Prop Slip On my 280
 

As some of you know im having major prop slip issues with my newley procharged 280. The guys at BBLADES sent me a 30p B1 to test and i only saw 73mph at 5200. That puts me at 26% prop slip. Thay told me the ideal % is 12%. With that I should be running 87mph. Brad and Brett gave me 2 options. try a "bigger" drive spacer than i already have. "i already have a 1" Or thay want to send me a 29p Hydromotive P5 5 blade cleaver prop. So I guess were gonna test the P5 first and see what happens. The only bad thing about that is the Hydromotive prop is over $1100 with out labbing and the B1 was $550...OUCH!!! Ill keep ya posted on the results.

I personally would drop the drive down deeper and stick with a B1 prop. I think your drive would live longer once you get the slip numbers where you want them. Also, given the HP a little extra slip isn't necessarily a bad thing. 15% might be a happy medium.

Is the 280's transom notched? Anyone ever try a neutral or drop box on a 280?

The transom is notched.

i haven't fully tested my laser yet...im curious to compare my results to yours...

I put a 1" spacer on and got down to 20% on a labbed 26 from bblades. We are still working on getting the slip down without reducing the rpm. Were you on the limiter running the 30P? Brett told me it might be better to have slip than to reduce the RPM. After blowing through 35 gallons of fuel on Sunday trying to get my top speed dialed in I have decided to focus more on cruising speed than top speed. My problem is too much weight on the boat. I refuse to offload the cooler, beer, amps, subs, microwave,margarita machine, fridge, a/c, anchor, etc to achieve a top speed.

Ill know who to tie up to for a floating wet bar. .

Love your thinking!:drink:

I already have a 1"spacer so i may be able to lower the gimble via the noched transom to get a lower X dimension. And i was right on the edge of the rev limiter

Tested a different prop yesterday from BBlades. It was a hydromotive P5 X five blade 29p 15" diameter. My top speed stayed the same at 73mph and i droped 200 rpm to 5000. That calculates down to 20% slip. Im still way off from where i want to be. I need 7 mph to be happy with this procharger purchace.

Where is your propshaft centerline in relation to the hull (not at the notch)? How deep is the notch at the transom?

Couldnt tell ya? Where do i measure from and at what trim height do i measure the prop at? All the way down i assume?? And what do you mean by ( how deep is the notch at the transom??)

Brad had me measure my X dimension. Its 5 1/2". He told me it needs to be atleast a half to 1 imch lower. So i guess i have to find a way to lower my prop height???? Any suggestions?

Have the drive to where the propshaft is level and take a long straightedge from the hull out to the drive. Measure down from the straightedge to the propshaft centerline. Brett at BBlades will want to know that number. Since it has a notched transom, I'm just curious how deep it is and how far it extends. I find it odd PQ was so far off on the transom cutout from the factory and that these boats run better with spacers. The purpose of the notch is to allow you to run the drives higher up, reducing drag. The notch feeds water up to the prop. If you have to bury the drive to get the slip numbers down, you have to wonder if the notch design is just plain off. Makes me wonder how these hulls would react to an extension box. I'm just afraid that if you drop the drive to where your slip numbers are good the drag will negate any gains and the speed won't increase. Just spitballing here...I'm definitely no expert.

All that makes sence. by lowering the prop it would put more out drive under water causing more drag. I know there is a way to tune this set up to get my slip # down. Bob280 ran 80 with the same HP and same boat. His was NA instead of blown. only diff.

with the numbers that bob gave me. i pluged them in and he was getting 16% prop slip. So i know its possible.

PQ did ALOT of playing around with X-dim on the 280's. Most run much better with a 1"-2" spacer. Thus I am not surprised on the numbers the OP is getting. Drop it down another inch!

If you already have a 1" spacer, you can a second 1" spacer to make 2" or remove the 1" and add a 2". Are you running a stock lower or IMCO/Speedmaster?

I agree. Drop it down and see what you get.

Ive got it Josh... the solution to all of your prop slip issues... and your fuel and noise issues too!!!
http://i53.photobucket.com/albums/g4...62_300X300.jpg

2 paddles would work much better, assuming the old lady would help

Lol. Good ****.