AdamITR

What size (gauge) wire do I need for the install ... 12?

B18CXr

depends on what circuit your killing

Drew M

I used 4 awg. for my battery wires.

Chris

are there rules as to what you are allowed to kill?

What would be the safest? Spark.. fuel??

Willard

nope... just make it dead.... whatever it takes.

Will
-who would chose the method that is 'safest' for the motor

B18CXr

IM for details

Chris

so, what is safest for the motor?

Thanks.

Drew M

I would think spark is safer. You won't be leaning the engine out and it is instantaneous.

Tyson

you cut the positive battery wire and put the switch in between and you also cut the alternator wire to the other pole of the switch. cuts the power to the whole car and the alternator, as the alternator can supply all the power needed once the engine is running. ppl talk about resistors and what not across the alternator pole to protect from a quick shutoff, but ive found it unneeded for the electronics on my CRX. the very few times that i've tested it, it seems to work fine, and i hope that i wont ever have to test it again except for a random tech inspection.

Chris

yea, thanks Steve IMed me the same info...

wouldnt want to run lean..

I am learning so much lately!!

Tyson

according to the rules, you have to cut ALL power (except fire suppression if installed) so [plugs] arent enough.


[Modified by Tyson, 2:06 PM 5/21/2002]

Willard

Don't forget about 'other' electrical items that are effected when you take care of the spark.

Drew M

When did I say anything about injectors?

My kill switch does the following:

1) Cuts off the main battery power (power side before the first distribution block)
2) Cuts the power to my MSD unit (power side just before the box, alternator cannot bypass)

The battery is killed and with no spark the engine can no longer turn the alternator.

So where did I say anything about killing the injectors?

Tyson

injectors....plugs.... blah.

i dont know much about how the MSD works,but if you say it cuts the alternator then im sure it will cut the power to the car. but like i said, if you want to stay within SCCA GCR, all electricity has to be killed in the car. but if you just want a kill switch to have a kill switch, do whatever you fancy.

DB2-R81

The proper way to install it is explained here, check the diagram, also why you need a resistor!
http://forums.improvedtouring.com/it...ML/000281.html


[Modified by DB1-R81, 2:15 PM 5/21/2002]

Crazydave

Some one makes a big cut-off switch with extra leads with built in resistor for cars
with alternators

{edit} see the next post for diagram


[Modified by Crazydave, 7:44 PM 5/22/2002]

Drew M

So you are saying that they are all the same?
No . . . what I said was that it cuts the ignition. The motor stops running which stops the alternator.That is what the main battery cutoff does.



Replace the "coil" (round thing in the lower left) with "MSD Ignition Box" and you have EXACTLY how my kill switch is hooked up.

Once again. The INJECTORS (blah) are not involved here.




[Modified by Cobra, 6:41 PM 5/21/2002]

Tyson

Sorry, let me explain myself a little clearer. I made the mistake of saying injectors when I meant plugs, as in spark plugs. It was just a dumb brain fart. Please forgive that. Cutting power to the plugs will make the engine stop running. AND since you also cut the power to the battery it suffices as a legal SCCA electrical kill switch, if that matters to you.

for the record:
17.27 Master Switch (bit paraphrased)
All cars shall be equipped with a master switch easily accessible from outside the car. Master switch shall be installed directly in either battery cable and shall cut all electrical circuits but not an on-board fire system.


[Modified by Tyson, 5:04 PM 5/21/2002]

Grumpy

This is how I test them.

Start car. Run engine to 2500 RPM for 5 sec. While at 2500 RPM turn off switch.

CAR MUST STOP RUNNING.

While switch is off apply brakes.

BRAKE LIGHTS SHOULD NOT WORK. (Assuming it worked with power on.)

ELECTRIC FUEL PUMP MUST HAVE ZERO (0) VOLTAGE.

Check main power lead from alternator.

MUST HAVE ZERO (0) VOLTAGE.

Pass ALL these tests and you are complying with the strictest interpretation of the rule. Some tech inspectors will not be this comprehensive in testing. But you never know when one will.

Grumpy