience.

I would propose to replace 'battery' by 'electrical' as follows:
AA. Kill Switch
1. Switch to cut off / isolate electrical power throughout the car, obviously
marked with standard lightning bolt symbol and off position is clearly
marked.

Once again, I apologize if I offended you, this was not my intention. I really appreciate all the work you and Don are doing for the series.
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Re: Kill switch

Postby walterclark » Wed Jan 07, 2015 7:45 am

Accepted.

IMO, disconnecting the battery on a running engine is asking for trouble. The regulator associated with the alternator output uses the battery as a filter to reduce spikes present in the alternator diode raw output and and to improve regulation otherwise. Disconnecting it can result in damage to electronic devices connected to the vehicle including ECUs.

I would suggest you go ahead and make that proposal.
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Re: Kill switch

Postby Rabbit Farmer » Fri Jan 09, 2015 8:44 am

I have the opposite understanding of this current rule...

Switch to cut off / isolate battery power throughout the car


The rule only states that the kill switch isolates the battery and does not mention the ignition.

Even the Mt Washington rules state:
A recognized battery shut-off switch must be used in all cars.


I believe what is in Lincoln's old car meets both rule requirements, therefore, were properly "passed" at tech at NEHA and CTTC events.

Yes, I agree that a proper kill switch should include the ignition, but it does not seem to be a current requirement.

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Re: Kill switch

Postby RacingFrog » Fri Jan 09, 2015 4:20 pm

Rabbit Farmer wrote:The rule only states that the kill switch isolates the battery and does not mention the ignition.

Even the Mt Washington rules state:
A recognized battery shut-off switch must be used in all cars.



Yes this was also my understanding, this is why I was proposing a change to also cut the ignition. From my reading, I have gathered that a cut-off/shut-off switch only isolate power from the battery but that a kill-switch also has to to cut ignition.
If a car crashes and the worker cannot shut the car off from the kill switch, I think this is an issue. Do you think enforcing the ignition cut-off would be a bad idea?

I also noticed at my crash at Burke that there was only 1 wire left going to my horn and I was actually quite fortunate that my horn was still working! So if the impact triggers the kill switch for some reason, is that going to cut the horn too? In which case, would it be safer to make the air horn mandatory for any class that requires a kill switch? (I will be switching to an air horn in the Vette for next season anyway).
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Re: Kill switch

Postby sachilles » Fri Jan 09, 2015 4:52 pm

In general I think an air horn is a wise addition for anyone running our hills. Most horns are in harms way during an off, having a good chance at being disabled.
Pretty easy insurance to zip tie an airhorn to the cage.
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Re: Kill switch

Postby walterclark » Fri Jan 09, 2015 6:33 pm

Yes, calling it a kill switch if it is ONLY required to disconnect the battery is misleading. If only disconnecting the battery were the intent it should have been referred to as a battery disconnect. I agree that added wording to include the engine in the kill function is appropriate.

My horns were half unplugged by my spin at Ascutney resulting a weak beep that was unheard at the checks. I plan to go with an air horn. If I had needed to hit the kill switch after the car came to rest, that would have removed power from them, so having a horn that doesnt need the battery is a good idea.
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Re: Kill switch

Postby RacingFrog » Tue Jan 13, 2015 12:29 pm

I have submitted a rule change proposal for the kill switch and the air horn (for cars equipped with a kill switch).
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