Is it time for timers on fuel shut off or ignition?

Will, just how are these Timers activated? Is it turned on once the car stages? Plus how expensive are these devices?

 

I wonder if a pocket GPS or something similar can be integrated into a main fuel line shutoff switch which would activate when the car either gains altitude or starts heading in the wrong direction? I had some other idea I posted last year but the entire thread was deleted.

 

How would you decide the time on the timer. What if you had a bunch of tire shake, and were on and off the throttle? If could be bad if the timer shut off the fuel at wide open throttle down track if you had problems early. If it was, say, 6.5 seconds, how long did Shelly's run take, from the hit of the throttle? Will, you saw Snow's crash, how long was it from start untill he was back on the ground facing the starting line? I'm guessing it couldn't have been more than 3-4 seconds, which would still leave him with 2-3 seconds, or more, of potential power if the throttle hung. The mercury switch, or something like that, has to be the best idea. We have some lift equip. that have ignition cutoffs it the machine leans too far over. I don't know how it works, or (fortunately) if it works at all, but they don't look like they have mercury in them. When the top fuel cars were having blowover problems a few years back, was this issue ever addressed? I'd think that someone would already have a solution for this.

bryan brown

 

As an engineering problem the solution is pretty simple. There have been for many years devices that can sence motion either azmuth or elevation that could be incorporated into the computer and control all functions necessary to shut the engine down, deploy parachutes, apply brakes, or to keep the car running straight down the track. The question is not how but how much money it would take and how much control do you want to give up to electronics. NHRA has a rule that says no telementry can be used so unless that rule is changed the remote kill idea is mute. Even if changed I doubt that by the time a crewmember reacts to the situation it would help much. As for the question of will shutting the magneto's down kill the engine I am not sure if you are in the lights if it would but can tell you that at any point up until the eight mile if the six shooter looses power it will immeadiatly kill the engine with the throttle wide open. I have experienced this not on purpose but by accident when the wire came off the six shooter battery. Will has raised some interesting questions concerning this problem. My son Chris Holley and myself are just finishing with building a new chassis for 06. The car is in the jig and we happen to be working on the wheelie bars (which we did not run on the old car). My thinking concerning the wheelie bars was that if they are strong enough that the car could not blow over as the wheelie bars at the very least would unload the rear tires and cause them to spin if enough pressure was generated against them. I know that Shelly used whellie bars and I assumed that the bars must have collapsed allowing the car to get high enough without unloading the tires. After looking at the bars we are building I realized that it would probably be possible even with the bars for the front end to get high enough for the air at great speed to blow the car over. The problem is the tire growth. When the tire changes heigth the wheelie bars clearance from the ground also changes allowing the front of the car to come much higher off the ground before any contact. Once the car gets up on the tire the bars are close to useless. Many of you might have figured all this out a long time ago but it left me with an empty feeling in my stomach. So what are the bars good for. As being used by some they will limit the squat of the tire at the hit of the throttle and can be used as a tuning aid. I am mainly speaking to the dragster issue. Havn't seen funny cars having a blowover problem. If they have a problem it is usually at the hit of the throttle or early in the run. It seems to me that the core of the problem lies with the driver.
When do you get out of the throttle? If the front end of a dragster is several feet in the air at the 1/8 mile that should be a good indication. If the g force or tire shake is causing the driver to black out then maybe we should be looking at who it is happening to and why. I have as many questions as answers. If all this is boring you I apologise.
Bob Holley

 

Hand Switch

Will; Just a little clarification. The positive on switch is not a kill switch, it is a fuel kill switch that requires the button (switch) to be held on during a run. This way if you run with you hand on the chutes after going into high gear, a delay could be built in for the blown cars.(or a-fuel) The computer would basicly tell you how much delay to put in the box. NO SUPER COMP JOKES

 

Will, I think you mentioned mercury switches. The thing about these switches is they sence position. If the driver was unconcious the results woud be when the front end came up it would kill the ignition. As soon as it did this and the car returned to the ground the engine would fire up with wide open throttle if the driver had his foot on the throttle. There are ways around this problem by using relays that will not reset. It would act like the rev limiter on the top fuel cars only they sence rpm not attitude. One problem with a lawn mower type shut off on the steering wheel is that all control functions durning the run would have to be with the same hand. If the driver was in a bad situation he might also not release the button. But that is another story.

