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David Love AI27
05-07-2007, 12:12 AM
I am gradually eliminating any unnecesary wires and "street" crap from the Mustang... Can I/should I remove the fuel pump inertia switch from the trunk... I fully understand the safety benefit but I would like to eliminate any problems from failure... I could move it forward so it could be reset while in the driver's seat... suggestions...

GlennCMC70
05-07-2007, 09:33 AM
move it forward so as it can be reached by the driver. if it turns out it trips too easily, then bypass it.

BSharp
05-07-2007, 09:47 AM
I think by mounting it closer to the driver it will greatly reduce it's effectivness. If the switch is in the rear and the car gets hit in the rear or the car backs into a wall at high speed thw switch will do it's job. If it is in the middle of the car it may not work because a loy of the force will be dissipated.

GlennCMC70
05-07-2007, 10:08 AM
that switch is desigend to work regardless of which end the of the car is hit. its an inertia switch. as long as its mounted to the chassis, you will be fine. i've seen them mounted stock in the passenger side footwell and a slight rear bump set them off.

BSharp
05-07-2007, 10:22 AM
I am not saying it will not work, just some of it's effectivness. If it is mounted in the center of the car and the car gets hit from the side behind the rear wheel and spins it may not trip because there was not much G force. It seems to me you would want the switch to be subject to all the same forces that the fuel tank is subject to and not be suject to unnessary ones.

Rob Liebbe
05-07-2007, 10:57 AM
You both have good points. Those things are set to be fairly sensitive and are used for the hits from either end of the car. Mounting location shouldn't affect its performace as you will still get enough force transmitted throughout the car to shut them off. The main function is to cut off the fuel pump in case the fuel system is compromised at either end of the car, not just at the tank area. (i.e. fuel line cut in frontal impact in the engine compartment) I don't know if those things are axis sensitive and need to be mounted in the same fore-aft orientation as original so I would test that out or just mount it in the same orientation.

I deleted mine from the system as the master cutoff switch and the ignition switch both cutoff the fuel pump circuit. But that doesn't help if I'm unconscious and not close to a corner worker station. But I didn't want a malfunction or a light hit to take me out of a race. Also, solder the wire back together instead of a crimp connector.

This is also a good way to get a car to stop running. It seems like a good alternative to the PIT maneuver the cops typically use. You just give a good hit from the rear, a lot less likey to send the perp spinning out of control.

Al Fernandez
05-07-2007, 01:23 PM
Does anyone know the level of force required to set this off? I know of several mustangs with them in that have...uh...lets just say "experience" with on track altercations that didnt shut their cars off. Come to think of it, I've never heard of this switch being the root cause of any downtime during a weekend at the track. They appear to be pretty solid to me.

GlennCMC70
05-07-2007, 01:30 PM
i think its just very common to remove this item. i would check and see if that switch was still in the car before i would assume they had one durring a crash and it didnt work.
i have thought of adding one from a ford to my car. but its already fast enough. :wink:

mitchntx
05-07-2007, 01:53 PM
Al, several years ago at a DE event at TWS CCW event, a young gent put a new 996 off driver's right exiting T4.

The off was violent enough that it activated some sort of inertia switch (speculation) because it would restart after everything stopped.

He had backed it into the deep grass and the turbos caught the grass on fire and subsequently burned the back half the car very badly.

That is the ONLY time I've seen it happen in 10 years of going to these events.

AllZWay
05-07-2007, 02:01 PM
Al, several years ago at a DE event at TWS CCW event, a young gent put a new 996 off driver's right exiting T4.

The off was violent enough that it activated some sort of inertia switch (speculation) because it would restart after everything stopped.

He had backed it into the deep grass and the turbos caught the grass on fire and subsequently burned the back half the car very badly.

That is the ONLY time I've seen it happen in 10 years of going to these events.

Picture of said Porsche.... After that, I am not sure I woud want that switch at all.

http://www.smittysspeedshop.com/images/tws/burntporsche1.jpg

David Love AI27
05-07-2007, 11:08 PM
Again, thanks for the input... believe it or not I'm a decent electrician, so I am going to add a bypass circuit to a toggle switch take I can activate from the driver's seat... this decision was promted by the picture and my fear of burning up in the car... my camaro has two pumps and both have inertia switches on them but impossible to reach without opening the rear hatch, think I will install aforementioned bypass on the Camaro also...

I will update this post once I have tested theory and if sucessful I will install on anyone elses car the has this switch...

I am thinking of using a momentary switch just to get the car to a safe place and making it necessary to analyse the reason for tripping the inertia switch... any discussion concerning a momentary over a straight on/off???

Al Fernandez
05-08-2007, 02:24 PM
hehe sounds like a full blown FMEA is needed eh? (failure mode and effects analysis)

I kinda like that momentary switch idea :idea: nice!

Todd Covini
05-09-2007, 12:59 AM
I bypassed mine many years ago in California after it tripped on the warm-up lap while scrubbing tires.

(serious g's)

-=- T

I'm serious.

jeffburch
05-09-2007, 06:31 AM
I bypassed mine many years ago in California after it tripped on the warm-up lap while scrubbing tires.

(serious g's)

-=- T

I'm serious.
Maybe had you left the thing in there it would've saved you from the OTE debacle @ Contender 1 8)

jb