How did I grow to (the age of) adulthood without learning this one?
While racing your engine or just driving down the highway, turn the ignition off then on again. You'll hear one or more loud explosions. Bystanders will think they're being shot at. Possibly your muffler will be destroyed.
This works with gasoline engines.

How it works:
When you turn the key off, the sparkplugs no longer fire. So that perfect gas-air mixture your car was running on gets pumped into your exhaust system. Then when you turn the key back on the sparkplugs fire and the hot exhaust detonates the rich mixture in your exhaust system like a huge potato cannon.

I did it with an old pickup with no catalytic converter. With a catalytic converter things might be different, but you know what? I'm not going to test it.
If your car has been running for long enough to heat up the catalytic converter it will probably burn the fuel-air mix before too much builds up. If the converter is cold it might act as a spark arrestor. Either way might result in a smaller volume detonating at once. And any damage is likely to be more expensive.

This fun new trick has cost me $90 so far.

Step 1: Step Two: Get a New Muffler

My mom and I are driving from Minnesota to California in the best little truck ever built, a '78 Toyota with the 20R engine and a manual transmission. Right now we're in South Dakota.
My mom was driving. Her key for the truck isn't well cut so it tends to jam in the "start" position, which will burn out the starter. I heard a funny noise and wanted to make sure the starter wasn't grinding itself to death while the motor ran, so I turned the key back a notch, which turned off the spark, then back on.
KABANG! the truck jumped a bit and now was very loud with no muffler.
After checking the damage we kept going with earplugs in and switched to sign language. "Great Sunset"
and "There ought to be more boats on that river" are pretty easy to sign, even if you have to invent the language from scratch.

I would have beat it back into shape and welded it with coat hangers, but time is short and I don't get to see my mom that much, so I checked with the garage at the truck stop when we stopped for the night in Murdo, South Dakota.
Fortunately they had the right replacement muffler, so for $90 I got the thing replaced at 10pm on a sunday night. Wow. Thanks Cole Venard and Bob at the Triple H Truck Stop! (605)669-2465

