Thread: VX impeller testing
08-26-2007, 02:58 PM #1
VX impeller testing
Put the VX 15-21 impeller on my Lowell 1390 EFI with the 43 Sonic Booms today.. Changed only the impeller, nothing else. EFI settings the same also. Used the stock 85 nozzle, full handling, plate at 980, trim tabs shimmed down .100, stepped stock sponsons.
Almost identical weather as last sunday, last sunday was 2330 RAD, this sunday was 2312 RAD.
Last week on a 14-25 dyna i went a best of 79.6, with others at 79.4 and 79.2...Rpms were 7260-7270 on every pass..
First pass today on 6 bars fuel went 79.9 at 7125.
On 4 bars fuel and another on 2 bars fuel i went 80.2, at 7138 rpm.
Water wasnt glass, medium ripple in the cove, in salt.
Rate of accelleration was slower, but not a lot. It was noticeable, but never lugged the engine at all. Of course with a 800 grate the holeshot was terrible, but thats not what were after here.
From a 30 mph stab of the throttle it did excellent. Pulled hard and solid all the way up, no bounce, no buck, trim all the way up, no superman, seat on, bucket in...
This is the impeller to have for ported big bores i think, especially with cooler weather on the horizon.. My ski was out of rpms with a dyna at 14-25, 2 weeks ago i hit 7300 with it, and my 16-27 bend on the dyna just lowered rpms dramatically without adding any speed, actually it lost speed that way, went 78.8 at 7080. So bending the dyna past 14-25 is a lose lose deal.. At least it was for me..
Wanted to try my 87 nozzle but didnt get around to it.
80.2 in da salty heat baby!!!!
08-26-2007, 03:15 PM #2
Great Post Rossnemo. 80+ How did you come up with the starting bend specs? the VX comes in @ 18/24 from Solas.
08-26-2007, 04:28 PM #3
08-26-2007, 04:32 PM #4
(How did you come up with the starting bend specs? the VX comes in @ 18/24 from Solas.)
This is what Dave at Impros reccomended i try..
08-26-2007, 04:48 PM #5
GREAT JOB ROSS! The new TB's put the torque up top, helping you spin that bid ol` pig tail.Ross,whats the height/root angle diff between the 2 props?
08-26-2007, 05:30 PM #6
Thanks for sharing your results R-dawg.....this is good information
08-26-2007, 05:52 PM #7
(Ross,whats the height/root angle diff between the 2 props?)
Dont know Woody, all im sure of is instead of the impeller blades being bent down to attain correct pitch on a dyna, they are bent up quite a bit to depitch from the stock 18-24..
I was surprised how good the mid hit still was.. I thought i would have a top end only, pig on accelleration ski, but not the case. Still pulls hard in the mid..
Pull the trigger at 30, and enjoy the ride!!
If i lower my plate angle, take off the trim tabs, run the fuel on the buzzer, find some fresh water glass.. Hmmmm, i wonder....
08-26-2007, 07:22 PM #8
I'm waiting on mine now. I'll keep ya posted Glad to hear you had a positive result.
08-26-2007, 09:10 PM #9
Congrats on your new #s Ross!! Glad to see you could pull it.
Try some diff nozzles if you can. Quit worrying about those damn rideplate holes every time.
08-27-2007, 03:47 PM #10
Congrats on the prop! I tried it lost a full mph. ran 82.8@7200 and switched back went 83.8 @7330. got there alot quicker. I also tried a modded 87mm nozzle only gained about 60-80 rpm's no speed either prop but had a bit more accelleration larger nozzle but lost a mph on the DF....
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