Performance upgrades

[UNSTUCK]

We've done a great job of destroying the OPs thread. It went from, "has anyone done any engine mods?" to nearly bashing people for even thinking of doing such a thing. I wonder if there is another forum on web that has people discouraging HP upgrades. It's almost sacrilegious.

Oh well.....

Our boats are very different. I have the 6.0 "409HP" vs his 5.7. I think Michigan is around 1000 feet isn't it? Much LOWER than me. I love the idea of running 29mph at 3000 rpm. That would be great. The more I go over this the more I realize a supercharger is the way to go. I could probably get by with just a cam, but that doesn't change the need for a tune, which is the biggest hurdle. I will really dive into this come March/April. Still too cold to play boat mechanic.

[freeheel4life]

Unstuck, does your MB have the trim plate?? Are you running around with the ballast in?? I don't see why you shouldn't get 24-26 at around 3300-3500RPM unless theres something I'm missing about the weight of your boat un-ballasted. Unless you are always boating at the 5k mark you've mentioned. Even then I'm surprised to hear you describing basically a WOT scenario at cruising speed.

[Bakes5]

Seriously....5k rpm at 22MPH? Even a 12 pitch 2419 ran my Z3 at 30mph at 4200 RPM. Did you do any progressive RPM vs MPH testing? If so...let’s see the data. I see 5000 RPM AND 22 MPH and I start thinking there is something wrong with your engine or boat.

[Bakes5]

I’m sure your better at engines and boats than I, just throwing out some basics....

Prop key?
Secret stash of lead from prior owner?
Injectors clogged?
Compression check out?
Throwing any codes?
Non retracting surf system?

IDK...5K and 22MPH sounds like a loaded wake boat that has hit its performance limit. My buddy has a 24 foot Supra SSV with the 5.7 and it has great power. I just can’t see how your engine is working perfectly and your at 22 MPH, near WOT, in an unweighted boat. Unless of course you have extra ballast, something dragging or something slipping.

[Brianrzr]

I love the tech talk and I’m glad to have gotten it started. I’m at 600 ft here with surf package. I’ve never WOT fully weighted, and I don’t know how accurate the speedo is, but I’m running 42 mph. The bikinis in the boat like to go fast. I am trying to understand why the 2:1 tranny simply doesn’t affect performance in the same way a prop with less pitch does, increase low end response and sacrificing top end. Like a 4x4 truck with its transfer case in low. One thing I have learned testing boats for work, a given weight requires a specific hp at reccomended rpm to WOT a certain speed. A steeper pitch drops rpm top speed is reduced and over all performance is sluggish. Less pitch increase low end response but the engine over rev’s also reducing top WOT speed. To achieve better OVERALL performance more hp is required. This testing is on bowriders, fishing boats and pontoons, not tow boats, so don’t beat me up too bad.

[chpthril]

sounds like a loaded wake boat that has hit its performance limit.

Ill say it again. These hulls are closer to a displacement (cruiser) hull then they are a planning hull. The hull will reach a point that no amount of engine power or prop or gear ratio, that will make it plan out.

Surf apparatuses like surf gate, TAPS-3, suck gate, etc, has made this even more clear. In other words, proving the theory. Heavily weighted in the aft, and we are fighting physics, not lack of engine power, prop specs are gear ratio.

To the OP, it will be easy to build that 5.7 into a high RPM/high HP performance engine. IMO, this is nto what I want in a water sports tow boat, unless im foot'n. it will be harder to build that 5.7 into a stump puller that peaks at a lower RPM , which is more ideal for what the boat is designed for.

[Germaine Marine]

We've done a great job of destroying the OPs thread. It went from, "has anyone done any engine mods?" to nearly bashing people for even thinking of doing such a thing. I wonder if there is another forum on web that has people discouraging HP upgrades. It's almost sacrilegious.

Oh well.....

Our boats are very different. I have the 6.0 "409HP" vs his 5.7. I think Michigan is around 1000 feet isn't it? Much LOWER than me. I love the idea of running 29mph at 3000 rpm. That would be great. The more I go over this the more I realize a supercharger is the way to go. I could probably get by with just a cam, but that doesn't change the need for a tune, which is the biggest hurdle. I will really dive into this come March/April. Still too cold to play boat mechanic.

Who has bashed you? I didnt see that. Definitely dont think as at all helpful. I just dont know of any performance upgrades that are going to steer your boat in the correct direction if thats what you are getting performance wise. Seriously.. I mean think about it. Your boat is really on one side of the extreme, so if you truly have cycled through all the correct props and are still on that side of the equation I question what a blower will really help. Josh are you sure that motor isnt hurt?

