I didn't want to say but when I saw that tensioner move that much I knew the life of the belt would not be long. Maybe in a small v-drive or a jet boat but not in offshore boat.

Totally agree. Plus, after a dyno pull, that head unit, you could cook an egg on it they got so hot.

If it wasnt a belt, it was the head unit of the blower blowing oil seals, fought carb issues the whole time when dealing with prosystems. Boat was a complete turd getting up on plane, lower rpms and stuff. Idled like crap, just sucked. I think we looked into cog setups, but forget why my buddy chose not to go with it, even considered a holley EFI setup from boostpower at the time.

Initially he had those carbs built from prosystems for the build. After getting them, and trying to dial them in , found out they were sucking the single needle and seat fuel bowls dry by the engine of the dyno runs. Upgraded to dual needle and seat bowls, that solved that issue. The carbs still sucked once in the boat.. Ended up switching to a pair of C&S aerosol blow thru's. Bolted them on, Mike Tkach and I talked with roger from C&S after a couple dyno pulls, and within no time and a few small adjustments to the power valve (C&S powervalve setup is way different than a typical holley), it had an EFI like fuel curve from 3000-6500rpm. The prosystems, no matter what we did, would just start out fat and end up way lean by the top end. The more boost we gave it, the worse the problem got. Seemed like that prosystems carb was good till about 10lbs of boost. Over that, it went haywire.

The boat ran mid teens with that setup, like on rails, and wasn't dialed in prop and drive height wise. But the low end still sucked. Better, but nothing like a roots or whipple. They made around the same TQ and HP as mike tkachs whippled 588ci on the dyno iirc, but on the water, they were a world apart. Mikes Fountain would pin you in your seat like a drag car with 4.56 rear when he nails it. Joes, was like it had 2.41 gears in it in comparison. He switched to the roots, lost some top speed, but says he loved the way the boat drove, idled, and did everything compared to the procharged setup. Was told his issues were from being blow thru carb. I could see that being true with the prosystems, as they would go pig rich getting on plane, etc. The C&S carbs, held a pretty good air fuel ratio at lower speeds, so Idk.

That being said, I have some friends who have ran low boost EFI prochargers on stock merc engines, and have had great luck with them. And of course articfriends ran his procharged setup making some good power for quite some time.

I know it's a joke that ProCharger even sells a procharger with an 8 rib drive that should go right the trash, blow through systems also leave something to be desired in a lot of applications. Randy fedo aka as CNC on here had nothing but problems w his pro system's carbs BUT later on came to find the way he introduced air into them in his home built innercooler boxes was causing his issues

I think my buddys M4 had the 12 rib belt? He had ran the hat from steve morris on his setup. I do remember there being a good amount of variance between banks, AFR wise. I believe it was due to the angle of the carb hat. I wanna say they told us to install a spacer under the hat, to help straighten out the air or something like that.

Saw Randys boat up in Traverse a couple years ago, that thing runs strong! I remember walking past it when tied to the dock, and noticed the size of his intercooler water feed lines, and was like "dam! he has some water going to those fukers!).

Randy fedo has m4 or m5 prochargers, his upper pulleys are quite large also and he has the plunger type tensioners. With his extra belt wrap hes never had belt issues. When i went to a 12 rib drive i had no belt issue's when i ran a 4" or bigger upper pulley, w 4" pulley i made 1000 hp, i never ran that pulley though in boat, i usually ran 3.85. I added re-inforcing ribs on head unit bracket to keep it from flexing which helped but everything had to be rubber band tight. With 3.70 pulley i made 1115 hp, was extremely difficult to keep belt from slipping but again blower was turning 60,000+ rpms. When i dynoed the procharger itself to see how much hp it took to turn it actually didnt take alot of hp to turn (i think it was under 75) , the belt issues came from having so little belt contact on pulley. A bigger head unit would have been the answer , fwiw, Smitty

Smitty we got the blow thru carb deal to work fine using a quickfuel, but we also ran a prosystems in a procharger box, worked fine but the box is a pain as you have to remove a dozen screws to do anything + remove the carb to remove float bowls..

Im sure your friend was running a 12 rib, the 8 rib is what comes w the m-1s and m-3s, the 12 rib is a option on m3s and i think std on everything above it, like i said, they dont hardly use any real hp to turn, it the fact that a 7.75 crank pulley is trying to turn a 3.70 blower pulley thats turning a blower 4.5-1 on top of that , i was experimenting w a extra idler last time my blower motor was sitting around here intact but between very few belt choices and limited space i never found a good spot to put it. I also thought about having randy fedo cnc me a lower pulley that was 8.25 then go to a bigger upper pulley but never got no where with that either plus again, 12 rib belts jump in giant increments so not a ton of options for neccesarily getting the right belt

Id put some low boost prochargers in my scarab (i still have 2 m3sc's and aw 504 innercoolers) but im getting too old to contort my body around in bilge, squeezing all that between backseat and engines would suck donkey balls, i will buy whipples first if it ever comes to that.

I just spit my coffee out...............thanks for that.........

IF i had a 38 AVS they would be a good bolt on having 3 feet between bulkhead and motors, this 15 or 18" though, no way. Everytime i wanted to do anything it would involve tearing all kids of stuff out, engines sit way lower in this boat than my baja. My son who works for me INFORMED me if i decided to put them in I'm on my own as he doesnt want to endure the pain either!