Author Topic: "How do I get flames to come out my exhaust?"  (Read 973 times)

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"How do I get flames to come out my exhaust?"
« on: September 04, 2004, 10:25:43 pm »
"Say do you have any info on setting up flamethrowers? I've heard lots of advice and would apprciate some from a real rodder. I'd be flamin a 63 cad thanks!"

"I have a '63 BelAir custom and I've been trying to rig up auto-exhaust flamethrowers . . . . . . . . . . . . . . . . . . . . . . . When I hit the switch and click it off again, the plugs spark. I also have my motor running rich so that raw fuel comes back through the pipes. I think I've done everything right, but I still haven't gotten it to shoot fire as of yet. Is there something I overlooked? Do I need to get bigger plugs or to run my carb richer? I thought you guys might be of help, seeing as how flamethrowing was a popular trick on the leadsleds of the '50s. Any help that you may have would be greatly appreciated."

Obviously.. as cool as this flame idea may seem, fire, flames, exhaust gassses, raw fuel and other things about messing with the material world of vehicles are very dangerous.. as with most things, we should know what we're doing and often times once educated, older and wiser... we sometimes look back at our crazy impulsive actions of youth and think - "Why did I ever do that?!".. Well in some cases us kustom crazies and leadsled fanatics often slip into the coma of nostalgia.. Flamethrowing Exhausts just may be one of those cases..
So.. here follows a view of the phenomona...

Disclaimer: Know what your doing before operating any machinery.. I'm not responsible for your abilities or actions - you are.. These are not instructions... Kids.. do not try this at home or attempt without mature adult supervision..
Some background:
For a good spark a coil creates high voltage pulse from low voltage via a primary and secondary winding in close proximity.. The current applied to its primary winding induces a sympathetic field in the secondary..

Letting the current flow to the primary coil then stop, causes it's magnetic field collapses.. which causes the induced field of the secondary to collapse which sets up a current flow to ground via the sparkplug.. The points function to let the current make and break it's flow to the primary coil...

All differences in output and input voltages in any coil are relative to the differences between the number of windings of the primary and secondary coils.. for all practical purposes any automotive coil would probably function well in a flamer setup...

Making and breaking of current to the coil primary is more critical under the hood where the engine needs specific timing of spark.. But apart from that precise timing, the distributor basically just cams the points which make and break current to the primary coil.. causing the secondary to trigger the plugs... For a flamer setup rapid make-break need not be timed.. just rapid..

Even Henry Ford got involved with flamers.. well sorta.. In the good old days, Ford coils were used for flamed exhaust.. these were neat little packages encased in cute oak boxes and had a coil and vibrator point setup within.. They used to be abundantly available.. then got to be collectors items.. and pricey.. so some started using other stuff.. regular ignition coils and a point setup of some sorts... an electric motor spinning a cammed shaft with points on the cam or a buzzer/vibrator setup.. anything to rapidly make break the current to the remote coil.. Presently with the advent of microchips, most exhaust flamethrower kits available today probably use some sort of solid state unit to trigger the coil...

So much for what goes on with coils and points.. What is this thing called Flamer?.. Basically a remote coil/point for the flamer setup.. usually in the trunk.. With a switch on the dash that diverts power from the engine to the remote flamer.. plus plugs in the pipes....

Any questions?.. If you're into it, one answer is to buy a kit...


Here is some info on kits available from a couple of fellows who helped me with research for this page........

Charlie's Customs and Hotrod's have provided me the instructions from the Flamethrower kits they offer. These fellows are both trying to provide you with high quality flamehrower kits... I personally have not seen or used either of the kits... No doubt there are also other providers of these items.. And of course.. there is always the scratch built do-it-yourself aspect..

Here is a Flame Letter in the finest
Do-It-Yourself tradition of kustoms..

Bob Pandragger Writes:

The key to flamethrowers is to rig the electricals so that when the second (flamethrower) coil is live, the coil firing the engine's spark plugs is dead. This is the only way to get a good flame without fouling your engine's (as opposed to exhaust) spark plugs with an excessively rich mixture. YOU DO NOT HAVE TO RICHEN THE MIXTURE TO HAVE FLAMETHROWERS; doing so will only make the car less drivable.

My Cad has a cheap radio shack 12v motor in the trunk which opens and closes a set of points using a homemade eccentric (3/8" aluminum rod drilled through off-center). This acts as a fake distributor to allow the secondary coil to build and release its charge. Only one spark plug per exhaust pipe is necessary.

This is the operating procedure: First, make sure that your car is warmedup to normal operating temperature. This is especially important in humid climates as the humididy caused by condensation in the exhaust pipes during warm-up tends to kill the flame. Next, rev the engine up to a high-but-safe RPM(this can be done by shifting to neutral while rolling). Now flip your toggle switch. This should be of the HOT-HOT variety; when you flip it, it will kill the underhood coil and fire up your motor-coil combo in the trunk.

Now the engine is freewheeling, spitting raw unburned fuel-air mixture out the exhaust. Keep the gas pedal pinned firmly to the floor. When the engine has wound down to a couple of hundred RPMs (you can do this by feel, but a tach is recommended), just flip your switch back to normal running position for a few moments until the RPMs build up again; then flip it back for more flames. Believe it or not you can get flames for about 4-5 seconds per burst using this technique (remember, bigger engines wind down slower, so that's an advantage).

Now, about exhaust pipes/systems. BIG WARNING: DO NOT HAVE ANY HOLES OR LEAKS IN THE EXHAUST. A leaky exhaust will cause the flame to travel forward into the pipe and cause an explosion in the mufflers (if you have them). Yes, I learned this one the hard way. Next: you will notice that most flamethrower-equipped cars have HUGE exhausts. This is for a reason: the larger area results in a slower rate of flow through the pipe. This is how you get the nice, yellow flames. You can run a standard 2" pipe (I did for a long time) but you will get a blue jet-like flame (like a propane torch).

Only use the big pipe for the last two feet or so of exhaust; that way if the flame travels into the pipe the restriction will help blow it out before damage can occur. Finally, try to position the spark plugs close to the end (opening) of the pipe for the same reason. Mine are about 4" in to keep them hidden.

If anyone has any more questions they can Email me and I'll try to help.
Happy Weed Burning!

Well.. there you have it... a picture of the flamin' part of the hobby/lifestyle/culture.. Whatever you decide to do with this overview, remember.. Organic material is usually flammable....

Keep Warm - Mel

Oh.. And regarding the professional dudes and gals who concoct all sorts of ways to create huge show flames at Car events as crowd pleasers (isn't it amazing what we human animals find compelling..).. If you've seen these folks in action, you'll notice it happens under controlled situations and I suggest on street vehicles, you do not even ponder fiddling with adding any other flammables to your exhaust stream... and if you decide to attempt it anyway.. Don't.. Professionals at the car shows hopefully know how Not to blow themselves up and maim innocent bystanders... Show flames are not street flames!!!.. Live responsibly...
global warming is going to strike two days before the day after tomorrow


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"How do I get flames to come out my exhaust?"
« Reply #1 on: September 05, 2004, 05:12:58 am »

[TKC] ~<{LTC}>~

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"How do I get flames to come out my exhaust?"
« Reply #2 on: September 05, 2004, 05:21:43 am »

global warming is going to strike two days before the day after tomorrow