New Acme 430 Prop Report

I’ve seen a few posts lately asking about how the new Acme 430 prop ran on my boat this summer so thought I would give a little review.

First a little history, 1981 Ski Nautique with a 351 Ford. I rebuilt the motor a few years ago, heads are RHS 180’s with 54 cc Combustion chambers, high rise dual plane intake, Cam research cam, forged pistons at 10:1 compression ratio. Heads have been professionally ported and intake and exhaust manifolds have been gasket matched by me.   It’s been a great running boat pushing north of 350 hp (desktop dyno says 380hp but I don’t believe everything I see on the computer these days).

My problem has always been finding the right prop for the boat, I’ve run OJ 13x13, 13x14, 12x15, 12x14, and an Acme 540 13x12. After all that I’ve always come back to the Acme 540 but that too was a compromise, best top end I could get repeatedly out of the boat was 54.6 but the motor was spinning an ear piercing 5700 rpm. I sent the prop back to Acme twice for cup work and at the recommendation of Bill Weeks this spring we added .180 of cup to it.   That brought my rpm down to 5500 but still not happy I continued to bug Bill over a period of 2 years to get him to make a 13x13 right hand prop and finally late July the persistence paid off. He produced a 430 which is simply a right handed version of their 431 13x13 which has been around for some time.


To compare the new Acme 430 to the 540 with.180 cup, the holeshot is exactly the same.
Pulling up a skier you could not tell there was a different prop on the boat so I would consider adding pitch and not losing holeshot a success. My wakeboarding rpm was exactly the same as the 540 which leads me to believe the extra cup on the 540 was working at low rpm but the prop was still slipping up on the top end.

Top end with the 430 was consistently at 54.6 with a stray run or two of 55.1 BUT my rpm dropped to 5200 which was a major goal from the very beginning.

Biggest noticable improvement was in overall drivability of the boat.   With the 430 the boat doesn’t feel so top fuel dragster-ish but now has some real feel to the throttle and handles so much better. The boat is super responsive but not as violent to drive as before. Hole shot is still great, top end is acceptable without spinning the motor out of control
(5200 seems so relaxing after free wheeling at 55-5700).   The biggest difference is in the mid range. Pulling a 200 lb strong slalom skier out of the water was simple but impressive was how fast the boat gets to 34mph, you'll run right by it if you don't back off as soon the skiers up. With the 540 in that speed range you could almost feel the "tires spinning" as Dana called it when you put the power to it. The new 430 grabs and goes and the motor has the torque to turn it easily.

The 430 is also much smoother than the 540 but that may simply be the result of multiple times on the block being tweaked.

Bottom line is money well spent, I would think that anyone that has gone beyond the typical gt40P head upgrade in a pre 82 Nautique might want to give this prop some consideration.

I just did a back-2-back test ACME 422 12.5x15.5 CNC VS 13x15.5 OJ CNC. The trailing edge of the ACME blade is straighter, it's diameter smaller. The OJ is a rounder, traditional "ear" design I guess it's called.

The OJ was a few ticks faster at the same mid RPM as the ACME. 0.4 - 0.5 km/h faster. I also felt a little more transom lift with the OJ. WOT the RPM's were lower and top speed was lower, but it's been a week (dirtier hull colder water). I think this was more due to the transom lift. The OJ had a familiar feel to it,, like my old OJ.

The ACME spools up with a turbine feel - like it has less rotating mass. Also smooth, it seems to have more response to throttle, eg an Italian engine, but at the same time a bit less stump-pulling grunt.

those are my impressions anyway...

Nice report back here on the 430, I also was impressed with the 431 back when I was a running a LH 1:1 setup in my 83. I was in the same rpm ball park, IIRC I didnt quite hit 5200, closer to 5160-5180, but at a consistent 52.x mph it was the fastest I ever got that engine combination to run. It was smooth and all around the best prop I tried. I think I had it on the boat 2 weeks before I absolutely destroyed it idling up to a pier to drop off a friend.

SharkSN, your results are pretty much exactly in line with all the head to head comparisons I have done or seen reported on here. You being of of the guys most interested in slalom wakes it would interest me to know do you think the increased transom lift of the oj had any postive effect on your slalom wake? Which of the two props would you consider better for your day to day use?

SharkSN wrote: 0.4 - 0.5 km/h faster.

Since when are you guys using the metric system...??
My converter is all messed up now

Edit: sorry Paul, didn't know you are from Canada till I Googled Sproat Lake...
(Guess that's why Pete always hammers on completing one's profile... )

I did ski the OJ prop last week and have to say the wake felt great. I think it does lift the transom a bit more.

hotboat wrote: I just picked up a 430 for fathers day and am very pleased , got a quick run in though it was sprinkling but the rpms were 5200-5400 and 56-57 mph on the garmin.

I guess that "hotboat" moniker is no joke! Those are some very stout numbers... did you ever share with us the details of your engine build? Im assuming this is your Martinique? Based on Alan's numbers on that hull, might be knocking on the 400hp mark.