Tahoe q7i prop

Jez774

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I have a 2006 Tahoe Q7i with a 5.0L mercruiser with alpha one leg. Boat had a 3 blade 19 pitch Aluminium prop. I have replaced it with a 4 blade 14.5” 18 pitch aluminium. Boat plans a bit faster but I have lost 5knots in the top end. 35 not 40 knots at just ended 5k rpm.
I want to go to a Ss prop. Any recommendations? I was going to go back to a 3 blade 19”

also have purchased smart tabs and have had issues trying to get them fit, anybody got the same boat and can share photos of there experience with smart tabs
 

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Scott06

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Try an enertia they aren’t cheap but generally hear good results on them.good balance between acceleration and top end, good bite when trimmed out.
 

QBhoy

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What’s your gear ratio ? Numbers are a little odd maybe if you’re getting 5000 rpm and assuming 1.47 ratio and that low speed.
 

QBhoy

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Ah. Just saw you went to 4 blade too. That will drop your speed. Try an enertia or a tempest plus. Best of them. In my opinion
 

Scott06

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What’s your gear ratio ? Numbers are a little odd maybe if you’re getting 5000 rpm and assuming 1.47 ratio and that low speed.
I think typically a 5.0 carb engine will have a 1.62 ratio in this size boat.
 

Jez774

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What’s your gear ratio ? Numbers are a little odd maybe if you’re getting 5000 rpm and assuming 1.47 ratio and that low speed
It’s a alpha one leg assuming it’s the 1.62 ratio.... I may not of been maxed out. I’ve never fit full throttle as I am sure my rev meter is dodgy and don’t want to go crazy
 

Scott06

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It’s a alpha one leg assuming it’s the 1.62 ratio.... I may not of been maxed out. I’ve never fit full throttle as I am sure my rev meter is dodgy and don’t want to go crazy
The ignition module has a rev limiter in it so you can’t overdo it
 

QBhoy

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I think typically a 5.0 carb engine will have a 1.62 ratio in this size boat.
Ah. Is it a carb ? I presumed it was an mpi at that age. And the rpm mentioned. It would be assumed perhaps likely to be a 1.47. But chance it could be a 1.62 being a little larger than my boat. Unless my boat is unusual having a 1.47 ratio. She will have a little more power than a standard 5.0 mpi I suppose.
 

QBhoy

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It’s a alpha one leg assuming it’s the 1.62 ratio.... I may not of been maxed out. I’ve never fit full throttle as I am sure my rev meter is dodgy and don’t want to go crazy
If it’s an mpi. I can’t advise you enough to get a $200 vessel view mobile kit for it. Especially for getting her propped as perfectly as possible. That will give you deadly accurate rpm info to within 10 rpm of actual. Not to mention dozens of additional functions too.
 

Scott06

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Ah. Is it a carb ? I presumed it was an mpi at that age. And the rpm mentioned. It would be assumed perhaps likely to be a 1.47. But chance it could be a 1.62 being a little larger than my boat. Unless my boat is unusual having a 1.47 ratio. She will have a little more power than a standard 5.0 mpi I suppose.
Three of my friends boats, all 19-21 ft lake bow riders (two bayliners one four wins) all with 5.0s(two carb 220 hp, one 260 hip mpi) all came factory with 1.62 drives. My sea ray 200 factory used a 1.62 for both carb and mpi 5.0s and mpi 4.3. The 4.3 carb came with a 1.84. I think you have a lighter more go fast type hull hence the 1.47.
to the op make sure you get wot rpm so you can asses what prop will work well. Not unusual to loose some top end with a 4 blade. every 4 blade I’ve used except one gives up 3-4 mph but has better holeshot. The revolution 4 I run now actually bested the enertia I tried because I can trim all the way out with it and get more of the hull out Of the water. I think this is just an odd confluence of beamy heavy hull.
 

Jez774

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If it’s an mpi. I can’t advise you enough to get a $200 vessel view mobile kit for it. Especially for getting her propped as perfectly as possible. That will give you deadly accurate rpm info to within 10 rpm of actual. Not to mention dozens of additional functions too.
All
Three of my friends boats, all 19-21 ft lake bow riders (two bayliners one four wins) all with 5.0s(two carb 220 hp, one 260 hip mpi) all came factory with 1.62 drives. My sea ray 200 factory used a 1.62 for both carb and mpi 5.0s and mpi 4.3. The 4.3 carb came with a 1.84. I think you have a lighter more go fast type hull hence the 1.47.
to the op make sure you get wot rpm so you can asses what prop will work well. Not unusual to loose some top end with a 4 blade. every 4 blade I’ve used except one gives up 3-4 mph but has better holeshot. The revolution 4 I run now actually bested the enertia I tried because I can trim all the way out with it and get more of the hull out Of the water. I think this is just an odd confluence of beamy heavy hull.
so yeah it’s a carb 5.0L V8. Definitely a 1.62 ratio. Yesterday at full throttle trimmed up going with the current and wind, 2 people and half a tank of fuel (85L) I got 41 knots and 35-6 in the opposite direction.
This is with the 14.5” aluminium 4 blade 18 pitch. I’m looking at a 4 blade solas 14.1” diameter 19 pitch second hand of the old Facebook marketplace. I guess I will be pushing max rpm a little and dropping more speed but probably a better hole shot
 

