Sent 05 Ex to RF Powerboats
09-24-2011 | 07:53 AM
#211
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From: KC, MO
09-25-2011 | 09:19 AM
#214
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From: Fort Worth, TX
So you have money invested equal to that of completely new engines and you have mix matched pistons? What are the bore diameters now? What block?
09-25-2011 | 10:20 AM
#215
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From: KC, MO
Trust me...this isnt they way I wanted this to go down.
09-26-2011 | 11:28 AM
#216
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From: Fort Worth, TX
I hope things come together. I watched your thread years ago when you were upgrading your 525's. My friend was doing it at the same time on an identical boat. Luckiliy he has left his alone. He has had some detonation issues though and other gremilins all along the way. Working off the 525 base system just seems to be a headache. Are you still on that system or MEFI?
09-26-2011 | 01:15 PM
#217
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From: Taunton Ma
2-5 Thousandths of an inch is so small in an automotive or race application that cylinder would just be left as a "loose" hole and have a little more piston to wall clearance. At that size it prob weighs within 2 grams of the other pistons and could be easily balanced to the set.
09-27-2011 | 12:14 PM
#218
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From: Satellite Beach, FL
The motors started life as 500 efi's.The motors are now 555 cubic inchs, have afr 357 cnc heads with Vortech Superchargers, and make a little more power than the 850 (that I call them)however when someone looks in hatch and sees the stock 500 efi intake they do not believe the power they make. They actually made a little more than 1000 in both horsepower and torque. However I am unable to turn them to 5800 rpm in the boat regardless of the prop used which is were it made over 1000. I really believe the 500 efi intake are not able to flow enough volume to support the rpms I would like. I can put on a pair of 31's and spin 5700 or I can spin 34's 5600. My engine builder warned me about this and it will likely get changed before next year
My x dimnesion is 18" and I am running SCX uppers with -2 sc lowers with 1.3? gears ( the scx uppers are geared a little different so I do not now the exact number). Prop is Mercury labbed 34 maximus with 15 1/4" diamater.
The only problem I have had with drives is during the middle of this summer one drive developed a shifting problem. We tore the upper apart and the gears looked brand new (encouraging). The shifting problem turned out to be Imco puts a rubber plug in the hole above the shift shaft. The plug is to long and after a little wear on the cone clutch it would no longer shift. I cut the plug in half and it has been problem free since. The drives are 2 seasons old and have about 180 hours and close to 7000 miles on them. The first season of these drives they had 850 horsepower and 800 foot pounds of torque (about 100 hours and 4000 miles). i guess with all this talk about breaking these lowers we will tear them down over the winter and have a look.
I should also mention that i really believe in Torco #6 drive fluid in these drives. I believe when you use like mercury High performance gear oil that it is so thick that it get slung away from the gears and flows slowly and can not get back into contact with gears (kind of forms an airpocket around the gears) where as the torco flows very similar to water even cold. I have no proof of this but have had great results after changing.
The boat has been 117.9 MPH and this was during August. When the water and air temp cools down I really expect this number to grow.
If you have any more questions I will try my best to answere them.
Allen
My x dimnesion is 18" and I am running SCX uppers with -2 sc lowers with 1.3? gears ( the scx uppers are geared a little different so I do not now the exact number). Prop is Mercury labbed 34 maximus with 15 1/4" diamater.
The only problem I have had with drives is during the middle of this summer one drive developed a shifting problem. We tore the upper apart and the gears looked brand new (encouraging). The shifting problem turned out to be Imco puts a rubber plug in the hole above the shift shaft. The plug is to long and after a little wear on the cone clutch it would no longer shift. I cut the plug in half and it has been problem free since. The drives are 2 seasons old and have about 180 hours and close to 7000 miles on them. The first season of these drives they had 850 horsepower and 800 foot pounds of torque (about 100 hours and 4000 miles). i guess with all this talk about breaking these lowers we will tear them down over the winter and have a look.
I should also mention that i really believe in Torco #6 drive fluid in these drives. I believe when you use like mercury High performance gear oil that it is so thick that it get slung away from the gears and flows slowly and can not get back into contact with gears (kind of forms an airpocket around the gears) where as the torco flows very similar to water even cold. I have no proof of this but have had great results after changing.
The boat has been 117.9 MPH and this was during August. When the water and air temp cools down I really expect this number to grow.
If you have any more questions I will try my best to answere them.
Allen
Planning on sending mine to RF to get it dialed in.
09-27-2011 | 06:53 PM
#220
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From: Satellite Beach, FL
Give us a call at 252.561.6070 for a service quote....we can talk shop and work with you to accomplish what you want to do within budget......you may also be interested in our high performance driving school. We offer one on one instruction in YOUR BOAT!! Our company is founded by Reggie Fountain and sons and we are all at anyone's disposal that is looking to improve performance or cosmetics.
