Top speed and top speed, that is the question
 

Hi Guys

This thread is not only about top speed, includes also a small report from boating and the weaves from the Oslo Fjord.
Oslo is the Capital of Norway, which is a country in North of Europe.

The boating season in Oslo started rather good this season. The weather has been nice temp sunny but a little windy.
Let’s hope it will continue like this, the weather in Norway is
unstable and changes a lot, there are summers with hardly any boating weather at all

My Formula 242 SS 454 330 hp Bravo 1 has already 30 hours, after a totally rebuilding of the engine this winter. Runs good, the first oil shift has been done, after the first 5 hours.

I have tested the top speed twice:
First time, alone in the boat 1/2 gas, 50 mph by GPS, maybe I could have trimmed it out a little bit more.
Second time 4 people with gear and 3/4 gas, 46 mph by GPS
The Prop is Quicksilver 21 Mirage Plus, and the boat is bottom painted.

Should I be happy with this result??
46 mph with 4 people and gear 3/4 gas and 50 1 person 1/2 gas, does that make sense??

A couple of videos, yes the comments are in Norwegian

http://www.youtube.com/watch?v=gLKPZub92oo

http://www.youtube.com/watch?v=1O07k...eature=related

Hello, i am totally new to boating, and recently bought my 1st boat. 1987 F242 SS 454 magnum alpha one (should be 330hp version) i don't know the history of the engine but believe it to be 100% stock with the original 600 hours on it. With 4 guys (we all go 250 pounds plus each) and a 1/4+ tank of gas i GPS @ 46.7mph at 4300rpm. Thats the most rpm i can get out of it and have a feeling i should have more....when i 1st put the boat in the water i thought i saw 4800 rpm....but i couldn't get it into reverse without stalling......after a minute or 2 of playing with the cables/neutral kill switch i got reverse to work but the boat is now hard to shift into neutral. ANyway i think the throttle cable might not travel as far as it did before. The prop is a 19P, i'm gonna have to ask around to see why someone would have put a smaller prop on it.

I had the exact same boat as you and saw 46 on gps with a 350 mag (270 hp). I was spinning a 19 pitch Mirage at 4200 rpms with a 1.5 ratio alpha one. I sold the SS this spring and am building an LS with 550 hp+ 439. I'm still waiting on the engine so nothing to report on the new ride!

Thanks for the respond
If you have a 454 Magnum it is aprox 365 HP at 5000 rpm and you should have 21P or 23. Alpha should be lighter and quicker than Bravo1.
You should not go smaller, if it is a 454 Magnum with 365 hp in your boat. When said that, it is a possibility that before 1988 Mercury called
the 454 with 330 Hp also Magnum, I am not shure about that. But somebody at this forum knows.
I am spinning 21P it is a litle slow out of the hull, but cruises fine and I get 4500 - 4600 when trimmed out.
Could be that 19P is a better allround option for the 454 330 hp, specialy if you have many people boating with you.
I had a 17P before, which was to small

Regards
Rune

Thanks for responding

So you sold the SS, well I am going to stick to mine for a while. I love the ofshore hull with the daycruiser lay out. You need to have a very big performance boat, to have this much cabin space :-). When said that, I also think the LS looks a little sharper with the longer front deck, and a bigger sunpad.

Your new project is very interresting, please keep us upgraded
Do you have any pics of your old and new boat???
What kind of speed are you hoping to get out of this package?

I got all the original manuals with the boat...the guy that sold it to me advertised it as 365hp, the manuals say it's 330hp and rpm is 4200-4600. I went out again today....me, my gf, my puppy and a couple coolers and 1/2 tank of fuel 47.8mph gps @ 4300 rpm. I wonder a few things.....like i said i'm new to boating but not to power. The manual says that the engine is tuned to run as low as 86 octane fuel. Maybe i can get it to run a lil better by making sure base timing is at least as far advanced as factory spec maybe 2-4 degrees advanced seeing as i run 91 Octane in it. If i can't get my rpms up any more with the current prop will i be able to spin a 21p to at least the factory suggested 4200 rpm minimum? I'm guessing not. I'd like to think that with less fuel, a fresh tune up, check/advance base timing 2-4 degrees, and a new K&N or equivalent spark arrestor that i can see 50mph.
Question: What spline # prop fits my boat so that maybe i can try to score a 21p prop for cheap on ebay(mirage i suppose as that is what i was told came stock) Thanks

I'm not sure if this helps, but in 1987 the 454 magnum was rated at 330 HP with Alpha 1 drive, 1.32:1 gear ratio and rpm is 4200-4600.
I'm not sure what year your boat is, but if it is an '89 or '90, it would have the 365HP with Bravo drive if it is a Magnum. I don't have the specs on the 330 HP, but the 365 version had forged internals and square port heads, totally different engine.
Back in '87 or '88, the bigger power came with TRS, IIISSM/IVSSM Drives. If you need more rpm, drop to a 19 Mirage.
Hope this helps
BC

Hi Cold Sweat

This is the info from Max: (a little further up this page)
Hello, i am totally new to boating, and recently bought my 1st boat. 1987 F242 SS 454 magnum alpha one (should be 330hp version) i don't know the history of the engine but believe it to be 100% stock with the original 600 hours on it. With 4 guys (we all go 250 pounds plus each) and a 1/4+ tank of gas i GPS @ 46.7mph at 4300rpm. Thats the most rpm i can get out of it and have a feeling i should have more....when i 1st put the boat in the water i thought i saw 4800 rpm....but i couldn't get it into reverse without stalling......after a minute or 2 of playing with the cables/neutral kill switch i got reverse to work but the boat is now hard to shift into neutral. ANyway i think the throttle cable might not travel as far as it did before. The prop is a 19P, i'm gonna have to ask around to see why someone would have put a smaller prop on it.

So actually he is running a 19P prop today!! And should be more into 4600+, then 4200 - 4300. in 1987 the 21P did not exist. I think the factory are refering to Mirage 21. I do not know the different from a 19 plus to a 21?? Could it be that the engine is a little tired after 600 hours??

Anyway regarding Formula fact sheets the 1988 242 SS 454 330 hp Bravo1 should reach top speed of 52 mph. I do not know I do not know if that is by speedo or radar. Surly not by GPS in 1988

See attched regarding 454 Magnum

I'm not a prop expert, but there is an rpm difference between the older Mirage props and the Mirage Plus. I believe about 150-200 rpm less with the Plus because of added cup for better bow lift.
Those factory speeds were off some, and your engine may also be getting a little tired. To be honest with you, your speed isn't really that far off with 4 guys as you posted. Play with the trim some more, you might get the rpm your looking for. Like you said, the boat is new to you.
If you plan on a rebuild later, don't go too wild on HP, that Alpha won't take it. If I can help you with anything, let me know.
Good luck, BC

Formula 242 SS Factsheet