HOW MUCH TO CUT OFF MY WESTCOAST PIPE
Doug Keller
rick raymond wrote:
>
> I have a 750 with XI crank and cases, and a sx cyinder, The cylinder was
> ported for mod racing. I dont know any of the speces on the porting other
> than the racer I purchased it from tends to push things to the limits. I
> have the motor in a 440 hull so I am using a WESTCOAST WORKS PIPE with a
> limited tailcone there are five notches on the tailcone to cut to shorten it
> Does anyone have any sugestions on how much to cut off or a method to
> determine how much to cut off
> Any Help is really appreciated
>
> Rick Raymond
Rick,
Probably the easiest way is to buy another tailcone (I think the retail price is
about $30). Test it as is...cut it one "notch" shorter, test it again...cut it
one shorter, test again...when it gets better then worse, cut the second
tailcone to the length that gave you the best ride. If you have any questions,
give us a call, or email us at te...@teamwpp.com
--
Douglas A. Keller
Director of Computer Resources
Westcoast Performance Products USA, Inc
3100 E Coronado St
Anaheim, CA 92806
714-630-4411 * 714-630-4460 FAX
http://www.teamwpp.com
rick raymond
Dan DePardo
Hi Rick;
Rather than cut the cone, why not try tuning the pipe temp by bypassing
more or less pipe cooling water. I've had *great* success using this
method on my own Coffman's pipe, and other cast pipes.
Install a "T" (use one large enough so that it's not a restriction) into the
headpipe water supply line, and run the base or open port of the "T" to a hull
bypass fitting. You may already have this type of bypass installed, I dunno.
(I recommend using 3/8 inch hose and barbs for all of your cooling lines by-the-way)
Then build a selection of restrictors (I use the aluminum ferrules intended to be
crimped onto braided steel cable ends to keep 'em from fraying, they fit into 3/8 hose
perfectly) drilled in 1 mm increments, 2-6 mm should do it.
Install a restrictor into the bypass line to the hull fitting, run the boat full
throttle for awhile, then immediately check your pipe temp and hoses.
If you can "sizzle" water on the body of a cast aluminum pipe, it's a little
too hot, and your rubber/silicone interconnects will suffer.
I've found the best results with running it as hot as possible without
hurting your couplers/hoses. With a 750 in that little hull, you've got low
end to spare, so you will probably will notice little if any loss in low end by
running the pipe hotter. If you can't get the pipe temp up with just a bypass,
you can also restrict the headpipe input slightly, but be careful since this
will make a much bigger difference in temp, and be sure that you're jetted
on the rich side, since a hotter pipe will allow you to pull more RPM.
A good digital tach is almost mandatory for properly tuning a pipe.
I've installed a mechanical spring loaded valve in my headpipe bypass line.
By selecting the correct tension spring, I can adjust "when" the water bypass
opens, since the engines cooling water pressure varies with RPM (jet pump pressure).
By using this valve, I have excellent low end out of my Kawi 650, since the bypass
is closed up until approx. 3000 RPM, which keeps the pipe cooler for good low RPM
performance, along with "arm-stretching" top end (7160 RPM) once the valve opens.
Anyway, before you hack your pipe, I'd try heating it up first. I suspect you'll be
very pleased with the results!
Dan "Exhaustive tuning" DePardo
fpcrew
Doug Keller wrote:
>
> Probably the easiest way is to buy another tailcone (I think the retail
> price is about $30). Test it as is...cut it one "notch" shorter, test
> it again...cut it one shorter, test again...when it gets better then
> worse, cut the second tailcone to the length that gave you the best
> ride. If you have any questions, give us a call, or email us at
> te...@teamwpp.com
Oh, the old "hack & try" method! I thought that went out out years ago!
If that's the best solution to determine the proper length why don't you
get two tail cones when you buy the pipe? And to think we make you turn a
little screw to accomplish the same thing. Just giving you a hard time
Doug, I could'nt resist that one!
--
The Factory Crew
"Horsepower is a Beautiful Thing"
http://www.factorypipe.com
Dan DePardo
fpcrew <fpc...@factorypipe.com> wrote:
>
>Oh, the old "hack & try" method! I thought that went out out years ago!
>If that's the best solution to determine the proper length why don't you
>get two tail cones when you buy the pipe? And to think we make you turn a
>little screw to accomplish the same thing. Just giving you a hard time
>Doug, I could'nt resist that one!
