Experience with Aerosport IO-375?

Does anyone have some performance numbers yet on this engine on a -7 they might be willing to share? I tried asking on older thread with no response, and thought I would bring it up again in a fresh thread. If it is still as yet untried, I apologize.

It seems like the best bang for the buck at this point. Numbers, and overall impressions with either high or low compression pistons are appreciated!

Thanks,
Damon

Bob B. from Washington has an IO-375 in his -7. I think it is the low compression version putting out 195hp or so. His plane was Grand Champon at Arlington 2011(I think). We run very close in speed in the SARL events. He was trailing me when I blew my exhaust off at 215+mph. I aborted and he followed me to ensure I landed safely at Waterville.

Bob is a real sportsman and friend. Here we are parked safely during the GNAR III trying to find a welder.

Thanks Brian, I appreciate that!

Anybody out there running with the high compression pistons?

Check carefully on prop selection...

Apparently they are pretty finicky about prop selection for the high compression cylinders with this engine... Check with Aerosport directly on their requirements.

I would call ECI, they manufacture the engine. I bet they have the data points you are looking for.

Prop

Talked to Sue today, looks like the MTV-9 is approved for the high compression, so I am good to go there!

I just purchased the 205hp version of this engine 'over' the IO-390 for my RV8 Slider Fastback project (Aerosport, again ). I simply don't want the weight of the IO-390 on the nose of an RV8 . I've flown plenty of angle valve RV8's and I just don't like the weight on the nose. I've got an RV7 with the angle valve engine and prefer the parallel version on the side by side RV's as well.....same reason. If you've built and flown enough of them you can appreciate my comments.....if you only have one you may not agree or understand , IMO go with the parallel valve engine and you won't regret it .

Curious why you would go with an MT prop over a Whirlwind? Plus although the 200RV prop is a great choice, Whirlwind has a new foam core '74RV' prop for the higher HP 4 bangers.

N355DW said:

Talked to Sue today, looks like the MTV-9 is approved for the high compression, so I am good to go there!

Click to expand...

rv6rick said:

Curious why you would go with an MT prop over a Whirlwind? Plus although the 200RV prop is a great choice, Whirlwind has a new foam core '74RV' prop for the higher HP 4 bangers.

Click to expand...

Mainly for static thrust - hang time in a hammerhead! Like my Pitts 12, I want to be able to stop in the hammer and fly off in knife edge! (Maybe the Vedenyev would fit the -7, hmmm....).

The WW is approved for the high compression as well, Sue told me, so if it was top speed I was after I would go with that.

Thanks for your comments! I agree with you on the 390, though I have read the -7 can use some weight in the nose, I am hoping the three blade prop, along with the inverted oil will put the cg where I can have the full 100lb baggage.

Not to mention the cost of a 390 these days!

I have about 150 hours on my RV7 with Aerosport's IO-375. Silverhawk fuel injection, dual Lightspeed EI turning a Hartzell blended airfoil prop. The engine has been trouble free. I probably average around 168 kts in cruise around 70% power and about 8.5 gph. I can't speak highly enough about the great service from Bart and Sue!

Initial experience

With only 46 hours of novice test pilot experience I can hardly be considered an authority on the Aero Sport Power IO-375. Nonetheless, I will share those observations I have made so far. (My prior experience includes around 900 hours in a Cessna Cardinal behind an angle valve IO-360.)

My IO-375 was built using the parallel valve Lycoming case and cylinders giving me roller tappets with low compression pistons installed. The stroker crank is from ECI and a Superior sump and cold air induction round out the bottom. It is equipped with dual P-mags, the Silver Hawk fuel injection and turns a Whirlwind RV200. It starts and runs smoothly at low idle although I do not generally idle with a closed throttle.

I have used the standard Vans cowling, tightly fitted with the SW (now Meggitt Troy) 8406R oil cooler mounted on the baffle aft of #4. Cooling is more than adequate on standard days with CHT?s even on climb out not exceeding 360 and oil temps struggling to get up to 178 with 1/3 of the cooler blanked off. I am not concerned about the coming Texas heat.

The higher displacement is accompanied by a slightly higher fuel burn than experienced with the Cardinal. Max speed recorded so far is 184 KTAS at 7500? WOT and 125 ROP. That run was during phase one testing and may not be optimized. I am going to repeat max performance runs soon now that I have become better acquainted with the plane and the engine is reaching break-in.

Recent cruise at 7500?, WOT 68% pwr and 30-50 degrees LOP produced 173 KTAS burning 9 gph. Leaning to 8.8 gph was well tolerated and resulted in slight reduction in power and speed as expected. I have also tried leaning at lower altitudes with 60% power and 8.6 gph producing 160 KTAS at 3500?. CHT?s run 300-320 when LOP and only modestly more at cruise ROP. OATs have been in the range of 55-75 degrees F.

So far I have been very happy with my choices and Aero Sport Power has been a pleasure to deal with. As I become more familiar with the plane and am hopefully able to better define performance figures, I will be happy to share them with the group.