Great experience with Hydromotive

[Murphy]

Sent my Quad-IV to Hydromotive as advised by others on this board to have a rubber hub installed. $60 plus shipping. An excellent deal. Anyway, I got a call from Tom at Hydromotive who wanted to ask about my Donzi. I'd told him I was running a Classic 22 with an SBC and Alpha SS. He asked about any mods I'd made, then came back with... "by my calculations you're maxing out at about 4800 RPM with this prop right now, correct? Yeah I say, but I thought that was getting alot from a mouse with that prop. He says, "I've got a setup just like yours here at the shop. That engine produces most of it's power in the 5200-5400 RPM range. So here's what we're going to do... I want to reduce this prop from 15-1/2" to 15" modify the cup just a bit and lab finish it. That will give you back 400-600 RPM with no loss in prop performance. If you thought you loved the Quad-IV before you won't believe it once I'm done with it". He thinks I may pickup as much as 4-5 MPH once we get everything working together. Needless to say I was pretty juiced about all this. Really nice to have somebody with that much experience and knowledge interested in helping a weekend boater like me. Says alot about their organization.

Murph

[MOP]

Man O Man these guys always seem to go the extra mile, more bugs in your teeth next year!

[smoothie]

They are 5 minutes away from the office so needless to say I been there a "couple" times...and they always have a few minutes to talk.

[BUIZILLA]

Murphy:
That engine produces most of it's power in the 5200-5400 RPM range. So here's what we're going to do... I want to reduce this prop from 15-1/2" to 15" modify the cup just a bit and lab finish it. That will give you back 400-600 RPM with no loss in prop performance. He thinks I may pickup as much as 4-5 MPH once we get everything working together
Murpheek! you've got my undivided attention, let us know how it turns out!!

J

[Murphy]

Absolutely will let you know how it goes (if Spring ever arrives). I'll be able to tell what the prop change produces since I haven't changed anything on the boat this winter. I know the engine is capable of 5400 RPM cause it got there easily with my 3-blade Cleaver. I liked the way the boat handled so well with the Quad IV that I didn't mind losing some RPM's. If this new setup gives me the same handling and the RPM's back I'll be one happy camper.

Murph

[BUIZILLA]

I have a really stupid question...

does the Hydromotive 4 blade do anything over a stock 3 blade to help stabilize slow speed wander on a single I.O. setup in a deep V hull?? My Four Winns 205 is a perpetual fight at idle speed to stay in a straight path, without constant correction. Looking for a solution.

I have a 14 5/8x23 SS 3 blade turning 4700-4800 rpm, what size 4 blade do I need for a Cobra drive? Volvo 350-310 carbed, runs 55-57 mph now. I cruise at 3200.

Opinions ??

thanx, J

[MOP]

V hull wander is inherent to the beast, it was explained to me at tech school that it is the wash of the hull hitting the drive unit. I have to agree having had a 20 foot V single screw V-Drive it did not wander and all its weight was in the back like an I/O, which someone tried to say caused it. On my 16 I put the tabs way down it completely eliminates the wandering! Don't forget to bring them back up before you punch it and go into massive bow steering dive. Been There Done That!

[smoothie]

Hey Murphy,Just curious did you have a chance to give your new prop a spin yet?

[Forrest]

I too recently talked to Tom at Hydromotive as well about getting a welded-steel hub converted to a rubber hub. After talking for a few minutes about re-propping my 302 Ford/Alpha SS 16 Donzi, he told me that he has a boat with a 600HP small-block and an Alpha SS that runs in the low 90 MPHs at 6500 RPM using their 14-3/4" diameter four-blade outboard motor prop, the Intimidator Quad IV O/T (http://www.hydromotive.com/int_quad4_OT.html). He went on to say that his boat will run in the upper 90 MPHs with the Intimidator III, three blade prop, but the boat was difficult to control, and for that reason, he didn't recommend it. He also went on to say that since I'm running a small boat, I should drop down from my 23" pitch 3-blade cleaver to a 20" pitch Quad IV O/T and turn my engine closer to 5500 RPM with lower pitch prop. That way the boat becoms much easier to handle and will be faster because the lower pitch prop has less paddle-wheel effect than higher-pitch props. Faster because the engine can crank out more HP at the higher RPM providing that your camshaft and valve train will allow it. That makes since because a larger boat, or a boat with twins, will not be adversly affected by the lifting action due to the paddle-wheel effect. Well, 5500 RPM is still not past red-line on this little F-word engine, but it sure will suck gas with a 20" pitch prop!

