So I finally got my rebuild single application 575sci with Teague 700HP intercooler kit installed in the boat with about 7 hours on the new motor. I spared no expense when doing this rebuild and so far things are running well. Unfortunately I am still running my same 28p Labbed Bravo one prop and since I only gained about 400RPM at 7lbs of boost I only gained about 1mph. Based on a theoretical HP of 700hp am I being over optimistic by thinking I can spin a regular or labbed 30p? What are other 29 NuEra owners with a similar power package running for props and what are your top speeds? Also based upon my Air/Fuel Wide Band gauge, I recently installed, I am reading about 12.75 at top speed. Does this sound too rich or too lean?

In regards to my Bravo One/XR, I am very aware of this weakest link. One of the other parts that I upgraded was the stock Merc Flywheel Coupler with a Marine Design Group, Drive Guardian. I am very easy on the stick while getting up to speed but the Drive Guardian is suppose to eliminate a lot of the Torque spikes from outdrive abuse on the Ocean. I am keeping my fingers crossed. Several Race Teams have had a lot of success with the Drive Guardian on their Bravo outdrives.

So I guess my Post either made no sense or no one with a 29 NuEra has this info for me?

Did your reply pm.
There are not that many 29's in existence..... less where people have what you had....and doing what you are doing...... try a stock 28. I think 30 4 blade was too much. I hear Maximus works well with the 29. That prop was not yet around in very early 2000 so I'm only going on what I hear.

Jim,

A little more info on your current speed and rpm would be needed to determine if you could spin a bigger prop. We built a 29 NuEra mid cabin with a Merc 600 and if my memory is correct that boat either ran a 30 or 28 maximus and ran in the high 80's.
Do you pull the 28 to redline? If so, how quick does it achieve that rpm? Another thing to think about, generally out in the ocean in my experience most boats are able to spin one pitch higher than it would in fresh water. I would NOT run a maximus with your current outdrive. You will blow up the bravo very fast out in the ocean even with that drive guardian.

Diff boat but the biggest wheel I usually run is a 28, but I can spin it to 6K and hold that. Its a dog out of the box loaded up though - your blower mills pulls harder at the low end than my mill.

Ive pulled a 30 maximus but it was also in freezing temps and even then it was too much wheel.

Your rig oughta pull like a bastard now Jimmy.

Id have somebody work on a 28 and see of they can add a bit of pitch to make you a 29 lab - might be the optimum wheel for you.

I might actually do that myself.

I think going to a 5 blade the ocean is too much grip an JR is right, but the drive guardian is a new deal for most and Im eager to see how it works out.



UD

Lavey jr
I have never been able to go more than 76, until the new engine. I gained 400 RPM and my max is 77 mph. These speeds were based on the labbed 28 I got with the boat. The max RPM was 5100 before the new motor. So now my max is 5500. I believe I am getting to much prop slip.

UD,
If I punch it the motor will scream but I can not feel it. I think I am getting to much prop slip. I may send my labbes 28 to bblades to get reworked. Any advice on any other prop shops?

How quick does the engine spin the 28 to 5500 RPM? With the numbers you gave, you are around 20-21% slip which is pretty high. You said when you punch it, the RPM's scream but don't feel the boat go. The reason for that is your high slip numbers. A good start would be to get your prop worked on and add some cup to it going up at least 1 pitch OR if possible try and borrow a 30 bravo 1 lab.

Your all around numbers will get better if you went with a 5 blade. BUT there are many negatives to doing this running the out drive you have, engine HP especially being supercharged, and running primarily in the ocean...

Different boat but just some numbers to put out there... 2750 NuEra with Ilmor 710, Teauge Platinum Bravo 1, and A LOT of accessories making it a pretty heavy 2750.
I've been in this boat in many different scenarios. Near freezing temperatures, 90+ degree Lake Havasu, and out in the ocean on an average day. Here are the results...

Freezing lake day - 93 MPH spinning a Maximus 30 lab to 6000 RPM. Equates to 17% slip.
Hot Lake Havasu - 75 MPH spinning a bravo 1 28 lab to 6000 RPM. Slip 29%...
Average ocean day - 80 MPH spinning a bravo 1 28 lab (possibly worked to a 29 I'm not sure) to 5700 RPM (water conditions didn't allow for max RPM). Slip 20%.

Those numbers are very different with very different conditions. It's hard to give a perfect answer to you setup needs but it is safe to say you need to go up in pitch. If you can currently achieve your 5500 RPM number pretty quick out in the ocean then I feel you can spin a bravo 1 30 lab. I hope some of this helps.

"If I punch it the motor will scream but I can not feel it."
If the drive Guardian is fresh to the mix, is it possible some of the slip is coming from it? I know they are settable and that would be suspicious to me. It would be interesting to know how it was set and by whom...
Generally speaking, unless you have changed prop or drive height, prop slip at higher speeds should be similar to pre I/C installation.
Mine is a totally different boat but I have been running a BBlades labbed 27P Hydromotive P5X and slip is below 15% above 70MPH. Running Imco -2 shorty so slip is higher than I like at lower speeds but that is the price you pay:-)

Interested to hear what you learn...
-Paul

PS. Oh, forgot to ask - Did you add a transom mounted water pick-up for the I/C? just to be sure it is not interfering with flow across the prop. I have heard of this causing substantial problems....

Thanks everyone. I am going to borrow or rent a 30p bravo as a starting point. If I am reaching 5200 rpm then I may get it Labbed to hopefully get closer to 5,400 rpm. If not I will try a 29p