Superjet bored nozzle

C

ColdFusion

I Am Canadian!
Location
Victoria, BC Canada
Hey All,

I can't leave well enough alone....I want more BOTTOM END!!

So I've heard boring out the jet nozzle can help there??

A few questions:

1) How much to bore? (I've heard 2mm bigger than stock)

2) How's the bottom end gain?

3) How much top end do you lose? (I don't care...but good to know).

4) How far back to bore? I assume back to the point the nozzle starts to narrow??

5) I would guess any machine shop should be able to do this?

EDIT 6) I've heard keeping it tapered is better than a straight bore?

TIA

Cheers
 
Last edited:
Idok

Idok

F1pro
Location
Nations oldest muthaF+++kin city
it will help, +2 over stock...

if you run a WW cone your results may vary.....I use a f/s cone and a bored nozzle with a skat 12/17 and have NO cavitation whatsoever..

others, like I said have had differing results
 
C

ColdFusion

I Am Canadian!
Location
Victoria, BC Canada
QJS said:
Give us your engine and prop specs.
Chris.
Click to expand...

Easiest way is to check my signature link ;-)

Here's what it would tell ya:

2000 Yamaha Superjet 701 cc
Mods on it:
# Factory B pipe
# UMI Steering and Bars (zero degree)
# Stock Dual 38's
# Solas I prop (cut back by Impros)
# Worx Intake
# MSD Enhancer
# Front Sponsons
# Blowsion scupper valve
# Rule 500gph bilge pump (not currently hooked up...but it's in the hull)
# Blowsion lowered pole bracket
# Freestyle Hydro Turf kit
# Primer kit
# ATP foot holds
# ATP hand holds
# Riva girdled head (race and pump gas domes....pump gas in now...180 psi)
# Riva flame arrestors
# R&D reed stuffers and Boyesen power reeds
# RAD lightened flywheel (61x..switched from 62T stock)

Cheers
 
sportfish258

sportfish258

LPW bored mine and lightened the stock fly wheel at the same time.I noticed a gain in the bottom/mid. It was more from the fly wheel I'm sure.Do both together it is a cheap safe mod with real results.
 
Q

QJS

X-
Location
GONE
Yes I would say you will notice a good increase in hit by boring the nozzle with this setup.
Chris.
 
C

ColdFusion

I Am Canadian!
Location
Victoria, BC Canada
Rickster said:
Get rid of that I prop, and bore the nozzle to 85mm (with trim) or 85.5 (without trim).

You will notice a huge difference.

:arms:
Click to expand...

Thanks Guys!

Rickster....you mention dropping the Solas I prop. It came with the ski....I have no idea what the pitch is. All I know is it was a race ski....but not anymore ;-)

So is the Solas I more for racing? Does it come in various pitches?

Suggested freestyle prop?

Oh yeah....so far nobody has touched taper bore vs straight bore??

TIA

Cheers
 
Speedfreak

Speedfreak

Location
So. IL
I replaced a solas I prop with a 13/17 concord and bored the nozzle over the winter and was really disappointed. I was expecting a huge difference but I couldn't tell that I done anything.

IMO I would have that I prop repitched 1 or 2 numbers below what ever Dave at Impros suggested. That will save some money and then have the nozzle straight bored for $10 at any machine shop to 85.5mm. Then you have saved enough money to get a wetwolf cone. I still haven't read any solid benefit to taperbore vs straight.
 
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