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XP -500SS - Full Wet 450lbs!!


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#106 LRD

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Posted 20 February 2013 - 05:14 PM

Spent 5 days in So Wy last week and learned a few things.  With the new track, 141 X 15 X 2.25 was lucky to get coolant temp down in mid 130's and routinely saw 150 +.  This year with the track punched down the center with a rectangular hole 1" X 2"  and with the new longer snow flap I mad, most of the time was 120 degrees,and sometimes lower.  The theory on the holes down the center of the track as far as cooling is this, snow inside the track as it comes around the rear axle will get thrown through those holes up at the heat exchanger. A cool engine  makes more HP than a hot one!!

 

 

Exhaust back pressure experiment,  had enough time to do a few changes with reducer bushings in the pipe stinger the first morning while the other guys were clutching. 

 

First pressure test on trail at 9000 ft full throttle, largest ID bushing in place, around 7700 RPM and 1.65 PSI. 

 

Second test with middle size reducer bushing netted about 7800 RPM at 1.85 PSI.

 

Third test with smallest ID bushing I had, raised RPM  to about 8020 at 2.85 PSI.

 

I did not utilize the 3/8" bolt that I added to the stinger that threads into the bore of stinger.  This could have raised pressure even more.

 

I did nothing to the clutch settings with these test, just made the ID of the stinger smaller to get these RPM (HP) increases.  Not sure how much HP picked up this way but guessing between 5 to 10HP and the engine sound is sweet. Shift RPM went up over 300 RPM!!!

 

I quit at that point as it was working great and wanted to check my jetting as more HP needs more fuel. Pretty sure 3.5 PSI will be safe and make even more HP.  When I get my wifes 09 TNT I'm long tracking for her done, will have a stock engine pipe and can to get a baseline PSI number from. 

 

Have also had some hard staring issues sometimes at higher altitudes 11,000 ft.  So end of last year went down # 15 pilots.  They worked great and ended up with 2 turns out on mixture screw.  Not the first engine that I've ported being to rich on the pilot jets.  My first rotax was a 617 I put in my Phazer with a pipe I built

with 38 TMX carbs.  Think I had 12.5 pilots that were way to rich and I sized them down by putting a fine strand of copper wire through them.

 

Clutching, QRS. Have run a green spring (180/303) and switched this year to a blue/blue (157/221).  Was looking for more track speed as I'm suspicious the 303 finish is so high of lbs it might stall the upshift.  Also

The lighter finish 221 will allow using much lower helix angle as the 221 will upshift much faster than 303.

 got the blue/blue to work pretty good but took a pretty low helix abgle to still get decent backshift and a real responsive throttle.  Used to having instant full shift rpm when I blip the the throttle. Am going to rework my spring checker so it can handle the large OD of the QRS springs and then see if its possible to shim the blue/blue up to about 170/250.  Think that would be a great compromise.

 

The whole deal with the blue/blue spring, looking for more track speed.  Speedometer busted so not sure if I

got it or not, but it competed with 1st generation well doo 800's and amazingly a 08 XP 800 summit with the 150ish track and an incredible pair of 2010 700 RMK's with 150ish tracks and about 135 HP.  They were the ones to beat.  Stupid doo and poo quit making 700's.  Can say the sled has never run as well as this trip. Last day climbing long pulls in 2 ft of fresh, just kept going and going!!

 

 

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#107 LRD

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Posted 20 February 2013 - 05:30 PM

For measuring exhaust pressure

 

Here is a link to the 0 - 15 PSI digital pressure gauge I'm using   http://www.omega.com...D=DPG3500&Nav=  I ordered it with manual shutoff, doesn't automatically shutoff after 5 minutes.  Welded a 1/8" pipe thread fitting to belly of pipe and then connect with an adapter from Napa about 18" of of I think 3/16" brake line, then another adapter to change brake line fitting to 1/8" pipe thread.

 

At the end of the brake line I have a 3 ft length of stainless steel braid line from a previous failed experiment with a mechanical dial exhaust pressure gauge that didn't work a year ago.  When testing I leave the hood off and put the gauge in the tank bag. You need to get some distance between the pipe and the gauge to get the exhaust temp down.

