More Power?

[onevalkyrie]

Hey guys I have an 08 RZ 4 with the 340 HP and although I can't really complain about the power for hole shot and pulling, I am a little disappointed in the top end speed. If we are "loaded" which we usually are, about 38-40 is all I can get out of her. My question is will doing whatever modifications are possible to get whatever extra HP there is available help out on the top end? I noticed on the tests published on http://www.boattest.com/boats/1853/test_results.aspx that you get 42.8 MPH @ 5000 RPM and a nice 46.8 @ 5800 RPM. I realize that this is a 409 HP vs. my 340 but would a little more help? Does anybody know exactly what would have to be done and how much more is available with minor modification?
(Whew!!!)

[chpthril]

Hate to tell you, but you bought the wrong kind (towboat) of boat if you want top end

If you want more top-end, a prop change will help, but at the loss of bottom end, which is what you need in a towboat.

[da.bell]

prop change for sure. But I agree with chpthril. You need a hotboat if you want speed.

[nothingbuttige]

they are both right....These motors have plenty of power but are geared for the holeshot. If you change your prop for speed then you will sacrifice holeshot power. This must be your first wake board boat...

[Tanner]

Call Acme and see what prop they recommend. I know Acme suggested a different prop than Tige had on the boat for me. I gained another 5 mph and actually had the same amount of holeshot from stock after going to their recommendation. I don't know how that's possible as one usually falls off as the other is gained.

[talltigeguy]

Sounds like you are in Texas, so should be pretty close to sea level, which is probably where the tests were done. There were probably also done on glassy water, with 1 or 2 people in the boat and 1/2 tank of gas and no gear. I think the tests are true, but were geared towards getting the best results, not reflecting what most of us actually do.

I agree with a prop change, being wary that your experience may not be as pleasant as Tanner's. You might sacrifice one for the other.

[onevalkyrie]

I hear what you're saying but I think I will check with acme and see what they have to say. I'm also going to contact MP and see what, if anything they might have to add. As usual you all came through with something anyway. Thanks to all.

[talltigeguy]

I hear what you're saying but I think I will check with acme and see what they have to say. I'm also going to contact MP and see what, if anything they might have to add. As usual you all came through with something anyway. Thanks to all.

It seems that occasionally guys ask about trying to get more horses out of their engines, and it boils down to the fact that these engines are already about as amped up as possible, so further gains are negligible if you want to get more out of the engine. I would like to hear what MP tells you. It seems like it has been a while since someone has asked, so it would be good to know if anything new is out there.

[Domsz06]

I think u will find that the money you have to spend to get even five mph more will not be worth it. Speed costs money. Ask any hot boater out there. That's the reason most live in trailers and pull their boat with a rusted blazer. Not trying to offend anyone out there with a hot boat. Just bad expeirences with them in Oklahoma.

[ragboy]

I have the 24Ve, with the 340hp, and even completely loaded with 2000lbs of ballast and additional people, I can still get 42 mph. However, I can only get 43ish unloaded.

[rensink]

The 08 rz4 loaded with stock ballast, 12 people, 2 block bags with the 400hp motor and it ran 45's on a good day, normally 43's

[onevalkyrie]

I have the 24Ve, with the 340hp, and even completely loaded with 2000lbs of ballast and additional people, I can still get 42 mph. However, I can only get 43ish unloaded.

Ragboy did you ever notice what RPM you were running? I could live with the 42 or 43 for sure. When I'm showing 39.5-40.5 I'm right at 4950-5000 RPM.

[rogersbm82]

Are you running with the tapps plate all the way down?

[Jason B]

My buddy has 2 props. He changes them according to what's on the days agenda. Swapping them out takes all of 5 minutes--if you pause for a beer.

Too much of a headache for ME, but he does it all the time. If that's an option for you, it's an easy fix for a few hundo $.

[chpthril]

Bought GPS and you guys were right the speedo was off big time. At 17 we were doing 21 and the faster you went the more gap in the numbers. At 30-32 indicated we were going 40-42 according to the GPS. I wish that was all the bad news but alas there is more. Got some debre in the water intake and started over heating. We took suction hose off at the water pump and backwashed everything and got going again. Oh and I almost forgot my suposedly brand new tower has the threads stripped out on the top where the tower and the uprights connect. Other than that, boy do I love Tige. We'll see if that relationship continues after I tell them what I think of there great (poor) disign in some areas.

http://www.tigeowners.com/forum/showthread.php?t=5360

What did your dealer do to correct your inaccurate Speedo? Did you recheck w/GPS after?