2008 Avalanche, Prop question

[Troy 234]

Hey Y'all.

Last time out in the boat this fall, I was loading the boat with help from someone, and instead of doing it my normal way I listened to him and ended up tagging my prop on one of my bunks (tore up my new Gatorbak bunk.)  I took the boat back off and did a test run on the water with no ballast and didn't feel any vibrations or anything. Didn't have time to test with ballast in the boat. 

So I am taking this opportunity to upgrade the prop. I talked with Jim at ACME and he suggested the 1631. Since I have been using my factory 497 for the last 8 years and no issues, mainly surf, roughly 2000lbs ballast, he thinks the 1631 would be best. I tried some searching and only finding old threads (old boat = old threads) and no one mentioned the 1631 which I think is a fairly new prop. Anyone running a 1631? Thoughts? Jim says it has great hole shot and will keep the RPMs down while surfing also. 

2008 Avalanche, 330hp Black Scorpion, roughly 2k lbs ballast (listed), usually 2 adults and 2 kids on the boat, custom a-plate. Don't know what other details is needed.

[InfinitySurf 302]

The factory 497 you have been using is 13 dia x 17.75 pitch with .105 cup (pretty good to have a prop for 8yrs without dinging it) and the 1631 is 13.5 x 14.25 with .150 cup. Seems to me that the new prop will drop your rpms for sure, since you are increasing diameter by 1/2" and changing pitch to less revolutions. I think as long as your motor has the power, anytime you can get a little more diameter is a good thing since you are increasing the surface area that can "bite" into the water...Sounds like your low end has been good with the factory prop, what rpm is your boat running at surf speed? Running empty at WOT, what is your top speed and rpm? From what I know about props, my guess is this prop will reduce rpm by around 300rpm. This prop will give you a bit less low end grunt , but it should hold your surf speed better and will increase top end,  I know top end does not matter but if you had more low end than you needed before, the boat should run more efficiently. 

 I run both, 14 X 14.25 #1847 & #1633 props on my SV244, they are same size props with different cup (.105 vs .150) and I don't notice much difference between the 2 props except slightly lower rpm at surf speed with the .150 cup. Its a bigger boat than the C4 and I run over double the ballast you listed, both props do great for me both for low end torque and top end, so cannot imagine that prop wont do well for you on surfing since you are not at high elevation (assume "DFW" means you are in TX) and don't run a ton of weight.

If you buy from ACME, they will swap the prop for another if you don't like it for some reason and you just pay the shipping charges. You pay a bit more, but it could be worth it if you are not sure. JT Nettles Prop in Austin, TX both sells and repairs props for the best prices I have found and when you buy a new prop you get a $50 coupon for a pop repair so if your other prop is slightly damaged, you will have a spare. 

[Kojak 2]

I'd say go with what Jim is telling you.  I talked to him a season or so ago and followed his recommendation.  It made a big difference for my boat and set up.  

Jim knows his stuff! 

[Troy 234]

2 hours ago, InfinitySurf said:

The factory 497 you have been using is 13 dia x 17.75 pitch with .105 cup (pretty good to have a prop for 8yrs without dinging it) and the 1631 is 13.5 x 14.25 with .150 cup. Seems to me that the new prop will drop your rpms for sure, since you are increasing diameter by 1/2" and changing pitch to less revolutions. I think as long as your motor has the power, anytime you can get a little more diameter is a good thing since you are increasing the surface area that can "bite" into the water...Sounds like your low end has been good with the factory prop, what rpm is your boat running at surf speed? Running empty at WOT, what is your top speed and rpm? From what I know about props, my guess is this prop will reduce rpm by around 300rpm. This prop will give you a bit less low end grunt , but it should hold your surf speed better and will increase top end,  I know top end does not matter but if you had more low end than you needed before, the boat should run more efficiently. 

