Prop selection for 29 NuEra
 

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

Could be prop slip but that lessens as speed increases- mine slips a bunch at lower RPM but hooks up and pulls hard when I rev it out

Sound like the guardian slipping - if that motors revving - it should be pulling like a mofo.

Hard to tell without feeling it before and after.


UD

Test result from some prop testing this weekend.

Bravo FS 29p 4 Blade - 4,000 RPM - 51mph 5,400 RPM Max- 79.8mph
Revolution 28P 5X 5 Blade - 4.000 RPM - 61mph! 5,200 RPM Max - 77mph

The good news is that I can spin a 29p 4 blade no problem. I will try a 30P 4 blade next and hopefully see 83mph. I did not have access to one this weekend.

I really, really, like the Revolution 28p 5X for the ocean. Easy to plane and the mid range efficiency is incredible. Since I will seldom see speeds over 75mph in the ocean I think I may opt for the 5blade in the ocean and have my current prop reshaped for a 30P for the river and lakes.

Whenever I would throttle down below 3,500 RPM on my current labbed 28 the boat would really slow down and I would have to throttle back up again. I think between the swells, weight of my boat, single engine and a Labbed prop I am having issues maintaining slower speeds in the ocean. The 5 Blade seems to hold steady and I should get a lot better gas mileage knowing my speeds increase by 20% at the same RPM. I know a 5 Blade is very hard on a Bravo but I think if I am easy on the stick I should be fine. This is where the drive guardian should work well.

51 is not bad- 61 is really moving in the ocean - how does that setup work at 3500/3700 when pulling up a swell?

Did your rig pick up any MPH with the new setup?

UD

I was off on the 61mph statement. The 5 Blade I ended up purchasing was a Hydromotive 28P P-5X and it gets me to 56 at 4,000 RPM. At 3,000 RPM I am at 36mph. In regards to swells or snotty conditions I have not had the opportunity yet.

I was able to pickup 3mph with a 29P 4 Blade at 5,400RPM. I need to test a 30P 4 Blade next and I am hoping to reach 83mph. I choose the 5 Blade for now since it increased my Mid Range and I am hoping I can run the boat on plane at 3,500 RPM vs. falling off plane in the swells.

Late to the party!
 

Yes I am late but wanted to put my two cents in. I have had just about every prop on my 29. Merc lab four blade 26pitch, Gibbs 28 bravo 1 lab, 30 pitch Merc lab, Hydromotive P5X 25 pitch stock and have settled on 26 pitch Hydromotive P5X five blade lab. I recently moved from high elevation to Las Vegas and the below numbers were at Lake Mead or Mohave. My power is 565 cubic inch naturally aspirated estimated 700hp.

Numbers on my 29 went like this; 25 P5X (stock) lowest slip number at 9.87% 80mph 5600 rpm

26 Merc lab four blade bad porpoise at 80mph and probably was the fastest prop just never pushed it (5800 against my rev limiter)

28 Gibbs Merc four blade lab 80 mph slip was around 13.65 if I remember right check bblades slip calc that's what I use 28 true pitch 5600rpm

30 Merc lab 78 mph 5100 rpms just too much prop for my power but cruise speeds were very cool

26 P5X lab 10.78% slip at 82mph 5800 rpm (raised the limiter) My favorite prop on the 29 nu era (lake Mead).

I have bought a IMCO SC Lower to put on the boat in hopes of seeing 85 but will not know till spring. Also your AFR @ 12.75/1 is very close to lean probably makes great power and may be fine. If your O2 is in the tail pipe, fuel could be burning in the header and giving you a close but not perfect reading. Run the boat at WOT shut it down and pull the 7 and 8 plugs to make sure they have color. 11.8 to 12.5 would be safer (true readings). I have seen lean numbers on the tail pipe only to find the plugs to be fat. Always best to check both. Late timing can cause the fuel to burn in the tails. You should be around 30 to 32 total and be safe. 34 may find you more power but pull plugs.

Hopefully this will help. Love my 29!

Fastboatfella, how did your SC lower work out........ new favorite prop with the new lower?

Sorry for the delay in the answer to your question! Never did get it done, still sitting in the garage! We bought a foreclosure property close to Lake Mead in April, and have had to spend money there instead. Looks like a winter project at this point, the IMCO lower has 1.36 gears and I need 1.50 gears to make it apple's to apple's. We have been boating, but with the merc xr lower at this point. Still running the 26 pitch lab Hydromotive five blade, works very well. Further complicating things I took a position running the largest air-conditioning company in Las Vegas last March that has sucked the life out of me! LOL!