bobl

First you have to take operating conditions into consideration. My boat ran mid 80's all last year here. I took it to a radar shootout at Cumberland last year and it ran 89.2 at 5600 RPM. I pulled the engine and dyno'd it at 770 CHP at the 5600 RPM I was turning it, 815 AT 6000 rpm. Of course boating here you're losing about 8-9% power to the weather. I've set up quite a few 28's and the numbers work out pretty consistently. I suspect Steve is making much more than 700 HP. Steve ran my prop at Cumberland and got 90+ @ 5700 If memory serves me correctly. The last run I made with it here was 92.2 @ 6050 RPM. But that was on glass water and 95+ degree temps. You can see from the numbers the slip was much greater. That's because the boat is glued to the glass water. Run the same situation on 1-2' Chop and the speed would come up 3-4 MPH at that RPM, which is more indicative of the way Steve's ran at Cumberland (nice chop). The 28 Nordicflame is running has never seen true top speed, since it is used at high elevation. Also, remember my boat is an open bow. The balance on the boat is different than the closed bow version. From all I've seen the closed bow boat is a couple of MPH faster, all else being equal. Like I also mentioned I believe the ITS is costing me a couple of MPH. So, you add all that up it could equate to the differences we see.

Bob

Young Performance

I am just looking for some accurate numbers. That was the purpose of this thread. I NEVER said anyone was BSing. The numbers just did not add up. Nordicflame is supposedly making 300-400 more HP than steve, yet only running 3 mph faster. Doesn't add up does it!!!!
The number that is suspect to me, is Nordicflame's HP claim. I find it very hard to believe that a 548 ci motor makes over 1000 hp with 6 psi of boost on pump gas. No one else can seem to do it.
I think that steve's numbers are pretty close to where they should be. His dyno run made somewhere between 700 and 750 hp( I don't remember exactly) He added about 125-175 hp. That could easily add 15 mph, if he made 750 hp. Not to mention, that motor is a 502 with a small blower. With the boost that he is making, that is about what that motor should make for HP. There is nothing wrong with that and by no means should he be disappointed.
I didn't come on here to get in a pi$$ing match. I am not trying to outrun anyone. Just want to know what to expect for speed, ride quality and handling.

Young Performance

I agree with you Bob in that conditions will change speed quite a bit. Weight, temp and altitude will also play a big roll.

bobl

I built the 540 for that 25' Rage we had at Cumberland. It made 1005 HP at 8 psi boost with an M3 procharger. I dropped the boost to 6.5 and made 925. The engine in Nordicflames boat is similar, but has better heads and most importantly an R-tech intercooler. That's where he is coming up with his data. Remember, as has already been said. That boat is used at over 5000 ft. elevation and still running well into the 90's. He's never gotten to set it up and do any testing at sea level. So, those numbers don't compare directly to what we are doing.

Using the speed calculator from BAM marine's website validates virtually all of these numbers that we have documented. My boat ran 60 with a stock 375hp/496. Plug that into the program and change the HP to 770....It gives you 86 MPH. Hmmm, exactly what it ran. Steve's numbers work out to well over 800 HP. I also dyno'd a Raylar 496 at 553 and the boat ran 72.8. Again the numbers work perfectly. Nordicflames boat has seen 97(on the rev limiter) and the program says 1000 HP to get there. Again numbers seem valid.

Nordicflame

iTrader: (4)

No pissing match here...Geez man; we're just giving you numbers.

103 w/1200hp Paul Phaff
97+ w/estimated 1050+ (out of prop and 156kPa boost ~8.3 lbs @ Havasu)
93+ w/estimated 900+ (140kPa boost ~6 lbs @ 5000 feet)
92-94 w/923hp FTM motor
92-94 w/700hp Steve Zs 700+
84 w/ 734hp Larry Peto built 496HO Whippled
76 w/575SCi
73 w/553 Raylar
65 w/425 MAG HO
60 w/375 MAG

These are confirmed numbers...
I'm sure there are exceptions but you wanted a general baseline so there you have it.

Indy

Well..I can confirm the 65 w/425hp HO Actually I saw a max of 67 going downhill one day

SeaRay Jim

I used to kid BoatingBent (pre-Raylar ) that those speeds are great for keeping up with my Searay. We ran exact times at a radar run at Table Rock in 2005.

I can't kid him anymore, so I need a new target. Just kidding, 63.5 MPH would keep up for quite some time before I got too far ahead.

Young Performance

Nordicflame
Thank you for taking the time to post all of the numbers. Yes, Steve's does seem out of whack with everyone else's. However, I had just used the same dyno maybe two weeks prior and it was on the money. That doesn't mean it can't change. That is why I was believing Steve's numbers so much.
It also seems that the boat starts taking a bunch of power once in the 90's. Best I can tell, it starts taking almost 20 HP per mph. In the 60's and 70's, it seems to take 14-15 hp per mph, which seems about right.
Sorry if it seemed I was being an a-hole. Just want some accurate info so I can tell my customer what to expect.
Also, this boat ran 72 with a 496 Mag HO
Thanks, Eddie.

articfriends

iTrader: (1)

What props are you using to get your best speeds,I'm running 944hp in my baja 272 (540 w/m-3 at 10 psi boost,afr heads),runs 89.8 fully loaded w/30 pitch labbed on rev limiter at 6000,runs 92.8 (best run ) light with 32 merc labbed 4 blade at 5700-5800.My motor was probably around 900-920 hp in the boat,on the dyno the innercooler was getting pretty cold water on the big number pulls. Curious what kind of props your having luck with. I tried a maximus last year,boat was a real slug and sheared off a max worx prop shaft after a few passes. In comparison to stock speeds my boat only ran 62-63 mph w/stock 502,Smitty

Indy

Strange...I tried many prop combinations in all temp ranges, wind/current directions and barely got 67 And that was only ONCE Most people I know with the same boat got no better. A 5 mph difference is huge. Are you sure that number wasn't going over the waterfall?