 

The digital gauge works awesome totally  repeatable numbers.  Come back from full throttle run and hit button, gauge recalls low reading and then highest reading.

 

To give credit where credit is due have know about the pressure issue  since I built a ppie and can for that 617 rotax I put in my phazer around 91 or 92.  But never found out approximately what the pressure should be until Turbo Al from

Revelstoke wrote what he was seeing on snowest.  Then last winter lancelarue up in Alaska started a thread about it as he was having issues as it turned out  with to much pressure with his 860 big bore, and he also said he learned about it from Al. He also said he couldn't get repeatable readings with a mechanical gauge. 

 

And those of you that follow Kelsey, he says on his website you can't measure exhaust pressure.  You can, with this Digital Gauge,I've done it, with a mechanical gauge I couldn't, LanceLarue, and Turbo Al  also and guessing maybe a lot of other guys have done it and keeping it a secret. Sure wish I had this back when I was building 200 +HP triples for my customers. 

Outside of the cost of the gauge its free HP.  I have suspected for many years that the reason aftermarket cans make less HP is most of them don't create the proper pressure in the pipe, to loose compared to the stock cans. 

 

Good Luck

 

When I get some time will take a few pics of the gauge hooked up to the pipe.

 

Some things I'm still curious about?

When you wind the engine past the HP peak and HP falls, will pipe pressure fall or continue to rise.

If it falls means you can find the HP peak to tune clutches to without a dyno session.

With the pipe pressure corrected at 9000 ft to sea level numbers do you adjust the rave valves to sea level settings

or still set for high altitude?



#108 LRD

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Posted 20 February 2013 - 06:07 PM

Another change I made that really worked well, as recommended by Irondog and the kit is sold by Tom's. 

I made up some spindle bushings so my carbides were centered on my spindles. Rather than being offset

full in or full out.  With Alternative Impact summit Ti A-Arms this gave about a 39" ski stance and on the 20 miles

of trail down to CO it railed, even with the 141 X 15 X 2.25 track. Last year with that new track it was a bit spooky

if I pushed it to hard in the corners.  Total control this year!!!

 

Good Luck



#109 whirli

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Posted 24 April 2013 - 02:03 PM

awesome info.

#110 SnowriderKALLV

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Posted 13 November 2013 - 06:02 AM

Time to update LRD.

Some more tuning tips of the PowerBloc?

Any pic of your track porting?

 

Love this sled. Have been searching for a TNT or RS since I first saw yours but somehow they never turn up at a reasonable price 2008 TNT hold their value very well.



#111 SnowriderKALLV

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Posted 13 November 2013 - 07:39 AM

About the pipe pressure. What always comes up when talking about stinger diameter is. to tight or small and the EGT will rise to dangerous levels on a long WOT pull unless jetted rich and to rich it will not run properly on a short pull. So does the pipe pressure and egt follow eachother? Does the pressure go up when EGT rises on a long pull or does it stay the same?

#112 blastco2

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Posted 14 November 2013 - 12:04 AM

LRD Sure doo enjoy reading your posts/threads. Would love to hear more about this exhaust pressure thing. Sent from my Nexus 7 using Tapatalk

The world is full of people who can hear a loud bang, feel a sharp pain in their foot, notice smoke trickling out of their holster...and never put it all together.


#113 SnowriderKALLV

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Posted 14 November 2013 - 07:49 AM

Did you manage to use the Rev fuel tank?

#114 LRD

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Posted 14 November 2013 - 04:08 PM

Did you manage to use the Rev fuel tank?

Sadly not yet,  have been tied up  with Honey Dew stuff, built a composite 16 X 28 deck last summer was biggest project finished this year plus finally finished up all new siding.

 

Another thing on my wish list to build for my sled is a straight chrome moly steering column topped off with some old cat Titaium bars that weigh nearly nothing.

