Anyone try ACME #1442 prop?

What is the maximum RPM that you would expect to see from a 470 on a 1.23:1 trans?

What is the maximum RPM (Redline) on a '89 SN non-GT40?

bbrech1 wrote: I also went to the 470 from my stock prop (Federal 14x16) on my '89 with the 1.23:1. I was extremely pleased with the performance gains but noticed that the prop was a lot noiser than the federal, is this normal.

From my experience, yes. The 470 definitely has some sound to it- its smooth as silk but it has some serious bite.

I am very happy with the 1442. Much better all around than stock. Feels like a new boat, all the vibration is gone. I have only run stock gear until now so I have nothing else to compare it to. I am very happy with it. I would like to give the 470 a try, but don't want to purchase one just to try out.

Thanks for all your input...

I'm very interested in finding the best prop for my '94 Sport Nautique. I remember when I changed the prop on my '78 from the old stock Federal to the new ACME 540 ...WHAT A DIFFERENCE! The performance gains were unbeliveable!

Now, with the '94 I had to replace the shaft, strut and prop when I bought the boat. So I bought a NEW Federal 14X16 Supercup (identical to the original). I have a couple of problems with the performance.

1) The boat does not hold speed very well (like on my '78 - BEFORE I changed to the 540).

2) I have to use way too much effort to steer right when underway. I have adjusted the rudder as directed until the steering in a straight line is "neutral", but the effort to steer right is still too much.

I think these two problems could both be elliminated with a better prop.

So far, I haven't heard anyone raving about a particular prop for our 1.23:1 boats like they have about the ACME 540 for the 1:1 boats. But if someone has some good advice, I'd love to hear it.

boat dr wrote: it a cruel world out there and someone has to do the testing.

Doc, thats the way I see it too. I cant think of many things worse than having to perform several days worth of WOT testing. Being on the lake in late June can be pretty unpleasant, but someones gotta do it

81nautique wrote: That's a hugh task Tim but will be valuable info for the site. 1. holeshot or pulling power. may be best measured by pulling a slalom skier up and reporting on feel. 2.achieved speed to a set time, ie 3 sec., 5 sec., etc from dead stop, probably need a gps for this to be accurate 3.top speed and rpm achieved. 4.wake characteristics What are the specs on the 1442, is that the new 13x14 "big Block" prop? I can't find the data on amce or deltas site. How did you get your hands on all those props?

The 1442 is a 13.25x15 3-blade with .090 cup. A little more diameter and a little less cup than my 470 that I love. I have most of the props on hand (2 422's, 2 470's, a 612 and the Legend). The others (1442, 428, 498) are graciously being sent to me by Bill W at Acme and Eric at OJ for the purposes of this comparison.

Im planning on doing the following objective tests:

-WOT RPM
-WOT speed (GPS)
-instant holeshot RPM (unloaded)
-acceleration: time to fixed point (maybe 200' ?)
-RPM at 32/34/36

Due to the margin of error (lag) in watching the speed on GPS or the speedo, Im not sure I can capture any meaningful "0-36" or "speed achieved at a set time" type data. Im also not sure if a loaded WOT acceleration test would be meaningful since there are more variables with a skier- plus Im not sure I can find anyone willing to get yanked at WOT repeatedly. Ill definitely do a subjective test on holeshot with a skier for each prop though, as I want to get impressions of the wake differences anyways.

That leaves subjective skier (slalom, ~32MPH) impressions of:
-wake size
-wake shape
-wake firmness

...and subjective driving impressions of:
-holeshot with skier
-speed holding with skier
-bite/cavitation in corners
-smoothness
-noise

Ill take pics of the skiing wake at 30/32/34/36 or any other speed that is deemed significant.

Any other things that would be meaningful to measure or observe? Comments/suggestions are welcome!

That's a hugh task Tim but will be valuable info for the site.

1. holeshot or pulling power. may be best measured by pulling a slalom skier up and reporting on feel.

2.achieved speed to a set time, ie 3 sec., 5 sec., etc from dead stop, probably need a gps for this to be accurate

3.top speed and rpm achieved.

4.wake characteristics

What are the specs on the 1442, is that the new 13x14 "big Block" prop? I can't find the data on amce or deltas site.

How did you get your hands on all those props?

Tim, I remember a study on some old Chris Crafts where with the given prop pitch, the rpms of the prop and then using the speed that the efficiency of the prop was calculated. It may prove that larger props with less pitch are more efficient? Don't really know! It would be a interesting comparison.

TRBenj wrote: I'll be testing it in a month. Ill be doing a comparison test of the following props: Acme 422 Acme 470 Acme 470 w/ added cup Acme 612 Acme 1442 OJ XMP 428 OJ XMP 498 OJ Legend Im very curious how the 1442 stacks up. I told Bill Weeks that I would be sure to share the performance numbers with him as well- hes only heard back from 1 or 2 people on the performance of that prop. It might be worth it for you to wait a month. If you dont, Id love to hear your impressions!

What a comprehensive comparison! Can't wait to hear the results.

That's what Acme just recomended to me. I have a 1991 SN closed bow, GT40P heads, alum. Edelbrock intake and cam from Cam Research. I'm wanting the best acceleration. I am a skier, not a wakeboarder.