I'll give the guys a break while they fix it and wander around the shop for a bit.
<p>Truck testicle, I lol'd. Never seen them in Germany :-P</p>
This is a great post. It's awesome to realize that car enthusiasts share their thoughts about cars especially the <a href="http://www.car-stuff.com/muffler.htm">Muffler</a>.
yea i fly airplanes and they dont have mufflers but we have to shut the magnetos one by one and then off well i didnt do it quick enough and i got this big backfire. well that airplane is currently being worked on so yea
interesting trick for airshows etc showing off is to wind the engine up using the starter and run the choke rich but turn on the ignition last thing you do, your exhaust should fire about 30feet of flames out of them and your engine will wind up to an extra high speed for a sec this is for turbo-prop obviously jet engines are a null point and in piston engines this doesn't really do anything but may jsut get it going when nothing else will but yeah I knew a pilot (emphasis on past tense) who did that in the air during an emergency restart by accident and saved himself that time unfortunately he died from a crash my supsicion is that he did that as a last resort all i know is an engine fire caused him to crash don't know if it was that or not due to the fact that I heard the plane was half on fire by the time it landed, crash landing went wrong and fuel tanks went I wasn't there but I suggest you don't do this as some cylinder based planes just overload the cylinder and when the ignition fire you blow the rings or the piston rods to bits like when a diesel wont start and when it finally does you get a blast of blue smoke, it's the same idea except avgas is a a tad easier to ignite as the overloaded will knock
Wow. I've discovered these sweet little dots called periods- they make reading long passages possible. Props for the longest run-on sentence I've ever seen!
Oh long while ago, I used to be awful at english, my apologies for my record breaking behaviour. I have since learned from my past mistakes. See.
Hey sorry about that- I don't what I was thinking when I dropped that one. I'm sure you can speak your native language way better than I can... where are you from anyways?
Haha, I'm from northern Ireland, the awful at English referred specifically to grammar etc. in class... No worries anyway, it was a pretty bad habit of mine...
Just curious, but how'd you come by the name "killerjackalope"... i mean, i'm originally from 'out West' (Colorado, U.S., specifically), and i always assumed that jackalopes were a local native species. Were you traveling in the Western U.S., some time ago, or do jackalopes grow in Northern Ireland, too (or anywhere else you've been). I realize this is COMPLETELY 'off topic'. Sorry.
Eh I don't know really, I originally used it as a gamertage on XBL and it stuck, it just had a nice ring for me... Jackalopes are reasonably well spread folklore though so it's not surprising I've heard of them...
If a car muffler sounds like "a double barrel shotgun right by your head", that must have been pretty intense :)
*** OH HECK CHAA *** Actually, when I did it by accident in my old 70's boat<em> (big car)</em>, the car rocked to the side and it sounded EXACTLY like a stick of dynamite. <em>(which BTW is unbelievably awesome! And really scary... NOTHING like four M-80's, Forget the old &quot;1/4 stick of dynamite&quot; thing about M-80's, never was, an' never will be even close...)</em> I looked underneath the car because tons of small pieces of red fibreglass was blowing around the ground coming from there. And the muffler was peeled completely open and shrink-wrapped to the shape of the underneath car body. REALLY COOL, but it'll put a racing stripe in your shorts if you aren't expecting it... <br/>
Amazing,i saw the same fiberglass blowing out of a bus that was probably struggling to keep pumping out the power fact:bad drivers torture engines
A lot of people in Nebraska have testicles on their trucks. I think it's a hick thing, but I can't be positive.
I think it's mostly people who aren't sure whether or not they're hicks, but want to be.
Maybe they just want to be REALLY SURE their trucks are male. What, do they not want baby trucks or something???
well i live in hick ville and the only balls i have seen hanging on a truck came from the neerby snootyville and and the driver was a female... and i have seeen her driving it many times... makes me think...
if you could only do that with lawnmowers
Without wanting to sound mumsy, remember, when you are screaming down the freeway in your Hurtling Machine about to perform this trick, DO NOT TURN THE KEY ALL THE WAY OFF. 'Steering lock' looks bad on a headstone.
yep,just turn it far enough that the engine turns off,but the electrical stuff remain on
and most engines are supposed to pull the starter back after teh engine turns on
me and a mate of mine use to do the back fire trick in birmingham england the amount of people that jumped in bushs ha ha ha
Did you happen to mention that this only works on CARBURATED engines? I would suggest trying this in the low rent part of town: rrrrrrrRRRRRRRR .... KAPOWPOW. I'll bet you won't need anymore of those FAKE bullethole decals an your car with the real deals for souvenirs.
wont you need to block the end of your muffler to get more pressure and blow it out the bottom?
block them up and you'll get killed by carbon monoxide poisoning pretty quick...
No, you need it to be open...
I managed to destroy both of the mufflers on a 1976 GMC RV one night in Macon, GA like this. The ignition module in the distributor was bad and eventually started cutting on and off. We were between two three story concrete walls at the 75/16 interchange when the engine cut out, then caught agian after about 5 seconds. The explosion was so loud the car next to me swerved off the road and almost hit one of them walls. Sounded like a double barrel shotgun right by your head. Had to drive the rest of the way to Atlanta sitting on top of an open pipe Oldsmobile 455 V8. The mufflers were split open nearly two feet at the seams, and these were big tough industrial truck mufflers. I wouldn't want to do it again.
