Whipples on 6.2 MPIs & Bravo One
 

I'm very close to pulling out the credit card and buying a pair of Wihpple SCs for my 2003 Formula 292, and have afew questions for anyone with insight on this topic:

Right now the twin SB motors have 190 hours on them. Whipple says with mild boost (I'm thinking no more than 5-6 lbs.) and the addition of oil coolers, I should be able to get 500 hours out of the engines before tear down is required. Also said that the stock manifolds with thru-transom exhaust will be sufficient, not alot of gain to be had with aftermarket exhaust such as the CMI E-Tops, etc.(I said huh?).

I'm targeting 450 HP per side, up from the stock 320. Running stock Bravo One drives with the 1.65 gear ratio. Boat weighs about 7000 lbs. dry

Questions:

-Are the above expections for power and longevity reasonable, assuming correct maintenance (and no abuse)?

-Has anyone on the board Whipple'd a 6.2 MPI? Are there weak points anywhere in the internals that needed replacement either during install or soon after?

-Will the stock Bravo One be an issue? What about the gear ratio of 1.65, will I need to move down?

-I think I can Whipple both engines for a total of about $15,000, add another $6-8k if I need exhaust. Have no idea what gear changes in the drives would cost if I need them. If I grenade one or both of the B1s, things start getting really expensive, and the boat stays dry for a while.

-The really big question: I like my 292 for a lot of reasons, but wonder if I may not be putting too much time and money into trying to make this a 90 MPH boat, which could end up being potentially unreliable and without a lot of resale value. Has anyone else gone down this path and ended up wishing they'd just moved into a bigger boat with big block power and XR or better drives?

Thanks.

I believe that SPECTRAS ONLY has the same set up that you're looking to do. I'm sure that he can give some advice on the topic. The Bravos should hold up well. Even though you are going to make some good power, tha bravo will handle the amount of torque the small blocks will make. A good exhaust will always help a blower motor, but you may get away with stainless CMI tops with a through hull set up.


Darrell.

:I was going to do the same to my boat when I had the 6.2's. Got talked out of it by many people. Sold 6.2's and bought a set of blower motors. :cool-smiley-011: Best thing I could have ever done. You should be able to get decent $ for the small blocks. Went from 70mph to 90mph. You will most likely have to change gears if you get close to the 500hp range.
Jamie

Take the small blocks out, you can buy a set of used 496HO for aprox $20 000.00 (there is a set in the classifieds now) . Run them with your Bravos. Should have no issued with the drives. Relativly small boat for two bravo's to push, they won't be working hard. Then if when you sell, throw the small blocks back in, or sell the small blocks to help pay for the 496's.

Just idea. Don't get me wrong, I love my Whipple, but for the hp your looking for, I'd give some big blocks some thought.

If you do it the bravos should be fine....BBC putting out 500HP run with regular bravos regularly. You'll probably go from 28 to 32 pitch props if you keep the same gear ratio......not ideal, but acceptable. Swapping to BBC motors would be the easiest/cheapest but can you stuff them in there? That boat was built for SBC and may not be spaced properly for BBC. Also, your boat barely hits 70....the addl. HP will get you past 80 but probably nowhere near 90. and with any upgrade....if your going to keep the boat for 3-4 years or more then do it, if not.....then don't.

Formula has never offered big blocks in the 292, and it would be a very tight squeeze - Not alot of room to work in the bilge as is, so in that hull it is going to have to stay mouse-motor powered.

As for top-end once Whippled...I wish I had a crystal ball on that one! Mid-80s would be acceptable, but 90 is what I'm shooting for.

Your boat is 8 ft 3 inches wide just like mine.......I have (2) 540's stuffed in there, don't tell me about tight!!!! :D As for speed predictions...I added about 130HP per side and gained 10 mph over the stock set-up. Whipples would add about 130 it appears which should be about 10 mph in my book. SBC can be done, but will have to be built from the bottom up and VERY STRONG to get your boat to 90 (just my $.02). Adding 5+ lbs of boost to a stock motor WILL cause you to build a better bottom end sooner vs. later.

Hmmm...I really like the V-Bottom for those rough days in SF Bay or when I'm outside the Golden Gate, but if I want speed for (relatively) cheap, I may have to go cat...

I did a search for SPRETA ONLY to send him a PM but the search function came up with nada. Hopefully he'll see this and respond to relate his experience with SCing the twin 6.2 setup.

Rob:
Be careful with this idea. The 6.2's have been troublesome when they are stock and naturally aspired. A forced induction set-up could easily push them over the edge very soon. I wasn't aware Formula never offered the 292 with big block power. That could be inaccurate.
With the additional horsepower you can go to a 1.50:1 ratio and have a better propeller selection. Make sure your Bravos have the latest gear sets available from MerCruiser. Good luck.

I understand that the 292 twin stepped hull was designed specifically for the weight of small block. Putting big blocks in there would move the CG back and be ass heavy. Remember, it really has only around 27 feet of running surface...