Thanks Gary!! Great info...
I better start saving up for those Raylars

Hi bobl,

We always have a 1-2 chop around Long Island which is ideal for the Nordics. We are also in salt water as well which adds to the speed somewhat. We also have a light breeze most of the time with low humidity and 75-80 degree temps. All these factors add up to an almost ideal running condition.

We have a 2004 35 with 525's.....93.7 GPS

Bob,
Wow, those #s are identical to mine, with minor variations for weather and load. I'm using a blueprinted 28" P5-X. I had 6 people on board Sunday, and with 4 of them being girls, quite a bit of their "accessories".
We ran 82.6GPS. Weather was mid 90s, water was high 80s.
1/2 tanks. I'll take it.
Now that I have the Garmin 172c, I've been comparing it's readings to my Gaffrig/Livorsi recall analog GPS speedo. It's interesting that my GPS speedo has just about always been a little slower than than the digital handhelds I've compared it to. I figured it out. The Garmin updates significantly quicker under accelleration.
Therefore, if I don't make a long pass, the Gaffrig hasn't reached max speed, vs the Garmins. Trivia, but interesting.
Regards,
Steve

LIOPA, now I understand the performance differences. Thanks. I've seen my top speed vary as much as 8 MPH from one condition to another. My best is 87 and my worst is 80. One day the air was really bad and the water was glass. It was so sluggish I thought the engine broke.
Bob

We don’t mean to beat on you LIOPA but it’s really hard for us that test and monitor test so closely to understand your numbers. As you can see from the following “verified” test, your test results are way out of the norm. If you were to graph these in Excel there would be a big blip on the screen
They sure don’t run like that out here in the west half of the USA; Regardless of conditions.
Think I’ll move East
Dave

496MAG 61-62 verified
496MAG HO 64-66 (I think INDY once got 67 with the tide, in salt water and down hill)
HP500EFI Almost 67.5 GPS/70.1 Radar in Family and Performance Mag
HP500EFI ran 71.2 with stock 28 at 5150rpm in Powerboat and Hotboat
525EFI ran 74.1 at Havasu in the Spring (75 dry degrees) verified
Mild 540EFI (550hp) 73-75 verified
Merc 575SCi 75-76 verified
565ci/609 dyno hp XR ITS drive 75-76 verified
Illmor 625hp ran 76.6 in Powerboat
LIOPA 525EFI 78 and going for low 80s
HP500EFI with M3 ProCharger w 5lbs ran 79.7 in Powerboat and Hotboat
Larry Peto 580ci/675hp/700lbs tq ran right near 80 verified
Steve Zs 575SCi bumped up to 725-750hp runs 82-85 verified
565ci/Whipple ~800hp XR ITS drive 85-87 verified

Steve,
my dash mount GPS is very slow to catch up with the hand held but when it does they are within .5mph.
Dave

Dave,
Since the handhelds I've run have usually been stuffed in a can coozie and drink holder, I've never actually watched them under hard acelleration. We've just set them to catch max MPH. My new 172C is up high on top of the dash, and it's easy to see. It scrolls like slot machine when you punch the boat. The analog is usually 4-5 MPH behind it until the acelleration falls off around 80 or so, then they begin to equalize. If I hold it for say a 1/2 mile or more, like yours, they read very closely.
Here's another little bit of GPS trivia regarding antenna mounting.
I know this breaks the rules, but I already have one antenna for the Speedo, an XM antenna, and compass on top of the dash. The Garmin external antenna was pretty big so I mounted it UNDER the deck on the bulkhead near the stereo head unit. Works perfectly. So you don't need to rail mount or drill more holes in the dash, if you don't want to. It even worked in the garage, under the deck while I was mounting it so I figured it would well on the water. By the way, I also bought the "Eastern Lakes" chip to enhance the screen. Wow.
It knew what street I was on, which way the boat was pointed (without moving!?) and the feet above sea level at that location. It was another $100, but seems like it's worth it.
We were at Lake Cumberland last week for their Poker Run, and it showed the no wake zones perfectly as we entered them.............
I tried the 172C internal antenna, but with our low profile windshields, the antenna hit.
Best Regards,
Steve

I still have the Lake Michigan area chip in mine. I need to upgrade so I can have the nice features for Powell, Mead, Havasu, etc...
I mounted my Sirius puck under the deck and it worked perfect once I got it out from under the bow rail
RV mounted the GPS antenna under the dash and it seems to work well as well. I hate extra stuff mounted around.
Dave

Since we are all in the speed sharing mood...I thought I would share with the rest of you some real cool fender cleats that I Installed on my 28.......
I found these at Cabalas for $14.99 Each