Trying To Blow Up A 4.6-Liter With Nitrous, Ft. Cleetus McFarland

YouTube sensation Cleetus McFarland may be most famous for his stripped to the bone, twin-turbo Corvette named Leroy, but he’s also got a fleet of oddball project cars such as this 4.6-liter Mod Motor-powered retired police interceptor Crown Victoria, named “Neighbor”. We’ve featured McFarland’s antics with this car previously, when he dumped gallons of compressed air into the intake tract on the dyno, looking for power.

Apparently that small success lit a fire in him (no pun intended), as he has decided now to plumb a massive wet shot of nitrous oxide into the glorified taxi cab, on his new dyno. Rather than just blowing up the engine, McFarland and team decided that it would be better to actually see what kind of power levels the engine would handle before failing. Besides being entertaining, McFarland’s unique approach to things does yield actual experimental data.

For the test, they will be performing pulls naturally-aspirated, with a dry-shot of nitrous, followed by wet shots (nitrous and supplemental fuel injected at the same time) of increasing amounts until failure. For the test, they have plumbed a fuel pump directly into a 5-gallon fuel jug full of E98 ethanol, powered by a 12-volt jumper box. Not a clean installation by any stretch of the imagination.

After a baseline pull of 197 horsepower and 255 lb-ft of torque, which is significantly down from the previous baseline of 220 horsepower, the team gets ready to spray all the engine’s woes away. Because the engine is running so rich in naturally aspirated form, the team has no worries about the system’s ability to handle a dry shot by itself.

If you look at that wideband reading, you can see how nasty-lean the system went with the 175-horsepower dry jets. However, as a testament to the robustness of the 4.6-liter Modular, the engine survived to undergo further abuse.

After a quick pull with the dry shot, the engine picked up 45 horsepower and 38 lb-ft of torque, with just the nitrous in the feed lines, through a 100 horsepower jet. After rejetting with a “175 horsepower” dry jet in the nozzle, and opening the bottle for the full run, the torque and horsepower numbers made an incredible jump, even with the engine going ridiculously lean, picking up 145 horsepower and 110 lb-ft of torque over the baseline pull.

After their rigged fuel enrichment circuit failed due to a stuck solenoid, the crew rigged up something even more half-assed–a gravity-feed fuel enrichment circuit out of a suspended water bottle. However, what’s the old saying? “If it’s stupid but works, it’s not really stupid” definitely applies here, as their cobbled-together fuel enrichment actually had positive results on the dyno.

Plumbed with a 250-horsepower jetting, the next pull only netted 14 more horsepower, but an additional 50 lb-ft of torque, for 357 horsepower and 415 lb-ft of torque, largely due to the overly rich fuel condition, if we’re guessing.

As you can see, there curves are pretty erratic, thanks to the extremely cobbled-together nature of the nitrous system. However the power increases, even with horrible air/fuel ratios, are real, speaking to the effectiveness and overall tolerance of nitrous as a power adder.

Going for the coup de grace, the team plumbs in an AN-4 line straight into the intake lid. No nozzle, no jets, just straight nitrous line. I think there is a small part in all of us that has always wondered what would happen in this scenario, except we all have the good sense not to actually try it. Well, thankfully not only does McFarland not have that sense, but he also has his own dyno.

For those of you familiar with how a nitrous safety burst disc works, you probably know where this is going… the force of undiffused, unjetted nitrous line immediately ripped the airbox lid off of the intake. The Cleetus solution? Self-tapping screws to hold everything together.

As expected, the engine didn’t survive the unjetted attempt, with what appeared to be a nitrous backfire causing rapid unplanned disassembly of everything forward of the intake ports, along with a small fire in the engine bay.

So while this may just seem like sophomoric screwing around on a dyno to most, we choose to look at it from an educational standpoint. The largest lesson to be taken away from this video, is that nitrous oxide injection is a lot more tolerant of a missed tuneup on a street car than many people think.

While in a competitive drag race engine, which is already on the ragged edge, tuning-wise, a missed call can lead to a melted piston, as a mild power adder on a mostly stock street car, nitrous is far safer and more tolerant of mistakes than the masses might believe. So while not exactly as scientific as proper destructive testing in a laboratory environment, there is still educational merit in Cleetus McFarland’s hijinks. At least, that’s what we’re telling ourselves.

Well, if you try hard enough to make bad things happen, you’ll end up getting your wish. This explosion only happened after Cleetus and team went to the extreme to make it happen. While entertaining, it’s also educational, as you can see how much abuse nitrous, in a mostly-stock application, can actually take before failure.

About the author

Greg Acosta

Greg has spent fifteen years and counting in automotive publishing, with most of his work having a very technical focus. Always interested in how things work, he enjoys sharing his passion for automotive technology with the reader.
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