 

Good Luck



#115 LRD

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Posted 15 November 2013 - 11:53 AM

Here is likely the most info  I know of on pipe pressure

 

Lancelarue - Pipe Pressure
I thought I would pass this on.
Finally found a good accurate, waterproof, shock resistant low pressure digital gauge to measure pipe pressure. In past experience I could hook up 3 analog gauges to the same plenum and get 3 different readings. Maddening to say the least.
Omega 3500B is the gauge. I configured this one 0 to 15 psi and it runs on battery. Has actual,high, low, & recall so you can make a pull up the mountain and pull it out of your pocket hit recall and wa la!!!!!
Should have done this years ago---------
06' Summit X W/163" flex,2 wheels in rear, drop & roll. 860R, 42.5mm bored carbs, custom airbox w/ 3" ducted out right side bezel in dash, twin crankshop Mondos, Paragon, C-3 belt drive, Mtn Tamer rear w/ floats all the away around,extra cooling tubes in tunnel, premix, 5 gal race tank, >


Lancelarue - Pipe Pressure
Already figured out the heat soak problem that's been running me around in circles with the 860. Never would have believed it, but the can wouldn't flow enough. 2 1/4" inlet
2 1/2" between chambers with a 2 3/8" outlet.
Modified a different can now my pressure finally went down so I need to tighten up the pipe.
WHAT A DIFFERENCE !!!!!!!!!!!Now happy motor!!!!!!!!!!!!!!!!!!!!!!!!!!

LRD
How about a link to where you found this gauge. I googled Omega 3500B and got everything but a gauge!!!
And what kind of Lbs are you reading and looking for in the pipe. If I remember right TurboAl said a number of years ago about 2.5 to 3 PSI were good #"s. Where do you have your sensor,
midddle of belly etc.?
Thanks and Good Luck

Lancelarue  -  Pipe Pressure
I went with the same in & out on a straight through style can and dropped 1 1/2#'s.
I needed to drop .6 #'s. I have a bolt in the stinger to adjust the pressure so I need to turn it in some more to bring the pressure back up. I'll see what it takes to keep my target pressure up at altitude and count the turns on the adjusting bolt. Only takes a minute to adjust.
I ordered the guage with automatic shut down in 15 minutes so I wouldn't have to worry about forgetting to turn it off (batteries). Now I'm wishing I wouldn't have done that as when I'm testing a new change like the can I have to keep turning it off and on after each test so as to not lose the next test data if it shuts down. Not a big deal but ----- Here's the address http://www.omega.com....D=DPG3500&Nav=

Lancelarue - Pipe Pressure
I think to play it safe a person should take some baseline readings off a stock Ski-doo or Polaris with "their" guage and go with that to start with.
Like I said before the other problems I had with the analog guages all reading different. I always had a pressure guage hooked up when I was running the dyno and every guage would be different sometimes over a # different!
Al and I have been talking for years and yes he see's 3#'s at his shop @ 1,500' elevation. I checked a sled the other day again and it showed 2.93 #'s here @ sea level baro about 30.6".
I can tell you you will be amazed if you're under pressured, and you start to turn the bolt in, the seat of the pants dyno goes nuts.  Same holds true if you're too high a pressure.  No top end on my motor, noise out of the intake was terrible and of course the inevitable heat issues. !!?????
You can pick up your pressure pretty much where you want. It's just a pressure vessel. I put mine about 3" ahead of the stinger in the rear cone so it's easy to plumb to on the sled. Keep your plumbing as small diameter as you can to the guage with as short as you can. This time I went with 12" of 3/16" brakeline tubing to 1/8" npt and then to 3/16" hose.
I also put a quick connect chuck makes it nice.

Lancelarue - Pipe Pressure
One thing a guy needs to keep in mind, No matter who's pipe you're running, or who's can, if you're not running the build that the pipe & or can was designed for, at the correct altitude it's a crap shoot. If you're running a mod motor that's " out of the box" you don't know what exhaust is actually doing with YOUR motor with YOUR build, at YOUR altitude, it's just a guessing game.
We have pretty big air in Alaska and lower elevations & this will really make a difference.
The other thing is the actual design of the can you have. I've never played around with the stock cans because of their size and weight but I believe my 06' Summit X stock outlet is 2 1/4". Might flow my motor here because of the design, but I kind of doubt it. Anyway, I don't want to pack it around !!!!!!!!!


