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Adirondack SnowGoer DTR Shootout trail mod entrants

D&D has committed to six sleds:
08 F8 trailport, twin pipes
SkiDoo XPR800/ 862cc with D&D single pipe/ Ypipe
F1000-1200 twin pipes
F1000 trailport twin pipes
other two sleds TBA

Chuckaroo Motorsports
1240 MachZ twin
08 SkiDoo XPR800 trailport w/  DynoPort  single pipe  (will dyno this sled next Thursday)

Full Power Performance Apex turbo, Nytro turbo.

Excell  Nytro w/ custom exhaust

Allan Ulmer three sleds (two MPI SC sleds Nytro and Apex plus one tba)

CJ Motorsports 08 SkiDoo 800R/ 860 big bore, single pipe stock muffler

DynoPort tba

Crankshop - Larry you need to come this year!

HTG tba

JD Powersports Cat T660 trail mod





 


Adirondack Shootout Decisions for 07

George Taylor and I are in the middle of this 18th annual Shootout, between new sled dealers, aftermarket companies who are providing trail mod sleds to show their wares, and SnowGoer/ SnowWeek magazines who are partners with DynoTechResearch in the Shootout at Woodgate this year.

This year SnowGoer is bringing a video crew to tape the Shootout, which will be televised on Fox Sports Network this winter. Also video clips will be seen on SnowGoer's website after the shootout.

Factory stock sleds will be 600 class and 800 class sleds.  Perhaps since Polaris won't have their new 800 delivered by 12/1  the SnowGoer guys Tim Erikson and John Prusack will have the currently available Dragon 700 to represent the 800 class?

SnowGoer has elected to delete the "Lakeracer" class we ran last year--race gas is no longer allowed. All aftermarket "Trail Mod" sleds will have their tanks pumped out and replaced with Old Forge 93 octane unleaded.

Any entrants dyno tested by DTR prior to Shootout can have HP numbers posted by SnowGoer.

All trail mod sleds will run DTR supplied pump gas, stock OEM suspensions, Uncut OEM tracks and standard trail carbides not sharpened. Sleds can be lowered a max of 2" from stock front and back.

Trail mod sleds will run1000ft.

Trail Mod sleds must be entered/ sponsored by an aftermarket company doing business increasing sled/ engine performance. $500/ sled any number of entries OK'd.

Aftermarket companies can opt to have results NOT posted by SnowGoer if problems arise, but $500 entry fee will be forfeited.

More to come as we approach December.

Tim Erickson called, will have some lake mod sleds at shootout.

Adirondack Shootout 2008

We're contemplating changes for this December.

This is Shootout #19. Amazing, since it seems like yesterday that Jerry  Bassett and I created this concept of me dyno certifying stock sleds then us doing some sort of field shootout with guaranteed stock sleds. Shootout #1 was held in a farmer's field in central NY, Tim Bender was the shootout test driver, handheld stopwatches and a radar gun provided data. Tim caught our first cheater that year, noting that the carbureted 650 Indy accelerated like a dragster, impossible to be box stock! Turns out somone had compromised the sled hood seals and installed dragrace clutches. Jerry Bassett deleted that sled's data from Shootout #1.

Eighteen years and a few caught cheaters later, here were are again.

But this past few years with SnowGoer awarding a Shootout Trophy for "most improved" performance for stockers out-of-the-crate to "dealer prep", there seems to be some finger pointing about detuning box


 

A/F ratio comparison of Dragon 800 pipes


This data shows an implication of higher airflow CFM with the BMP and SLP pipes. Fixed fuel flow from EFI plus leaner A/F ratio = assumed higher airflow CFM. Adding HP with higher airflow is always good, and I should have noted that in the article. The day after the test session, Casey Mulkins was on Chautauqua Lake doing multi-mile blasts at 8200RPM with the Dragon 800 w/ BMP mod and no extra fuel. All is well and fast so far.




A technical description of Fuel Atomization by Kevin Cameron

 

 Descriptions of how carburetors work tell us that fuel spraying from the needle jet is atomized by the airflow and…

 

Wait. Stop right there. How is it atomized, and why? What makes the atomizing finer or coarser? Let’s look into it. Long ago, a fellow named Hochschwender photographed droplets suspended in a rising stream of air. They weren’t “teardrops” at all, but were squashed spheres, flattened by air pressure of the air streaming against them. Then they popped, reformed into a ring, then burst into a necklace of much smaller droplets.

