15k BTU on 2200 watt generator

1957 Chevrolet, 283 Cubic inches. 1957 Ford, 312 Cubic inches. If you ever raced either one, you will know a little about engine size, power, and efficiency, In case you weren't around, the smaller engine prevailed. The saying was that the only way to get a Ford to go fast was to push it off a cliff.

What generator runs dual cams and 8,000+ rpm? Does Ferrari make generators?

First off , 79 cc engine vs 121 cc engine.
Rated output is at sea level, probably 59 degrees F.
Now go to 115 degrees and or 9000 ft and see if the smaller engine still makes the rated power. I think a Honda went big on the engine to satisfy more variables.

Now about OHV vs OHC.
All car/truck engines ( not rotaries )besides flat head fords are over head valves, they use center block cams and pushrods and rocker arms. With this design you can make a more narrow engine because the heads are not as wide or tall. Going OHV you can stuff a V8 in a small car like a corvette.

OHC engines do great at higher rpms and the heads flow more within 4 or 5 valves per cylinder. Most new cars especially 4 or v6 are “hemispheric”. They get good mileage and make more power up top. Go with a big engine bay like a truck and stuff a DOHC engine like a hemi style and you are really cooking, just need space and it costs more to make.

"What is better about an OHC design?"

Among other things not already listed, when you have a DOHC (or Dual Overhead Cam) design, it allows both the intake and exhaust cams to be timed differently (varied to each other) at different RPM's. Honda's VTEC engine to name one. That option allows the engineers to optimize the valve timing for the entire range of RPM's allowing the engines to generate substantially more power with minimal flat spots in the power curve. That's for complex high performance engines which typically generators are not. OHC's also make it easier to have 3, 4, and 5 valves per cylinder which can be done with OHV engines, but not as easily. Now, . . . back to your regularly scheduled program.

Chum lee

Two 2000's would easily do the job also.

2 of the 2200's would easily do the job.

As no one has yet suggested the following, I will.

Contact Micro Air directly and ask them your question. They will work with you to select a generator that will do the job. They have tested many of the smaller generators with their product, and they can advise you as to which ones can do the job and which ones cannot. They are incredibly helpful.

-Speak

marcsbigfoot20b27 wrote:
My 13.5K with 59 LRA would not start in Phoenix @1400 ft if over 60 degrees with my EU2000i.

Added a Micro Air Easy Start, would not start reliably over 85-90 degrees.


Switched to EU2200i.......tested it at 115 degrees in ECO mode and it starts and runs fine.
Tested at 7600ft ~80 degrees in ECO mode started and ran just fine.

Tested my 2200 at the end of the break in, maxed at 2400 watts to electric heaters, not sure how long it would go at max.

Thanks for a detailed response.

twodownzero wrote:

otrfun wrote:
Honda EU2200i has an OHC 121cc engine vs. the new Yamaha's EF2200iS 79cc OHV engine. IMO, an OHC engine is an inherently better, more efficient design.

What is better about an OHC design? I understand the desire for the larger displacement (more power to turn the actual generator). But I find both of your other claims to be questionable at the last.

There's nothing more efficient about an OHC over a conventional OHV design. Some of the best, most efficient, and most powerful engines on earth use OHV engines. 2 of the big 3 use OHV gasoline engines exclusively in their full size trucks, and Ford just released details on their newest engine, and guess what? It's OHV. There is nothing wrong with OHV engines. I'll admit by bias, though. I won't own ANY vehicle with an overhead cam engine. I have zero interest in them and to this day, I'm convinced they are a solution in search of a problem to solve.

Also, if 79ccs will make enough horsepower to create the rated output, I also dispute that a 121cc engine to do the same thing will be more efficient. Gasoline still burns most efficiently at 14.7:1, and an engine almost twice the size will have to burn more fuel even at the same load, unless there is some kind of vast disparity in design where friction or some other variable makes up the difference (not likely).

No, there's nothing wrong per se with an OHV engine. OHV is fine for lower RPM applications like the lower revving, high torque truck applications you speak of. However, you'll rarely see OHV in high-rpm applications. An OHC design has a lot less moving mass in the valve train assembly (vs. an OHV design) which allows for more efficient, accurate control of the valves at higher rpm's. This is the reason why the vast majority of cars on the road on the road today use an OHC configuration. If OHV was a better design I assure you car manufacturers would use it---but, the fact is they don't.

I'll think you'll find the 121cc Honda has very similar fuel consumption ratings as the 79cc Yamaha. With all things being equal, I'll always vote for the stronger mass of a larger displacement engine. When I said "more efficient design" I was referring to increased mechanical efficiency an OHC engine offers vs. an OHV engine (as I noted in the previous paragraph).

All said and done, YMMV. You prefer OHV. I like OHC. That's ok--lol!

twodownzero wrote:

otrfun wrote:
Honda EU2200i has an OHC 121cc engine vs. the new Yamaha's EF2200iS 79cc OHV engine. IMO, an OHC engine is an inherently better, more efficient design.

What is better about an OHC design? I understand the desire for the larger displacement (more power to turn the actual generator). But I find both of your other claims to be questionable at the last.

I'll probably regret stepping into this...

The only claims I see are about engine size. Are they incorrect? The comments about engine design and efficiency are clearly labeled as opinion.