Wrong Prop????

[3 z's]

I have a stock 1988 Vegas XT with a Stock 1999 225 OPTIMAX. I am running a 26 pitch big eared chopper, speeds not bad at 82, but I am running around 6300 RPM's which is too much for the OPTI.

Naturally I would like to go faster, but need to drop the RPM's. Is this possible? My only experience has been with this prop. I would appreciate any input on OPTIMAX performance and props!!

Thanks a bunch in advance!

[vector mike]

It would be nice to drop RPM's and go faster but I think you might have a tough time doing it. I would suggest calling some of the big name prop dealers like Mazco, Hoss, Mercury Performance and anyone else you can think of. These guys have a lot of experience and should be able to hook you up with the right prop.

[pyro]

Use a GPS for checking speed. Speedometers are almost always off. The slip calculations indicate your speed to be 73-78 mph, unless you're somehow running under 5% slip, which would require anti-gravity. This range of speed is based on the Vegas XT's typical slip values, which commonly range between 9% and 15%.


If you want nothing but top end, get a 28" big-ear chopper (48 13372 A4 28P.)

Also, fill in details on setup with your boat: stock gearcase? nosecone/lwpu? Engine height? (with motor trimmed neutral and level, how high is the propshaft's centerline in relation to the hull's pad?) What kind of jackplate/how much setback?

I'm not familiar with the Optimax motors as far as how much RPM they can take. Here's what I run:

1989 Vegas XT
1989 Merc 200 XRi (around 215 hp bone stock, so I'm told)
Land&Sea hydr. jackplate, 5.5" setback
dual cable steering/solid mounts (I hope you have these!)

Here's the numbers:
28" big ear chopper: 78 mph @ 6400 RPM (16% slip)
26" Trophy Plus: 76 mph @ 6150 rpm (10% slip)

Both props were run 1" below the pad.

Assuming that your opti is starting to fall off the horsepower curve above 6200 rpm, and assuming that your setup can be improved, then yes, you can probably drop rpm's. You may be able to pick up another 1 or 2 mph with the right setup. Get a GPS and verify speed. Post some pictures of your boat! Vegas XT's rule!

-Chad

[WATERWINGS]

Don't you have your props and speeds switched?

WATER WINGS

[3 z's]

Vector Mike, thanks I will talk to some of the big prop manufacturers.

PYRO,
As far as as the gps and set up go, last summer GPS same prop 79mph with full tank of gas. My rig is all stock, 1988 Vegas XT, stock gear case, no jack plate, no solid mounts, the motor is a 1999 225hp OPTIMAX mounted at the second set of mounting holes, about an inch and a half above the transom. I have never measured the distance off of the pad.

As far as the OPTI goes, the fuel economy is great but the rest pretty much stinks for speed. Its got a rev limiter on it that shuts the motor down over 6300 RPM's.


Water Wings
As far as the props and speeds being switched, it's definitely accurate. With my old stock 200 merc with the same setup, I was clocked by a cop radar at 78. I don't know if I am just lucky or what but the boat really flies!


To all, I wish I knew about this site before yesterday. It is awesome, I don't fully understand half of what you guys are talking about but I will definitely learn. I will look into your suggestions and will definitely post some pictures. KEEP IT coming!! XT's definitely rule!

THANKS for your help!!

Dan

[pyro]

Get a jackplate! Plug the top two sets of holes for increased engine height. (you have a water pressure guage, right? get one.) A nosecone and low-water pickup will hurt your bow-lift potential on a heavier hull like a Vegas, many have learned this the hard way. You won't neen the cone until you start hitting 85 regularly anyway. Have fun!

-Chad

[Danco]

Unfortunately your really got the wrong engine for that hull. The Opti has alot of benefits but weight is not one of them. Heck I bet that engine weighs in at half the weight of your hull! But you can make it work. Start with 3Z's suggestion of a jackplate. If your Opti is 2000 or newer you have the intakes on the bullet. Merc makes a set of intake scoops you can get for $40. You won't believe how high you can run your engine with good pressure. Remember the 3.0 liters are low pressure/high volume so 10-12lbs is all you need at WOT. As for props you need to get ahold of a 28 Trophy. That's the ticket. Trophy's have huge amount's of lift and work great on Opti's. Your holeshot will be huge and midrange handling with excellent. They can also be improved by a good prop guy. Good luck.