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Spritely GT40 |
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M3Fan 
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Joined: October-22-2005 Location: United States Status: Offline Points: 3185 |
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 Topic: Spritely GT40Posted: June-09-2007 at 3:43pm |
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While I was waiting for Hollywood's hung-over ass to get to the lake this morning, I thought I'd do some speed trials on the near-perfect water. Now, I know I don't have the hot-rod mods that some of you have, but I was pretty proud of my totally stock GT40 EFI engine today. I was such a nerd about it that I actually took video of the WOT tests with the ACME 422. I actually saw over 5000 RPM during this testing, but the video only captures about 4950, which is not bad at all. Trust me, it got to 5k. This is not an easy prop to spin up that fast!
Here is the video And here's a quick still frame: 
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2000 SN GT40 w/99 Graphics/Gel
2016 SN 200 OB 5.3L DI https://forum.fifteenoff.com |
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TRBenj
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Joined: June-29-2005 Location: NWCT Status: Offline Points: 21141 |
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Posted: June-09-2007 at 9:21pm |
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Thats impressive- Ive only seen one GT40 in a Ski Nautique spin to 5k with a stock sized prop. That was my uncles '95 and I always thought that hull was faster than the TSC1, as his '97 didnt run as fast.
Not sure how easy it is to see with the digital gauges, but Id be interested to hear what RPM youre getting out of the hole (WOT from idle). |
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M3Fan
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Joined: October-22-2005 Location: United States Status: Offline Points: 3185 |
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Posted: June-10-2007 at 12:24am |
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I'll find out next time. In these tests, I put the throttle down with the hand that is holding the camera, then put the camera on the gauges as soon as I could. I'll need another in the boat to get the WOT from idle shot.
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2000 SN GT40 w/99 Graphics/Gel
2016 SN 200 OB 5.3L DI https://forum.fifteenoff.com |
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Doc97
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Joined: May-28-2007 Location: United States Status: Offline Points: 9 |
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Posted: July-06-2007 at 2:47pm |
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I've read a few recommendations here that these engines like to run at WOT every once in awhile. This weekend I had a few minutes alone in our 97 SN (stock GT40) and opened it up. It topped out at 5300 RPM which raised a bit of concern since the manual says the top end should be 4800. How absolute is that 4800 limit? At what point should I change the prop to limit the top end? I bought the boat three years ago and as far as I know it's the stock prop.
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Nautique2001
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Joined: June-14-2004 Location: Massachusetts Status: Offline Points: 2832 |
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Posted: July-06-2007 at 2:57pm |
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That video was cool. Sounds very smooth at WOT. You must be pleased with the 422. Great post.
Ken |
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reidp
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Joined: December-06-2003 Location: Mooresville, NC Status: Offline Points: 1804 |
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Posted: July-06-2007 at 3:17pm |
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Doc97,
If your tach is functioning correctly and the engine is really turning 5300, then you're do for a prop change right now. Post your prop size if you can to give the late model experts here a reference point and verify your tach if you have a means. Anyway, 5300 is too high for top rpm, but it would also have you turning a higher rpm all the way across the operating range at any given speed, which certainly won't help your fuel consumption. As an added bonus, your boat will more than likely run faster turning 48-5000. |
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Darrel
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Joined: June-16-2004 Location: United States Status: Offline Points: 340 |
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Posted: July-06-2007 at 4:14pm |
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Thats pretty cool. Is your 422 original or has it been balanced, repaired..? Have you run a 470 yet? I am in the market for either a new or a backup prop.
Those are simaler to the #'s I got last weekend in my 95..4850 rpm 46.5 mph on the airguide speedo, 422 w/ a small nick. |
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M3Fan
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Posted: July-06-2007 at 4:27pm |
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It's a new 422. Purchased last May. It's slower out of the hole than I'd like, but it's great in the middle and top end. I have a re-furbed 612 3-blade that I'll try out in the near future as well.
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2000 SN GT40 w/99 Graphics/Gel
2016 SN 200 OB 5.3L DI https://forum.fifteenoff.com |
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Darrel
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Posted: July-06-2007 at 5:06pm |
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Thanks M3, I ran a OJ 4 blade at the beginning of the weekend, out of the hole w/ 422 was noticably better.
Does anyone know what the expected performance diff between an ACME 612 and a 470? Thanks |
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TRBenj
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Posted: July-08-2007 at 2:44am |
According to Bill Weeks, the 470 will turn 50 more RPM and be 1/4 MPH slower than the 612. I havent run the 612 yet, but will do so very soon. In case you didnt know, the 612 is NLA. It was deemed too similar to the 470, so Acme dropped it from their line. |
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79nautique
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Joined: January-27-2004 Location: United States Status: Offline Points: 7872 |
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Posted: July-08-2007 at 12:18pm |
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Tim are you bring all of these props with you to GL.
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TRBenj
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Posted: July-09-2007 at 2:02pm |
If I have room in the truck, Ill bring both 470's and the 612. Probably wont bother with the 422 or Legend. |
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Darrel wrote: