Today we’re trying something a little different here at the Autopian. We (probably like you) watch a lot of car and other vehicle-related videos. Some of these video creators have some fantastic and pretty original ideas and we think some of them deserve a spotlight every now and then. Personally, I’ve watched countless hours of Vice Grip Garage, Mustard, and Bus Grease Monkey. My wife and I have this dream of being like VGG’s Derek and rescuing some old abandoned junker. Maybe a diesel something! So, every now and then, one of us will highlight something awesome happening in video. Back at the ol’ lighting site, I used to write about a YouTuber called Robot Cantina. The host behind the channel works with some downright silly ideas, like pairing a Honda Insight with a Harbor Freight Predator engine and trying to have a working car out of it. On a recent night, I decided check in on what’s going on. The wacky host has gone further with the Harbor Freight Insight project, adding a supercharger and trying to hit 70 mph. And then he decided to power a Saturn with a lawnmower carburetor. Recently, the mad scientist of a host decided to see if manually deactivating cylinders in a Saturn SC1 helps gas mileage:
For years, automakers have been offering cylinder deactivation. In concept, cylinder deactivation is a system that allows an engine to provide full power when it’s needed, and better fuel economy when it’s not. This happens through disabling cylinders, effectively making the engine have a smaller displacement. The Clemson University Vehicular Electronics Laboratory explains why this matters: General Motors, Honda, Honda, Mercedes-Benz, Toyota, Volkswagen and more brands going back a whole century have used some form of cylinder deactivation. For an example of how this works, let’s look at GM’s Dynamic Fuel Management. In this system, a controller monitors accelerator pedal input to determine the exact number of cylinders that the engine needs to run well. It does a calculation 80 times a second for this. Cylinder deactivation effectively decreases the displacement of the engine by closing the intake and exhaust valves and cutting fuel injection for a particular cylinder. The pistons in the deactivated cylinders compress the trapped gases and are pushed back down, thus expending zero net work. The remaining cylinders compensate for the loss in power due to the inactive cylinders by operating at a higher combustion pressure. As a result, for a given load on the engine, the throttle valve is more open allowing the cylinder mean effective pressure to be closer to the optimal level and increasing the efficiency of the engine. An electromechanical system controls the engine’s hydraulic valve lifters. The system’s solenoids use oil pressure to help activate and deactivate the lifters’ latching mechanisms. The lifters of a deactivated cylinder are then made unable to open valves. GM’s cylinder deactivation gives its engines 17 cylinder patterns to operate on. But what if you’re a backyard wrencher working with a car that doesn’t have such a feature? Well, as Robot Cantina will show you, just remove the rocker arms and the hydraulic lifters of the cylinders that you no longer want to run. At first, Robot Cantina decided to deactivate cylinders 2 and 3 of their Saturn’s four. Our host also 3D printed out plugs to fill the holes where the lifters came out of. The YouTuber also had to remove the fuel injectors for the selected cylinders. Amazingly, upon startup, the Saturn SC1 and its 1.9-liter L24 engine appears to run smoothly. But that makes some sense, as cylinders two and three were chosen to maintain some balance. Around town, our host found that the performance felt off, but it still had enough grunt to get around town. The exhaust note also got louder and more raspy. You can notice the car’s panic as its check engine light flashes, which makes me giggle. For a test, the Robot Cantina host did a zero to 60 mph test. It took the effectively 950cc two-cylinder Saturn 34.54 seconds to reach 60 mph. They then continued driving, putting 164 miles on the car with it running on two cylinders. Next, the host reactivated cylinder two, making the car roughly a 1,425cc three cylinder. As a triple, the car sounded terrible and there were more vibrations. The engine also bogged down in certain gears. However, it did reach 60 mph in a faster 22.96 seconds. Our host drove 140 miles with the triple set up, but the ride was apparently pretty annoying. Finally, just for fun, Robot Cantina deleted all but cylinder one, effectively making the car a 475cc thumper. It just barely starts and hilariously, it sounds like a go kart. Running on just the one resulted in a slow, unresponsive mess. In the acceleration test, the car couldn’t even hit 60 mph. The engine bogged down at full throttle, making somewhere around 80 percent throttle the new maximum. And after three minutes, it still couldn’t get above 51 mph. Now for the data. Running normally without any tricks, the 1.9-liter engine should make 100 horsepower. And in the baseline test, the car reached 60 mph in 13.96 seconds. Slicing off one cylinder added on nine seconds, while the two cylinder took about 20 seconds longer than the four to reach 60 mph. And of course, the single cylinder couldn’t even hit 60 mph. All of that isn’t surprising to me. What did surprise me a little was the fuel economy. Running on all four, the Saturn did 42 mpg. Running on three, that went down to 40 mpg. And running on two, that went back up to 41 mpg. The single ran so bad, the host wasn’t able to get gas mileage data. I’m honestly not sure what I expected, but it wasn’t that deleting rocker arms and lifters resulting in pretty much the