Power-Up, HT383 vs. Supercharger

[Mikeski]

I am tired of having a great boat that feels underpowered for most of my activities. If I only wakeboarded I am sure it would be fine but I don't and I miss barefooting at comfortable speeds and miss a decent pull-up on my slalom ski. I have had more than 6 different props on my boat, changed the exhaust manifolds, and still find myself unhappy with the power available from the PCM 330ex.

Step 1 is to modify the FAE to a dual exhaust unit and remove the stock muffler. This should let the motor breathe as it did before I installed the FAE. It will also allow it to breathe more air as will soon be needed once I make the other modifications.

Step 2 option 1: Bolt on a Whipple supercharger
Step 2 option 2: replace the lower end of the motor with a HT 383 build

Option 1 is easier/quicker to implement but it costs significantly more and lower end engine failure is likely at some point in the future. Cost estimate is $7k, one weekend of work, one trip to Whipple Superchargers in Fresno for EFI mapping. This is a proven solution guaranteed by Whipple, expected results would be low 400's for horsepower and torque. I have received positive comments for going in this direction from at least one PCM employee that I trust.

Option 2 is cheaper but I will have to pull the motor to swap the components over to the new short block. Cost estimate is $4k, three weekends of work, and unknown hours of tuning to get the EFI tuned properly. Expected output to be about 400hp and 415+ ft. lbs. of torque from 2500-5000rpm. Note this is essentially the same as the new Indmar Hammerhead motor.

Step 3 would be to combine options 1 and 2 and have a motor with 500hp/500ft.lbs. on tap, but I don't think I really need that.

Here are the goals:
1. Pull a solid 34mph at less than 4,000rpms
2. Come out of the hole in wakeboard mode with a full passenger and full ballast load within a decent timeframe
3. Turn a small diameter prop to maintain a clean slalom wake
4. Pull a barefooter a solid 44mph

Out of all the props I have had on my boat the 644 and my current 1160 are not bad compromises when it comes to my goals but I am tired of compromising and I am ready to remedy the situation.

In some ways I feel like I am breaking new ground but I expect there will be quite a bit of interest in my results. I might even anticipate a group buy from Whipple or a motor builder if I can work out the details for this upgrade.

Thoughts?

[Mikeski]

Just for comparison purposes here are power curve comparisons for the 350HO vs the HT383. I expect the 350HO is very close to the PCM 330 Excalibur.

[Hollywood]

I'm sure you've thought of just buying another (o/b barefoot) boat, and dealing with the slow slalom pull up... I'd hate to see you throw all this time and $$ at it and still be speed limited by that hull, get your slalom pull but still not have the 44 mph.

[TRBenj]

If your goal is to turn a larger prop (ie, spin fewer RPM's at any given speed) and pick up top end AND holeshot, then you want to increase the amount of torque your engine makes... so going stroker (383) or forced induction (SC) are both logical choices- so youre on the right path.

A few things to consider- Im no Chevy expert, but you may want to see which option will require new heads. I have no idea how good the Vortecs are, but the engine will need to breathe in either case, so dont limit yourself here. I would assume a new cam is in order whichever way you go as well. As far as the SC goes, do you have the physical clearance to run one? I know it would be a tough mod to do in a direct drive, not sure what the 211 hatch will allow. With the stroker, you mentioned tuning- do you know someone who can tweak the PCM computer?

The SC sounds very interesting, but my vote would be 383... the bottom end should be stout and strokers are known to make great torque. The catch, as you mentioned, is tuning.

I will be very interested in hearing more about whichever option you choose!

[DanielC]

I do recall that around the turn of the millennium, MB boats was offering a boat with a Wipple supercharged engine. This is when the horsepower wars were going on, and Correct Craft was offering the Python engine. I believe MB also has used a two speed transmission. I have heard of some drag boat people using a Chevy Powerglide transmissions in boats.
I do not recall your model of boat you have.
I am not sure, but if your boat was offered with the Python engine, earlier in this decade, maybe a swap to the GM big block motor might be a way to go, but that might require a motor frame change, something that might be available from Correct Craft.
I also recall that around the time that Correct Craft was using the Python engine their engineers were also experimenting with the Ford modular (Triton) engine, with a supercharger on it for Ski fly. I believe this was part of an effort to keep using Ford as an engine supplier as the 351 blocks were used up, and no longer in production.
I know most of these comments were outside of the box of what you asked, but they are possibilities.

One option on the fuel injection is Mega squirt EFI, Look at www.msefi.com

[WakeSlayer]

What about retrofitting a BB Crusader in there? PCM still had them in 07 or 08, I thought. They do not list them now. Maybe your trusted source knows of one laying around.

[MikeC]

I would have a few concerns with the supercharger: higher probability of engine component failure; the obvious question - will it fit under the rear pad and is there enough room to get the drive pully over the front of the motor?; what does the power curve of the supercharged engine look like? And if the torque comes on too quickly can the transmission and particularly the walters v-drve handle it?; and finally resale - I know that shouldn't be a concern but if I was looking at a used boat I would quickly pass on a supercharger installed on a stock engine.

Changing the block or changing to a different engine would actually increase the value and give you a very drivable boat.

If you go with the supercharger there will be a lot of people on here waiting to find out how it drives, plus you would have one of the coolest sounding Nautiques on the water.

