Disclaimer: This review is not meant to incite a brand war between DA/3W/EVO/ZDZ. The names '3W', 'DA', and 'ZDZ' are mentioned only to give the reader a basis for comparison. Neither the EVO Factory, Roger Forgues, or myself are trying to say any brand is better than the other. All are proven to be good engines. All we are trying to do is let people know about the EVO. EVO 150 Competition Review: Initial Impressions: - Manufacturers Specs: Power: 17HP Bore: 47.6 MM Stroke: 42 MM Crankshaft: 3 Ball Bearings Gasoline Mix: 50:1 – 80:1 (See Notes Section) Ignition: Epower 4.8v-9.6V Lithium Ready Carb: Tillotson RPM: 1100-8500 Recommended 2 Blade Props: 26x14; 28x10; 28x12; 30x10; 30x12; 32x10; 32x12 Recommended 3 Blade Props: 26 x 14; 27 x 12; 27 1/2 x 13; 28x12; 29x12 Price: $1350 - Fit and Finish: My Competition 150 has the anodized finish on it. The crankcase is anodized black and the cylinders are powdercoated black. In addition, the hub, cylinder heads, carb block, and screws are anodized gold. That makes for a very aesthetically appealing engine, but I was curious how the machining work was. After much examination, I found that the machining work was even better than the finish. There are a few places on the crankcase that have not been anodized, such as around some of the screws, and those places show very clean machining marks. The different pieces of the crankcase (3 major sections, not including the mount) also fit together very well. I removed the cylinders and heads and inspected the inside of the cylinders and found the same thing. The honing marks were uniform, and the cylinder heads fit well. The heads are actually sealed by an O-ring, as are some car engines. The inside of the crankcase shows the same good quality machining. - Weight: - DA Without Ignition: 8 Pounds 5.5 Ounces - Ignition: 5.5 Ounces - Regulator: 1 Ounce - TOTAL: 8 Pounds 12 Ounces - EVO Without Ignition: 8 Pounds 10 Ounces - Ignition: 8 Ounces - No Regulator Needed. - TOTAL: 9 Pounds 2 Ounces So, there is a 6 ounce weight difference between the two engines. On a 40 pound airplane, that’s just shy of 1%. Everything was weighed several times on a postal scale, and each weigh-in returned the same results. Installation: - Mounting: I used custom aluminum standoffs that Roger Forgues sells. (http://www.forgues-research.com) This made the installation beyond easy. All I had to do was tell him what kind of offset I wanted and how far the spinner needed to be from the firewall. He had the engine in a CAD program so he could determine the lengths to cut the different standoffs. I got mine in natural aluminum, but Roger offers anodized versions as well. The engine is 1 ½ an inch shorter than a DA too. I don’t have a 3W here to measure the length difference on those. The EVO also has a different bolt pattern for the back plate. Roger is currently working on an adapter that will allow you to bolt the EVO right up where your DA was with no changes to the cowling or firewall. The prop hub is a typical 6-bolt pattern. The prop off your DA/3W will drop right on. - Carb Installation: The only reason I mention this is because there is one special item to note here. The EVO engines have a separate pressure line to run the diaphragm on the carb. So, if your installation requires it, you can easily rotate the carb 180 degrees. I did this to make accessing the needles easier. Also, EVO has attached a machined aluminum arm to the carb for your throttle linkage. It has three tapped holes in it so you can get your throttle geometry correct. They were tapped for metric, so I retapped one for 4-40 to match the hardware I already had. Ignition: - The EVO uses a standard battery operated, hall-effects triggered, electronic ignition. The Epower ignition module is actually built by the same company that does the ZDZ ignitions. That’s why the plug caps look so similar. In case you aren’t familiar wit the ZDZ style ignitions, the plug caps are held onto the spark plug by a setscrew, instead of a split-ring type clamp like a 3W/DA. Either way works just fine. It’s about 6 of one, half dozen of the other. The ignition does have two really neat features I’d like to point out. First, it can handle up to 9.6 volts. If you are running a lithium ion battery on your ignition, now you can get rid of the regulator. That’s one extra failure point you can eliminate. The second feature is that the ignition will automatically shut itself off after 1 minute of inactivity. It’s still drawing a tiny bit of current in this state, but this should help save your battery should you accidentally leave it turned on. Plus, this lessens the risk that someone could accidentally start an engine that was left on. Still, always treat any gas engine like it is ready to start unless you just verified it couldn’t. Running: - Starting: This engine starts just like any other 150 engine out there. Just flip on the choke and ignition, flip the prop until it barks, turn off the choke, and then flip the prop until it starts. After it was done breaking in, the engine would start in 4 or 5 flips. It seems to be fairly cold natured though. On cooler days, I usually try to run the engine at ¼ - 1/3 throttle to help it warm up. I flew it on a 50-degree day, and the engine definitely liked to be warm before it would transition above a high idle. If I tried to throttle up above ¼ before it had warmed up, it would try to quit. Leaning it down helps some, but I just opted to let it warm up for about 30 seconds before I moved the throttle. After the first flight of the day, it’s never a problem. Of course, you should always let any gasoline engine warm up before you run it at high RPM.
