Dyno proven 675-700 HP 540CI recipes?
07-20-2015, 08:24 PM
#91
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I disagree on the rpms vs cam vs cid.
07-20-2015, 08:34 PM
#92
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Have you tried any other props to see if it can pull any more rpms and get you closer to the power band IF it is up there higher? IF power curve shifted up a few hundred rpms and you had as much prop as boat could possibly pull previously maybe you have hit a point where it needs to rev a little more, just a thought, hope you find some resolution, I would think the tq band overall would be fatter but maybe not?
SB is right though. 25 cubes, on an engine making 1.3HP per ci possibly, 32HP per side. Not a huge deal, but , still something to consider.
My take is, the old engines, were a pile of chit, we know that. From a parts and assembly standpoint. Now, from a power standpoint, they weren't all that bad. Those pro comp heads, that had been gone thru by Gellner, probably flowed pretty darn good for what they were, the cam was mild, but not crazy mild, it was sporting 565 cubes, and overall, probably a real nice 5200-5400RPM setup (if they had been put together properly).
Now, You went with all new stuff. Good quality stuff. You lost 25 cubic inches though, and moved up in cam duration. I am pretty certain, that if you put your old combo on the dyno, pulled it off, and put new engine on dyno right after, that what you would see, is comparable numbers up to around 5500RPM. But after 5500RPM, the new engine would probably start walking away from the old one, the faster you spun it. Where the old engine would leave off, the new one would be taking over.
However, you're in a pickle now. You don't want to decrease pitch, due to cruising speed. Understandable. You may have a little more top speed in it, maybe not. Gonna be trial and error I think on that one.
I don't think that there's gonna be an easy fix here, if speed numbers are the goal, without a major change. This is why, I cringe when I see guys bickering over little stuff, and I do as well sometimes. But, on a boat like yours, its gonna take big power changes, to see speedo changes. Going from a 1050 to a 850, isn't gonna solve your issue, going from that cam, to a smaller cam, probably isnt gonna fix your concerns from a speed standpoint.
At the end of the day, we can argue this brand of head vs that brand of head, couple degrees of cam duration, .050 valve lift, 850 vs 950 carb, victor vs dart intake, and blah blah blah. The question is, WHAT WILL IT CHANGE IN THE BOAT. Is it worth going from a 325cc to the full CNC version of the head? Will that extra money net you 1mph, 4mph, or nothing at all? Will going from 9.5:1 to 10.5:1 , net you 1mph, 4mph, or nothing at all? You're exactly right. 40-50hp a side might make a nice difference on a stepped bottom fast hull. Heavy tank like yours, not so much.
I know you're probably frustrated Tim, because lots of money spent, with no gains in the performance department. I can understand that. I think you'll have some solid engines that give you some great service, so keep that in mind when you're feeling blue!
When you get bored, blowers are always an option! And I guarantee you will see some speed increase!
Last edited by MILD THUNDER; 07-20-2015 at 08:36 PM.
07-20-2015, 08:42 PM
#93
I went through the same thing on my cat...blower motor that would turn 5800 and pull a 32 pitch 5 blade on a 1.5 drive on the limiter. Switched to a high rpm NA motor witch 680+ at the crank but it was at 6250. So, go from a 32p 5 blade to a 26p labbed 4 blade and it is at 93mph which is where the stock 575 was back in 2001. Try some lower pitch props and let the motors wind.
07-20-2015, 08:44 PM
#94
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Very true and you and I have had many conversations lately and like I said as much as I hoped for more, I guess it is ok as I know the parts are good, I think I will work my props after I rule out the last few things and then enjoy, like I said earlier, if it runs every weekend I guess it's a gain, I just had some bigger results in my head, guess that was from dyno numbers other guys saw with same power setup... this is a heavy boat and I know that, top speed was never the goal, just hoped to see a 74-75 in the end, I might still.... maybe....
That was my suggestion as well.
SB is right though. 25 cubes, on an engine making 1.3HP per ci possibly, 32HP per side. Not a huge deal, but , still something to consider.
My take is, the old engines, were a pile of chit, we know that. From a parts and assembly standpoint. Now, from a power standpoint, they weren't all that bad. Those pro comp heads, that had been gone thru by Gellner, probably flowed pretty darn good for what they were, the cam was mild, but not crazy mild, it was sporting 565 cubes, and overall, probably a real nice 5200-5400RPM setup (if they had been put together properly).
Now, You went with all new stuff. Good quality stuff. You lost 25 cubic inches though, and moved up in cam duration. I am pretty certain, that if you put your old combo on the dyno, pulled it off, and put new engine on dyno right after, that what you would see, is comparable numbers up to around 5500RPM. But after 5500RPM, the new engine would probably start walking away from the old one, the faster you spun it. Where the old engine would leave off, the new one would be taking over.
