P20 setup

RossM · 29-10-2007, 02:17 AM

What prop would you reccomend for a p20 with a 200 blue printed xr2 on a detwiler lifter?
tried the yam drag prop off The Mutz Nuts and it was quicker and diddnt really notice it struggling,
soo was thinking 26 chopper as theres one avalable
do you think 26 would be a good pitch to use?
what should the engine spin to?
Not really been seeing more than 6100 with the laser 2 (23") and that was 64 mph on gps i think, was a while back so cant really remember!
thing is the yam pulled the same revs but it was 5 mph quick (also had an extra 2 people in the boat so not a direct comparison)

Also when pulling a skier the engine really bogs down and struggles to pull the skier out, once boat and skier up on plane its fine

Cheers guys

Burty · 29-10-2007, 01:08 PM

A small one, what gearbox ratio is it?
if 1.87:1 then i would say a 21" as you really want the revs in the high 6's to use all of the 200hp

RossM · 29-10-2007, 02:27 PM

Cheers for that Rob,
yep think its a 1.87
what u recon then 22 chopper?

The Docta · 30-10-2007, 09:22 AM

thats what I run on my R21 with 200 xr2. Probably not the fastest possible combo but works well for me and hole shot is still good 4 skiing etc

Cyco · 30-10-2007, 09:41 AM

21.5" ET or a chopper if your brave.

You should be reving the motor to 7000-7500 with no problems at all.
Proping the boat like this will enable you to still have good hole shot, plenty of mid range grunt if for example you have the bow tank full, and will still acheive a good top end speed.

I ran 73.9mph (gps speed not pub speed) with a 22" chopper that had been worked (serveral times). this was a bit of a hand full and my old P20 was set up very well with very little chime walk.

You will need to try lots of different props to find what suits, but be prepared to have some worked to really suit your application.

For best all round drivability I used a 22" Laser 11 small hub worked down to a 21.5" thined out blades with some cupping added, used to run very level with no bite as the boat re-entered the water and no chime walk.

I still have this prop if you get stuck, it's not for sale but you may try it.

Cyco

RossM · 30-10-2007, 11:55 PM

Cheers fellas, I will speak to my uncle (whos boat it is) and see what he wants to do,

does anyone know of a et for sale then? other than burtys hooky one

gazza · 01-11-2007, 10:29 PM

Quote:

Originally Posted by Burty

A small one, what gearbox ratio is it?
if 1.87:1 then i would say a 21" as you really want the revs in the high 6's to use all of the 200hp

Rob
I understood 2 litre blocks run 2.1 box and 2.4 2.5 blocks run 1.87.
but there again i've been wrong before.
I just remember helping out building boxes up my friends, a main dealer marine engineer many years ago.
Gaz

Cyco · 01-11-2007, 11:12 PM

Quote:

Originally Posted by gazza

Rob
I understood 2 litre blocks run 2.1 box and 2.4 2.5 blocks run 1.87.
but there again i've been wrong before.
I just remember helping out building boxes up my friends, a main dealer marine engineer many years ago.
Gaz

Most XR2's came out of the factory with a 1.87:1 box.
Ski racers generally used the 1.87:1 box
OCR racers generally used the 2.1 box

Rob is probabaly not best to answer this as he has never run an XR2 or a 2.0
What difference does the gear ratio make tho? you just prop to suit!

Do you have a point to your statement?

gazza · 01-11-2007, 11:27 PM

Quote:

Originally Posted by Cyco

Most XR2's came out of the factory with a 1.87:1 box.
Ski racers generally used the 1.87:1 box
OCR racers generally used the 2.1 box

Rob is probabaly not best to answer this as he has never run an XR2 or a 2.0
What difference does the gear ratio make tho? you just prop to suit!

Do you have a point to your statement?

Well actually i do have a point to the statment, it may seem i am wrong with the ratio, but Rob is only trying to say which prop may be more suited because unless you have bucket loads money or have access to a range of props, an educated guess with as much info should put you in the right ball park figure for which pitch to go for.
So whizz kid you can answer the exact prop question because i dont see you listing which pitch to go for,

Burty · 02-11-2007, 09:34 AM

Quote:

Originally Posted by gazza

So whizz kid you can answer the exact prop question because i dont see you listing which pitch to go for,

Quote:

Originally Posted by Cyco

21.5" ET or a chopper if your brave.

