2001 Sport or Air DD Top End

[LakeaustinSN]

I didn't want to hijack a previous thread on top speed, but had a question myself. I have a DD sport nautique w/ GT40 01'. I just changed out the digital gauges to Faria analogs and am will be finalizing my calibrations. Just curious what other DD sport or air GT40 owners were seeing as a top speed and at what RPM? Thanks for the help.

[MHayes]

RE: 2001 Sport or Air DD Top End

We have an 01 Air as well, but I couldn't tell you the top speed or RPMs off the top of my head. For calibrating, I recommend that you find a portable GPS unit to help with that.

[coloradonautique]

RE: 2001 Sport or Air DD Top End

or a slalom course and use the time tables. Yellow_Flash_Colorz:

[Rick]

RE: 2001 Sport or Air DD Top End

I have a 2000SN I figure 1 mph per 100 RPM. my top is 48 mph at 4800 RPM thats with a 12.5 X 15.5 prop.

[TRBenj]

Re: RE: 2001 Sport or Air DD Top End

I have a 2000SN I figure 1 mph per 100 RPM. my top is 48 mph at 4800 RPM thats with a 12.5 X 15.5 prop.

That assumption isnt quite right. My dad's 196 can turn the same prop (Acme 422) 4900 RPM, but his top end speed is only 46-47 according to GPS.

[coloradonautique]

RE: Re: RE: 2001 Sport or Air DD Top End

Hey guys, Is that ACME 422 12.5 x 15.5 the stock prop for the SN or did you guys change from stock setup? If it wasn't stock, what is stock for that boat and did you notice a big improvement with the new prop.

The reason I ask is because I have a 13x16 4blade OJ Legend on my 2001 AN at Denver altitude and the performance is lacking. Considering a change to a 12.5 x15.5 ACME 4blade or a 12.5x15 ACME 3 blade (highly recommended by ACME rep).

Any thoughts or experiences? Half an inch in diameter and pitch doesn't seem like a lot of improvement. Does the CNC machining really make a huge difference? I am assuming the Legend was not CNC machined originally.

Thanks.

[TRBenj]

RE: Re: RE: 2001 Sport or Air DD Top End

Not sure how many people have tried all 3 of those props (Legend, 470 and 422), but I have.

The 470 will turn 200 more RPM and outperforms the 422 even on a lighter, unweighted boat thats closer to sealevel.

Yes, you will notice a big improvement going to either Acme from the Legend- but the 470 is the better prop. If you search Ive shared my impressions (seat of the pants and speed/RPM numbers) before.

[boysrus]

RE: Re: RE: 2001 Sport or Air DD Top End

LakeaustinSN - As others have stated, I went throught the same upgrade and used a GPS to re-calibrate. For what it's worth, the GPS seemed to vary from run to run, so I ended up making multiple passes in both directions then adjusted my speedo to the average. I installed a PP shortly after, and the calibrated speedo runs very close to the PP.

Coloradonautique - I ran the original OJ prop for many years, then switched to 422 after dinging the OJ. Unfortunately, I did the swap between seasons - at the same time I did the Faria gauge replacement and added PP - so I didn't get good back to back runs, and I don't have speed data. The 422 feels good - maybe slightly quicker out of the hole and smoother - but not so much that it alone would take care of your issue (doggy out of the hole). The 470 sounds like a good swap - but I was waiting for you to get one and post your results!!!

Jeff

[coloradonautique]

RE: Re: RE: 2001 Sport or Air DD Top End

Jeff,
I am working on a trade for a 470. I will let you know if it happens and whether it makes a big difference. I did not get to clock any times or collect data on the old prop so it will be a seat of the pants (or more accurately "deep water pull") comparison.

Later,

Lorin