George,

 

Mazfix and Mazsport are both boosting to 280hp at the wheels. http://mazfix.com.au/perfproducts/rx8_upgrades.html.  Pettit Racing is seeing 270+ with 5-8#'s  http://www.pettitracing.com/rx8/index.htm  My goal has always been to match the IO540 at 8000ft and have a much lighter plane with new engine. No doubt I will be giving up some HP without the intercooler. One percent for every 10 degrees I think. If my cooling ducts and exit area work as planned I may add an intercooler. The goal now is to get the engine started and flying by summer.

 

 

Bobby

RV10

The power available on a dyno pass lasting 15 seconds tops, is a long long way from the usable power

for a long climb to altitude in an airplane. The rate of heat rejection must be huge. This is the downfall of the turbo engine. When coolant temps go up, sensors back off the timing to prevent detonation.

 

Detonation is charge temperature dependant. The higher the temperature the more likely you are to see detonation. No inter-cooler means higher charge temperatures.

 

The effective compression ratio of a normally aspirated engine goes down as RPM goes up because the ability to fully fill the cylinder with mixture is limited by port open times going down. So ignition timing is just not critical.

 

 Not the case with a boosted engine. Effective compression ratio can go up with RPM, so, usually

boosted engines have less than 8.5:1 rotors. Starting with 10:1 rotors and no inter-cooler, limits total boost, and timing control and boost control must be precise. Perhaps boosting just to maintain sea level performance would be a less expensive path.........

 

Apex seals are very hard, and will damage the turbo on the way out.

 

Lynn E. Hanover