 

Why should this be? The grand old man of fluid mechanics, Ludwig Prandtl (1875-1953) outlined the matter. Liquids are held together by molecular forces of attraction. Inside the liquid, these forces are largely “invisible” because they act in all directions, but at the surface, they act like a skin under some slight but measurable tension-the so-called surface tension. In the absence of other forces, surface tension pulls the droplet into spherical shape. Just like the rubber skin on a water balloon, surface tension produces pressure inside the droplet. This is proportional to surface tension, and inversely proportional to droplet size. Opposed to this is the pressure of the air hitting the drop, which tends to flatten it. This is called the dynamic pressure, and is proportional to the density of the air and the square of its velocity. As the flow slows in hitting the droplet, its kinetic energy is converted into pressure energy.

 

Fuel shoots from a carburetor’s needle jet, straight out into the intake stream, which is speeding past a hundreds of feet per second. The fuel droplets are heavier than the air, so they can’t instantly accelerate to airflow speed, but lag behind. This difference in speed subjects them to dynamic pressure, which flattens them in good old Hochschwender style, bursts their centers, and explodes them into halos of tiny droplets. If the airflow velocity is high enough, and these smaller droplets have not yet accelerated up to speed, they too, may in turn be flattened and burst into yet-tinier droplets. In short, Hochschwender and Prandtl proposed that for a given air velocity, there was a corresponding droplet size to which fluid would inevitably be broken down by this process. To estimate what this size might be, Prandtl suggested that a droplet would break when the dynamic pressure of the air equaled the droplet’s internal pressure, created by its surface tension.

 

This gives us part of the reason why smaller carburetors are easier to tune than bigger ones; they produce higher venturi velocity, which physically beats the fuel droplets down to smaller sizes. These smaller droplets evaporate promptly to make an easily ignitable mixture that engines thrive on. Engines are often designed to give mean intake-duct velocities near 350 feet per second. Using this velocity, Prandtl’s formula gives a droplet size of about 100 microns, or .004 inch. This is not bad for a rough calculation, for in fact droplet sizes from carburetors range between 50 and 200 microns. Why so big? Remember that this calculation is for the case in which the droplet is hit with full stream velocity. In reality, by the time mid-sized droplets have been formed from the break-up of big ones, the air will have accelerated them quite a bit, so the relative droplet-to-air velocity will have fallen. The droplets are coming up to speed in the airflow. That permits some bigger ones to escape unbroken.

 

Now consider a limiting case. The air-blast fuel-injection system used on Orbital Engine Company’s automotive two-stroke engines works as follows: There is a pre-chamber, connected to the engine’s combustion chamber by a small orifice. Fuel is injected into the pre-chamber, forming large-ish droplets in the 50-100 micron size range. Next, a tiny valve opens, admitting a burst of air to the pre-chamber at 60 psi. This drives the coarse fuel/air mixture out through the orifice, where the flow reaches the speed of sound, and into the main combustion chamber. Naturally, the air, being lighter than fuel, accelerates quickly through the orifice, leaving the fuel lagging. This produces a very great speed difference between the droplets and the air accelerating past them, and the result is extremely fine atomization—down to a mean droplet size of 10 microns, or ,0004 inch. When we try this number in Prandtl’s formula, we get a corresponding velocity of 980 feet per second—satisfyingly close to the speed of sound.

 

There are endless racing and hot-rodding epics in which the hero struggles to get big, hi-po carburetors to work on his modified engine, but just cannot combine all necessary aspects or performance—acceleration, top speed, throttle response, freedom from detonation.

 

Yet it all makes sense. Tiny fuel droplets from small, high-velocity carbs evaporate fast and ride happily with the air to their hot destiny in the cylinders. Big droplets from monster mixers prefer to resist and misbehave every way they can: wetting the walls, refusing to turn corners, failing to evaporate fully, even splattering against sparkplug insulators where heat bakes them to conductive carbon film that shorts out the spark. The engine misfire-“shoots ducks,” in the old hot-rod lingo-and doesn’t clear until high rpm brings the intake airspeed up enough for good mixture to resume. Sudden throttle movements leave these liquid sluggos loitering in the intake pipes while the now-lean air/fuel charge hastens to the cylinders.

 

The unhappy result is a “momentary interruption of service,” with detonation—the spice of the tuner’s life—a likely possibility.