- Transition: The transition on this engine is incredible! The transition with a Menz 32X10 is lightning quick, and is very smooth both in vibration as well as sound. The engine has a unique sound to it, but it tends to sound more like a 3W than a DA. Don’t try to tune it for the typical DA “pop” or it will not run properly. Just tune it for a slight burble at lower throttle settings and for transition. I set mine to run as rich as possible while still maintaining a good transition. A good test is to see if it will load up just slightly after idling for 30 seconds. It was actually very easy to tune. I just had to ignore my urge to make it sound like my DA…. I had a small carb airflow issue I had to fix, but that was a cowling issue. Every gasser that’s been in this Extra has needed the carb shielded from direct air.
- Top End: The top end on this engine is even better than the transition. My Extra weighs 42 pounds dry, and 45 pounds full of fuel (64 ounces of fuel). The EVO pulls it around like it weighs 39-40 pounds dry. To put it into perspective, I had a vertical drag race with another airplane a few weeks ago. He had a 50-ounce tank on a 39-pound plane. I was on the beginning of my flight. He was on the end of his. We both had Menz 32X10 props, and it was a dead tie. I don’t have any tachometer figures since I hardly ever use one to tune an engine. I tuned the high end so that the engine never sags in LONG uplines. I also tried several deep snaps on uplines. These snaps were close to 3D snaps, so they were far too deep for any IMAC routine. Regardless, the engine did a very good job of pulling the plane through all things considered. It has no problems pulling it through multiple IMAC quality snaps.
Notes: - Fuel Burn: I think I’m going to remove the two 32 ounce tanks and opt for a single 50-ounce tank. Reason being, after a 14-minute flight, I’ve only just begun to draw from the second 32-ounce tank. I can save some weight by loosing some fuel.
- Piston/Cylinder Fit: One person asked me if I had noticed any “piston slap” in my engine. He had noticed on another he had seen that it seemed like there was an excessive amount of clearance between the piston and the cylinder wall. His observation was of a cold engine though. The pistons expand as they heat up, as metal parts do. After the engine has warmed up, that clearance shrinks down and everything works properly. It’s a little opposite of how an ABC engine works. This is yet another reason why you should let the engine, or any gasser for that matter, warm up before you throttle up significantly. Any other gas engine shows these same signs too.
- Gasoline Mixture: EVO recommends no less than 80:1 oil/gas mixture, however if you run Amsoil 100:1 it will still be fine. Right now I’m burning up what’s left of my Amsoil before I switch to Brian Cooper’s 50:1 oil. I tried some of his oil several years ago, and it was excellent oil. I just made the switch to Amsoil in case I ever needed to borrow a tank from someone else. However, the Amsoil has caused me some carbon problems, so I’m switching back to Brian’s oil.
Final Thoughts: So far I am very happy with this engine. I’m not going to run something that I think will cause me to have problems. I have done everything imaginable to get this engine to act up in 3D, and so far it hasn’t missed a beat. I haven’t even been able to get the exhaust note to change during extended hovering. So if you are in the market for a 150-sized engine, don’t overlook the EVO. It only costs $1350, and has the performance you need for your larger 40% birds.