QBhoy

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All

so yeah it’s a carb 5.0L V8. Definitely a 1.62 ratio. Yesterday at full throttle trimmed up going with the current and wind, 2 people and half a tank of fuel (85L) I got 41 knots and 35-6 in the opposite direction.
This is with the 14.5” aluminium 4 blade 18 pitch. I’m looking at a 4 blade solas 14.1” diameter 19 pitch second hand of the old Facebook marketplace. I guess I will be pushing max rpm a little and dropping more speed but probably a better hole shot
Ah. Got you. So it’s a carb. Rpm range will be 4400-4800. A little less lower than the mpi version then. Im not a fan of 4 blades for this sort of set up really. Can’t think I’ve known one to work well for something like this. The rev 4 is the only exception really. But need big power to turn them well. You’ll always lose speed with a 4 blade over any good 3 blade. I don’t think there is a 4 blade that would do better than any well suited 3 blade well pitched prop for this. I would urge you to stay clear of solas props. Terrible quality and finish usually and the tolerance for QC on pitch is a guessing game most times. I really don’t see how a tempest 19” or similar would be beaten on a set up like this. Or if you are feeling flush...an enertia.
ive tried loads of props of all sorts over the last few years on a few different boats. Can’t see past the tempest, laser 2 and enertia really.
unless you are totally obsessed with towing or wakeboarding...usually no need for a 4 blade on that boat. Even at that. You’d have a hi 5 prop if you were. My thoughts anyway.
 

QBhoy

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Three of my friends boats, all 19-21 ft lake bow riders (two bayliners one four wins) all with 5.0s(two carb 220 hp, one 260 hip mpi) all came factory with 1.62 drives. My sea ray 200 factory used a 1.62 for both carb and mpi 5.0s and mpi 4.3. The 4.3 carb came with a 1.84. I think you have a lighter more go fast type hull hence the 1.47.
to the op make sure you get wot rpm so you can asses what prop will work well. Not unusual to loose some top end with a 4 blade. every 4 blade I’ve used except one gives up 3-4 mph but has better holeshot. The revolution 4 I run now actually bested the enertia I tried because I can trim all the way out with it and get more of the hull out Of the water. I think this is just an odd confluence of beamy heavy hull.
Hi Scott.
My boat certainly isn’t a lightweight to be fair. It remarkably heavy for her size and style. She weighs 1400kgs dry (3100 lbs) and about 3600 lbs with fuel and a couple onboard. She is almost half a ton heavier than your average bayliner 17/18ft boat at that. She is about 8ft wide too.
But there is no doubt she is designed to be quick. She has a apex stepped hull and a pad to run on when running quick. She also has a rather poorly suited cam in her too. Full exhaust system helps a little maybe too. But defo a 1.47 ratio. I’d think there would be a few 5.0 mpi with 1.47 ratios perhaps.
 

Jez774

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Jan 11, 2021
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Ah. Got you. So it’s a carb. Rpm range will be 4400-4800. A little less lower than the mpi version then. Im not a fan of 4 blades for this sort of set up really. Can’t think I’ve known one to work well for something like this. The rev 4 is the only exception really. But need big power to turn them well. You’ll always lose speed with a 4 blade over any good 3 blade. I don’t think there is a 4 blade that would do better than any well suited 3 blade well pitched prop for this. I would urge you to stay clear of solas props. Terrible quality and finish usually and the tolerance for QC on pitch is a guessing game most times. I really don’t see how a tempest 19” or similar would be beaten on a set up like this. Or if you are feeling flush...an enertia.
ive tried loads of props of all sorts over the last few years on a few different boats. Can’t see past the tempest, laser 2 and enertia really.
unless you are totally obsessed with towing or wakeboarding...usually no need for a 4 blade on that boat. Even at that. You’d have a hi 5 prop if you were. My thoughts anyway.
Thanks for your thoughts! I will be heading in the same direction i was previously, 19” 3 blade Ss, I’ll see what comes about
 

lrdchaos

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Feb 11, 2008
Messages
265
I had a 2005 q7i with a 5.0 mpi and Bravo 1 out drive, I would run a 19p high-five. Pulled out of the hole like a tractor and would run around 52-53 top end.
 
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