Extension Box on a 27 Fever stepped hull
 

Has anyone tried extension box on a 27 or 29?? If so how did it work out?

anything to get the drive up would help . But it would be scarey w too much hp.

Yea just curious if anyone had some data of doing it. I am putting a -2 imco on the boat as I did some testing with one and without changing props it went the same speed but at a higher slip. I have to replace my drive so I am going to get a -2 with some spacers and see what works the best. But also considered an extension box as well. I bumped power over the winter, and looking into speed gains in efficiency, bottom, and drive line at this point.

If you can get it high enough to run a Maximus 5 blade or a herring. You will have much lower slip numbers that ever before. I am at about 11.5 ( different boat than my old 27). With the prop style I ran on my 27 i got 6800 rpm s at 83 mph. With the herring it's 98 mph at 5600. So gut your drive up. Contact Bblades and rent some props ;)

there is one that ran 104 at LOTO a couple years back. The center of his prop was even with the bottom of the boat. ( or close to that)

Looking like I'm probably going with an AADS phase 3 build with cryo'd XZ gears. I am going to stick with 4 blades, 5 blades are just too hard on bravo drives. That's crazy fast for a 27 fever lol. I am just curious if the extension box itself is worth any positive speed gains, or is there a better place to put the money

Not a stepped hull, but I beleive JimV is running one on his 27 with big power. Money is probably better spent on custom prop work.

I am going to play with the -2 imco, spacers, and then eventually prop work once I figure out where it likes the X dimension to be.

i have a 27 with a 800hp and a 27p 4 bade it starts chine walking hard in the low 80's had it up to 85 on friday but it was like glass on the lake any suggestions ?

What year is your 27?

96 step hull

Stock Drive height? what size are your tabs? What are your drive and tab settings?

stock drive height and stock tabs gonna go out today and play with the tabs and see what kind of results i get

counter steer

I have a 97 29fever stepped hull with a 735hp motor. The fastest I've been able to get it to is 78.9mph. Doesn't matter what prop I try that's the fastest I can get it to. I've tried a bravo 28, 30, and 32pitch prop. One hydro 29p but couldn't get on plane. How are you guys getting high 80's out of yours? Should I switch to a 5blade prop or have the 30p labbed? I get the exact came rpms and speed with all three props. 5400 rpms and between 78-79mph, 54oo is the where the rev limitier is set at.

TGM I've always questioned some numbers I've seen. I'm not sure if there was any change in the step from your 97 to my 08, but I think you should be well into the 80's for sure. I run legit right about where your at with light fuel and 2 people. 5 blades will get you out of the hole and better mid range, but you will loose some on the top end. I think something else is missing in your setup besides just the prop.

I don't have the answer. 28 to 32 and the same rpm is strange. you should have lost rpm. 4 to 6 hundred at least. What are you checking the speed with?

I would agree with Feverz29, the 29 single is should be very close to the same speeds with same power as the 27. I only have 7 hrs on mine, first 5 was taking it easy, I have hit 83 a few times at a clip, and I need to do some prop changing. Very weird about the props, you should see roughly a 400 rpm difference between those prop changes

Not no high jack this thread but I would do a seach on drive height. MY 98 29 Fever is 1 inch down from the newer Fevers. My had a 2 inch spacer when I bought mine. Imco shorty might be in your furture...

Im not sure I follow your post, are you saying yours was a stock drive with 2" spacer? What are you running now, as I am currently having a AADS phase 4 upper with imco -2 lower built for my 27

I removed the 2 inch drive spacer and gain 11MPH.. Original owner wanted better hole shot. Around 200ish they raised the drive height. They are faster with stock power. Do a seach and you will find what I am talking about..

Yea I know they raised the x in that year area. My question was what drive you removed the spacer from. So if I'm understanding you correctly you had stock length drive with a 2" spacer is that correct ?

Found this post like to see if there is anymore info on the my drive was 4 1/2 below the bottom put a -2 short things are better but not seeing the speed increase happen 2000 27 fever 600hp 5 blade px5 hydro 70 mph best

How many RPMs?
Stock 1.5 XR drive.
I'm right at 600 myself. Same prop. 28 pitch. 74 gps half tank and 4 people last weekend. 79 today by myself and 20 gallons 5100 RPMs.

http://i37.photobucket.com/albums/e6...psp4l7viw4.jpg

5300 rpm
Bravo 1.5
Px5 hydro
70 mph
Slip 13

Can't turn a 28 pitch it's nuts
The px5 is 24 pitch
Stock 26 bravo spun up to 5100 69 mph
Boat and motor like the 5 blade
24 bravo 1 5500 73 mph
Have tried a lot of combos i think my X factor I am still wetting the drive to much at 2 3/4 below bottom

i have a 93 27 ft fever, getting ready to drop a 540 in. goin to put a imco sc drive on it with a -2 imco lower. 1.5 ratio

what do you guys think would be a good starting point as far as props? and how do know when to put spacers in the drive?

try and bear with me very new to the performance side...

How much horsepower and how much torque you're max rpm you're looking for also

How far below the bottom of the boat is your outdrive

Can you send or post a pic I see you have a super charger thinking of a 250 want to see how close it is to the hatch and the front bulk head

Best I have on my phone right now. I can get more in a week or so. It's tight but clears. Flame arrestor is aftermarket. Barley clears with the intercooler.

http://i37.photobucket.com/albums/e6...psvh09eac9.jpg

I should have no issues then with a 250 from the blower shop what size is the carb and do you know how far below the bottom of the boat is your drive