[Germaine Marine]

Unstuck, does your MB have the trim plate?? Are you running around with the ballast in?? I don't see why you shouldn't get 24-26 at around 3300-3500RPM unless theres something I'm missing about the weight of your boat un-ballasted. Unless you are always boating at the 5k mark you've mentioned. Even then I'm surprised to hear you describing basically a WOT scenario at cruising speed.

Something just seems way off in the weight department or the motor is hurt. That boat isnt that heavy.... and we have ran other boats with much more weight....

[Germaine Marine]

To recap from an earlier post:



Can you imagine trying to get across Powell going only 22 at 5k? What would you consider to be a safe cruising engine speed? 3k? I'm ok doing it at a slow 22 mph, but I just can't be happy doing it at 5k rpm. Props, as you said, will not get me what I need. You can tweak cup all you want and it will totally change the prop, but you will never get more than a few hundred RPM change. At least I didn't.
Look what Tige is now doing. 2:1 transmissions and 17" props. That is one way of solving the problem. Also notice that the engines are only getting bigger too.

My prop list from last summer:
1st. 1235 Fast, good prop for listing stock ballast. No chance with 5000 lbs ballast.
2nd. 2937 SLOW, great prop for 5000 ballast. Our best surf prop. All around too high rpm for my comfort.
3rd. 2315 Dont really remember this one. Think it was still too high of RPM but wouldn't pull the full ballast.
4th. 2419 Good for about 3k lbs ballast. Usually around 3900 rpm surfing. Cruising still high and slow. We kept this one as the best compromise.

My goal is to surf at 5000 lbs ballast at under 4000 rpm and cruise in the upper 20's closer to 3000 rpm. The Supra SE 550 I tested in November blew me away at its power with that much ballast and LOW engine speeds, so I know it can be done.

Whats super weird is the 6.0 builds more power down low compared to the new raptor power plants, and its by a long shot.

I will say this.... 5k is alot of weight man. I can count on my hand the guys running that weight and most are in 25-26 foot machines coupled with elevation. Can you get the boat to plane with that weight? Maybe the compromise is moving to more bow weight? Just spitballing...

[dakota4ce]

I have had the same exact boat—and something seems amiss. BUT: I have never run at 5000’.

But mine ran fine with a 15x11 IIRC at 1400’. I put the 15x10.5 on it (or x10?) and could have surfed with a cement truck in tow.

Again, 1400’ though.

Personally? I would run a bit less weight than 5000 and install some slappers on this boat, assuming the motor is all good. The wave will be great!


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[UNSTUCK]

Unstuck, does your MB have the trim plate?? Are you running around with the ballast in?? I don't see why you shouldn't get 24-26 at around 3300-3500RPM unless theres something I'm missing about the weight of your boat un-ballasted. Unless you are always boating at the 5k mark you've mentioned. Even then I'm surprised to hear you describing basically a WOT scenario at cruising speed.

It has the trim plate and we run it in different positions based on what we are doing. It has to stay down while surfing or we have no chance at building any speed over 9 mph. Ballast was empty for the lake powell example noted earlier.

Seriously....5k rpm at 22MPH? Even a 12 pitch 2419 ran my Z3 at 30mph at 4200 RPM. Did you do any progressive RPM vs MPH testing? If so...let’s see the data. I see 5000 RPM AND 22 MPH and I start thinking there is something wrong with your engine or boat.

I did not record any data and I don't remember different speeds vs mph right off. The engine is fine and I doubt the tranny would allow 60 hours of slippage over last summer.

I’m sure your better at engines and boats than I, just throwing out some basics....

Prop key?
Secret stash of lead from prior owner?
Injectors clogged?
Compression check out?
Throwing any codes?
Non retracting surf system?

IDK...5K and 22MPH sounds like a loaded wake boat that has hit its performance limit. My buddy has a 24 foot Supra SSV with the 5.7 and it has great power. I just can’t see how your engine is working perfectly and your at 22 MPH, near WOT, in an unweighted boat. Unless of course you have extra ballast, something dragging or something slipping.

There is no prop slippage, no hidden ballast, engine runs great, and no surf system other than a suck gate.

Who has bashed you? I didnt see that. Definitely dont think as at all helpful. I just dont know of any performance upgrades that are going to steer your boat in the correct direction if thats what you are getting performance wise. Seriously.. I mean think about it. Your boat is really on one side of the extreme, so if you truly have cycled through all the correct props and are still on that side of the equation I question what a blower will really help. Josh are you sure that motor isnt hurt?

Noone has bashed me. Can you explain to me why a supercharger wouldn't get my boat going in the correct direction? I listed my props hoping you or someone could tell me where I went wrong. Again, how could an extra 100-150 HP not help? I have no reason to suspect my engine is damaged.