Lancelarue - Pipe Pressure
My next project, now that I think I'm going the right direction is going to be a friend's Polaris 910. This should really be good with the heat soak issues with this motor. I'm thinking it will be interesting the results when we get done with the pipes at these lower elevations-------


LRD
Thanks for the great info. I fooled around with pipe pressure way back in 91 or 92 when I put a 617 Rotax in my Phazer and had to design and build a pipe and can to fit it into a space about the size of an XP or Rev. I was aware of pipe pressure from my Tom Turner 2-stroke software when I designed the pipe. So I had put in a sort of butterfly valve with a large hole through it that was in the outlet of the can and could be rotated externally for more or less restriction.

Currently on my TNT big bore mtn mod with pipe and can have a couple different size restrictors (small flanged tubes different thickness) that slip in the end of the pipe. Have been afraid to really go after it without being able to actually measure the pressure first with the stock can at flatland altitude.

Kind of funny RKTEK wrote a tech article on his website claiming you can't measure exhaust pipe pressure!!!

Thanks again for the great info!!!

Good Luck

Lancelarue - Pipe Pressure
Thanks. I wish I could say I came up with all this on my own but 90% I learned from Turbo Al over the years and what I realized when I had the dyno going

PTE800
Here's some thoughts that are from Dyno Tech Research's dyno session on a RK Tek 925 Big bore Artic Cat.
Now we fitted the pipe with the dyno instrumentation that registers pipe center section temperature and pressure. This sensor replaces the stock sensor (creates max timing at about 900F). When we disconnect the stock pipe center section probe, the ECU defaults to max timing. Rider X and Tech X had surmised that if this 2012 stock muffler were a bit “loose” for Billy Howard’s stock 800, the 925cc top end’s added airflow CFM could create optimal conditions.
To generalize, 4 psi seems to most often a best average pipe pressure for best torque and HP.
Too low, and too much charge/ air mix can be allowed to short-circuit out the exhaust
making only extra EGT and no power. Too high, and often deto-producing active radicals
can be packed back into the combustion chambers creating havoc. But today, the stock
800 muffler seems just right!

Lancelarue - Pipe Pressure
I've read this. Interesting that is what they see there. Sure had me wondering after I received my new expensive precise pressure guage (±0.25% Test Gauge Accuracy ). This is one of the reasons I said earlier to set your own baseline with YOUR gauge on a stock Polaris or Ski-doo. I don't know what Cat does. I've heard that they do run pretty "loose".
Seems strange they're wanting to tune the system with the can and not the pipe?

Lancelarue - Pipe Pressure
Well I'll tell you this has been quite an education this last month or so. I've tested several combinations of pipes & cans including stock to get baselines.
You can really get in trouble quick with the wrong pipe / can combinations. ( I have quite a few pistons re-nicked cylinders from the last 10 years to prove it).
We have such a huge altitude variation here where I live. We've had huge dumps right here at sea level and we go to 6,000'.
On my new gauge I'm seeing 3#'s on stock and aftermarket systems that work. The motors just love it there. Drop down and you can hear it and feel it in the throttle response for sure. The danger area is when you go over that it will still feel / sound good if you're not too high, but things really start "glowing"!!!!!!!!!!!!!!!!
Tested everything from full on mod 860 big bores to 440's. What an education!!!!

LRD
If its not a secret or whatever could you describe/or pics of the apparatus you are using to adjust your pipe restriction? From what you have said sounds like you have something that works fairly quick and easy.

Lancelarue - Pipe Pressure

As I described earlier, drill a hole & weld a nut to stinger to run bolt into pipe to adjust restriction. People have been doing this for years. The difference is I finally spent the money and bought a guage to measure it accurately.
Generally am dealing with too much pressure because of mods / big bore situations so I oversize the stinger to be able to adjust with the bolt. I've noticed if a person goes too big, and you have to run the bolt down too far, motor doesn't seem to like it? In my case when that happened, I just put a reducer ring inside to get closer to target pressure, then just fine tune with the bolt.
On a Skidoo race 440 we just drilled the pipe sensor plug in the middle of the pipe(06' ) welded a coupler cut in half & then put a " T ". One side of the " T " goes to guage, other side I ran 1/4" copper tube out & down to can outlet hole. Sent the kid out with the guage and a pair of vice grips to tune his pipe pressure!!!! Wa la---Pipe pressure dropped from 3.9#'s ( stock pipe & can ) to 1.8#'s with the tube open. He sqeezed the end down until he hit the target # which was 3 #'s. DONE. Ready for race. This was a quick fix to get away from having to modify the pipe etc. Sled ran awesome.
Say the next race is at 3,500' instead of here at sea level- pipe pressure will drop because of altitude, so, maybe won't need so much bleed off. At any rate, totally adjustable to keep the motor happy and the pipe working without the dreaded pipe heat soak issues on the long straights.
On the 8oo's and bigger I usually weld a 2" stinger and reduce down to adjust pressure. Example would be a 800R in an 09' XP. SLP Pipe with a "Thing" can which is a really good combo. Modified exhaust valves that open fully approx 4,500 rpm, Boyesons,13.25 to 1 compression- 2" outlet with a 44.5 mm restrictor should be close. ( We'll be finishing one today). Stock pipe / can pressure is 3#'s. That's where we'll be when we're done.


