HP500EFI and Whipples: Change gears or props, or both?
 

Running HP500EFI's and Bravo-1 28's on a Formula 382. Would I have to change the gears, the prop pitch or both? (XZ drives)

Stick with 1.50 gears and try 32P props, If not enough prop try a 5 blade hydromotive prop. or herring. I had problems with a similar size boat and the 1.36 gears.

I agree with Ray, I would stick with the 1.5's and run 32's or better yet, 30 Heiring 5 blade props. The Heirings have been working incredibly well in the applications that I've seen and its very possible that your Formula would react well to them, especially if you go with Imco shorties, but stick with the 1.5's.

Ideal world is to put 2" shorties with Heiring 30 or 31 5 blades, I bet it would be a rocket. The SC will make plenty of power to get the boat on plane, so typically most OEM boaters go with a conservative X dimension (most, not all :D) so they plane with stock power, but with the SC, different ball game, typically a higher X and then the 5 blade really becomes effective vs. the 4 blade bravo one. Most of the Formula's I've seen have had a conservative X dimension but a good hull, so something like that may be worth look into.

Thanks,
Dustin

JUST RUN IT,THEN FIGURE OUT WHAT YOU NEED BECAUSE YOU WILL NOW HAVE A GOAL.

I have a 35 twin step Fountain, whippled EFI's. I am running Imco SC's with standard length gearcase. They have 1.34 gears, and I run 28 4 Blade Hydro's. Your 38 is alot bigger boat, and heavier. I would stay with 1.5 gears. They are supposed to be faster as it takes less HP to turn the props. I was at 36 pitch bravo 1's and had alot of stern lift. I changed gears to give me more prop selections.
Randy

The 2" shorties..........is that just the lower part of the drive, or do you have to change out the whole drive to IMCO?

Just the lower part.

As another reference,
Went from running Bravo I 28's at 4900 RPM before the Whipples, to Bravo I 32's at 5100 RPM afterwards. From everything I've read or heard about, it seems people have had best results swinging larger props at slower speeds (i.e. big pitch props with 1.5 gears).

-Bayley

What's the price for 2 of the new type, and what would be either the total hours needed, or what should I expect to pay for total turn-key installation including sea strainers?

I think the new type are about 7500 each, Guessing 20K - 25K +-. It depends on how much rigging it needs. Do you have low water pick ups? You will need them too or an external pickup for each engine.