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"GOOD" things that happened to me over the weekend...

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#21 ·
It's to bad the season is almost over,my blowers get installed on the Dominator October 1st and it is getting winterized after a test run to get everything dialed in
on the motors,so I won't get much seat time till
next summer.
I can see it's going to be a long winter staring at the
boat in the garage!!!
 
#24 ·
Sorry to hear that Bayley:( had mine go after running her to long with a bad Impeller. Luckly I just broke 2 pistons, but while I had it apart, I had everything checked out. after 300+ hrs of being procharged at 6 lbs, I got a call from my engine builder that everything looked fantastic except for the 2 broken pistons!!!even the bearings looked like they came out of a truck with less than 10,000 miles. It didn't even need to be bored out.
So 2 pistons and a complete set of rings later. I was back on the water ;) I think you'll be very happy with a set of 502's. good luck :p:
 
#28 ·
Bayley sorry about the boat. I was really looking forward to the run. O well I guess it could of been worse....I made it out later in the day with a friend. After a long day/night of parting we left the beach grill and the single motor decided to take a dump on us. Ended up spending the night out there and getting a tow in the morning......2 broken boats for me in one day. Maybe I am bad luck.

Working on a ride for both of us to the moot now.
 
#29 ·
Dude! Sorry to hear it. I guess the stroke is the same with the 502's and 454's. That's why your re-using the crank and rod's.

Check some of those Mustang 5.0 Mags for some engine tips using Wipples. That exact charger you have made it's debut on 5.0 mustangs back in the early 90's. The only thing different would be how it is connected to the upper plunum.

Anyway, the 5.0 guys had the same exact problems the boat guys are having toyday back when they started bolting these things onto 5.0's. You would'nt believe the 1/4 mile times these guys where turning. About 2k got you into the 9's and 10's. The guys running turbo's got into the 7's at over 200 mph. So I know you can get some serious grunt out of those 502's with the right setup.

All of the guys I ran with preached low compression and ringed heads with high boost. There was also some very specific piston and ring setups too, some of which were specific to how much boost you intended to go with. Some of them used a very short pistion with a longer rod to reduce the overall weight of the piston/rod assembly. Very expensive but effective.

Good luck bro! I'm sure you'll be even harder to keep up with next year. :D
 
Discussion starter · #30 ·
Thanks for all the kind words guys (and gal).

Kanokster, I'm really hoping for the best when I tear things apart. Hopefully, I caught the problem early enough to where I didn't do any extra damage to the rotating assembly (could care less about the blocks right now).

Harddrive, I was always a believer that o-ringed heads and fancy-schmancy blower pistons were over kill for what I was trying to accomplish.

...I'm now a changed man.

I still don't think O-rings are absolutely necessary on anything 5 psi or less, but I'm a solid believer on a set of blower specific rings and pistons. Over this past week, I've spoken with a number of engine builders who have first hand seen the effects of supercharged Mer Cruiser engines. The stories I've gotten point directly to piston and ring failure. I seem to be on the "short" side of the life with a Supercharger. It sounds like most guys are getting about 400 - 500 hours before the rings / pistons start falling apart. I've yet to heard of a rod or crank failure on a MAG or HP500 motor with a blower of some sort running less than 7 psi of boost.

I'm obviously gonna have to have the heads inspected, and I am seriously considering having the head o-ringed and upping the boost to about 10 psi. My only concern at this point would be blower efficiency (can it push enough air?) I'm figuring a 502 with a healthy cam at 10 psi should be making around 750 - 800 hp. I've got all winter to do this, so I'll keep everyone up to date on the project.

-Bayley
 
#31 ·
Damn Baley, just when I think I would be able to keep up with you by next summer you have to go and throw a wrench in my plan's.
Well I guess next year will just be another summer of
looking at the back of your boat while I am chasing you
around the lake.
Oh well as long as my Dominator is in the 90's after I
install the blowers than I will be content.{For a while}
 
#32 ·
Bayley for those blowers to pump 10 psi, don't they have to turn twice as fast? Does that not scare you a little.