same fuel economy. In the end, Robot Cantina’s experiment was a bit absurd, but it looks like it was tons of fun. And the host was able to answer the question of how a Saturn SC1 drives after you mess around with its engine. I could see myself doing something like this just for the giggles. I’m also curious, have you done something like this before? If so, why? And as we’re always looking for feedback, do you enjoy posts about videos? (Top photo credit: Saturn and Robot Cantina) https://www.farmcollector.com/tractors/schramm-pneumatractor/ And I had to chuckle at the care he took to carefully wipe off/clean the swanky Saturn valve cover after reassembling everything. Our kinda guy. Ahem! “General Motors, Honda, Honda, Mercedes-Benz, Toyota, Volkswagen and more brands going back a whole century have used some form of cylinder deactivation. For an example of how this works, let’s look at GM’s Dynamic Fuel Management. In this system, a controller monitors accelerator pedal input to determine the exact number of cylinders that the engine needs to run well. It does a calculation 80 times a second for this. An electromechanical system controls the engine’s hydraulic valve lifters. The system’s solenoids use oil pressure to help activate and deactivate the lifters’ latching mechanisms. The lifters of a deactivated cylinder are then made unable to open valves. GM’s cylinder deactivation gives its engines 17 cylinder patterns to operate on.” There’s a graphic and everything! Now the question is: Why didn’t it save any gas? Yes, but not elegantly and not entirely by unfettered choice. In 2012, the first time I took my three-cylinder, two-stroke SAAB 96 to a Lemons race, the middle piston decided to come just a little bit apart towards the end of the race, destroying the spark plug and deeply scoring the cylinder wall. The team figured we had little to lose at that point so I took the car back on track and finished on the remaining two cylinders. Performance, already poor, was noticeably poorer. I had driven the car to the track and hadn’t yet set things up for flat towing, nor did I have a trailer, so again figuring there was little to lose, I decided to see how far towards home I could get before needing a tow truck. After all, closer is cheaper. As luck would have it, much of the driving was in stop-and-go freeway traffic so I wasn’t actually impeding anyone even as the car grew slower and slower as well as noisier and noisier. It made it about 100 miles home and was within five blocks of my house when it stalled at a red light. Surprisingly it roll-started after I walked it with the starter over the crest of the slight incline at the intersection and then made it all the way into my driveway before stalling again. I never tried restarting the engine after that. Ten years and two engines later, with a bit more luck I’ll drive it back to the same track this weekend for another Lemons race, although admittedly this time around I’ll be working as staff. Having said that, the 96 in general is a solid car and parts availability is… fair to okay-ish for nearly everything. Some brake parts are very hard to find, so make sure all that is in order. When (not if) rebuilding the engine, Tom Donney Motors can supply new pistons and bearings that are significantly better than the original designs and are well worth it. I understand there are companies and/or individuals in Sweden who also offer improved versions of these items but I haven’t yet had to look into that. Treat the transmission with great care, as it is slightly more fragile than it should be. The freewheel mechanism in particular should never be abused by suddenly revving the engine into engagement, as this will break things. Ease into the throttle until fully engaged. Really, a light touch when changing and engaging gears is a good idea all around. Transmissions can be rebuilt but it is more of a struggle these days and/or a longer wait for one of the dwindling number of specialists to do it for you. Do, however, use the freewheel except on very rare occasions such as descending long inclines when there’s a concern about overheating the brakes. Otherwise, driving around with the freewheel regularly locked out is bad for the engine, as this results in engine braking without sufficient lubrication. Of course, driving around without engine braking is yet another reason to make sure the brakes themselves are good… Beyond that it’s hard to know what to say without knowing something about the specific car you’re considering. I like my 96 and most other owners like theirs as well, but at this point it’s very much a self-selecting crowd. Yes, but not by choice. The Renault was already running on 3 of 4 cylinders and only in second gear when I got it. How the rings got baked onto the piston to cause no compression is still a mystery to me. All issues were resolved with a trip to the junkyard for some parts, but even though the car ran correctly, that made it no better. If I’m chilling on the couch with my sweetheart and a beer for instance, I’m not going to suddenly subject her to the dulcet tones of a four-cylinder engine running on only one cylinder. Likewise if I’m hanging out in bed, or casually browsing while I eat my breakfast. Most of my internet consumption is like that, so unless I’ve intentionally set out to watch some videos, I’m probably not going to. That said, the article was fine and I enjoyed it. The fact that it was based around a video didn’t bother me. I don’t spend a lot of time watching car videos on YouTube unless I need to know how to change the timing belt on a Subaru Outback or something, so I would not have known about this had you not written it up. Now I have someone else to check out.