Yeah, that's what happened with mine. Module bad and that's how I found out... It had a catalytic converter too. (cold). But no fatalities from flying platinum coated balls. In fact the catalytic converter (CC from now on... Too much typing) was OK. no damage to the CC-whatchamacallit at all. I think they'd probably be safer than a non-unit overall just because they might prevent the phenomena if the CC was hot like the other post suggested...
I would like to thank you for answering the question I've asked myself way too many times. Yes, those WERE balls hanging from the bumper of that truck. Now to answer the greater question of "Why?"
why not and for that matter... whose balls... and how did he (i hope) loose them...
They belonged to a local politician who, along with Diane Feinstein and &quot;Smilin' Chucky Schumer&quot; (D-NY), wanted to completely outlaw guns... Now he's totally OK with people protecting themselves... Which reminds me, I proudly carry the pupal sack of one: &quot;Iron Balls McGinty&quot; as a tobacco pouch. That boy could really fight <em>until I took his sack with my blade...</em> I'm a biker, and whenever I roll into some cruddy little 1-Honda Town, and some local fool wants to fight a 6-foot, 6-inch, maniac biker, I can usually de-fuse the moment by simply rolling a smoke. They just turn grey when I pull the pouch tight with my teeth after shaking out a smoke. Something about the wrinkled brown sack with hair on it I reckon...<br/>
Hmm. Perhaps I don't know enough about cars, but I can't figure out why stopping the engine by stalling it guarantees that good teeth on the flywheel will line up with the starter. Won't the flywheel stop in a random place?
The starter doesn't need to turn because the <em>wheels-&gt;transmission-&gt;and finally -&gt;the engine</em>, is already turning. All you need do is to turn your ignition on and the engine will start again and at the same time it will open the exhaust valve and let a wee bit o' flame into the exhaust pipe and then <strong>Kraaaahhh! Boooom! Whoosh! Scream! &lt;rending of flesh&gt; car doors, sirens, vomiting, yellow plastic, morgue, moldy eternity... </strong>Just kidding, only the muffler blows. You'll be totally safe. Ab-so-friggin-lutely zero chance of disfigurement or even the heartache of dismemberment to deal with. In fact, this procedure is highly recommended for any 16 year old new driver. &lt;kidding again&gt;<br/>
wow, so much typing for a little info. But it was totally worth it!
i'm not sure what to think about the truck testicles....
don't even.
This ripped apart the down pipe on our 92 honda accord. good thing we we're gonna replace it anyway.
i dont think i learned anything during this instructable but i sure laughed me ass off like dannyboy!
haha buy me some and send them to me
My brother had an old Datsun hatchback with a manual trans that had well over 200,000 miles on it. Needless to say some parts were in need of repair. He would watch the rpm's as he punched it. At the right moment let off the gas and listen to the gunshots. Friggin' hilarious! We would drive around and hunt for pedestrians. We got this one guy, on his bike, under an overpass....I never laughed so hard. The dude totally dumped his bike....I'm laughin my ass off just typing this...awe man, that shit was funny. Kinda felt bad for the bicyclist.....oh well...good times, good times.
Yer one funny guy Tim. I continuously laughed my ass off through this whole Instructable. Thanks for keepin' me awake! I'm so glad I found and joined this site today. Look forward to reading more of your posts.
My car's manual warns against push-starting it because the raw gas going into the catalytic converter would make it extremely hot, causing a fire hazard. The same might apply here.
Ive used an air bleed about six to eight inches behind the collector flange (ahead of the cat) and the stock fuel map on my toyota 22r. The downshift burble sounds from the tailpipe combustion is sweet music to me!
with most newer cars it's almost impossible to do cause of the fuel injection and the cat (the catylitic converter burns off exess gasses making it cleaner) if you want to make a nice bang you need to do a couple of things. 1 gut or remove the cat 2 make your car run richer ,ecu adjustment,carb adjustment or high rev then downshift (i do not recomend doing any of these) just run the car stron for a while and any of these will increase your chances of backfire during shifting or hard deceleration you can also just wire in a sparkplug on your muffler this works as well but if cought with it you will be fined
It has nothing to do with the catalytic converter as to why you can't make it backfire. It doesn't work on fuel injected vehicles only carbuerated engines because when you turn off the key on a fuel injected car the fuel flow automatically stops however carbueraters use venturis (fuel siphoned due to passing air) and continue to pass fuel and when you turn the key back on the spark plugs fire again igniting the now fuel rich exhaust pipe.
Same for me... I had to restart my old car while driving because of a computer problem, too. It had a cat. Nothing happend. (except for me sometimes nearly crashing because the brakes and the steeringwheel were way less responsive...)
I've stopped/started my car while on the highway more than i can remember to reset an unresponsive carputer power supply and this hasn't happened so far. i do have a catalytic conv so that must help . . . granted i don't think i'll try it while gunning the engine :P
the RX7 comunity does this all the time just high reving and letting off the gas down shifting and slamming on the gas again i have seen many a cherrybomb go the way of it's namesake LOL

About This Instructable




Bio: Tim Anderson is the author of the "Heirloom Technology" column in Make Magazine. He is co-founder of www.zcorp.com, manufacturers of "3D Printer" output ... More »
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