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View Full Version : alpha how much pitch



craigdskilling
08-31-2010, 05:25 PM
So I lust put on a 25 labbed prop hoping that the rpm would come down.They did to 6000 but would like it to be a little more.How much pitch can i go on a alpha 1:50 ratio.

BigGrizzly
08-31-2010, 07:48 PM
A 26/27. each inch of pitch is about 200 rpms.

craigdskilling
08-31-2010, 09:02 PM
Can my alpha take a27or bigger.

BigGrizzly
09-01-2010, 10:09 AM
pitch is not the problem, horse power and rpms is.

craigdskilling
09-01-2010, 08:34 PM
I am pushing 400+hp and I now that my outdrive is my week link.I just bought a25 labbed from dickb it brought the rpms down to 6000 from my 23 that was over spinning.Not only am I worried of my outdrive but my motor as well.I drive my18 at 3000to4000 all day and give it short spurts of full throttle for a few sec.I would like to try a 27p but I read some where on this site that 27 are not that great.I love the 25.

mrfixxall
09-01-2010, 09:40 PM
I am pushing 400+hp and I now that my outdrive is my week link.I just bought a25 labbed from dickb it brought the rpms down to 6000 from my 23 that was over spinning.Not only am I worried of my outdrive but my motor as well.I drive my18 at 3000to4000 all day and give it short spurts of full throttle for a few sec.I would like to try a 27p but I read some where on this site that 27 are not that great.I love the 25.

just remember the more pitch the harder it is on the drive..my suggestion to you would be to change the gear ratio to a 1.36, go on offshoreonly.com and look up mrgadgets, he is the drive gooru and knows his chit,he does something with the gears the makes the drive last 2 times longer then oe drive..

osur866
09-02-2010, 02:14 AM
If your turning a labbed 25p M+ to 6000 rpm's I'd think the 27 would still be up around 5600 where does your engine make max HP and torque at???

BigGrizzly
09-02-2010, 09:31 AM
First let me straighten you out on the 27, not being good. That is the Mirage plus 27 they talk about, Throttle up called it the widow maker. truth is it is not that bad but fat from good.I use only Turbo TXP s in that pitch. Head and shoulders better especially in handling. Now if you drive like you stated I would split the difference and go with a non-labbed 26 TXP or the like. Fixx has a good solution but costly. Me I would leave it and prop it.

craigdskilling
09-02-2010, 10:07 AM
That is the way i drive,I only like having the power there when there might be another donzi who always wants to race :nilly:.The torque is lots in the bottom end but cant use that without ripping the drive of so that said from 3500to throttle down to6000 puts you in your seat.I also have a drive shower on also to help.I have some pics in the show your engine.I hope to get out this week and gps the speed.Grizzly how much would the 26 that you talk about cost and that would give me more top and bring the rpm down.thanks guys:).

BlownCrewCab
09-03-2010, 07:28 AM
You should be right around 85mph if you can spin a 25" @ 6,000rpm.

craigdskilling
09-04-2010, 10:44 AM
It's saturday here in kitchener and freezing cold down to 19degress.So that being said not looking good to go out:(:(.Blowencrewcab i hope your wright about going 85 all i now is from my old stock 350 to this is awesome.I now that im flyinig but not sure how fast except when i come back to the dock and get dirty looks from people like im craze or there just jealous.they just dont get it.:bonk:

craigdskilling
09-23-2010, 04:44 PM
I have a chance to buy a alpha ss with the gear ratio of1.32 would this work with my power to rpm.

Planetwarmer
09-23-2010, 10:10 PM
My Alpha drive has a 1.32:1 ratio. Its been on the boat since 1987 with no problems. I thing the closer the gear ratio is to 1:1, the closer the 2 gears are to being the same size so that one isnt vastly stronger than the other.

I have a big block Chevy 330 hp (of course).