Building a 572 with m3 procharger
 

So just looking for some opinions making sure I'm not over doing or under doing it here... looking at building a 572 with an m3... so planning on using the dart m block.. afr 357cc heads.. havent decided on pistons yet as one guy I talked to said do 9:1 compression and the a could others said to keep around 8:1... also think about going solid lift cam... just planning for the winter project so trying to get a bunch of opinions on what all to use.. all the do and don't... I know there is alot of different answers but trying to get as much info as I can.. any help be appreciated

The M3 is pretty small for a 572, 9:1 works well, solid roller on a 112, AFR heads are good, what is your HP goal ?

Roo, I see that you are new---welcome to the forum. Do you have a reputable engine machine shop for your project in your area?

I do not know how much you know, but power adder systems that make boost can usually hide a lot of mistakes and cover a lot of "sins" compared to a Naturally Aspirated engine with a smaller window of choice when it comes to parts selection. That being said, NA engines are more sensitive to cam and head selection compared to a blower engine that makes a lot of instant power almost everywhere--- but a little more careful thought needs to go into selecting a cam profile---it is a little more critical to get the cam profile correct almost like you would for the attribute of a Naturally Aspirated engine--- they're more sensitive to cam and head size, etc..

I do not know much about Pro Chargers, but from what I have gleaned over the years and seeing some Pro Chargers built destined for marine usage, they tend to have some slight "delay" or "lag" as they kind of spool up building boost like a turbo does----not like the instant response of a roots or screw type/Whipple supercharger systems. However, the Pro Chargers Do work very well once they're spooled up.

, but If it were me, Pro Charger application or NOT, I would always stick with a hydraulic roller cam for ease of maintenance and stay on the smaller side of the cam duration profile---and stay away from the temptation of going with a BIG cam.

It depends on your application and what your goals are, but if you are going to make a mistake on choosing a cam profile, then it is better to make the mistake of choosing on the smaller side of a cam duration/profile. At least that is where I would start with a cam---especially for a Pro Charger.

Also, this is just me again, but an AFR 357cc head sounds a little too large for a 572cid engine for marine use under 6000rpm---will it still work? Yes, but at the expense of mid-range Torque especially as a Pro Charger is spooling up and needs some assistance from the cam and heads that work better down lower in the mid RPM range to give it a little more kick. I tend to believe you would be better off with an AFR 335cc Cnc'd size head design vs their 357cc size---but AFR is an awesome head design company so you have a good head company to begin with.

Personally, I do not like or care for how a Pro Charger system looks under the engine hatch of a boat, but they Do make power---they're runners !!!

Okay, so here's my disclaimer----You can/will get 101 different opinions and suggestions on this website. There's a lot of ways to skin a cat and my opinion could look like the proverbial "poo-poo platter" compared with someone else's input on here and rip me to shreds. I am NOT an engine builder...just an old retired, Marine hi-perf enthusiast who loves boats/BBC engines and has witnessed a lot of marine engine stuff in my life. So, it does not mean I am right or wrong---it's just my own .02 I hope your project goes well and you meet your goals.

Well I wouldn't say I have particular goal in mind... I not looking to set any records just want good reliable power honestly... I figured the m3 would be alittle small but again not looking to run on the ragged edge... and when I first thought about this engine I was gonna go with a 335 afr head but the guys at afr said that he really believes the 357 are the best choice...

Roo,

If I'm spending your money....

Molnar crank and rods, JE pistons and AFR heads. I don't have a clue on specific numbers, just going by general consensus on quality of parts.

On the ProCharger... Owning one myself, I'd suggest exploring the Whipple option. I'm not totally pleased with how the boost comes on with my ProCharger. I have the M1 3lb kit that ProCharger developed specifically for the Merc 496, and It works well enough, given that you can't really pour any REAL boost on those damned cast pistons, but I'd much prefer the boost come on a bit earlier than 4200 RPM, given the engine maxes out at 5K. I'm still at negative manifold pressure at 4K RPM. In my case, it's probably for the best, as I'm still running this through a stock B1 outdrive that I don't really want to blow up. Your results might be a bit different with the M3, but, seeing the comments here about it being a bit small for a 572, I'm thinking it won't be much. If I had my 'druthers, assuming you're already either running a sturdier outdrive or are planning on it, I'd much rather have a more linear boost curve. Take this for what it is.