[CDMA]

5500 isn't so nice on the drive either... the irreplaceable SS :confused: :confused: :confused:

Chris

[smoothie]

Chris,Tom told me that my TRS is good to 6500 with merc racing oil eek! ,he says outdrives have the same gears etc.as the outboards that crank 8000 g's but 5400 is the most I want to turn.

[Cuda]

I had a 24 turbo prop on my 20 foot Formula with 330 horse 350. I could not get the hull to free up, it always felt like it was pushing the bow down. Some of this may be due to the rocker built into the hull.

[Rootsy]

Interesting Forrest, VERY interesting...

[Rootsy]

I really am interested in trying a hydromotive on my 16/SS combo... I do not know if the Quad IV will be optimal... but i am really interested in the Quad IV PLUS (for high X dims) and the Quad IV OT or the other outboard 4 blade they manufacture that is pretty much neutral for lift... the T-4X i believe... though the diameter is pretty small...

[Murphy]

No chance to test the new prop yet. Still in the 40-60 degree range here in Central Illinois. Seems like it rains every weekend lately. Won't be long now though.

Murph

[Rootsy]

I spoke to Tom @ hydromotive yesterday for a good hour. he was adament that the quad IV WAS TOO MUCH prop for the 16 / 18. he told me to run the quad IV OT and we are targeting 5400 rpm with the cold weather. so i called this morning and ordered a 27P quad IV OT... it should arrive tomorrow and hopefully i'll have results by monday. with the 25 cleaver i am running about 16% slip and he was confident that going with the OT we could bring that into the 10% range and get more speed out of it than the cleaver as well as exceptionally better midrange, out of the hole, handling and turning... we'll see... best part is, i like the fact that they will work with you if the prop you get is not enough or too much...

i'll let ya all know how the 16/SS likes it...

[roadtrip se]

Me like mine. Jill too.

Labbed 28 with welded on diffuser ring. Very stable, great hole shot, and no lean. Jill requests it every time she rides. 76 to 78.

29 labbed mirage is faster at 79 to 81. Much spookier at top end. Walks and leans.

Hydro is a great every day prop for a classic.

Todd

[Forrest]

Wow Root, a 27" pitch and 5400 rpm??! What gear ratio are you running in that SS?

[Rootsy]

Forrest,

i slapped a degree wheel and pointer on the propshaft and i spun the motor over TDC to TDC, did the math and came up with 1.59:1. 1 revolution of the motor = .628 (226* of rotation) on the propshaft

this equates to a .909 *standard alpha 1.5* upper gear assembly, which i verified when i had the top off and a 1.75 ratio in the lower, which craig colabella told me was from the 3 litre Outboard sportmaster setup.

i was spinning the labbed 14 1/4 x 25 cleaver against the 6000 rpm rev limiter pretty easily, so we figured it was good for 6200 - 6400 in that configuration...

[Rootsy]

Ran the quad IV OT this morning.. what a day... but to get to the guts of it.. the SS and the 16 classic ran well with it but not as stable as with the cleaver. the OT comes out of the hole well and accelerates well, even for the large pitch i am spinning. she grabs well and takes off about 3000 rpm. i can turn it 4900 - 5000 with the trim all of the way in. netted 75.6 mph @ roughly 5400 - 5500 rpm (rev limiter is set at 5500). had a bit of a chop on the lake and it was windy, the hull felt light and just a tad skittish... after the lake roughened up later with the wind and wake and i burned off some fuel she got a bit more skittish. the hull was rock solid with the cleaver. from my calculations i am getting way too much slip so i don't know if i didn't feed it enough trim or too much trim or what not... i best be checking my gear ratio calculations again too...

3000 rpm - 35 mph
3500 rpm - 44 mph
4000 rpm - 52 mph
5200 rpm - 72.5 mph
5500 rpm - 75.6 mph

she really seems to shine on the top end vs the mid range... i really think i could do well to lose a 1/4 - 3/8 of an inch in diameter...

also something which puzzles me is that the prop wobbles. when i sight the prop shaft it looks to run true but the outer hub wobbles as well as the blades... i do not know if it is a prop issue or if the proshaft is truly bent... but the inner hub and shaft end seem to run true when watching it spin in gear... i'll do some measuring here soon...

