Can i gain more speed using a different props? 525hp trs drives mirage 25s spinning 5200 rpms 73mph all day with 4 people coolers 1/4 tank of gas???

I believe the correct Lab recipe done to the existing propellers could gain you about 2 mph. This is if the engines will be fine running at 5400. And depending on the current condition of the 25 Mirages. Are the props the + series?

Brett

Drives are the problem. It's not a race boat, have to question if labbing is really worth it?

I don't seet he drives to be a problem with only 11% slip.

We Lab more propellers for pleasure boats than race boats with great results.

Labbing the props is a $750 investment that could reap .5-3 mph. How much will it cost to make drive changes or engine enhancement to get the same results?

I don't know. But I do see potential in Labbing the props. Again, depending on their current status.

Brett

No question labbing works. Those drives have a lot of drag. Although not cheap a different drive pkg would wake it up. Jmho

My experience with a '87 30' Scarab was labbing helped. Brett, could you just a little more cup, drop the slip to 9% and stay closer to the current RPM?
PG, keep the cooler, drop two friends and you could make 75-76 MPH

No there not plus's but the drive do have bullets. The previous owner told me the boat ran 80 mph. The best I've been was 75 with 2 people 1/4 tank of gas 5200-5300 rpm. there are a few little nicks and dings in the props. I'm not sure if the prop's we ever worked. I dont even know the correct trim angle i run it about 6 on the drives and 1-3 on the tabs. Is there a way to tell if the prop's have been worked?

Seems like alot of trim. The prop will usually have a sharpened edge due to blade thinning and you may see some evidence of machining. Maybe a prop with a bit more bow lift may prove some gain.

pg, do you have the SS Alpha drives? These do have a little more drag if mounted low.


E572, welcome to the board. I assume you have an Eliminator? What props are you running?


Sharpened edges are a common way to tell if the props have been worked in one or another way. This is not a Lab Finished stamp however. Machining marks would be interesting and I love to see them. (ugly)

Labbing correctly, will add the bow lift you need. As far as trim angle, some boats need more trim to actually reach their potential. Less trim needed using prop geometry to create trim can actually supply less performance. I guess what I am saying is you have to weigh the propeller geometry to the hull characteristics to determine the better route. Yours is one of those boats that want transom leverage..............

Brett

Hey Brett, left you a email on your site yesterday and also started up a thread trying to get you to chime in. Merc Labbed 28 b1's. Planning could be better but not too too bad but think I need some more revs and speed up top. Have an honest 3-5 mph I feel I could sqeeze...(bet you've never heard that before haha!) Guys notes had him at 88 all day long with 5 or 6 different unknown setups, I found 80.