Galen Wolffit (wolffit) wrote,
Galen Wolffit

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Thunderchicken + Alcohol = tEh shit!!

So the thunderbird now has these two fighter jet style arm/disarm toggle switches on the center console. Rather exotic looking, like something straight out of Night Rider they sit there in stark contrast from an otherwise shitty red velour interior that looks like it's from the 80's and is not in good shape...

Some background.

Start with a very simple concept: Forced induction cars, such as those with a turbo or supercharger create higher cylinder pressures, and as a result are more prone to detonation/pinging. Detonation is bad, on a forced induction engine detonation will put holes in the pistons and blow head gaskets in just a few seconds. To cool the intake charge down after it's been compressed you install an "intercooler" after the turbo or blower. It's like a radiator, but for air. Intercoolers only cool the air so much though, and after a number of seconds of high "boost" they can heat up, leading to increased air charge temperatures and increased likelyhood of detonation.

Enter the realm of alcohol/water injection.

Normally water is bad for engines, you don't want it getting put inside. But for forced induction, that combination can result in about a 90F drop in air charge temps. You literally inject water into the air charge before it gets combusted. Add alcohol, up to about 50%, using methyl/ethyl, and you get a nice bump in octane too, further preventing detonation.

So you start out driving the thunderbird and get on it, the boost gauge reads 7 psi when you dig deep into the pedal and hey, it's got some oomph. Flip the first switch's cover and set it to ON, and a little red light at the tip of the switch glows red.

Now when you get on it, you hear the whine of a high pressure pump in a 3 gallon outboard boat gas tank positioned behind the drivers seat. This happens at around 5 psi of boost, and a small red light shows up next to the gauge indicating that yes, alcohol and water are being injected into the engine. Hey, it feels peppier now.

Arm the second switch, flip it. And now when you get on it, the boost gauge swings far to the right and hovers at 20 psi, and your ass is now firmly stuck to the back of the seat as the car rockets forward... turbo shrieking like something has gone terribly wrong. But it hasn't. In fact the engine pulls hard and smooth now.

3 gallons should be enough for about 15 minutes of constant full throttle, which is a very long time. I'll probably need to fill it every 1500 miles or so. I can get the alcohol from the hardware store in 1 gallon container, and distilled water keeps it below 50%. By keeping it below that percentage, if there is a backfire it's unlikely to ignite the alcohol.

The whole system is self contained and sealed, since it's designed for an outboard motor and has a handle and can be carried around on it's side.

Total cost of the project: Under $100

A ton of thanks goes out to my friend Adam for helping with this project. Without him I'd never have finished it this weekend.

- Keman
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