>--
>The Factory Crew
>"Horsepower is a Beautiful Thing"
>http://www.factorypipe.com
Yeah. Why don't you get two tail cones when you buy the pipe!? ;-D
High technology marches on....
Dan "Keep away from my stinger with that hacksaw!" DePardo
rick raymond
In article <320690...@factorypipe.com>, fpc...@factorypipe.com says...
>
>Doug Keller wrote:
>>
>> Probably the easiest way is to buy another tailcone (I think the retail
>> price is about $30). Test it as is...cut it one "notch" shorter, test
>> it again...cut it one shorter, test again...when it gets better then
>> worse, cut the second tailcone to the length that gave you the best
>> ride. If you have any questions, give us a call, or email us at
>> te...@teamwpp.com
>
>If that's the best solution to determine the proper length why don't you
>get two tail cones when you buy the pipe? And to think we make you turn a
>little screw to accomplish the same thing. Just giving you a hard time
>Doug, I could'nt resist that one!
>--
>The Factory Crew
>"Horsepower is a Beautiful Thing"
>http://www.factorypipe.com
If only I could fit a factory pipe in my hull I wouldnt hesitate. I think
factory pipes are the best for almost all applications. I really like to
check around for the best aftermarket parts before I buy. But if Factory
Pipe makes one for your pwc I look no further. By the way I am not putting
down West Coast as they make allot of great stuff but there energy is spread
out in allot of different areas. I have other westcoast products on my ski
and they work great.
Rick Raymond
Doug Keller
Rick,
Basically, the hotter your pipe runs the more horsepower it will
generate (which carries with it the greater risk of failure - something
racers deal with all the time). Making the tail cone shorter will give
you more top end and less bottom end.
There are two (at least) ways to approach this problem. Dan's suggestion
will provide the desired results as long as you are careful, but it
carries a higher risk factor - possibility of seizing the motor (if you
run it too hot/rich) while testing to find the right mix. My suggestion
of cutting the pipe carries much less risk of damaging your motor. Maybe
I read you wrong from you post, but I got the impression you would be
more comfortable with the safer route - if I was wrong, I apologize.
If you are more interested in the highest performance and are
comfortable with the risk of figuring out the right mix - go the way Dan
suggested (done right you'll get the best performance). If you aren't as
comfortable with the risk and are most interested in reliability, cut
the pipe. You can try the first ring, take it out and ride it, see if
you like it better - you can try it another time if you'd like - you
only would need to buy a new tailcone if you went past the ring with the
best performance.
If you have any questions give us a call at 800-292-9394.
TEAMULTRAC
In article <4ufktr$e...@news.interlog.com>, Jeff Logan
<jlo...@interlog.com> writes:
> Those who don't know how much you have
>contributed to this group may think so but the regulars
>all love your posts.... even if you do get sarcastic!
>Actually thats part of what I like about your posts.
>
>Keep it up Dan, and keep shredding with that X-2.
>
>Jeff Logan
That goes DITTO for me too. Keep up the great work Dan!
Carl @ ULTRAC
Dan DePardo
Doug Keller <do...@teamwpp.com> wrote:
>Rick,
>
>Basically, the hotter your pipe runs the more horsepower it will
>generate (which carries with it the greater risk of failure - something
>racers deal with all the time). Making the tail cone shorter will give
>you more top end and less bottom end.
>
Well, Doug, that's the same effect as running the pipe "hotter".
You effectively shorten the pipe due to an increase in sonic wave
velocity.
>There are two (at least) ways to approach this problem. Dan's suggestion
>will provide the desired results as long as you are careful, but it
>carries a higher risk factor - possibility of seizing the motor (if you
>run it too hot/rich) while testing to find the right mix.
Uh, there is *exactly* the same risk with cutting the cone, since you're
tuning the pipe to be more efficient at a higher engine RPM. ANY time
you increase the engine's RPM capability you run the risk of engine
damage if you don't adjust the carburetion stoichiometric balance or
air/fuel ratio. More RPM will result in more airflow, provided the
intake tract can flow an additional volume of "air", and this additional
"air" requires an additional dose of fuel to achieve a balanced air/fuel
mixture.
