4 Strokes

O-200(100hp), New $22,000+

Corvair(110hp), New $??,???+, and weighs more than O-200.

Rotax 912(100hp), New $18,000+ to $25,000

 

Rotax 914(115hp) Turbo, New $34,000+

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2 Strokes (Lighter Engines, but with lower TBO's depending on Rpm's used, but 1/4 to 1/3 the cost)

 

Skidoo/Rotax 670 (92hp at 6400rpms) = In Sled use, Stock 670 112hp at 7750rpms. $8000

 

Made 1993 to 1999. 1998-99 there was a 670HO 20hp more than Standard 670 at same 7750rpms.

 

A Skidoo/Rotax 670 with a Turbo, with 11 lbs of boost Dynoed 205.4hp at 7750rpms on the Dyno, At 6750rpms, what the 618UL(74.6hp) was run at, it made 163.4hp.

 

 

Some 670 Big Bores that are possible.

Rotax 720(??hp at 6400rpms) estimate 118hp, with 4lbs of Boost with a Turbo, 167 hp is possible.

Rotax 740(??hp at 6400rpms) estimate 122hp, with 4lbs of Boost with a Turbo, 172 hp is possible.

Rotax 748(??hp at 6400rpms) estimate 123hp, with 4lbs of Boost with a Turbo, 174 hp is possible.

 

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Any Engine, that can use lower over all rpms, will last longer. A Stock 670 with a Turbo, if built right, and using just 4lbs of Boost can make 130hp at 6500rpms, 120hp at 6000rpms, (110hp at 5500rpms), 100hp at Max 5000rpms, 90hp at 4500rpms, 80hp at 4000rpms.

 

There are a few 582UL's and 503UL's, using Max 5500rpms  flying, that have 1300+ hours on them, with just a Decarbon every 200-250hrs. With the New Synthetic 2 Stroke Oils, and Ceramic Top Coated pistons they are seeing 700+ hrs without a decarbon.

 

If your going to be taking off, flying from Higher Altitudes, you may want to add a Turbo, and Fuel Injection to any of these motors that don't have it. Fuel Injection can also eliminate Carb Icing problems and give better GPH. A Turbo can add up to 40% more power, depending on amount of Boost used.

 

Since most Q2's require minimum 65+hp, and I consider +10hp, so 75hp to be minimum, and most People do use the O-200(100hp) on them, you do have your limits, based on HP used, and Takeoff Altitude. There is some Mods for the O-200, Higher Compression Pistons, Cam, and I think you can go one size bigger on the Intake Valve, but I have never seen posted the HP increase you get doing each Mod. I would guess in the, 106hp to 120hp range depending on the Mods used. An O-200 with a Turbo, with just 4 lbs of Boost could make 135hp at 2750rpms if built right.

 

A 100hp@2750rpms  O-200 Engine rated at Sea Level is only 91hp at 3,000ft

A 100hp@2750rpms  O-200 Engine rated at Sea Level is only 88hp at 4,000ft

A 100hp@2750rpms  O-200 Engine rated at Sea Level is only 85hp at 5,000ft

A 100hp@2750rpms  O-200 Engine rated at Sea Level is only 82hp at 6,000ft

A 100hp@2750rpms  O-200 Engine rated at Sea Level is only 79hp at 7,000ft

A 100hp@2750rpms  O-200 Engine rated at Sea Level is only 76hp at 8,000ft

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A 100hp@2750rpms  O-200 Engine rated at Sea Level is only 73hp at 9,000ft

A 100hp@2750rpms  O-200 Engine rated at Sea Level is only 70hp at 10,000ft

A 100hp@2750rpms  O-200 Engine rated at Sea Level is only 67hp at 11,000ft

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A 100hp@2750rpms  O-200 Engine rated at Sea Level is only 64hp at 12,000ft

 

Just My 2 Cents

Rich