Shorter lower drive units
 

Does anyone have any experience with adding shorter Bravo lower units to a 32 in order to raise the X dimension? I have been advised not to add any more power to my engines (600) while retaining Bravo One drives. I really don't want the additional expense of moving to heavier duty equipment (speedmasters etc.) in order to add more HP, but wouldn't mind a few additional mph's if simply installing shorter outdrives will accomplish it. How will this effect planing? I know it will be worse but I wonder how much worse. How much more top end?

Curt, I have the same boat and was wondering the same thing, also how would boxes work on a 32

Regarding the boxes, I had it pointed out to me by an APBA racer that Reggie built "an extention box effect" into the back of the transom from the factory. Take a close look at your transom beneath the swim platform. You will notice that the drive housing sits about a foot behind the bottom of the "runing surface" or pad. I had never thought of it that way but that is exactly what the extention boxes are designed to do...move the drives away from the back of the running surface. So based on that he told me that I would be wasting money on boxes. Leave it to Reggie, he knows all the tricks!:p

[QUOTE]Originally posted by Curt
. Take a close look at your transom beneath the swim platform. You will notice that the drive housing sits about a foot behind the bottom of the "runing surface" or pad. I had never thought of it that way but that is exactly what the extention boxes are designed to do...move the drives away from the back of the running surface.

The technical term for this trick is known as a "notched transom"

Their is MPH to be had their. It is just what you are willing to trade for it. Dustin Whipple gave me the name of a dealer that put 1 in shorter lowers on his 35. Boat ran 3-4 mph faster, but was harder to get on plane, especially with a load, fuel, people, ect. Benny Robertson, when he was still with Fountain, said 2 in shorter lowers and 5 blade Hydromotives was worth 4-6 MPH on my 35 twin step. Never tried out his advise, and he isn't with Fountain anymore. The less drag the faster speed, but it can really be expensive and time consuming testing props. If their was someone with a proven combination it would sure make things easier.

Beak Boater, that's exactly what I am hoping someone will provide here. A proven combinaton that works. I've been through a God awful number of trials and tribulations with engine parts and props already. Hell I could write a book. I really don't want to purchase shorties and then find out I can't plane off with me and a beer cooler on board! It's hard to imagine that 1 or 2 inches can make that much difference. Where did Benny Robertson go?


Hey twinn29, I knew there was a term for that "trick" but I could not remember it for the life of me when I was posting. Thanks for the refresher.

Beak Boater,

Gator One has run -2 sportmasters on his 35 with different gear ratios and several different props. He would be a good person to talk to about results.

Curt

I have the 2" shorter sportmasters on my lightning and they made a difference in performance and handling.

Step have you been able to try yours

What was the increase in performance.

Gatorone,

Haven't put sportmasters on the boat yet. Bought new XR uppers to mate them to, so I'll be swapping out whole drives. I have to change the gimbal bearings, boot sleeves, and insert trim limiters in the trim cylinders. (converting from upgraded Bravos to XRs).
What props did you end up running? I've had a couple people tell me to try Herrings; good out-of-hole, good cruise, and minimal top end loss. Did you try these?

Step

[QUOTE]Originally posted by GATORONE
[B]Curt

I have the 2" shorter sportmasters on my lightning and they made a difference in performance and handling.


Gator One, what did you gain? How much effect on planing. Where did you buy the shorties? What was the entire cost of everything associated with them...drive housings, gears, lower shaft, props etc.? Did you even have to change props? This is the last performance item I am considering for my rig so this is important! :D The end is near.:drool: :drool:

Curt,

So your keeping the Fountain going even with the water down;) Maybe this summer you will have to visit Smith Mountain Lake, we have plenty of room and our water is up (at least for now)

Will Murray:p

Hey Will, screw the water, they can't run me out of town! There is still a ton of water in the lake, it just isn't at anyone's dock. So dock hopping is out for a couple of years but throwing it in and tying up out in the middle should be the same as always. Most of the marinas are extending their docks and ramps to accomodate. I will miss going house to house but you have to learn to adapt. We do plan on taking some road trips this summer somewhere. Smith Mountain might be a destination. How far of a pull is it from Lake Murray? And by the ay why do y0ou give a tinkers damn about Smith Mountain anymore? You are in boaters heaven now!:cool:

It is very nice in South FL, however on my budget I need a place on the water before I can afford to have the Fountain here. Dry storage for it is almost as much as rent:eek: Looked into trailering it, but I would rather save and wait. Plus I may be moving again:D

Will

[QUOTE]Originally posted by Curt
[B]
Curt, I picked up around 4 mph,as far as getting on plane I don't have any problems with stock five blades or four blades with a lot of cup. My X is 21and7/8 from the notch and 29 and 7/8 from the V. The lower units retail for about $6200 each but you should be able to pick them up for around $4500 each. I did change props during testing since I added whipple coolers two weeks later. Your props should be ok as long as they can take some more cup. As far as changing anything I did not have too because they mate up with my XR uppers. They also add a great deal of stability at full throttle. As for my set up I am running 36 bravos and beating the hell out of the rev limiters at 5600 and running 105 on the GPS. The boats leaving to go to Fountain next week to get the props dialed in and the bottom blue printed. By the way I was at the Lake Murray poker run last year.

Curt,

Do you ever give up?

Dave

Gator One, I remeber you I think. Didn't you and your wife tie up to a bunch of us in the "hole" for a while? You have a brand new looking 35 if I recall correctly. Nice boat! Thanks for the advice. I may end up having to change props if I do this because I am already at 5600-5800 rpm at 88.4 gps. I think I will have to up the pitch if it picks it up as much on mine as it did on yours. I would just like to peg 90 mph one time...or maybe twenty times:p since I am sooo damn close now.

NO!;)

Seriously, I think after this; if I do it, I will be done. Tyler did call me Saturday night to tell me about a carb spacer that dyno's 20 to 40 more hp just by bolting it on. He is going to ship me a couple soon to try. What the hell, that's an easy one.

ttt
Come on guys, surely someone with a 32 has tried this before. Any help would be appreciated. I get so tired of experimenting and emptying my wallet in the process. God, I could write a book on the parts added that were simply money wasted. It drives me absolutely :crazy:

Curt,

If you don't mind sharing, which carb spacer is Tyler referring to?

Thats a good increase in HP for just a spacer.

Mark

Yea it's hard to believe. Tyler Crockett is developing them now. He said he dyno'd one on the "Grumpy old Men" race boat and got 40hp and then he dyno'd one on a 502 non race boat and got 20hp. He will be marketing them soon.

Curt,

Thanks for shareing.

Interesting that he is doing his own. Wonder if it is similiar to the "Super Sucker" by High Velocity Heads?

Any more info? Price est.?

Mark

Don't know Mark. Call Tyler Crockett at Crockett Marine Engines at 810-324-2720. He can give you more detail than I can. All I know is they are still in the developmental stage.

Anyone...anyone????:)

ttt.
Anyone else with experience with shorter drives on a non stepped 32?