What RPM'S are you turning on MVVS 40 GRRT?
 

I have new MVVS 40 GRRT mounted on a Diamond Dust turning
11,200-12,100 on the ground. The engine has about 8 tanks of 5% fuel through it using a APC 9x7.5 - 9x6.5 with minimal increase in RPM. This engine should turn more RPM than i'am getting and it definitely shows in the air. Any suggestions?

What RPM'S are you turning on MVVS 40 GRRT?
 

It probably needs a lot more break in time. You're asking too much too soon.

GRRT
 

You are running too large a prop for the GRRT. You are not getting on the pipe. Try an APC Q-40 prop 7.4X8 CF. This is the Q-40 practice prop. Call Performance Specialties or Darrol Cady, they stock them.

RR

What RPM'S are you turning on MVVS 40 GRRT?
 

we had a 8x10 going alot faster than that... but MVVS's take forever to break in

What RPM'S are you turning on MVVS 40 GRRT?
 

If this is the GRRT with the rear tuned exhaust/rear intake with the 11mm bore venturi (wide open throttle all the time-stock) or 9mm throttled carb, it should be turning in the 20K+ range easy. This is an FAI Pylon Racing engine! RPM=POWER. Mine is set at 22,000 on the ground (really smoking rich) so I don't burn plugs (as much) as it unwinds in the air. Turning a 7x9 prop. You have it WAY over propped!! It's tuned to run up there...max power is at 25~26K. Running it there though will burn it up quicker (plugs too...WOW!) than at 22K or so. Also, WEAR EAR PROTECTION!! This engine is LOUD when revved..but man, does it sound AWESOME.

Got mine on a Dust...wow. :cool:

Also, if ChuckAuger reads this...I FINALLY GOT MY AIRSPEED INDICATOR!!! Email me and get back in touch! I'm gonna build a new Dust this winter to put it in though...I've worn out my current one pretty well.

Carl

Yeah I read it..
 

But I just crashed my Dust a couple weeks ago!!! Augered in, low, fast, downwind, wide open, rolling, you can imagine...

Still curious to hear what you get off the airspeed indicator...

Folks here are just as obsessed with speed as at RCO..I'll bet they could sell a gross of them if they work right! LOL

I'll email ya..

What RPM'S are you turning on MVVS 40 GRRT?
 

Well, my problem was an incorrect pipe setup that came with my engine. I spoke to Jeff at DD and he was nice enough to send out 2 different pipe header's to try at no charge. Great guy to do business with. I will also try a APC Q-40 7.4x8 prop. Thanks for the help.... Scott