However, you're in a pickle now. You don't want to decrease pitch, due to cruising speed. Understandable. You may have a little more top speed in it, maybe not. Gonna be trial and error I think on that one.
I don't think that there's gonna be an easy fix here, if speed numbers are the goal, without a major change. This is why, I cringe when I see guys bickering over little stuff, and I do as well sometimes. But, on a boat like yours, its gonna take big power changes, to see speedo changes. Going from a 1050 to a 850, isn't gonna solve your issue, going from that cam, to a smaller cam, probably isnt gonna fix your concerns from a speed standpoint.
At the end of the day, we can argue this brand of head vs that brand of head, couple degrees of cam duration, .050 valve lift, 850 vs 950 carb, victor vs dart intake, and blah blah blah. The question is, WHAT WILL IT CHANGE IN THE BOAT. Is it worth going from a 325cc to the full CNC version of the head? Will that extra money net you 1mph, 4mph, or nothing at all? Will going from 9.5:1 to 10.5:1 , net you 1mph, 4mph, or nothing at all? You're exactly right. 40-50hp a side might make a nice difference on a stepped bottom fast hull. Heavy tank like yours, not so much.
I know you're probably frustrated Tim, because lots of money spent, with no gains in the performance department. I can understand that. I think you'll have some solid engines that give you some great service, so keep that in mind when you're feeling blue!
When you get bored, blowers are always an option! And I guarantee you will see some speed increase!
SB is right though. 25 cubes, on an engine making 1.3HP per ci possibly, 32HP per side. Not a huge deal, but , still something to consider.
My take is, the old engines, were a pile of chit, we know that. From a parts and assembly standpoint. Now, from a power standpoint, they weren't all that bad. Those pro comp heads, that had been gone thru by Gellner, probably flowed pretty darn good for what they were, the cam was mild, but not crazy mild, it was sporting 565 cubes, and overall, probably a real nice 5200-5400RPM setup (if they had been put together properly).
Now, You went with all new stuff. Good quality stuff. You lost 25 cubic inches though, and moved up in cam duration. I am pretty certain, that if you put your old combo on the dyno, pulled it off, and put new engine on dyno right after, that what you would see, is comparable numbers up to around 5500RPM. But after 5500RPM, the new engine would probably start walking away from the old one, the faster you spun it. Where the old engine would leave off, the new one would be taking over.
However, you're in a pickle now. You don't want to decrease pitch, due to cruising speed. Understandable. You may have a little more top speed in it, maybe not. Gonna be trial and error I think on that one.
I don't think that there's gonna be an easy fix here, if speed numbers are the goal, without a major change. This is why, I cringe when I see guys bickering over little stuff, and I do as well sometimes. But, on a boat like yours, its gonna take big power changes, to see speedo changes. Going from a 1050 to a 850, isn't gonna solve your issue, going from that cam, to a smaller cam, probably isnt gonna fix your concerns from a speed standpoint.
At the end of the day, we can argue this brand of head vs that brand of head, couple degrees of cam duration, .050 valve lift, 850 vs 950 carb, victor vs dart intake, and blah blah blah. The question is, WHAT WILL IT CHANGE IN THE BOAT. Is it worth going from a 325cc to the full CNC version of the head? Will that extra money net you 1mph, 4mph, or nothing at all? Will going from 9.5:1 to 10.5:1 , net you 1mph, 4mph, or nothing at all? You're exactly right. 40-50hp a side might make a nice difference on a stepped bottom fast hull. Heavy tank like yours, not so much.
I know you're probably frustrated Tim, because lots of money spent, with no gains in the performance department. I can understand that. I think you'll have some solid engines that give you some great service, so keep that in mind when you're feeling blue!
When you get bored, blowers are always an option! And I guarantee you will see some speed increase!
07-20-2015, 08:46 PM
#95
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I am borrowing a set of my buddys labbed 23's tomorrow and hope to run them Friday night and see results.... I only have enough time to rule out one thing a week lol all parties that I talked to from beginning thought I could turn these 25's higher with these engines.... that's why I expected a little more...
I went through the same thing on my cat...blower motor that would turn 5800 and pull a 32 pitch 5 blade on a 1.5 drive on the limiter. Switched to a high rpm NA motor witch 680+ at the crank but it was at 6250. So, go from a 32p 5 blade to a 26p labbed 4 blade and it is at 93mph which is where the stock 575 was back in 2001. Try some lower pitch props and let the motors wind.
Last edited by Full Force; 07-20-2015 at 08:49 PM.
07-20-2015, 08:58 PM
#96
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Maybe it`s all the beer and rubber dildos weighing you down