You should be reving the motor to 7000-7500 with no problems at all.
Proping the boat like this will enable you to still have good hole shot, plenty of mid range grunt if for example you have the bow tank full, and will still acheive a good top end speed.

I ran 73.9mph (gps speed not pub speed) with a 22" chopper that had been worked (serveral times). this was a bit of a hand full and my old P20 was set up very well with very little chime walk.

You will need to try lots of different props to find what suits, but be prepared to have some worked to really suit your application.

For best all round drivability I used a 22" Laser 11 small hub worked down to a 21.5" thined out blades with some cupping added, used to run very level with no bite as the boat re-entered the water and no chime walk.

I still have this prop if you get stuck, it's not for sale but you may try it.

Cyco

Cyco · 02-11-2007, 01:43 PM

Quote:

Originally Posted by Burty

What do you need the boat to do?
ultimate top speed and not too much concern for hole shot or good alround performance maybe pulling a skiier now and then?

For ultimate top end always go with a chopper.....but you have to be a good driver or very brave!!
Pitch depends on the boat set up and weight and what gear ratio you are running. The pitches I have listed are for use with a 1.87:1 gear set.

For alround performance either the ET or a laser 11 small hub.
Some mates have tried and swear by Trophy 4 blade altho I have never seen the top end results myself.

And as said before let the motor rev to at least 7000rpm.

The Whizz kid

Ash · 02-11-2007, 02:26 PM

.. can somone please explain what 'hole shot' is

Ta

Cyco · 02-11-2007, 02:34 PM

Quote:

Originally Posted by Ash

.. can somone please explain what 'hole shot' is

Ta

Pull away.......how quick you can get 'out the hole'.

The Docta · 02-11-2007, 03:37 PM

Well I im a 15st lump and I can still get up on my skiis with my worked 22 chopper spinning on a 200 Xr2. Also I wouldnt say that I was Fabio Buzzi but have no reall problems controlling my boat at flat out.

Dont think you have to be that brave to run a chopper? Just sensible!

Ive also heard from a v reliable source that its a raker (worked 24??) you want for max speed and controll on a Phantom with XR2

Carl · 02-11-2007, 03:52 PM

on my p 20 with an xr2 1.87 box,and no lifter i ran a laser 11 22",boat was quick and very stable.

Cyco · 02-11-2007, 09:52 PM

Quote:

Originally Posted by The Docta

Well I im a 15st lump and I can still get up on my skiis with my worked 22 chopper spinning on a 200 Xr2. Also I wouldnt say that I was Fabio Buzzi but have no reall problems controlling my boat at flat out.

Dont think you have to be that brave to run a chopper? Just sensible!

Ive also heard from a v reliable source that its a raker (worked 24??) you want for max speed and controll on a Phantom with XR2

What hull?
What speed is flat out?

Cyco · 02-11-2007, 09:54 PM

Quote:

Originally Posted by Cyco

What hull?
What speed is flat out?

Ok just read your advatar, a 21 ring is not quite the same as a P20!!
You have alot more beam and weight to start with.

Also you mention 'ski's' as in a pair, the pull up required for 2 ski's is nothing of that required to pull out a mono skier.

I would guess that your top speed is about 63-65mph??

The Docta · 02-11-2007, 11:10 PM

Yeah - thats about right mate. Pleanty quick enough for me though.

7.5k! Now thats what I call brave

Surely if a R21 is heavier but the hole shot is fine for skiing and a bit of wakeboarding, then it should be even better on a lighter P20?

Incidentally, my props a worked small ear chopper. Are they a bit less forgiving than the big ear choppers??

brett duke · 13-01-2008, 08:36 PM

Quote:

Originally Posted by The Docta

Well I im a 15st lump and I can still get up on my skiis with my worked 22 chopper spinning on a 200 Xr2. Also I wouldnt say that I was Fabio Buzzi but have no reall problems controlling my boat at flat out.

Dont think you have to be that brave to run a chopper? Just sensible!

Ive also heard from a v reliable source that its a raker (worked 24??) you want for max speed and controll on a Phantom with XR2

Mmmm I remember the last time you attempted to ski!!