PQ290,

I disagree with this. If you're pegging your rev limiter, even if only proverbially, with a bunch of throttle left, the last thing you want to do is stab it to full throttle and check your rod integrity. The way I see it, you prop up and see if it takes the rest of the throttle throw to get to WOT. If it does, you should be going faster. When our PQ was struggling with bad injectors, and we had propped down to try and make the boat a bit more usable. After getting the injectors worked out (thanks, Smitty), we had the exact scenario you have now: Pegging the rev limiter at 2/3 throttle. I propped it back up, to our original prop pitch, and we are now loading the engine properly, and the boat runs strong. It very much sounds like you are in the same state we were in, only 2" of pitch down.

I'm not disagreeing with what Griff is saying, I just don't think the way to prove or disprove it is to risk slinging a rod through your block. You can't really hurt anything by overloading your engines with too much prop. But you certainly can by over revving them with too little.

I would take up the offer you have on the table to test a couple of 26s and see where that ends up. Then go from there. If you've still got stick left at 5000RPM, look for some 28s, or maybe some Hydromotive 26-27s.

Thanks. Brad.

I took it that he didn’t think it would spin 6000 with current props.

I bet the 26s will give you the best overall performance. Maybe throw a pair of 28s on this Fall when the weather is cool and you’re almost out of gas😄

Hoodoo,

Does he really want to, though....?

Thanks. Brad.

On the rpm, do you have a rev limiter?

Best way is get a GPS speed ver rpm say starting at 3000 and do it every 500 rpm, after trimming for the best speed . That what we have always done, then start thinking about where to go with he props.

Good to hear the motors are working out.

LOL I’ve never been accused of overthinking stuff but I don’t think 6k is Armageddon. This just tells me my 30’s were small and 32’s were probably close to were I wanted to be.



https://cimg2.ibsrv.net/gimg/www.off...c212b50fe.jpeg

Hoodoo,

All good. OP stated, though, that the engines didn’t make power above 5K. That tells me he want to prop it for 5K. Right?

Thanks. Brad.

Yes

Still helpful to know where your starting from.

Hoodoo, You and I have vastly different engine builds. I did not go with the greatest internals. I did have everything balanced etc. just not forged stuff and even though the dyno pulls went to 5600 or so, they did not make power past 5000 rpm and like Brad mentioned, I didn't see the need to go WOT and see where it landed. If it would have gone bad, I don't have the resources to rebuild. I know I have enough to run at least the B1- 26" props. Optimistically I am hoping I need the 28". I did not set the rev limiter yet but was thinking 5400 rpm? I know everyone is not tuned into my build but it used to run 4200 - 4300 rpm with the same props and it was 60 mph GPS. I have gone from 600hp total to 1,000hp. I have easily picked up the 7-800 rpm to 5000 and there is a lot left. I am pretty sure I will be able to meet my goal of running in the mid 70's once I get the props figured out. Thanks for your comments.

So I know this info is not the same for every boat, but if right now, my WOT with the current 24's was 5000 and I wanted to run my WOT back to 4200 then I would run the 28" props correct? Would the boat be faster in this scenario?
This 2nd question is just talk because I didn't try it but yesterday if I pushed the 24's up to WOT and it happened to be 6000 rpm then again, I would run the 28's and that would bring it back to about 5200. I know the boat would be faster in this scenario. Am I understanding this correctly? Thanks for your help.