I've been out prop testing about 6 different sets of props (bravos and maximus). The Maximus I ran seem great all around except I need a few more rpm's/ speed and a little more bow lift. These are 28 labbed maximus with the difuser ring still on them. If I have that cut off, what kind of additional rpm should I expect? How much effect of bow lift will it have?

2002 382 Formula
630hp, no boxes

I cant give you an idea on RPM's but I will tell you that you can get more bow lift, or I should say less stern lift if you cut the diffuser rings off. We have a couple sets of them and we have take a full inch off. You can see where they are welded on. We take them off right there.

If there is an issue, you can have them put back on too.

I haven't any experience with the Maximus, but tried taking the difuser ring off the P5X and couldn't get on plane. Had it welded back on and easy to plane.

Taking the difusser off ring can help with reducing stern lift therefore improving bow lift.

There is a long disertation as to the length of the dsiff. ring on a Max. Back space in this forum to see my explanation.

The weld you see is not due to welding on a stainless ring but due to the wax that creates the mold that creates the raw casting. The amount of the diff ring is also a fine tune on the Max props.

Removing the ring can bring up to 100 rpm+ or -.

Diameter adjustments can help too.

Let us know if you need help.

UPDATE....I might have F'ed up.


Cut the rings off........These things vibrate like hell getting on plane now. Seems to cavitate, blow out then hook up and go. Could removing that dam ring cause this????

At least you were able to get on plane! How was your top end affected?

The shaking is probably the cavitation,.. props slippage.