Thanks. Brad.

My m1 on my 509 I have at the moment doesn't take that long to build boost... I mean if I am cruising down the lake at 3000 rpms I'm not into boost but if I give it throttle it builds it instantly... myself personally likes the procharger... I haven't had a Whipple I hear they are super nice pieces... like I said I'm honestly not looking for tip top every last little but of horsepower... but I Wan good reliable power is what I'm after

I'm not sure a about proper Pro Charger sizes with any given engine size, etc... but I agree with Brad and would personally rather select a Whipple over a Pro Charger. A Whipple makes instant power and look much like a Roots type of blower under the hatch and gives it more of the "cool look" factor,

There are lots of factors involved, money, personal goals, application.etc. Some guys prefer to pick out a HP goal first and it is just another option about how to make your power goals, but I am kinda the same way you are about my power goals and try to realistic about it.

I'm not racing, or looking for every last drop of HP I can get out of an engine or trying to break any speed records or set the world on fire, and somebody somewhere is always going to be a little faster than you are.

So, my outlook is I just try to keep it relatively simple and just want good, efficient, reliable turn-key power and I think it all begins with the amount of cubic inches being used (what $$$ you can afford) and try to build as best as you can from there off of that. For the most part there's reliability in Cubic Inches.

I like to make good power and aim for a peak RPM number vs horsepower figure, but it all depends on the combination---engine CID, heads and cam. Most of these kinds of boats top out between 5000-6000rpm range.

I usually try to pick out the RPM range at peak power and let the combination of parts basically dictate what kind of HP it will make at that RPM---whatever that HP number may turn out to be.

Without a goal, you can make an easy 750 with a NA motor that size. The M3 will have to spin faster to match an M4, and make more heat in the intake. The new Prochargers spool faster than the old ones and they don't die at top end like some of the other brands. Do you want to break the vert shaft pulling out or peel the face off of the gears at top end.

My buddy had a procharger , had to put the stick to the wall getting on plane, the thing sucked, made no power at low rpm and getting on plane was a joke.
Good luck thou.

Roo,

This was my general experience. It's really not that bad for me, though. At the end of the day, I *AM* pulling more prop and running faster than any NA PQ280/496HO I've ever heard of, but only by a little; 28P, instead of 26P and 76MPH, instead of 65-70. I guess it is inarguable that I am stuffing more air through the engine than I would be NA, boost or no boost on the gage. In my specific case, I really can't do much more than that, given the cast pistons and stock Bravo outdrive. But, when I have to pull the engine for a refresh, we will be correcting the piston issue with JEs, and, if we ever have any real issues with the drive, it'll be replaced with an SCX. Then I will be looking to replace the ProCharger with a Whipple, seeing the success Kallucca had with his Checkmate 280ZT.

The major malfunction I see with ProChargers is that they have all the disadvantages of turbocharging, with none of the advantages of a positive displacement supercharger. With a ProCharger, at low RPM, the air really doesn't HAVE to go down the intake if it really doesn't want to, so any real boost waits until the RPM gets to a point where the air doesn't really have that choice. With a Roots or a Whipple, this isn't the case. The air has absolutely no choice but to go down the intake. The end result is a more positive and linear boost curve. At the end of the day, it seems considerably easier to build a strong, reliable engine with a positive displacement blower than a centrifugal, and I suggest a Whipple because it takes up essentially the same space as a standard intake/carb would. Kallucca was able to tuck one under the sundeck of his Checkmate and is pulling ~950HP. You wouldn't have to push it that hard, and still have plenty of HP, only it would be present throughout your RPM curve, not just at the top.

Thanks. Brad.

I'd take a Whipple over a Pro Charger/Centrifugal any day of the week. A Whipple may not run quite as cool of an air intake charge as a Centrifugal such as a Pro Charger, but they run cooler than a Roots supercharger----And those Pro Charger systems look look sucky ugly under a marine engine hatch (just my .02)

...and I would still go with an AFR 335cc Cnc'd ported head vs their 357cc head for a 572cid engine running @6000rpm and below----and that goes for the Cam profile too---go more for the Torque from than a Horsepower number----I'm just sayin' brother. Most of these BBC marine engines usually respond well and make good reliable power around the 5500rpm range so, try to target your Cam selection for that rpm.

