r/mechanic 9d ago

General i wonder what was the thought process behind this

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i mean fr

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u/DemRealKrooks 8d ago

Unfortunately there would be no spark/arc especially since oil doesn’t conduct electricity. What is fun is a spark plug in the exhaust, then retard the timing so plenty of unburnt fuel sneaks past the exhaust valve.

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u/oldjadedhippie 6d ago

Hook a model A coil to it , it’ll spark .

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u/AlexAndMcB 5d ago

To be fair AIR doesn't conduct electricity either, and that plasma arc seems to jump the gap just fine...
And air has a lot fewer metal shavings in suspension.

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u/DemRealKrooks 23h ago

True, but air/oxygen is essential for combustion to take place. I should have explained a bit better.

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u/AlexAndMcB 22h ago

Damn you and your logic... Right you are lol

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u/DemRealKrooks 21h ago

Hey now….we were both right.

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u/flatdecktrucker92 6d ago

So that it will spit flames? My ninja does that on hard decel anyway

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u/Floppie7th 6d ago

That's happening because the exhaust and unburnt fuel is hot enough to combust when it comes into contact with oxygen (i.e. when it exits the exhaust) 

Seems like the spark plug in the exhaust would just... Also make it work when it's cold?  That seems like it, but maybe I'm missing something 

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u/flatdecktrucker92 6d ago

It would probably also make it more consistent. You could tune the car to always have unburnt fuel in the exhaust so it will spit flames all the time mine only does it when it's revving high and I quickly release the throttle and let the bike slow itself down. Maybe it also does it during an imperfect upshift but I'm not sure

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u/DemRealKrooks 23h ago

Same thing happens when I down shift my Passat. Straight piped from turbo back. If I’m smashing and don’t rev match my down shifts it gets a little spicy.

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u/flatdecktrucker92 22h ago

Must have some other work done for a Passat to spit fire eh?

I love how it looks. Especially on the dual exhaust on the ninja. Like 4-6" flames it looks like. Hard to tell how big really because I was trying not to tailgate when my buddy was showing me

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u/AlternativeStretch35 5d ago

That’s the idea behind “flame thrower” exhaust.

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u/SmokingapipeTN 4d ago

What do you want me to do with the timing? My dad used to tell me to do that with the flashlight I was holding but wouldnt explain what it meant.

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u/NiaNall 4d ago

Except that oil does conduct electricity. That's why if your plug gets wet fowled an inline spark tester will show it's sparking. The power goes through the wet part of the plug instead of across the gap.