Zoomspeed

I was wondering. If power is cut to the trailing plugs whiel the car is running, Will it be able to continue running?

911GT2

Maybe, but there would be a lot uf unburned fuel if it did. Remember, the trailing plugs fire twice for every one time the leading plugs fire, so you'd be losing 2/3 of your combustion. It might run, but it might flood.

Why do you ask by the way?

Zoomspeed

Well first I saw 93blackFD's thread about his flames. Then a guy I work with who has an older chevy truck put some spark plugs in his exhuast and a cut off switch for his ignition to shoot flames out. I didn't like the way he did it on his truck because if you dont flip the switch back before the rpms get to low then the truck will die. Although it did get home some really long lasting and blue flames.

So, this just gave me the thought what if I could hook up a relay, some extra coil packs and plugs installed in the exhaust, and switch. When the switch is off all would run normal. When the switch is on it would cut power to the trailing coils and instead power the coils which run the plugs in the exhaust. I figured that cutting the power to the trailing coils woud leave unburnt gas which would then go down the exhaust pipes hit the spark plug down stream in the exhaust and ignite it. Ultimately resulting in some REALLY big flames.

I didn't know the trailing plug fired twice for everytime the leading plug fired though. Would this work if power was cut to the leading instead of the trailing then?

I dont really intend on doing this though. I'm to affraid it will melt my bumper. Just got bored in class one day and started thinking aobut it, then started drawing some wiring diagrams and stuff. Just wondering if it would really work.

Zoomspeed

any more thoughts ont his guys?

NewbernD

iTrader: (1)

I don't think this is accurate. In every combuston event there is one fire from the leading and one fire from the trailing (unless you happen to have a MSD ignition..) Can you explain what you're talking about, please?

911GT2

Check out the "red and blue" videos on this page. http://www.rotaryengineillustrated.com/animations.html

If you watch carefully, you'll see that the two trailings plugs both fire at the same time. But since the rotors are offset X degrees, the plugs don't fire at the same time for each rotor.

Basically, the trailing and leading plug on rotor 1 will fire, and at the same time the trailing plug for rotor 2 will fire, even though it has already passed the combustion phase. Then when rotor 2 gets back to combusiton phase, its leading and trailing will fire, but the trailing plug on rotor 1 will fire at the same time.

So for each respective rotor, it's L+T, T, L+T, T.. etc.(L= leading, T=trailing.)

The L+T of rotor 1 match up with the T from rotor 2. Lets see if this works.


Plugs Firing
Rotor 1-----L+T------T-------- L+T
Rotor 2 ------T------L+T------- T etc.

Get it?

911GT2

Well wait a minute, if the car is in gear, and you're off the throttle, the fuel injectors don't fire anyways, right? (based on the fact that my PFC shows injector duty of 0.0% when in gear and off throttle) So you'd only be burning the unburnt fuel from the last combustion cycle. If theres no fuel theres no need for spark, so maybe it would work...? hmmm...

93BlackFD

no, leading plugs fire at same time... and yes, twice

when you let off the gas pedal your spark plugs cut off anyways, only on automatics do they keep firing

your exhaust should be hot enough to ignite the fuel

jwhite94RX7

Except that the trailing side plugs are the ones on top. (Like 93BlackFD just beat me to saying.)
See page G-19 of the FSM. So you've got it backwards.

911GT2

I always F that up. Anyways, the principle still applies.
Thanks.

NewbernD

iTrader: (1)

Yes, and no.

If we're counting times that the plug actually fires, then yes, the leading plugs fire twice as much.

If we're counting how many times the plugs fire and "contribute to ignition" then no. There is only one firing of leading and one firing of trailing that is significant to ignition.

So, as it applies to your original argument, you wouldn't lose 2/3 of your ignition. You wouldn't lose 1/2 or really even 1/3. More like 1/10.

jwhite94RX7

I concur.

Zoomspeed

actully with this idea I was thinking it woudl shoot fire while on the pedal. At least that was the intent.

Some good info in this thread.

93BlackFD

no, it wouldn't, it would bog...

Kento

You'll be spending an inordinate amount of money on rear bumpers....

Zoomspeed

lol yeah I know, thats why I enver intended to do it int he first place.

1QWIK7

iTrader: (33)

you guys know your ****, i like that..