I don't know if you're looking for a builder or not, but here's some good helpful advice--- do yourself a huge favor and call "articfriends" (Steve Smith/Smitty) here on OSO...he;s a Marine Hi-Perf engine builder and Tuner with a dyno and has done many "fix it" jobs that customers had gotten screwed over for various reasons. Steve is on here in the Technical Q&A section quite frequently and is brutally honest, experienced and very knowledgeable, and is a super detailed tuner when it comes to all this stuff. And he can help you with the right cam and head selection. I've know Steve for over 20- years. He's at least worth a phone call.

David Vizard was speaking to some really good supercharger tech advancement the past decade or so.

Speaking largely to the Magnuson Superchargers, and the end feed style with MPI. Essentially they have a freewheeling option for cruising etc, so they don't have much parasitic losses.

This is great for automotive applications. Marine light throttle on plane would be working enough to consume the blower feed. You still may pull a vacuum depending on your low cruise speed, but optimally, at your comfortable higher end cruise speed, the blower is not producing boost. Not making pressure, so not heating the air, and not wasting crank energy from making pressure.

Still benefiting from the blower air flow, filling the void of the vacuum you would be pulling without it.

You can then use the rest of the rpm/throttle for more spirited boating, getting into the boost levels.

Would only a 6/71 + sized blower would be able to support that?


How would a centrifugal supercharger with lag perform on large rough waters when you had to work the throttles to the water?
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Kaama is often very reasonable here on OSO. On many of my deep dive searches for info...his posts go way back. A dedicated enthusiast for certain.
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I've really appreciated his humble words of wisdom.

Bottom line...were all here to push the envelope of the sport/hobby....'cause that is a large part of the draw and fun of it. Along the way, we're going to make mistakes...if we don't...we're not trying hard enough.

One factor...there is no current comprehensive marine performance book. The Denis Moore offerings are unobtanium. It takes a lot of effort to harvest the OSO data over the years.

OP: M3 supercharger, I hope it works out for you, let us know how it goes...looking forward to the pics.

I had a look at the specs. Good for 1200hp from 400-600 base engine. I run in salt water...so I always think of the worst case, and I don't like a water to air charge cooler, unless it was stainless...and you of course lose some thermal conductivity with 316L.

I don't have room for air coolers...but I should not be running more than 5-6psi. Raising or cutting into the sun pad, would get in the way of enjoying the wife getting the good news from the sun.

All depends on your HP goals. A M-3 gets "small" quick on a 572 if your trying to make real HP, if your talking low hp like 700,800, 900, it will be plenty fine. A 572 should make 700 on its own though. All this talk about intake runner "head CC's" between the 335s AFRs and 357s, keep in mind AFR uses the SAME EXHAUST PORT in the 315, 335 and 357. To best of my knowledge the 357 exhaust port will flow exactly same as the 335, ZERO exhaust flow advantage. As far as the Intake, you can force feed air thru a mediocre port and the 335 is far from mediocre. Im not ambitious enough to go look it up this morning but if you research the various AFR heads, you will see as they get bigger and bigger they actually flow LESS at the lifts most marine engines use so do your research there. Alot of boater guys forget the majority of boat engines DONT turn the rpms to come close to using alot of these "big" intakes, heads, huge cams etc.
As far as prochargers vs accel tq, vs boost, yeah sure, put one on something and pulley it to make 3 or 4 lbs of boost on top end, of course your not going to see a bunch of mid range gain. alot of guys whove never owned either a whipple or procharger ramble on about this debate. My M-3 was pulled up to make 12 lbs on my everyday tune, Id have to go back and look at my dyno sheets but I made over a 1000 ft lbs of peak tq and over 800 by 3000, enough to shear off billet vert shafts and props hafts jumping on plane. Smitty

To each his own , My 35yr old pile of fiberglass with 510's and Vortech centrifugal superchargers , has no problem getting on plane in under 10 seconds , will run over 100mph any time , and nobody told me my engine set-up looked like ****.