[Rootsy]

Ok, follow up to the quad IV OT testing.

As i mentioned in my last post, the prop had exceptionally POOR low and midrange performance (35 - 25% slip decreasing as speed increased) and top end slip wasn't anything to get excited about (17%). from everything i have read, heard and even directly was told by hydromotive this should be significantly less. The control was also not there as the hull felt very loose and slightly unstable. The prop didn't like to lift the hull very well either and it was very easy to overtrim and lose speed. this may just be a trait of my setup.

As you watch the propshaft from the end the runout with the prop hub is significant. when viewing from the side there is distinct wobble from the thrust washer to the end. The blades do not track in a straight line but tend to follow the path of wobble when viewed form the side. from the side view it looks very much like a bent propshaft. A significantly bent propshaft.

I was quite concerned with my propshaft straightness so i grabbed a jig plate and an indicator and hurried home after work to check it out. i spent 2 hours investigating thoroughly on the boat to verify my drive is alright. began by running the Quad IV just to verify, then followed up with my 23 cleaver which spun pretty true. i then removed and ran bare propshaft and feeling with a flat piece of plastic as it was spinning in gear i checked for distinct wobble at the taper, spline and thread. i felt nothing so i went to the indicator for the final measurements. total runout amounted to 0.003 inches.

Lastly i inspected all wear and contact patches on the thrust washer and taper contact was even all of the way around. Contact with the prop also looks to be even all of the way around and i had the nut torqued w/ torque wrench to 50 ft-lb. i have never encountered this situation with a prop before. I may pop this prop on the surface plate and hit it with the CMM in the morning to verify some points... or just go the old fashioned route and use the calipers and height gauge... just for my piece of mind.

therefore i need to contact Hydromotive in the morning. Hopefully this is nothing more than a hub issue. but either way i hope they stand behind their product and are as concerned as i was to investigate it this deeply.

I just wanted to let you all know to maybe take a look at new props before you pop em on... any other thoughts and ideas? frown

[z22owner]

Murphy,

What sbc are you running? I am looking at replacing my 3-blade Vengeance on my Z22. What will your special setup run you when all said and done?

I was thinking of a Bravo 4 blade 24 pitch.

KP

[smoothie]

Root,it sounds like you didnt have a fighting chance for real results,Let me know if Tom doesnt made it good for ya,he's just 15 min. down the road and I can pay him a visit eek! :D Just curious,are you running a solid or a rubber hub?

[Rootsy]

Smoothie,

i called and had a 30 minute conversation with the production / process engineering fellow this mornign, i neglected to catch his name clearly. we had an in depth discussion on theory, etc etc etc. but he says that this wobble is NORMAL and that it will go away slightly when the hub settles in... it is rubber... and i believe is pressed in kinda slanted... easy to do when you lubricate a rubber hub and press in... he also suggested torque to 80 ft-lb so i went to 110 after work tonight and the wobble is less but still there... so i will give it a shot and then if i am NOT satisfied i will get a hold of tom and send it back for a replacement. in my opinion there should be no wobble in the blades, hub, exhaust tube, or anywhere for the money they charge.. i am not worried about it.. i am gonna run it a bit more and see...

also... they believe my boat is so lose because of the amoutn of pitch i am running and the prop is trying to surface and pick the back of the boat up, causing it to be squirrly... on planing hulls they believe in the philosophy of less pitch spun faster for stability and actually increased speed and efficiency...

[Murphy]

KP,
Everything about my Classic 22 is likely to be different than your Z. The 350 has a lot of mods, some to add performance, some to insure reliability. Hydromotive has my vote for 4-blade props. As stated, their modified cleaver design decreases bow lift which I like. The improved handling on this 22 has to be experienced to be believed. It may just be that I stumbled on the ideal prop for my Alpha SS drive and higher X dimension too. Call Hydromotive and tell Tom what kind of rpm and performance you're getting with your current setup. My guess is he'll know exactly what you need in a 4-blade.

Murph