Nose Cone Bravo 1 ?
 

I was thinking about putting a nose cone on my Bravo 1, I was wondering if I will gain any speed with this mod. My boat is a 1999 22ZX Donzi with a 454MAG EFI that currently runs 74.1 on GPS. What is best model to buy? Will it hurt performance? My boat is a stepped hull boat, and I have heard that nose cones dont help if you do not run over 80mph. I have a friend that ownes a welding company and he will do it for free. Any info will be helpful.

DON'T do it...you will go slower!...or worse yet, mess up your drive case!

I agree with Audacity, but you could still try one out. Just epoxy one on ( do not weld it ) and smooth out the margins with a little body putty. This way if you do not realize any gains then you can remove it with a little heat and repaint your drive. Try Precision Mfg. and Sales Co, Inc. 800-237-5947. They have one that is not as aggressive as others and sells for about $70.00.

a few years ago i did a test with 3 different ones....what a pain in my arse!..in the end,,,they all came off....spend your time in other areas look'n for speed!...merc does do their homework.

I agree,,, leave it alone !!!!!!!!!!

I tried one about six years ago on a FourWinns Liberator. No increase in speed , but it did improve handling in tight turns. Before the nose cone , in a tight turn , my prop would lose its bite.:( After the nosecone it could almost turn like a jet ski...well almost:rolleyes:

Nose Cone
 

I would avoid adding the nose cone. If you have it welded on, you must have the drive completely disassembled (so as to avoid damaging the seals/other components with heat), and there will be no tuning back, for what are likely to be little or no benefits.

If you epoxy it on, (to do it right you'd have to grind paint off to the bare aluminum) I don't care what kind of heat you use, you're gonna have an absolute nightmare getting it back off, not to mention you'll never get the drive refinished to factory original.

What you've heard about the 80mph mark is usually right. The likelihood of any benefits below that speed are slim to none, and you probably won't gain any MPH by adding the cone. The main reason for a nose-cone (or any "crescent-leading-edge" lower unit) is to minimize "blow-out", where the prop could cavitate at 80 or higher MPH. On some outboards, a cone might be necessary to raise the engine and still grab cooling water, but you'll never have to worry about that.

Don't screw up a perfectly good drive that Mercruiser spent millions to design.

You money would be better spent under the hatch somewhere if you're that compelled to tinker.

Good luck.

hey audacity,
 

Being a racer, what do you see in the different classes, as far as cones. I only know the basics concerning the factory classes, but someone told me that the F1 & F2 classes cannot run them and do fine at speeds well over 80 mph. Can you enlighten us on this??

that is correct...anctually it there are some theads on dialing in JAZ's new 37 AT at 107....with production merc drives. like i stated there are far better areas to spend your time find'n speed than on the low case on anything run'n under 95.....as you know F2 and F1 have a lot of restrictions in the APBA. i'm really not for sure about the SBI, i have not read their rule book.

stay away from the cones unless your going to use a shorter gearcase such as imco,been taken a bunch off lately,seen as much as a 6 mile an hour gain,work on your prop....shorten the diameter,thin the blades,etc....have it labbed....more speed there.....Joey i dont think your aloud anything but stock cases in SBI either.....unless you get into A or B and they usually use something like speedmasters or imcos cases......

I added a Hydramotive nose cone to a early Bravo drive. I don't think it is hurting anything, but I don't think it is helping either. It is epoxyed on and I took great care to do it correctly. If I want to remove this thing, what is the proceedure using heat? That seems like it could be kinda touchy.

I thought that the cones were more effective on the pre 1990 Bravos. Isn't the gearcase shorter on the 1988 and 1989?

I am running 89 bravos on a cigarette bullet. about 650 per engine and boat was dying at 75. talked to hydromotive and put a set of their cones on and have seen 82 to date and still need to get the props labbed to get another 300rpm to maximize the power. i am happy! but i did learn that the 89 bravos had a blunter nose than the newer ones and that was alot of my problem. i am now thinking about the imco 2" shorties.......anybody know of any good deals out there???

yes,I might.....at least one complete,maybe two,if not can build a second one for you

Yes, the 88, 89 and some early 90 Bravos have a shorter torpedo and benefit from a nose cone above 60. Its all about aspect ratio and clean water to the prop. I dont remember his name but the guy I talked to at Hydromotive years ago was a wealth of knowledge on this subject.

Offshore: check and see if you have the stuff to provide a pair for me! would like to know about em. you can catch me today on my cell. 912-313-8686 after 10. thanks....Russ

Unfortunately, I did a dumb ass thing. I installed the nose cone over the winter, and at the same time made some significate engine changes. So, I don't have a direct A,B, comparison on the performance of the nose cone. However, since I am not getting the performance out the the changes I had hoped, I was trying to blame the changes on adding the nose cone. I have heard from many sources that adding the cone is beneficial on the early drives.

I had a single running near 70 with an early drive and put a hydromotive cone on it. I used a CMM to make sure the tip was in line with the prop shaft when I did it. Was good for about 2 mph but the handling and steering improved significantly. Not sure if I want to try it on my twins now. Many other areas requiring my time and money.

formula31
 

what is a CMM?

Coordinates Measuring Machine. Its a big expensive 3 axis computer run piece of equipment that bigger machine shops would have to measure geometric shapes. Theres easier ways to do it, I just had this at my disposal when I did it.