Worlds fastest hydrostream viper

**Tom Foley** · 06-10-2015, 03:42 PM

Originally Posted by dwilfong

Let me ask this? I am planning on using a 1.62 gear on my moded pad Vector. My thinking is with a light boat and the higher prop shaft RPM. I can spin a small pitch prop at higher prop shaft speed. This way I will not have to spin the crap out of the eng. Also the smaller pitch prop will not push the boat around in the ass..
Seams a 28P at 7500 eng RPM would be more than enough to make ya squeal.
Any thoughts?

You want to spin the engine , this is not a 3 liter you are dealing with . RPM is your friend .

**dwilfong** · 06-10-2015, 03:57 PM

8000RPM with a 27P at 10% slip would be 115MPH.............................with a 1.62 lower...............
Remember theses little boats are not tanks...................

**carlton ruth** · 06-10-2015, 04:17 PM

28 or a 30 cleaver with the 260. I ran a 32 to 106 with my vking at 7400. If I can get it to 82-8300 rpm with a nice 28-30 would be ideal

**RONNIE** · 06-10-2015, 04:18 PM

8700 rpms 1.87 gear 10% slip is 111mph theoretical actual was 112mph a few times. didn't always have good batterys in my gps. it was fast enough

**dwilfong** · 06-10-2015, 04:30 PM

That's what I'm saying. sling a small prop at high prop shaft speed.
It is easer to multiply toque with gears than prop pitch.
Run a stupid small prop at high RPM.
The prop tip speed would have to be keeped less than 200mph to make it efficient.
That would be 8100eng RPM with a 1.62 lower and a 14.5" dia prop.
That would be 110mph with a 26P prop at 10% slip.

**frederick55** · 06-10-2015, 04:39 PM

Originally Posted by RONNIE

8700 rpms 1.87 gear 10% slip is 111mph theoretical actual was 112mph a few times. didn't always have good batterys in my gps. it was fast enough

If you want to "be The Man", you have to "beat The Man". "The Man" is telling you how it's done. You're lucky.

**CUDA** · 06-10-2015, 04:55 PM

For what it's worth ..... My 260 Super Stock set up in Lake Racer is a 2:1 with a 22 pitch Yamaha prop, when we check the ECU after the race , the top RPM is right at 10,000 rpm , we do used 26cc heads , we have to weight 1,540 lb after the race, I've been DQ for 2 lbs

and we do hit 100mph , just, but this is drag racing, ET is king.

**dwilfong** · 06-10-2015, 05:16 PM

5000RPM prop shaft speed is the mark.

**CUDA** · 06-10-2015, 05:48 PM

I sold my 1975 Viper in 1977

Inline 150 two blade prop.
Bought a new Viking in 1978 200 Black Max
Then a new Venus in 1979 200 Black Max
Then in 1982 the Hydrostream factory MVP race Venus boat built for 1981 Havasu, driven by the late GREAT Ron Baker ,. OMC factory racing prop guy Harold Nauss (SP?) built 235hp +

**patchesII** · 06-10-2015, 06:15 PM

A ported 2.5 with a 1.62 and a 28 will be a dog. Lugging a motor with too much gear and prop is tough on them.

**afr** · 06-10-2015, 07:39 PM

rpm is king if you can afford the problems it creates or you can just be slower and have just as much fun and have your repair bills be maintenance only
one thing is for sure about these guys they get it done but it cost them a lot
just my thoughts on it

**jasonpijanowski** · 06-10-2015, 08:07 PM

let the know it all come around hear with that 32 cleaver and he would go home with his head between his knees...lol

**JWTjr.** · 06-10-2015, 08:19 PM

Originally Posted by RONNIE

8700 rpms 1.87 gear 10% slip is 111mph theoretical actual was 112mph a few times. didn't always have good batterys in my gps. it was fast enough

You may be a decent Viper driver but you need to call me back, jack. You do my seat yet? I wanna come get it next week!

**CUDA** · 06-10-2015, 08:40 PM

Originally Posted by afr

rpm is king if you can afford the problems it creates or you can just be slower and have just as much fun and have your repair bills be maintenance only
one thing is for sure about these guys they get it done but it cost them a lot
just my thoughts on it

Maybe a OMC does not like to spin high RPM's , more of a torque motor, Yes I still own one

BUT Merc's LOVE to spin high RPM's with out problems , as long everything is in good working condition, the 2.5 Merc is one special motor, and I'm not prejudice...
At least when it comes to manufactures...

**afr** · 06-10-2015, 09:42 PM

Originally Posted by CUDA

Maybe a OMC does not like to spin high RPM's , more of a torque motor, Yes I still own one

BUT Merc's LOVE to spin high RPM's with out problems , as long everything is in good working condition, the 2.5 Merc is one special motor, and I'm not prejudice...
At least when it comes to manufactures...

still cost ya upwards of ten grand plus just for the power head let alone 5 6 grand for a mid 2/3 for a lower unit then the trim computer
long before you start on 1500 dollar or more wheels

oh and red line on the v8 is 6400 5400 on the 2.5 but the 8 will just carry a dead hole till it breaks it slap off