I' am afraid you are leaning more toward hp and away from reliability! 10psi seems like those blowers will be working awfully hard. With that much air compressed in the intake you may want to look at an air dump for deceleration and idling? But I don't know to much about blowers, yet!

Just thinking back to our conversation about throttle response with all that compressed air.

I am interested what you find when you open her up!
 
Discussion starter · #33 ·
At 7 psi on my 454, the blowers were just starting to get into the sweet spot. I'm thinking their shouldn't be any problems running at least 8 psi with this blower on a 502. I've talked with Dustin in the past, and he said this supercharger will start to run out of steam around 12 - 13 psi on a 502. I suppose I can find a compressor map for my specific blower somewhere, but I'm not too concerned.

As for idle dump, it's already got the blow off valve as part of kit. I don't think I'm really spinning the blower fast enough yet to require one, but it will be nice when I start increasing the boost some.

I'm sure I can bench build this motor until I'm blue in the face. However, the true test will come on dyno day. That's when all my bullschitting comes to a screeching halt!
 

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#34 ·
Bayley,
Sorry about your motors. It happend to friends of mine early in the season on LOTO. Good luck in your search. I will send you pics of my Labor Day trip across Lake Michigan from Fish Creek WI to Leland MI. Have you done Lake Superior yet? Next summer K-Man and I are trying to organize a trip to the Apostle Islands and possible Houghton/Hancock area. :D
 
#35 ·
Bayley, I find it interesting that the boost curve is has a flat spot around the 4200 to 4600 rpm range.

Doesn't that make you think that there is something beyond the throttle body that is controlling impacting that boost curve?

I don't believe it's the heads, most likely it's the upper intake. Has anyone ever sent an upper plenum out to be extrude honed? It has to raise the numbers on that boost curve.

Just a thought.
 
Discussion starter · #37 ·
Milord, it's 11:00 AM Monday morning and you're already coherent?!? Miracles can happen! :D Had a blast, got to get everyone together again some time soon.

Harddriver,
I've heard some "hub" about the intake manifolds on the MAG's being a little restrictive. I am guessing this is why Merc re-vamped the intake for the HP500 EFI series. It doesn't make sense for them to make an entirely separate manifold for such a small production line.

I'm not too concerned though, that's the beauty of forced induction. I might tackle the upper and lower with a dremel over the winter and try to open things up a bit, but extrude honing is not in the budget right now... unless someone has a little "business" they need taken care of for them. ;)

Also, I wouldn't take the dyno plot as gospel for what the blower actually does. It was a very quick run up and I'm not totally confident the engine was at WOT from 3800 to about 4500 rpm. The pull from 3800 to 5300 took about 2 or 3 seconds. Too fast in my opinion, but then, I wasn't the one running the dyno.

As for "catching" John (local guy with Whip'ed HP500 EFI's) I'll be happy if I simply keep up with him.

-B
 
#39 · (Edited)
Bayley, I strongly agree with you on the Not needing to "O" ring the heads. I use to do that myself,(on previous motors), even after being warned by my engine builder that it's not the way to go. But like everything else I had to learn the hard way :nono: He said it's cheaper to replace a blown head gasket, than a broken Piston,Rod, or crank. If your blowing head gaskets under 15 lbs of boost, your not setup right.(most common reason is detonation) and by putting ring groved heads, your just pushing the problem further into the engine. Instead of blowing a gasket, your breaking something else...My engine builder has built lots of Blower 502 engines pushing as much as 20+ lbs of boost, and when there set up right, they never blow head gaskets. Even my 502 at 6 lbs of boost after 300+ hrs the head gaskets look great.
Good luck with her, and it sounds like you got it figuered out good.
Claude
 
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harddrive
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