DPA, what all did you install and how does it perform?

Hard to tell. It was the 375HP 496 and I was loaded good with the whole family and full fuel. I installed Raylar's 450HP cam kit and stage 2 ECM recal. Pulled the turbulators. The best this boat did was 73 on speedo by the prev owner. I got about 2 MPH better and running at 5100 RPM. Ray told me to run at 5200. I think once we get the over rich condition solved (sooty transom) and a average load I could see a few more MPH. I may need a prop change if I run 1/2 fuel and two people. I just need to talk to Ray now.

Got this from Bob today. He should have the original link updated w/the info soon but here's a preview. Go to: www.fullthrottlemarine.com and click on High Performance Projects for the full story.
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"We’re back. Several months have passed and we’ve completed the Raylar install and testing. Sorry it’s taken so long. Just too much work and not enough time. As this article is directed at results, I’ll save the details of the install for another time. The instructions were thorough and it went together without a hitch. Now it’s back to the dyno to see what we accomplished. The one caveat to the project is that we sent the PCM to Whipple for their stage 2 programming. They tweak the fuel mixture, raise the rev limiter and adjust the spark timing to be much more aggressive. This requires a 120 degree thermostat and 91 octane fuel. We installed the stock exhaust manifolds, with turbulators removed for our initial tests. We made several pulls, tweaking the fuel pressure up and down to get a feel for what air fuel ratio worked best. It made best power at 13:1 air fuel ratio. More than a few points either direction and the power started falling off. Off course this is what Ray had already told us, but being hard headed we had to see for ourselves. The numbers? 530 HP at 5400 RPM. We’ve already established that the turbulators cost us 8 HP, so I didn’t see a need to revisit that. Keep in mind that Raylar’s testing was done without water mixing with the exhaust, whereas these tests had complete wet exhaust. This would certainly account for some HP loss as compared to his testing. Next we bolt on the Dana exhaust manifolds. Again we make several pulls to adjust the A/F ratio and arrive back at the 13:1 number. This time we get 553 HP at 5400 RPM. Very nice numbers and right in line with the manufactures claims. Let’s see what it does in the boat. This time the test conditions were the same altitude as before, about 10 degrees warmer air temperature and smooth water. We were able to consistently get 72 mph with a best of 72.8. Cruise A/F ratio is a bit lean so we were forced to raise the fuel pressure a couple of pounds to bring that in line for now. We’ll send the PCM back to Whipple for some fine tuning in the fall. In summary, with the Raylar kit, Stage 2 programming and Dana exhaust we picked up 9 mph. As a comparison, these numbers are slightly better than what that boat will run with a Merc 525 EFI under the same conditions."
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He also mentioned that one of his Raylar customers recently had an opportunity to race an identical boat to his, except it had the Merc 525 EFI engine. They ran dead even for about 5 miles.

Here's a link to the entire article... http://fullthrottlemarine.com/496%20...%20Article.htm

Brake fluid takes paint off.

Bob,

When you tested the Nordic "S" exhaust routing versus straight out exhaust routing, did you happen to have the IMCO corner exhaust tips with internal flappers installed that Nordic uses with the "S" setup?

Are the Raylar setup hp numbers from flywheel or prop shaft?

Thanks,

Bill

No, I didn't have the Imco tips installed, they were straight tips.

Raylars numbers are at the flywheel.

Bob

Excellent addition to an already excellent test program to clarify the effects of various components on hp.

Great info!

Bob, this is great information! I have a 31 foot Scarab II with twin 555ci / 700 HP / NA / TRS setup. If this was your setup, what exhaust would you use, Danna, IMCO, Lightening, CMI, or KE? I need to purchase two sets next week and you would obviously have more non bias knowledge then 99.9%. Any suggestions would be just as helpful as your awesome testing. Thank you for educating me.