Thread: '04 GPR1390GK Update
10-18-2010, 08:45 AM #1
'04 GPR1390GK Update
After dropping a valve on my KPG1390, and then having a EFI controller fail and wipe out two cylinders....I had a GK1390 laying around. Decided to drop it in and see how it ran.
I have been playing around with a lot of different pump and prop setups and thought I would post them here for some feedback....
My mods are as follows:
GK1390 Fixed valves
Riva Girdled Heads 91 Oct
Stock Keyway (removed 3* key from the KPG)
R&D Powershot (Thanks Water Woody)
IR plate stage 4
D plate modded
1200 water box free flow
Fernando Jetworx kit
05 ho pump
SS 800 Grate
Cut R&D Tabs
First prop I tried was a 6S8 boat prop..... 18/24 stock. Turned it 6700 @74.8 really sucked on bottom end especially with fixed valves
Second prop was the custom setup I got from Tommy (2fast4u) 158MM Riva wear ring with 158MM DF setback, 13/22. Was able to turn it 7100 @ 77.1 Holeshot fair...but stab it a about 3500 and you better hang on.
Yesterday put a modded boat prop 18/22 on and was able to see 7090 @ 75.3. Hole shot still sucked.
I am waiting for my DF 13/23.5 to come back from Impros to try it out.( sucked up a rock and really messed a blade up) plus I am pretty sure I am a little rich on the top.
Should I put the 3* keyway back in? Does this performance appear to be what should be expected?
The old setup used to perform better, but I never really got to test it out before the valve dropped. I seem to remember the KPG1390 turning around 7200 @ getting 78-79, but that was in not ideal water conditions...but I also had to mix about 20% Sunoco 108 due to higher compression.
10-18-2010, 09:04 AM #2
I have a df 14/22 that the leading edge like you got chewed up...cavitate like mad but once on plane she goes...turned 7280 yesterday with the cooler air...why don't you like the 13/22 setback..you got some nice #s...might repitch to that...btw explain the "set back" advantages..is that something Impros can do to the DF...
10-18-2010, 09:19 AM #3
I have a ported 1300 with keyway. It ran 78.9 yesterday with a 14/23 impros prop set back 50 thousands. I think the dyna flys are going to be a lot more fun to ride.
10-18-2010, 09:40 AM #4
I do like the 13/22 158MM setup...just had a few different things and decided to try them all....I am sure Impros can do a setback. What I understand it helps eliminate cavitation, but there are more experts on here for this than I am. I am sure someone will post up more advantages.
10-18-2010, 09:48 AM #5
10-18-2010, 10:35 AM #6
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