Bravo Xr with 2 inch shorter Imco extreme problems please Adivise.

[bajaboater502]

Hello Gentlemen, I am hoping that in this great vast of knowledge that someone here can help. I just recently had a Bravo 1 XR upper and a 2 inch shorter Imco extreme lower in satin finish installed on my Baja 272. This is coupled to a merc 500 Hp with about 130 hours on it, spinning a 26 pitch Hydromotive 4 blade that has been lab finished. I just took the boat out today for it's first test run and I am dissapointed to say the least. The boat will come up on plane fairly well if I have the tabs down and don't hammer it and is something I kinda expected, and can easily live with. However it now runs 8-9 mph slower than the the way it was with the original bravo one on it. I am running the same prop and can not understand why this happened. I was prepared to buy a new prop if i picked up some rpm, which I did ( about 200 rpm) but I think the rpm gain my have been created by slippage when I trim it out. When I trim it out and hit the about 2/3rds up to where I normally trim it the boat wants to turn right for a breif second and then a little past that it is ok again until I trim down under high speed then for a second it wants to go left (not as hard as when it pulls right while triming up). I hit my normal rpm of 5100 with a speed about 58-60 (down from 68-72 before), if I then trim it more the rpm pick up to about 5300 and it backs off to about 57 mph which is why I think it is slipping at this point. This boat ran a solid 67-72 before. I have hydraulic steering ram on order for this boat, and a m-3 procharger sitting here wait to go on, but I don't want to do this until it i get this handled so I don't mask a hidden problem or make it worse. I know this post got a bit long but I aprieciate any help. Thank you Ron
Ps. I was using gps before and after for the speed readings, plus i can feel its slower. Thanks again.

[mike37]

Originally posted by bajaboater502
Hello Gentlemen, I am hoping that in this great vast of knowledge that someone here can help. I just recently had a Bravo 1 XR upper and a 2 inch shorter Imco extreme lower in satin finish installed on my Baja 272. This is coupled to a merc 500 Hp with about 130 hours on it, spinning a 26 pitch Hydromotive 4 blade that has been lab finished. I just took the boat out today for it's first test run and I am dissapointed to say the least. The boat will come up on plane fairly well if I have the tabs down and don't hammer it and is something I kinda expected, and can easily live with. However it now runs 8-9 mph slower than the the way it was with the original bravo one on it. I am running the same prop and can not understand why this happened. I was prepared to buy a new prop if i picked up some rpm, which I did ( about 200 rpm) but I think the rpm gain my have been created by slippage when I trim it out. When I trim it out and hit the about 2/3rds up to where I normally trim it the boat wants to turn right for a breif second and then a little past that it is ok again until I trim down under high speed then for a second it wants to go left (not as hard as when it pulls right while triming up). I hit my normal rpm of 5100 with a speed about 58-60 (down from 68-72 before), if I then trim it more the rpm pick up to about 5300 and it backs off to about 57 mph which is why I think it is slipping at this point. This boat ran a solid 67-72 before. I have hydraulic steering ram on order for this boat, and a m-3 procharger sitting here wait to go on, but I don't want to do this until it i get this handled so I don't mask a hidden problem or make it worse. I know this post got a bit long but I aprieciate any help. Thank you Ron
Ps. I was using gps before and after for the speed readings, plus i can feel its slower. Thanks again.
what maid you think you needed a 2" shorter drive

[Havasu Hangin']

Can you try a 5-blade Hydromotive?
It may help with the slip.

[bajaboater502]

I just ran a bravo one 4 blade 28 pitch with slightly better results. I went with the shorter drive after mind went out. It was recommended by a few other guys with bajas similiar to mine and they had great results. I don't think I can get ahold of a five blade easily and not sure that will increase the speed back to where it should be. Thanks for the help so far. any other ideas?

[Dr. Eagle]

Sounds like the X dimension is too high. Maybe you should go back to the original lower...

[mike37]

Originally posted by bajaboater502
I just ran a bravo one 4 blade 28 pitch with slightly better results. I went with the shorter drive after mind went out. It was recommended by a few other guys with bajas similiar to mine and they had great results. I don't think I can get ahold of a five blade easily and not sure that will increase the speed back to where it should be. Thanks for the help so far. any other ideas? this is the key part of your post similiar to mine add that 2" back

[Havasu Hangin']

Originally posted by bajaboater502
I don't think I can get ahold of a five blade easily and not sure that will increase the speed back to where it should be.
More blade in the water will reduce slip. You can try a bigger diameter...or the new 5 blades are the trick (but expensive).
Less slip = faster speed at the same RPMs.

[bajaboater502]

Sorry it took so long to get back to this one, I was out of town on business for a month and my laptop took a hit. I got ahold of a 26 pitch bravo 1 and what a difference it made. back to last years speed plus 1 mph (69-71 mph with stock 500 hp)and it planes like a champ. The shop is still gonna try a 1 inch spacer to see if it helps or hurts. going to install a whipple next week ( took the pro charger back after riding in a whippled boat, glad i didn't install it) on this 272, so it runs like the other 272 we have. so now I need a 30 pitch bravo 1 anyone have any leads on one? Thanks for all the input.