You have one of the better looking installs I have seen, love the custom intercoolers.

This is coming from a old school street rod/ biker guy so I am a bit picky on motor looks.

M3 on that big engine ought to make some JAM. Sounds fun :)

I'm curious, what boat are you putting this motor in ?

Oh its going in a smaller boat... its in a baja h2x.... I know over kill and some with think im dumb but it's what I want... its a fun smaller boat with my 509 and procharged set up... so be even more fun with the bigger stuff in it...

Yes i have read alot on here and to be honest thats all I usually do is read and not post or comment or any of that... so I tried to message smitty and it said I had to have ten post so thats why I registered and make a post... all this knowledge does help a ton... and as far as the 335s thats what I was originally going with and then a buddy thats helping me with this stuff actually called and talked to a guy at afr and that's where he said I would be better with the 357...
And then all this talk about the spinning a motor at higher rpms.. thats not what i want.... my 509 is that way a couple turb taking off but on plane the thing is great... its getting alittle tired now but still runs good and pulls good... but the place that built my motor the thing made peak power at like 6500 rpms... so been told that motor is way over cammed and that's why it's such a turd on take off... so I have had my run of bad luck paying lots of money only for it to be done wrong...(long story won't even go into the first 3 years of the 509)... so I know there is plenty of knowledgeable people in the marine world so trying to soak all in and do it right this time....

Well, they probably didn't want to hurt your feelings---(only kidding)...If you like it then that's all that matters. I believe every person is proud of his own stuff and I meant no offense, brother. Anyway, it sounds like a runner---glad you have enjoyed it all these years

To be honest and I don't even know if it's possible but been told if I do it right should be around 1000 hp... and yes I agree if it's not there I aint gonna a be mad or upset or any of that... want good reliable power and torque . Which I get you have to be careful or you'll blow drives and all that... but im after making good all around hp and torque is where im trying to focus on... and yeah I was trying to keep it to where I would spin 5500 or maybe 6000 but don't want it to have to live there... honestly trying to set it up so my midrange around the 3000 mark i can cruise with ease not turning alot of rpm but can also get out of the hole... now I'm not saying I wanna punch it out of the hole but if I'm loaded with adults I want it to have enough s*** to pull it self and to be happy

Great thread, great reading!

My Dad built a Glen-L Scamper boat...only 15' long. Put a wJ Jacuzzi jet into it in 1969. He had to wait a year to get it...they were on backorder. The Uniflite Vietnam patrol boats used the Jacuzzi.

He originally put a pinched out 283 engine into it. Then in 1975, got the BBC bug and put an LS5 that he warmed over with a Racer Brown Cam. Never went faster....but the upgrades he made were heavy. But he enjoyed it...

I think most folks have a genuine concern for safety...but if you're not in the driver's seat...it's hard to judge.

I tend to 'err on the more adventurous end of things, but I try to temper that with a healthy risk vs reward.

And if I remember correctly, I think that was with a set of AFR 315cc Cnc ported heads on either your 509" or 540" engine---it was about 20 years ago so it's hard to remember all the details. Those little AFR 315cc heads made a total of 1115hp with your Pro Charger

Yeah I over build things for sure... never gonna be trying to do 100 in the boat or anything but like to know its all there if you wanted it...

Yes, I made 1115 on kill with my afr 315s on a 540. They were modded however professionally focusing on exhaust flow by Rick Lapouttre a local expert head porter.

Nice, With all the comments you are making and the critiquing you are doing you must have some serious engines yourself

I was just curious, I ran a M4 and M5 Procharged 598 in a 26 DCB, definitely need full hydraulic steering. I didn't have trouble pulling out with 1.35 gears and a 32 pitch prop. The 572 will make a major difference, build it with a 4.5 crank.

yeah I have full hydraulic steering but am running the 1.50 gear in drive...
and how come you say to build with the 4.5 crank and not the 4.250.. I was gonna use the standard deck height block and not tall deck... was trying to stay away from buying new exhaust as exhaust isn't but a couple years old

A 9.8 deck 4.50 x 6.385 x 4.25 = 540.........good combo I built a pair a few yrs back still going strong today.....na efi no hair dryers.....:drink:

Good luck with your build