 

why not use a fuel shutoff rather than a spark shut off? would there be a delay?

 

If a engine is dieseling the ignition has nothing to do with it.Need a roll over swith to shut off fuel.The down side is no matter what it is,it will have to be the same on every car.Some sort of a long mercury switch would work.Obviously would have to be long and at a specific angle,to keep the tire shake from setting it off.Would also have to run a relay to keep the fuel valve off until it was manually reset.
Would be worth the trouble thats for sure.

 

could you make a switch that would only allow the engine to be at WOT for a specific amount of time... then start cutting fuel? But also make it to where you could pedal the car and reset the amount of time?

 

I thought of this a long time ago for funny cars.
Install a spring loaded actuator for the fire bottles, fuel pump, ignition and chutes that has a melt-able link in it to set off the fire bottles etc. in case of a fire if the driver was unable to.

To answer jr's question you could install a time delay relay. The relay would have to have electronic contacts because of tire shake etc. The time delay relay is called a delay on break relay. In other words when (x) amount passes the timer times out and opens or closes sets of contacts.

Bob Kraemer

 

When an engine is diseling it is caused by an engine failure. The engine is running off the oil or oil and fuel that is being pulled from the pan into the manifold. There is really not much you can do about this situation but it rarely occurs. The other situation is that the engine because of the cyl. temp., compression, etc. it is has preignition that sets off the fuel charge in the cyl. There is not much you can do quickly to overcome this situation either except shut the fuel supply off. This situation does not seem to be a problem as it would have already showed itself up on top fuel engines. Looks to me like the easy solution is to put a timer or msd programer on that would activate fuel shutoff and ignition kill. The pro stock cars are already doing this with the ignition. I personally think if you are going to prevent something it should be what caused the situation in the first place which is the blowover. We are looking at this from a dragracers prespective with the tools that are familiar to us. That may be enough, but there are devices out there that could be used to shut the engine off if the attitude of the car (elevation) changed more than a predetermined number of degrees. I don't have the cost or havn't looked at how it could be intergrated into the system but will look into it.

 

Hello, I am new to insideTopAlcohol.com and would like to point out that I am not directly involved with the sport, but I am a huge fan. I don't know much about the inner workings of these cars, but I thought I may add an outsiders point of view. Instead of just trying to shut the motor off (either by fuel, ignition or both), would it be possible to disengage the clutch once the RPMs hit some ceiling value? I assume this could pose a problem if the car was just to spin the tires, but at the same time, I would think that since the weight of the car is still putting some load on the engine, that there would be a difference in "tire-spin" high-rpm and "absolutely-no-load" high-rpm. So basically, instead of trying to kill the motor, try to disconnect it from the tires. Ultimately, whatever the best solution is, I'm sure there is going to be some situation where tireshake, a "wheels-up" launch, or something else could trigger the car to shut off. However, I think the odds of these scenarios would be small... even then, I think any team would rather have the round loss than the loss of any loved ones, crew, or fans. Thanks.
Matt

 

In APBA's premier class of outboard tunnel boats Formula One,SST120. It is required for all boats to be equiped with an inverted kill switch.This switch consists of a steel ball encased in a cylinder about 8'' long at the top of the cylinder is a toggle switch "ON" position down. there in a small window at the top of the cylinder for a visual check of the switch position and to reset if necessary.
I have driven these boats. They turn @ 4 g's plus! they are as violent on rough water as some tire shake, and as most of you know,prone to blow over. I have blown one of these over above 100 mph. it is nothing nice and like the dragsters, happens so fast that there is no catching it. Just the blow over itself carries g forces in unnatural directions to forward movement that it is very disorenting.
A switch like this could easily kill mag and fire an air cylinder to shut off fuel in one switch.

 

^ may be a link with some information, also pricing?

 

A photo of one can be found @ www.seebold.com/html/parts4.htm
Any fabricator could make one in a half an hour. Be glad to build one for you to try.