 I run both, 14 X 14.25 #1847 & #1633 props on my SV244, they are same size props with different cup (.105 vs .150) and I don't notice much difference between the 2 props except slightly lower rpm at surf speed with the .150 cup. Its a bigger boat than the C4 and I run over double the ballast you listed, both props do great for me both for low end torque and top end, so cannot imagine that prop wont do well for you on surfing since you are not at high elevation (assume "DFW" means you are in TX) and don't run a ton of weight.

If you buy from ACME, they will swap the prop for another if you don't like it for some reason and you just pay the shipping charges. You pay a bit more, but it could be worth it if you are not sure. JT Nettles Prop in Austin, TX both sells and repairs props for the best prices I have found and when you buy a new prop you get a $50 coupon for a pop repair so if your other prop is slightly damaged, you will have a spare. 

If I remember correctly my surf RPM is 2800-2900??? its under 3k.  I have no idea what my WOT speed and rpm is. I might have done that once 8 years ago when we bought the boat. Fastest I go is 30 when I slalom ski and that is extremely rare (like I haven't skied in probably 5 years). Normally, if we are empty we go about 25 and that is about 3k rpms. Don't see any reason or need to go any faster. 

Correct I am in the Dallas/Fort Worth Area. Home lake elevation is 649 when it is full. 

My plan was to go with Nettles and send my old one in for them to check it out. Don't think it is bad at all, and it will be a great back up. Jim at ACME seemed very confident that the 1631 would make me very happy. 

[InfinitySurf 302]

19 hours ago, Troy said:

If I remember correctly my surf RPM is 2800-2900??? its under 3k.  I have no idea what my WOT speed and rpm is. I might have done that once 8 years ago when we bought the boat. Fastest I go is 30 when I slalom ski and that is extremely rare (like I haven't skied in probably 5 years). Normally, if we are empty we go about 25 and that is about 3k rpms. Don't see any reason or need to go any faster. 

Correct I am in the Dallas/Fort Worth Area. Home lake elevation is 649 when it is full. 

My plan was to go with Nettles and send my old one in for them to check it out. Don't think it is bad at all, and it will be a great back up. Jim at ACME seemed very confident that the 1631 would make me very happy. 

I think that prop will do well too. I mentioned WOT cause you can over rev with some props, I am sure you know all this tho. I almost never go over 25-30 either when cruising to my surf spot, etc... but always test the WOT when I get a new prop to be sure it falls in the correct range so I know, doubt there would be any issues with that prop tho, especially with ACME recommending it since they usually recommend based on data they have. If surf rpm is 2800-2900, that is really low and very efficient already, don't think the older engines had issues with rpm running so low that the engine was "lugging" and when you list, its more efficient anyway cause you do not have as much drag. Good luck with the prop!

[Troy 234]

So I was finally able to put the boat on the water this past weekend. Initial reaction is great.  The wave seemed like it had more push.  The lake was a little choppy and I had a new driver on the boat, so I was concerned about that too.  But all in all, so far I really like the new prop.  The fuel usage was up, but I think the first time on the water each year the fuel usage is more than normal (older fuel and running the boat to winterize and summerize) 

More to follow. 

[Troy 234]

First 3 times out this year, fuel usage was up. 4th time out and the usage was down. The last 3 times I got fuel at the same gas station but at different pumps. I am going to try the same pump for the next few times to get a better reading. I will say, the wave has more push with the new prop, with out a doubt. Very happy so far with the new prop, I do need to check for prop burn, I just keep forgetting when I get home to look. 

[superdtf 68]

On 7/8/2019 at 11:59 AM, Troy said:

First 3 times out this year, fuel usage was up. 4th time out and the usage was down. The last 3 times I got fuel at the same gas station but at different pumps. I am going to try the same pump for the next few times to get a better reading. I will say, the wave has more push with the new prop, with out a doubt. Very happy so far with the new prop, I do need to check for prop burn, I just keep forgetting when I get home to look. 

Your surfing will be more fun if you don't look...   ;-)

[Troy 234]

Well, just checked and still no prop burn. So far so good.  

[superdtf 68]

21 hours ago, Troy said:

Well, just checked and still no prop burn. So far so good.  

Don't look, just surf.  :-)