BCROCK
I played around with the restrictor bolt trick last season and melted a few motors.when I started i believe i was at 1lb and I think I ended up about 3.5lbs or 4. the motor ( flannery full mod 600) ran much better with the higher pressure but produced too much heat, basically doing what looked like a cold seize after 3-4 laps.is there a happy medium # or is just an expensive crap shoot till it doesn't melt?

Lancelarue - Pipe Pressure

Check your gauge on a stock motor. There's your baseline.

LRD
I bought the Omega Gauge as recommended except without auto shutoff early last winter.
Wow free HP found.
My sled is a 08 TNT 600 carb I built into a mtn sled with 15 X 141 X 2.25 track and 365 lbs dry weight, so performs great and very high fun factor because of low weight.
Engine ported and bigbored to 621.
Did some preliminary testing at low altitude in MN before going out west to get an idea of pressure in the system. Note I have Carbon Fiber cannister and expected it to be low and it was.
When we were out in the mtns first put in my largest ID reducer bushing for the stinger of the pipe and had only about 1.8 lbs of pressure. With 1.8 lbs engine would pull 7700 rpm on repeated runs. Then added my smallest ID reducer bushing to the stinger, pressure jumped to 2.8 lbs and r's went to
8100, right where I wanted them. Without the ability to check the pipe pressure and adjust accordingly would have had to pull a lot of weight out of the clutch.
I have been chasing this idea for 20 years and finally with the digital gauge can measure it accurately. Have previously tried a mechanical gauge for measuring exhaust back pressure and no consistency at all. Worthless!
My sled ran and performed the best it ever has in the mtns.
The testing tells me also if your exhaust system leaks anywhere your losing a great deal of performance.
Good Luck
Thanks Lancelarue, my sled rocks now a lot more than it did before

Lancelarue - Pipe Pressure

 

Sure is nice to get rid of another variable! Glad the guage is working good for you.
Have a set of big twins to tune here pretty quick. I can't wait to see what's going on--------


#116 LRD

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Posted 15 November 2013 - 12:04 PM

Here is the adjustable restrictor bolt for raising pipe pressure.  It will make finer adjustments.   Its simply a two nuts and bolt one nut welded onto side of pipe back at the stinger over hole for bolt to go through. Second nut locks bolt in place.

 

So far have only used my restrictor.bushings that slip into the end of the stinger of the pipe. Have 3 different sizes ID that I have used for tuning along with the gauge.

When I get a chance I will take a pic of the bushings and post.

 

Hopefully  this winter I will finally finish my wifes mtn conversion of her 09 500SS and get baseline readings on her stock engined sled.

 

I,ve been fairly conservative with the pressure I,ve set of 2.8 lbs at 8000 ft and then we go up to really ride between 9000 to 11000 feet.  And as you go up the pressure in the pipe will keep going down. So I think I,m still missing some HP

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#117 LRD

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Posted 15 November 2013 - 01:18 PM

Went looking and found some more old threads from 08 that got trying to measure pipe pressure, This time by the TurboAl

 

 

TurboAl
understanding flow capabilities of your sleds exhaust

ski doo posted in there service material to there dealer network last season showing some graphs on what cans did to there motors performance .
unfortunately the test was targeted at the operation of the sleds in low elevations. there correct but to be fair the test should have shown results at elevation. and a 7000ft reading would have shown totally different results.
riders, understand 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 diminished .
a can that showed tight at sea level wont show tight at elevation . a loose can will preform terrible 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

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?


