Fenderjack

iTrader: (2)

Ok just for sh^ts I was playing around with the prop slip calc.. I am spinning a 30p b1 prop to about 5300(will say 5250) on the rev box sometimes, with a 1.82 gear. Can't remember exactly from last year, but the gps numbers were in around 77-80 mph... I am getting 0 for a answer to prop slip, 82mph for the speed http://www.go-fast.com/Prop_Slip_Calculator.htm What the hell is going on here, 0 slip is impossible. I am not lying about it(numbers) so whats going on..

Thanks

John jr

Philm

Are you sure that you have a 1.82 gear? 0% slip is highly unlikely.

stirling

I just run your numbers in my pocket japanese calculator and you are right ,there,s 82,4 mph theoretical speed ,are you sure you don,t have a 1,50 ratio ,and run about 15-16 % slip ?? seems a lot of slip though ,but possible, I guess
Maybe the formal owner /dealer anyone changed the drive /lower so the ratio is not anymore whats written on the drive ,if you want to be sure about the ratio ,just turn the engine over at the pully (sparkplugs out turns easier) and put some masking tape on the prop and lower unit and mark both ,then turn the crankshaft at the pully and see how much more than one revolution you have to turn the crank to make one revolution at the propellor.

It could also be that the tach is off ,or the prop is modified to a 32 P

Good luck

A.J

Fenderjack

iTrader: (2)

I am positive it is a alpha 1 1.82-83(stamped on the drive), for sure a 30p prop. We put the drive on and the new engine in the boat (efi sbc) I took one of the tachs out of the fountain to see last year, it is right on... Weird huh."" ?? I am going to try a labbed 32 B1 on it to see if it will gain mph, like stated it will bump the rev box now... I just can't seem to figure out the 0 slip, it isn't possible.. Maybe i am retarded and am not doing the calc correct.. hmmmm
FIG IT OUT I THINK, when I put in my gps speed where it says actual speed, then calculate my thero speed I am getting 4-6% slip.. But that is LOW also Is this correct??
John jr

Fenderjack

iTrader: (2)

T T T for the nigh owls... Somebody has to know what the F^&K is going on.. Is the 6 % slip possible??

John jr

Plum_Crazy

This must be on the Stinger. Yes, it's very possible your slip is at 6%. I ran as low as 5% slip on my old Baja 196 with a Mirage Plus. At speed, not much boat was in the water. However, the boat actually ran a little faster with a labbed prop and about 8% slip.

Now, my Sonic is double that at 16%.

Fenderjack

iTrader: (2)

Yesir it is on the stinger.. So on a smaller boat the slip is often less. Also there might be 2-3 foot of the v in the water when balls out.. I am hoping it will spin the labbed 32 to 5k, but the labbed 32 should spin about the same as the standard 30... Thanks this makes me feel a lil less crazy..

John jr

Fenderjack

iTrader: (2)

Throttle up- B Blades, any input (if ou catch this thread)???


Thanks

john jr

tommymonza

I find it pretty hard to believe you are running 80mph with a 350hp smallblock.I know my boat with a stock 260 through a 1.5 to 1 drive runs 60 and it is a very effecient hull.

I can't imagine another 90 horse would push it another 20 mph faster

rssteiny

Are you using a gps or a speedo