ScarabMike

I wanted to get some feedback from the experts before I decide.

I have a 1997 31' Scarab with Stock 502MPI's. I purchased it last season from the original owner. There were some problems with the motors, so Merc replaced BOTH long block under wannantry last July.

Now that the warrenty has long since expired, I want to get some additional horsepower.

I was quoted Vortech centrifigul superchargers and Stainless marine exhaust system. I'm still running the original Bravo I drives with drive showers.

I know that I will eventually need to upgrade to XR drives for optimu reliability, but based on anyone's experience, can I get a season out of the Bravos?

I am pretty delicate with my boat and I make it a point to never come out of the hole hard. I like driving my boat, and as long as it's mechanically sound, I can drive it. that's pretty much my attituide and why I usually take it pretty easy and don't run it too hard. Of course, I open it up. I just don't overdo it.

Based on this info.
1) Do you think I can sqeeze a year out of my drives?
2) Is anyone else running this, or similar setup?
3) What kind of HP and/or speed increase can I expect with 5lbs boost.

FYI: unning about 73GPS now.

Thanks for the help.

Clay Washington

Well... you asked for opinions, so here they are...

If you are going to supercharge your engines, then I would HIGHLY recommend that you get Whipples. I have one on my (single engine) 502 and it ROCKS!.

Whipple gives you the low end torque that you need for a decent holeshot. When you add 50% more horsepower, you will need to add about 4 more inches of prop. Without huge low end torque, you will barely get out of the hole.

However, that huge low end torque comes at a price. I have broken my stock forward gear in my Bravo 3 twice! I now have an IMCO "Heavy Duty" forward gear, and it has lasted (so far).

How long the XR drives will last with supercharged engines will greatly depend on your driving style. If you ease the throttles forward, they will last longer than if you "slam" the throttles forward (like I used to do).

In any case, a 31-foot Scarab with supercharged 502's should be a nice "sleeper"!

Good luck!

ScarabMike

Clay,

Thanks for the info. When I asked my dealer about the Whipple chargers, he said that they have had more success (reliability?) with the Vortechs becuase of the fuel delivery system. If I remember correctly, 1 had a booster pump and one actually replaced the pump. I believe that Whipple had the booster pump and the fuel pressure ran very high. Good? Bad? I don't really know why this would be an issue.

I'm interested that you are running a Bravo 3. I had one on my last boat with a factory 7.4MPI and blew the gears also. Just a thought.

When I first got the boat, I would slam it out of the hole also. I was just loving that fact that I had a muscle boat that would get up and go so quickly. Well, a few repair bills, and a drive coupler later, I learner that it is much more fun to take it nice and easy out of the hole and enjoy the ride EVERY weekend.

I plan to upgrade to the XR drives, I just wasn't ready to do all the $$$ at once.

I'm still racking my brain over it.

Clay Washington

ScarabMike,

You Bravo 1's should last longer than my "stock" Bravo 3 did because a Bravo 1 has more slip than a Bravo 3. Even if you break the forward gear, you can buy a "heavy duty" gear to replace it. A gear is MUCH CHEAPER than an entire drive.

I would recommend that you find a mechanic that has experience with Whipples and do those now. Leave the outdrives alone (for now). If they break, then you can decide what to do.

However, with the additional horsepower, you may need to seriously consider getting hydrolic steering.

Good luck!

P.S. I have IMCO manifolds and they work well for my supercharged engine.

ScarabMike

Thanks for the info guys.
I'm going to do some more homework.

I'll report back.