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 had a 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 maintain a constant pressure reading as we went up in elevation.

really surprise that doo hasn't done it as they do have the tech knowledge to do it .
that all led to the can i build that uses acoustics to accomplish what we achieved mechanically.
wave physics .

to know which can has a good pressure reading associated with the main pipe it is attached to is a matter of hooking up a low pressure gauge 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 comparison to your engines compression here to

there are a lot of gauges capable of doing the test . a digital one is way expensive but is the best .
even a cheap vacuum pressure gauge from your auto store would work.
make a nipple in the pipe and use some steel brake line .

check your reading at home , compare it to the elevation reading or through a range of elevations as you head up the trail. 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

 


the pipe pressure reading at sea level is 3 lbs at wide open throttle
the pipe pressure 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 .

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 pipe max pipe pressure readings at elevation...it is a good one to take a stock pressure reading at low elevations. has always been our base line.
use the pressure gauge 3 inches from the small outlet at the back of the main pipe . this location works well in being able to plumb a gauge into
you can put it in the middle section of the pipe as well.

use your gauge 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 . gauges can vary a bit so by using this approach you can match that pressure at elevation, there by knowing you are making the same pressure a the stock can did a the 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.hotseatpe....ID=4144&DID=29

And from another thread in Sept 08
TurboAl

 

 

you can make pipes work but you dont need to guess on it . trouble is no one has said how you can know . when checking pipes , do it at the elevation you will ride in . there is a simple field test you can do , does require a small mount of pre work on the pipe but is going to allow you to select the correct outlet for the pipe for your application .

what is needed is to determine the running pressure in the pipe , pick one on the twins , the test is done at wide open throttle .only takes a short time to get the reading .
what you are looking for is a 3 lb max reading pressure wise . increase outlet or decrease outlet to acquire the correct reading and you will get the very best out of what ever pipe you choose . twins or single .

how do we do this is a matter of drilling a 1/8 hole in the rear cone just about 2 inches from were it gets its smallest . weld a short piece say one inch long brake line to the pipe over the hole , easier to drill hole after welding short piece of brake line to it .
now get a small vacuum , pressure gauge from your local auto store , not an expensive item or find a mechanic that has one and borrow it .
fix this in a spot you can ee tape what ever and connect between the pipe nipple you have and the end of the pressure gauge .
you can get a pretty decent idea on a jack stand and a bit of brake held on to simulate a load and not let the motor over rev , this will give you a very good idea beore running a stretch to have the pipes up to temp as there is a small difference to pipe pressure at cold reading and one at proper temp .

when taking a reading at elevation we don't run up the trail with a hose attached to the pipe and gauge due to you will melt the hose . put it on for testing only /
held wide open and you are pulling hard on the system you will get a very good idea on the number .


just so you know the pipe pressure drops on a parallel with the compression change you see in an elevation change . 3 lbs pipe pressure at sea level is only going to be 2 lbs at 7000ft . compression will be 150 sea level , 120 at 7000ft .
that is why it is important to test at the riding elevation .
 
LRD
Those who don't know who TurboAl is, Al owns a high performance shop in Revelstoke, BC and also is the inventor of the "Thing" exhaust can which through acoustics very s pipe pressure with altitude changes.  Al has also over the years been a great source of clutching knowledge.
 


#118 SnowriderKALLV

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Posted 15 November 2013 - 01:53 PM

This is really great info LRD thanks for sharing.

#119 LRD

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Posted 15 November 2013 - 01:55 PM

Here is one of my Stinger reducer  bushings and the Omega 0 -15 PSI digital gauge

The bushing slips into the stinger end of the pipe and the small lip keeps it there once you put the can on.



#120 banditpowdercoat

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Posted 15 November 2013 - 07:18 PM

Hmmmmm, Thx for the read.  I use Omega products lots at work. IT Tech.  Never thought about pipe pressure.  Gona be getting supplies to test mine me thinks


Dan Pesonen

If it ain't broke, modify something till it is.....
Frankensled original

Frankensled V2.0

5.5' truck box, 11.5' l sled, What's the problem Officer? It fit's great with the tailgate down!!!