understanding flow capabilities of your sleds exhaust

[turboal]

ski doo posted in there service mateial to there dealer network last season showing some graphs on what cans did to there motors performance .

unfortunately the test was targeted at the oporation of the sleds in low elevations. there correct but to be fair the test should have shown results at elevtion. and a 7000ft reading would have shown totally different results.

riders, unerstand that a sled at sea level looses 30 hp by time you get it to 7000ft .air is thinner as you go up and the motors ability to have the same volumetric out put is dimminished .

a can that showed tight at sea level wont show tight at elevation . a loose can will preform terrable at elevation in its ability to help the main pipes performance.

the compression reading at sea level say is 160lbs
the compression at 7000 is now 130lbs

the pipe pressre reading at sea level is 3 lbs at wide open throttle
the pipe pressue at 7000ft is 2.2 lbs

we have always had the ability to dyno test at these two elevations
and the info is very valid .

ski doo should have been more concerned with who supplied them there priamary clutch components than an after market can concern.

when you want to select a can , consder these facts,
what elevation do you oporate at .

the fellas that oporate over 8000 really are running sea level 600's up there .

when considering twin pipes keep this in mind as well . can save yu some greif on a beautifull snow covered day and your buddies are rippi n it up and your not.

 

[badass1000]

thank you for the info.
could you let us know or post some graphs of how stock sleds with your can and others dyno at elevation. I am very interested.
thank you
jeremy

 

[beans]

Hey Al,

Have you done any testing on y pipe/single pipe combos. I am interested in in the results. It is tough to sift through the info for truth when all I have seen are manufactures claimed numbers.

 

[MARV1]

More concerned about who supplied their clutches? NOT! Their clutches were made to Doo specs, no one elses and their supplier knew they were not gonna be right and offered properly spec'ed clutch kits for them.

 

[DARKO]

More concerned about who supplied their clutches? NOT! Their clutches were made to Doo specs.

Your saying Doo wanted and spec'd the clutches in 07 and 08 to have chitty bushings and the list of other issues ? LOL, or in your words "NOT" !!!!!!!!!

 

[turboal]

main flawed part in the primary was the spring tower cap .
i chalk it up to doo seeking a cheaper builder , this canadian builder got to costly with the stronger dollar ,
they headed some were else and the quality control got dropped .
they assure me the problem is fixed for 09
surehope so .

07 secondries got skimppy bushings compared to the 06 model year
they wear out 400 tims faster
only beat by the wear rate of the spring tower cap LOL's

seconderies i put the 06 bushig in the07 moveable half
little work on the lathe makes it accept it .

 

[byeatts]

Idea? How about a adjustable restrictor on the outlet of the can.Dial it in at elevation?

 

[LakeEffect]

So I am one of the unlucky few who only gets a couple trips to elevation a year. What is the best answer for me? 2 cans? Or is there one that will perform well at both locations?

An adjustable can like byeatts suggests sounds intriguing, but I doubt it would be that simple, is it?

 

[byeatts]

Very easy

 

[turboal]

exactly what i thought a good number of years ago . i built a sliding out let
had an end on the tube that came out the exhaust , on this tube i hada gradient of holes , was like a trombone.
went out as pressure built , had a spring on it , was a key item , had to have the correct rate .
worked extremely well . location of were it was attached made it prohibitive.
i was able to mantain a constant pressure reading as we went up in elevation.

really surprise that doo hasnt done it as they do have the tecknowledge to do it .
that all led to the can i build that uses accustics to accompolish what we achieved mechanically.
wave physics .

to know which can has a good pressure reading assciated with the main pipe it is attached to is a matter of hooking up a low pessure guage to your main pipe.
do it at the elevation you ride at, not in your parking lot at home unless that is the elevation you ride at.make a comparisipon to your engines compression here to

there area rampant of guages capable of doing the test . a digital one is way expensive but is the best .
even a cheap vaccum pressur guage from your auto store would work.
make a nipple in the pipe and use some steel brake line .

check your readig at home , compare it to the elevation reading or through a range of elevations as you head up thetrail. do the compression test down low and if you follow that test up with the pipe pressure you will see they fall together.on a stock can as you go from low elevation to higher elevations

 

[byeatts]

I have played around with this already as well. I used a orifice which slid into the can outlet and a cotter pin as a retainer. Had several restrictors of differant sizes.Did not use a pressure gauge however I like that idea,I was using RPM.EGT,s and track speed to dial in. At what location would be best for a pressure gauge?

 

[XP Summit]

If what Turboal is explaining is true then what elevation is the stock can tuned for? Can they tune it to perform well at all elevations? I wouldn't think so. I would think they would have a better idea than "Joe Rockets Can Shop" but there has to be room for improvements.


I

 

[portgrinder]

Ask your builder if they have a flowmeter....if they dont you might be introuble.

Bang on Al.

 

[turboal]

stock can is targeted at the lower elevation , just have to think of it in the terms of number of sleds built versus were they go . 80 percent of the 800 run under 3000ft.
stock can looses as it goes up, reflected in the pipemax pipe pressure readings at elevation...it is a good one to take a stock pressure reading at low elevatiions. has always been our base line.
use the pressure guage 3 inches from the small outlet at the back of the main pipe . this location works well in being able to plumb a guage into
you can put it in the middle section of the pipe as well.

use your guage as a base line o th stock pipe at the low elevation . this way you can see weather the pressure is 4 lbs or 3 lbs . guages can vary a bit so by using this approach you can match that pressure at elevation, there by knowig yo are making the same pressure a the stck can did a th lower elevation.

 

[LRD]

Thought I'd bring this back up as Speedwerx has a new pipe with an adjustable
stinger that they have a patent on it. I have been aware of pipe pressure also for about 20 years and the first time I adjusted for it was in Cooke City on a 85 HP Phazer with a butterfly with a hole in it in the stinger.

Currently on my 360lb mod big bore TNT I have a couple different sized sleeves that slip into the stinger.

Here is the Speedwerx pipe. Anybody no how their adjuster works?

http://www.hotseatperformance.com/p...0&St3=44250170&DS_ID=2&Product_ID=4144&DID=29