Robinson V8
I have never seen so much Balony as the operating costs that Robinson quotes on the LS1 V8!!
To start off, they state an I0-540 overhaul cost to be $40,000. What a crock, when a BRAND NEW one from Van's is $39,875. Not to mention that if you buy a core engine and rebuild it with six NEW Millineum cylinders you can still do an entire overhaul for no more than about $15K total (or a total envestment including core cost of around $25K.
Second, there is no way in hell that this engine will do better than a cruise SFC of .45 lbs./hp/ hr (.385 lbs./hp/ hr is totally absurd to believe when pulling 75% power of around 260 hp or so) when the best any Diesel engine can get is around .39 lbs./hp/ hr (no gas engine is going to match a Diesel). The 10 gal/hr fuel consumption value they give for cruise will be EXACTLY the same as what the Lycoming burns, which is 15 GPM. Horsepower is horsepower no matter what, and if the LS1 is pulling the same power as the O-540, then it will eat close to the same amount in fuel.
The whole operating cost comparison is heavily misrepresented to make it look like the LS1 V8 conversion is better, when in fact it is FAR WORSE. The upfront aquisition cost is greater, the TBO is less, the overhaul cost is not accurate, and also the installed weights are not correct (the base longblock LS1 with NO accessories is closer to 450 lbs, rather than the 390 lbs as stated earlier). The actual overhaul cost/hr is more like $7.50/hr as opposed to Robinson's stated $20/hr (the V8 is $6.67/hr according to them, which is damn close to what the Lycoming costs/hr).
There is not one shred of truth in what I see on Robinson's website. The LS1 V8 conversion will end up costing WAY more than what a Lycoming O-540 will, and will only end up being one HEAVY PIG in an RV10...in the end you WILL probably need the 350 hp it supposedly can make just to match the lower powered 260 hp O-540 (I personally doubt the LS1 V8 can sustain any more than the 260 hp the Lycoming O-540 makes simply due to the head gaskets blowing all the time at high % power loadings...the same problem that led to the development of cylinders attached directly to the heads on most all aircraft engines).