Whats super weird is the 6.0 builds more power down low compared to the new raptor power plants, and its by a long shot.

I will say this.... 5k is alot of weight man. I can count on my hand the guys running that weight and most are in 25-26 foot machines coupled with elevation. Can you get the boat to plane with that weight? Maybe the compromise is moving to more bow weight? Just spitballing...

I've looked all over for an L96 dyno chart from Indmar. Haven't found one yet. Your observation must be how it feels compared to a raptor. The raptor boats I've been in all feel stronger, but they have been smaller boats too. Not sure if I can get it to plain with full weight. Doubt it. I usually dump the inboard tanks when I need to take off, ie dock run or something. My setup is like this: inboard tanks at rear, 1200 each. Bags in rear lockers, 1100 each. Bag sitting on top of bow seats, 750. Usually 4 adults, 5 kids in the boat.

During our test drive in Idaho last spring the boat quickly jumped to, if I remember right, 36 mph on the 1235 prop, so I know it can physically go faster than what I want (no ballast filled). I would think I could run that prop or something very similar with a supercharger and get the surf weight/speed I want as well. Best of both worlds.

Anyone running a supercharged RZX3? What prop do you use?

[UNSTUCK]

I have had the same exact boat—and something seems amiss. BUT: I have never run at 5000’.

But mine ran fine with a 15x11 IIRC at 1400’.

Personally? I would run a bit less weight than 5000 and install some slappers on this boat, assuming the motor is all good. The wave will be great!

With the 15x11 my boat surfed perfect with full weight. I did not like that I was doing that at 4500rpm. I assume your boat was running the same engine speed? And it would have cruised at the same speeds as mine does, as well. Right now I only surf with the rear locker bags full, tanks empty to maybe half full and the bow bag could be full or empty depending on the day. So lately it's been nowhere near full weight. Slappers and charger are the plans this spring if we keep the boat.

[chpthril]

Can you explain to me why a supercharger wouldn't get my boat going in the correct direction? I listed my props hoping you or someone could tell me where I went wrong. Again, how could an extra 100-150 HP not help?

These hulls are closer to a displacement (cruiser) hull then they are a planning hull. The hull will reach a point that no amount of engine power or prop or gear ratio, that will make it plan out.

With enough weight and attitude, a hull will never plan or perform as desired.

[freeheel4life]

Doubt it. I usually dump the inboard tanks when I need to take off, ie dock run or something. My setup is like this: inboard tanks at rear, 1200 each. Bags in rear lockers, 1100 each. Bag sitting on top of bow seats, 750. Usually 4 adults, 5 kids in the boat.

During our test drive in Idaho last spring the boat quickly jumped to, if I remember right, 36 mph on the 1235 prop, so I know it can physically go faster than what I want (no ballast filled). I would think I could run that prop or something very similar with a supercharger and get the surf weight/speed I want as well. Best of both worlds.

So IF I am understanding you, you are keeping your bags full and your throwover 750 full, only dumping the tanks for a quick scoot?? So you have 2200 in the rear + 750 in a throwover?? Plus crew?? Total 3k+ and then not happy with cruising speed?? You want to smash around the lake in a 24' with that much weight then yeah, you need a few more ponies. Or you could just hit the empty switch. I could be missing something though.

EDIT- You also asked what supercharged RZX3 are running. You would really have to find out specifically props from guys that aren't running the 1 1/4" shaft (pre 2:1). Don't get to go play on big $ boats much so cant give you much beyond what they came propped with. We have a charged 16 RZX that's shrinkwrapped and stored in storage. I can try and check later and see what its propped with. All our other RZXs have been 2:1 and running 17" wheels

[dakota4ce]

With the 15x11 my boat surfed perfect with full weight. I did not like that I was doing that at 4500rpm. I assume your boat was running the same engine speed? And it would have cruised at the same speeds as mine does, as well. Right now I only surf with the rear locker bags full, tanks empty to maybe half full and the bow bag could be full or empty depending on the day. So lately it's been nowhere near full weight. Slappers and charger are the plans this spring if we keep the boat.

I had a cup adjustment on my prop to make it a bit taller and surfed right around 3900-4000. I cannot recall specifically what we did—might be able to find it in old emails.

And I basically never go over 25mph but I don’t recall that being a problem or excessively high rpm.

I do recall the cup adjusted prop being much better than the stock cup. If memory serves me we took it to .150 cup from .75? Which -sorta- makes it like a 15x12 in a slightly different way.

That is all a guess, I would have to look back to attempt to confirm.


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