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tmdog
05-26-2005, 04:05 PM
Was running a Turbo1 25" at 4400 RPM. Figured engine was not up to its potential and ordered a Turbo1 23" to boost RPM to 48-4900 Rpm. Put that 23 on and turned 53- 5400 RPM. WTF, that is not suppose to happen. Talked to Throttle Up and Julie said either the 23 is not a 23 or the 25 is not a 25. Today, I sent the 23 back to Precision Prop for evaluation. The 25" is in like new condition and never been in the shop. What do you guys think? Why would there be 1000 RPM difference in a 2'' pitch change. :confused:

Trueser
05-26-2005, 04:30 PM
I had the same problem yesterday, Not sure what to do yet. More testing this weekend

23 turbo 4400 rpm
21 turbo 5200 rpm

Greg K
05-26-2005, 05:46 PM
Was running a Turbo1 25" at 4400 RPM. Figured engine was not up to its potential and ordered a Turbo1 23" to boost RPM to 48-4900 Rpm. Put that 23 on and turned 53- 5400 RPM. Today, I sent the 23 back to Precision Prop for evaluation. The 25" is in like new condition and never been in the shop. What do you guys think? Why would there be 1000 RPM difference in a 2'' pitch change. :confused:

Same day and conditions (water, temp, trim)? Did you have a gps on board to tell us the speed differentials if any? When do you plan to run the 25 again ?

tmdog
05-26-2005, 09:10 PM
The test was done on the same day and condition. No GPS, only tach for reference. After testing the 23, swapped back to the 25. Same results, low rpm. I must say the 23 at 5400rpm indicated a higher speed. My speedo said low 70,s.

tmdog
05-26-2005, 09:18 PM
It is a known fact that many members are running the Turbo props on a 18. What I would like to know what pitch are you running and horsepower? I estimate my power at 350 maybe more. I was most sure I could swing a 25 on an Alpha drive.

metraman
05-27-2005, 08:50 AM
I seem to be having a issue with a 25P lightning labbed by precision I tried a 23P Mirage and ran 800 more RPM a little less MPH. Im trying a 25P Hydromotive this weekend.However as someone said in a earlier post Precision does not have issues.

Rootsy
05-27-2005, 09:38 AM
these props are manufactured with a "lost wax" method of casting... upon cooling the material does shrink and move... these props are finished, polished and inspected but once in a while things can go wrong... parts have tolerances also, precision's tolerance for average pitch is +/- 0.5 inches since they offer props in 1 inch pitch increments. you also have tolerances on rake angle, etc etc etc... a 23 " prop from prec. may be 22.5 to 23.5 inches in reality... a 25 may be 24.5 to 25.5 inches.. so really if you have a 23 that is 22.5 and a 25 that is 25.5 that is 3 inches of pitch and that equates to almost 600 rpm +/-....

JR

ITTLFLI
05-27-2005, 03:28 PM
I have gotten to know the guys at Precision and they would be more than willing to work through any dillemma's you guys might have.

I would call them. PRECISION 800 922-9955 ask for Chris

tmdog
05-27-2005, 08:02 PM
Rootsy is more than likely right on the tolerences of the two props. I am showing a difference of a 1000 rpm. I think the 23 is a22 and the 25 is a 26 in reality. That would make more sense in the 1000rpm increase.
Ittlfli, I'll take your advice. Previously, I talked to a lady at Precision and was given auth. to send the 23 back for testing. She also said my 25 was out of warranty, being 2yrs old. I think she erred in saying that because Turbo have a lifetime warranty on any manufactoring defect to the original owner. The 25 is in like new condition with 20 hrs. on it. She was somewhat "snotty" with a hurried attitude. I have that effect on people, so says the wife.