[thedude]

I'd start with a pair of ported/polished heads and a custom cam to suit your goals. You can do all this with the engine in the boat if your have a DD obviously. You can probably pick up a set of vortec heads off the internet and have them ported/polished to save time. Check around on the internet to see what guys with the late 90's tahoes and trucks are doing with their 5.7 liter small blocks...maybe www.gmfullsize.com could be a good resourse. Tossing a supercharger on an otherwise stock engine doesn't really allow you to get the full power potential from the blower...heads/cam/intake/exhaust all should be upgraded to get the most out of your supercharger.

It shouldn't take a good tuner very long to tune the ECM for the increased airflow and cam...if you could get him to actually spend a couple hours on your boat to do the tuning that would be best I'd imagine. We don't have the luxury of the strapping down to the dyno for tuning in a boat, unless you take the engine out and use an engine dyno. Or you could always go with a mail order tune, send him your ECM and he'll tune it in hopes that he gets it right the first time.

I'd start by checking out what guys have done with street applications for the vortec 5.7, and then see which ones you can/can't apply to a tow boat.

[bchesley]

I also think a tuner after a cam and port and polish will accomplish what you want. If you look at some of the GM crate motors out there they are getting crazy power from stock bottom ends. A friend of mine installed a 500hp crate SBC in a jeep that was naturally aspirated so it can be done. Look at turn key engines website as they have some crazy motors.

http://www.turnkeyenginesupply.com/

[Hollywood]

Jody Seals - Florida Inboards and Mike McKenzie - MasterCraft of Charlotte might be guys you want to phone.

I'd lean towards doing the bottom end before any possibility of a supercharger.

[bkhallpass]

Or you could just remove the 2 tons of stereo gear you are carrying :grin:

Whatever you do, it will be fun to watch. BKH

[ClemsonDave]

I'm with 'thedude'. I'm not big on whipple style blowers and it would be a very tight fit under a stock engine cover. Unless maybe if you can find a Speartech blower off the new Corvette ZR1.

You might be able to fit an ATI procharger on the front of the block somewhere. It will give you the high end power without the shock to the drivetrain of a PD style blower. I have a ATI D1SC on my 100% stock longblock LS6 pumping out apx 730hp at the crank (corvette). Still drives like stock. Plus a blower will not effect your fuel economy unless you are getting on it. I get 27mpg.

You could get a P1SC (smallest they make) pretty cheap ($800ish). Then you'd just need to figure out a bracket/tensioner/intercooler. I've got some ideas there too, if you're interested.

Either way, it should be a fun project.

edit: re-read your post. You're goals are not that far off. I'd just do heads/cam/tune and be done with it. Should be an easy 75-100hp or more.

[Mikeski]

Good discussion is beginning here, keep the comments coming.

While I like the supercharging idea, it really makes me nervous considering my current mill is only a 2 bolt main.

The 383 with or without new heads will have a four bolt main, this option is growing on me. I need to visit a few local speed shops, most speciifically Morgans Speed and Marine in Walnut Creek. Tim Morgan has been installing EFI on marine motors for over a decade, but he's not cheap. He may be able to map the MEFI for me.

The 211 hull is probably one of the faster Nautique hulls, running the sport 13.5 x 17.5 prop. the boat went 47-48mph when new. Since then I have done lots to slow it down but it seems that it takes in the neighborhood of 350ft. lbs. of torque to keep the boat moving at top speed, maybe 375ft.lbs. with a barefooter. I had no issues with the performance once planed off with that prop. The problem was that it did have enough torque to plane off with that prop running a fully loaded boat. Now that I am running a 13.5 x 16 prop., pulling the weight of 130lbs of extra batteries, dragging the FAE through the water, and pushing a full compliment of tower accessories through the wind I am barely getting over 40 top speed and about 38 while footing (and it takes a fair bit of time to get there). When I run the taller props it doesn't want to get out of the water, when I run flatter props I run out of power up top. If I can fatten the 2500-3500rpm torque curve up this should allow me to run the taller prop and not run out of torque up top.

I have been living fairly content with my current situation for 5 years and almost 500 hours. Now I feel it's time to step things up so I can get excited about my boat again.

[TRBenj]

edit: re-read your post. You're goals are not that far off. I'd just do heads/cam/tune and be done with it. Should be an easy 75-100hp or more.

I agree that you can probably add 75+ hp to the Excal just by warming up the top end- but remember, that will come from increased breathing. This will push the powerband up, and while it may not adversely affect low RPM power, it probably wont do much, if anything, to improve it. He would still be running the shorter 16" prop to keep the holeshot he has- though the top end will improve.

Like I said, if you want to improve top end, low end AND run a steeper prop, stroker is the way to go! Even if you are able to keep the stock heads though, I would expect you would need a more aggressive cam to keep the top end power from falling off too early.

[TRDon]

Mikeski, I have a supercharged 95 mustang 5.0 that has 2 bolt mains that i have been running 13 lbs of boost through it for the last 5 years without incident in a nutoriously weak casting block. It is all in the tune when it is all done.

For the record, I told my tuner,"At the expence of horsepower, make it safe." I wa sleft with a car that makes 430 flywheel horsepower and 445 TQ that doesnt get treated nicely a lot of times, but like the boat, I am rediculous in my maintenence schedule.