Weiand blower on a 330hp
 

Wanted to get it open and pinion on this, I have a formula 242 LS with a stock but fresh 330 HP. The engine has about 50 hours on it but it is stock with a basic ring and bearing job done to it. I was thinking about throwing a little Weiand 177 and a set of big valve #049's on and just doing a top end Basically, my question is how do you think the stock bottom end will do ? First off I'm not looking to go 60 or 70 MPH but dammit it would sure be nice to go at least 50 ! The boat right now maxed out is high 40s with a 21 pitch prop. My main goal is to achieve a cruising speed of about 40 don't really care how fast it is ! Yes, Maybe or Ka-Blam-O ? What's your guys thoughts !?

it has been done before.keep boost below 4 lbs and a safe tuneup and you will be ok,but don,t look for tons of power.

Thanks Mike, it should make about 400 wouldn't ya think ?

1st off what is wrong with the boat/setup? it should be faster than that. what rpm are you maxing out at? have you tried a 23? how bad is your current prop?? And you can pull 400 hp without the blower easily unless you want the blower bling and whine

400 to 425 is my guess.

I don't know if there's anything wrong with the boat phrahle, it has a 21 pitch stainless mirage 3 blade on it now but struggles to get on plane, but once on plane 4500-4600 rpm's at about 48 mile an hour on GPS, I put a 19 pitch three blade on it but the motor over revved at 5000 RPM and still only went 45 on GPS, so on to prop three, a 22 pitch four blade got on plane nicely but only revved the motor to about 4000-4200 rpm at about 45 mph on GPS, it did cruise nicely though, about 40 at 3000-3200 rpm's. It is my first boat and I'm learning more and more every time I'm out with it, just to me seems like it needs more power !

400-425 would be great to me mike exactly what I was thinking !

What rpm is your engine reving to now with the 21" in high 40's ? I've been many (other type) boats with 21's that run 50's and into 60's. Just wandering if your rpm is too low now.

4500-4600 SB, are them boats running 330's ?

using Bam's speed calculator with a 225 constant and a very conservative 5000 lb guess at you weight it shows 58 mph...even with slip you should be llow mid 50's. Do you have bottom paint? trimming correctly?? prop in good condition??

I just noticed you said it was your first boat, are you trimming it?? If your running with the bow stuck, that will be like driving with the brakes on,

No bottom paint, tabs look to be stock I've played with them up and down but mostly all the way up. Trim the drive just a smidge up ! I took the prop in and they checked the pitch and balance and everything was good ! I checked timing that was right on at 8° I thought about throwing a few degrees at it to see if that would help a little but never got to it . To me the boat runs great, it's whisper quiet starts right up no smoke other than doing a compression test I pretty much went over everything . The lower in the boat has been replaced , I have no idea what ratio it is would that make a difference ?

Try more trim, lots more than just a smidge.

Then the RPM's come up also right !?

I like trim:lolhit: Blondes Prefered :evilb:

Check the boat to see if its full of wet wood and foam.

To get you started on trim..... In calm water, once on plane and a decent speed (does not have to be wfo..) bump the switch llet the boat settle see what it does, bump again and repeat, no big changes, just bump the switch.. Eventually you will feel the boat "lighten up, it will ride different, the speed will come up, the rpms will come up. If the prop blows out (loses traction) you went to far.. if the bow is all over, you probably went to far. everyboat will like a little different trim, every driver will like a little different trim. If you can not make the boat 'light' then something somewhere is wrong. hyd. lines from the pump reversed, wrong prop etc.... triming for sea conditions is a bit more advanced and would be lesson 2.0

Hell I'm still learning and getting my resin bucket dialed but I have the advantage of a world champion throttle man sitting next to me in the boat giving me pointers,,,, And yes there is a definite difference between the way the boat rides before and after. faster AND smoother....

Gotcha phrahle we'll save that for another day, I did screenshot your reply so I know what to do this spring thank you. I had a survey done on the boat it is a little wet but it's about average that what the guy doing the survey said and it is 27 years old LOL !

Where you located??

Is the prop an old school Mirage (faster) with a rubber hub or a later Mirage Plus (holeshot) with the Flo Torq hub and the vent holes? If the latter, are the vent holes opened or plugged? The holes won't make a difference on top end, but they will getting up on plane. If you're blowing out trying to get on plane and the vent holes are open, start by plugging them one at a time.

I have an 86 242ls with a bravo one drive. It took 420hp to get 62mph with a 23p prop. Guys running 330hp usually get 55mph while 454 mags with 365hp usually get 58-60.

Michigan, north of Detroit !

Prop has the rubber hub

Your close, when spring comes we will figure out whats up...... if your set on the blower...there has been a 525 sc floating around on powerboat swap shop.. any idea what gen your motor is?

