I6 chopper

[Juggernaut]

i want to buy a chopper for my MX15. its got a 1500, on 5.5" setback. probably too much, i know, but thats besides the point. i need sugguestions as to what prop i should buy to see over 65mph. pitch/diameter/company. i dont know much about chopper companies as to whos got good quality. PLEASE HELP!!

[Juggernaut]

just found a lazer II on ebay. 13.5" dia X 24p 48-16994A40
will this prop work well on my boat?

[David]

You should buy a 26" inline chopper, if the prop calculator can be believed.

http://www.rbbi.com/folders/prop/propcalc.htm

The Laser will be fine if you don't run it too high, which you might need to do for 65...

I have the same Laser as a ski prop, and it will push my Ally into the low 70's. If I raise it too high the bow drops, the engine revs go up, and I'm happy I haven't hooked.

[Juggernaut]

26"p seems a little high considering the inline 6 engines should be run above 5600 rpm's.. also im not really sure what gear ratio ive got so i cant accurately use the calculator

[David]

I'm assuming 2:1 and that you don't want to go over 6000 rpm.

[SportJ-US-1]

I'm assuming 2:1 and that you don't want to go over 6000 rpm.

Aren't the XS motors rated at 5800 to 6300 from the factory? At least mine was.

[David]

150 rated at 4800-5800
150XS rated at 4800-6000

I'm sticking with 6000 max and not less than 5500 at WOT

which one does he have?

[Juggernaut]

i have the 1500, it is not the XS. the 1500 was rated for 5,300-5,800 rpm, (and the XS 5,800-6,300 rpm.) raceman used to run these engines, and he claimed they should be run high rpm. up to 6000 if i remember correctly. many people bogged their engines down trying to get more speed with more pitch, and ended up melting pistons. david, i agree with you. infact, its what im shooting for. 5500-6000 rpm.

[David]

It's fine for me to give advice about what rpm to turn when my own tach gives bogus numbers. My calculated slip is sometimes <0, so I am not buying what my tach is telling me. I have a gps. Anyone know how to calibrate a tach, or where to send it?

[Juggernaut]

no idea.. so you still think i should look for a 26"p 3 blade chopper?

[David]

24 or 26, whichever you find first. 24 would accelerate better, and for a lot of the time, that's better than speed.

Note that you need a small ear

http://69.24.70.63/adamsdock/chopper.html

[Juggernaut]

alright. thanx