tomcei

I just picked up a merc rev 4, 25 pitch and was comparing it to the bravo 1 26. The dia seems to be the same. Is that correct? And I wondered about the defuser ring area. It doesn't have the flair at the end like the bravo and is almost and inch longer. What's up with the longer straight area with out the flair?

Rebel_Heart

I'll be interested to hear the prop pros answer on this one. I have heard that the longer straight area has been used on other props for speed purposes?

Pat McPherson

Yes, I too would like to hear about the differences from our prop experts here on OSO.
The diameter of the Rev 4 is smaller than B1; ø14.625" vs. ø15.25".
I think the diffuser ring helps to keep the prop from blowing out coming on plane.
I can tell you the handling characteristics on my boat between the 2 props are vary different.
The B1 will provide more stern lift and the Rev 4 seems to lift the bow more similar to a M+.
Don't know if anyone has run a Rev 4 on a 28' Pantera.
I do know that they seem to work vary well on 24' Panteras and straight V 24' Supers.
As you know I had my B1 modified by BBlades for more bow lift and it works great now. I do like the Rev 4 better than a stock B1.

tomcei

It sure didn't look that much smaller than the b1, but that was just eyeballing it. The diffuser on the rev 4 is about an inch longer and has no flair that I can see. Wouldn't that help excelleration?

Pat McPherson

From what I gather the B1 with its larger diameter and availability in large pitch is meant more for the larger higher HP sport boats. The Rev 4 is meant for run-abouts and smaller sport boats.
As for the diffuser ring, it does definitely serve a purpose for better hole shot and acceleration. I have heard of removing them to gain speed and adding them on for hole shot.
Hey Brett and or Julie,
Please enlighten us...

throttleup

The diameter on the Rev 4 is 14 5/8" and on a Bravo I it is anywere from 14.75-15.00". Typically only the 32P, 34P and 36P have the full 15.25 diameter (occasionally I will get a large 15.25" 30P). So for all intensive purposes they are similar but thats were the similarities stop. The Rev 4 is a full lifting propeller and is actually advertised by Mercury as such. If you look at the shape of the baldes you will see a difference between the Bravo I and the Rev 4. Specific behavioral attributes though will vary from hull to hull though as you would expect. The diffuser rings have a little more extension tube on the if you will and effects your planning capabilities, it to is blade specific as to the length of the tube and flare.

tomcei

I'll let you know how it runs soon. I plan on testing the rev 4 tomorrow afternoon.

bbladesprops

Huh?

I have written a ton of stuff about the Revolution 4 in the past on this forum. If you are willing to page back you can find a ton of information.

Looking at the blades does invoke that there is a difference, but doesn't explain a thing. The geometry is completely different. In a nut shell, you'll have to come to my propeller class to get the long version, right Julie, just kidding, all in fun.

We developed the Rev 4 in the late 90's (is it that old?) as a 20 something foot boat under powered improve your performance all around prop. I know that sounds confusing but what I mean is.... Certain family boats needed a little help on the low end and in cruise areas, bow carry as well as not loosing top end. A 4 blade propeller was in order. The geometry worked great for those 350 mag boats and ultimately a ton of other applications including outboards. Without giving away certain secrets, it works.

You can't even put the 2 props in the same sentence. Everything about them is different. I wish we had 27 pitch Rev 4's. I've been campaigning for them for about 6 years.

Diffusers are another long topic, a really long topic. They can help a ton and hurt a little less. Call me, I can talk faster than I can type.

talon25

Trim her up Tom and let us know how she runs with the rev 4. Have fun!!!

Pat McPherson

Keep campaining, I want one...