There is a *small* additional detonation risk with adjusting the pipe temp,
since a drier pipe will produce a "louder" or "stronger" sonic wave that is
more effective as an exhaust port "valve", and will keep more pressure in
the chamber, but this results in "more power" as well!
Unless Rick is already on the ragged edge of detonation, due to an excessively
high compression ratio, or poor fuel,too much ignition timing, etc., I sincerely
doubt that he would have any more problems heating his pipe than he would cutting
it.
Heating it also has the added benefit of being "non-permanent".
In addition, chances are, he'll also need a new stinger to waterbox exhaust
hose as well due to the shorter physical length of a "cut" tailcone.
>My suggestion
>of cutting the pipe carries much less risk of damaging your motor. Maybe
>I read you wrong from you post, but I got the impression you would be
>more comfortable with the safer route - if I was wrong, I apologize.
>
I *really* disagree with the above statement! Doug isn't "wrong" and
he has no need to apologize, but "much less risk" is incorrect.
Same effect, different methods, both require "trial and error", both
carry risk. Any engine modification carries risks, but in my opinion
the rewards are worth it!
>If you are more interested in the highest performance and are
>comfortable with the risk of figuring out the right mix - go the way Dan
>suggested (done right you'll get the best performance). If you aren't as
>comfortable with the risk and are most interested in reliability, cut
>the pipe.
If either method is done incorrectly your reliability will suffer.
If you cut the cone, and pull more RPM, without increasing fuel flow,
you'll have problems. If you heat up the pipe, and pull more RPM,
without increasing fuel flow, you'll have problems. If the heating
is done carefully, in small increments, you can gradually increase
performance, and even back it off if desired, by simply changing
bypass restrictors. Try doing that by cutting the cone! Once it's
cut....that's all folks! ;-D
>You can try the first ring, take it out and ride it, see if
>you like it better - you can try it another time if you'd like - you
>only would need to buy a new tailcone if you went past the ring with the
>best performance.
>
You'll be able to get much finer "resolution" with a gradual increase in
pipe temp, when compared to cutting chunks off of the cone, and if
performance "falls off" by running it too hot, 30 seconds with a screwdriver
(swapping bypass line restrictors) will have you back where you were.
Try that after "cropping yur cone"!
The main risk with running the pipe too hot, on a mildly modified Kawasaki twin,
is melting your couplers and hoses, but if you keep it just below a "water
sizzling" temp, and adjust your carb mixture accordingly.... "wa-hooo"! ;-D
Anyway, I'm obviously biased, either method will work, and the choice depends
upon your point of view, but both methods will require a basic knowledge of
engine tuning to achieve a "safe" performance increase.
Westcoast should know what works for their pipe, and their "tried and true"
method involves a hacksaw. I'm kinda surprised that WPP hasn't kept up with
current 2-stroke exhaust system design and tuning methods and developed a series
of tuning "kits" (adjustable water bypass and/or restrictor selections) for
their pipes.
Then again, they obviously know a lot more about their stuff than I do, or ever will!
For the most part, Doug's advice is "on target", and reasonable, just "dated".
Dan "The annoying know-nothing, know-it-all" DePardo
Jeff Logan
Dan DePardo <ddep...@eecs.ukans.edu> wrote:
Yet another excellent post! (sniped to save bandwidth)
> Dan "The annoying know-nothing, know-it-all" DePardo
^^^^^^^^
Not at all. Those who don't know how much you have
contributed to this group may think so but the regulars
all love your posts.... even if you do get sarcastic!
Actually thats part of what I like about your posts.
Keep it up Dan, and keep shredding with that X-2.
Jeff Logan
"I love the smell of castor in the morning"
http://www.interlog.com/~jlogan/pwc.html
Dennis L. Copfer
teamu...@aol.com (TEAMULTRAC) wrote:
>In article <4ufktr$e...@news.interlog.com>, Jeff Logan
><jlo...@interlog.com> writes:
>> Those who don't know how much you have
>>contributed to this group may think so but the regulars
>>all love your posts.... even if you do get sarcastic!
>>Actually thats part of what I like about your posts.
>>
>>Keep it up Dan, and keep shredding with that X-2.
>>
>>Jeff Logan
>That goes DITTO for me too. Keep up the great work Dan!
>Carl @ ULTRAC
Me three!
dc
Whoever enjoys the most jet-skis wins!
Dennis Copfer