Whoop whoop!!!! Meet in the middle. Sunday fun day at the digger!!!!

I did hit 51 one time but the conditions were great ! Like phragle was saying may be just learning the boat !

It's a Gen IV , I owned the boat for three months and already had a short block cylinder heads intake carb oil pan in the garage ready for a build LOL !! Yeah I appreciate all the words and would like to get back with you in the spring time when we get it back in the water !

That boat should run mid 50's all the time with 330hp and trimmed out correctly.

Adding a 100 hp will gain you about 7 mph on the top end.

Do not spin a 330 more than 5000 rpms.

If you add a supercharger, you will need to run at least 91 octane fuel.

If this happens, I have a 23p Mirage Plus, a 23p Tempest, and a 22p Offshore 4 blade he can try. (And, if the wife wants any more of this magic stick, I'll have a new 23p Mazco by spring.)

If you have another block your going to build, find a take out forged crank and decent rods (same crank as a 502 but pay attention to gen) they are out there from people stroking 502's etc... and just build a 525sc clone

Thanks Griff after talking here today I may not have had it trimmed out correctly ? How I did it before is I had to drive trim up just a smidge and I could only get 4500-4600 RPMs out of it . I was wondering if you could get away with midgrade or if you had to run premium with the blower thanks for that heads up !

Thanks phragle, i'm not a Chevy guy so I'm learning all these things about these Gen IV, V & VI. A 468 with some good oval ports was my first thought but a buddy of mine has a 174 he would sell me pretty cheap that's why was thinking maybe just the blower on the stock short !

What your facing is the cast crank (in the 330 hp 454 vs. the forged crank in the 454mag /502) The forged crank is much stronger and will take much more abuse than the cast crank you have.

in the marine world a cast crank shouldnt be spun more than 5000 rpm and 500 hp is really pushing it. many have done it, but the safety margin just goes right out the window. Spend some time reading the various 454 threads on here and you ccan learn/figure out quite a bit.

Like to try that 23 mirage plus on my Mach 1. Wonder if it will get me to 70....... My 23 mirage gets me 69.6

When I bought one of my boats it was supposed to have 525sc's -- after losing a cam lobe I found out that they were actually stock 330's that had been bought as a long block and all the acc's and blowers were used to dress them... They ran fine at around 5 lbs boost for the year that I had them. based on speed I'd say they were putting out around 450 hp ( had chillers also) I don't see any reason not to do it as long as you run good fuel and watch your timing.

As far as the 330 now -- did you say that timing was at 8 degrees? Initial or overall? what is the overall timing? Should be around 28 in order to get any power out of it at all....my buddy had a 24' formula with a mag and it would run 58 mph -- it was a great boat...

Take the beer of the boat and you should hit 70 no problem...

Whoa whoa let's not talk crazy now.

Yeah that's what I've been learning phragle, but to do what I want to do to it would probably only take 400 - 450 hp I'm guessing , The Supercharger thing I think would be cool because of the bling factor the boats really clean and with a few things like that to it I think it be pretty cool looking and would be easy, bolt on !! I've also been looking at a few scat an eagle rotating assemblies, reasonable price little more work though. !

That's interesting and good to know delsol About them 330's with Superchargers ! Timing is set at 8 deg initial, it has a thunder bolt IV with a V24 modual I believe in it ! I never checked total timing I just assumed it was correct !

I had an 89' 242ls with a 330hp merc in it, ran 56-58 depending on load witha 22p 4 blade bravo 1 prop on it all day long. There's something keeping you from running faster, hook in the hull, water logged, trim issues, low compression, something. Find out what before you add a blower, you may be suprised at its performance when set up properly. I loved that boat, rode amazing, my only complaints were it's slow to get on plane and is way too sluggish when the tank is filled all the way up

Thanks gmgearhead, there's something definitely wrong I'm just not sure if it's me or it yet ! LOL When I tryed a 22p 4 blade I could only get it to RPM 4000-4200 maybe I needed to trim it a lot more than I did ? This boat takes forever to get on plane also, struggles bad but that was with a 21p 3 blade ! The 22p was way better out of the hole but again rpm'ed low. I want to build a new motor for it, just was comparing price on a supercharger on the stock 330 or a whole new 496 ! The thing is i bought it late in the season and only had a month to test & learn !

Honestly if i was you i would at least rebuild what ya got, even if it's just throwing a cam, set of heads, and intake/carb on it. You can make 450-500 hp that way and as long as you don't spin it much over 5k you'll be fine. Put some arp rod bolts in it and call it good. And yeah no matter what i would run a 4 blade on it, it's just too heavy of a boat to dick around with 3 blades, the cruising & planing is SO much better with the 4 blade on that hull