2012 info & updates

GEORGE TAYLOR--74 year old George Taylor has died of heart failure. He had been a partner with DynoTech and American Snowmobiler Magazine for 22 years helping organize and orchestrate the annual stock sled Shootout in the Adirondack Mountains. George owned Van Aukens Inne near Old Forge, NY which was Shootout Headquarters for many years until it was sold. But in his retirement George stayed on with me to help organize the dealers, shootout facility, promotion etc each year. This year, Tom Smith is helping out in George's absence. Long time Shootout attendies will surely remember Tom, former owner of Smith Marine SkiDoo. About 20 years ago at the Shootout (then at the Old Barn Restaurant in Eagle Bay) Tom goofed on his "dealer prep" setup and both his SkiDoo stockers (a 580 and a 670) seized at 1000ft. Annoyed by a large group of jeering hecklers in the crowd, Tom retaliated by dropping his pants and flashing a horrible-looking moon (complete with awful Brahma bull-like swinging testicles) to the 1000 or so grossed-out but pleased spectators. To those of you who are coming to the Shootout this December, please do not annoy Tom!   

NEW NEIGHBORS--Jeff and Dave from JD Powersports have moved their facility from Rochester, NY to the west end of my commercial building in Batavia. They've set up a showroom/ office and their production welding equipment (for tig welding Arctic Cat stainless steel turbo pipes and mufflers etc) and their own SuperFlow 902 dyno right next door to me. Now my one neighbor who sometimes expresses his displeasure over the noise coming from my dyno room can enjoy the sound of howling engines in stereo! JD has just finshed dyno testing their "anti-lag" mode that they program into the stock Cat ECU, and plan to bring a machine fitted with that to our "Turbo Time" shootout in December. 

GOOD NEWS FOR ETEC OWNERS--next week DynoJet is sending me a preproduction Power Commander V for the SkiDoo ETEC system. Finally, we should be able to properly add the fuel necessary to support added airflow from Boyesen Rad Valves, Ypipes, pipes, porting, big bores etc. I need someone with a stock Etec 800 to come for a free tuning session, to assess how much fuel we can really add in high density (high baro, low temp refrigerated air) with the new PCV. NEWS FLASH 1/28/13 JUST GOT THE FIRST SHIPMENT OF PRODUCTION ETEC PCV's $499 PREMAPPED FOR YOUR COMBINATION, INCL FREE SHIPPING/ INS + 3 YRS FREE ADDED MEMBERSHIP TO DTR.

NEW SNOCROSS STOCKERS NEEDED! Free dyno tunes are offered for new Polaris, Arctic Cat, and SkiDoo 600 sleds. Also if there is a hotrodded Yamaha Nytro SnoX machine that could qualify for a free tune. We need to know how the new stock 600 class engines compare. Remember this year the mod 600cc SnoX sleds must retain stock engines (?!) except for pipes, compression, and ignition timing curves, and we need to see how the factories have reacted to this seemingly strange new rulebook. Call Jim 585-993-2777

 

 

2005 F7 EFI shocker and new stuff being tuned...

Today we dyno tuned our first 2005 F7 EFI.
Kaz was bringing his his new sled to tune, figuring on relying on his D&D pac to drop fuel pressure to optimise HP. We had communicated by phone a few times and I suggested as I always do with EFI F7ers: install a 2 or 3 degree key ahead of time (all smart F7 riders need that). It's more economical to do that in your garage than on my dyno at $125/hr. Come here with timing key in place and we'll be done more quickly.
Normally that means a baseline test or two, 10-1 A/F ratio is typical, then reduce top end fuel pressure with a main jet, a D&D pac needle jet, or any other needle valve to do the same thing.
So Kaz brought his new '05 F7, remember he has a 2 degree offset key, and blasted two runs back to back cool and hot, 147 HP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Then we installed a Speedwerx single and added  more HP.
Then we choked down the fuel pressure with D&D pac and added even more.
That two degree key  adds a few HP but this is unbelievable. Base fuel  flow lb/hr on this '05 F7 was 99-100 lb/hr. One hour earlier we had a 03/04 F7 on the dyno, 110 lb/hr base fuel flow. Was this another anomoly like Mike "Ziggy" Zigmont's '04 F7? Or is this how the new "05's are tuned by AC?
I've got all the dyno numbers here, SFD files, etc,  if I can stay awake I'll post them tonight. If I can't stay awake I'll try later this weekend. Everyone needs to see this.

I'm dynoing three sleds tomorrow (Bikeman F8, Speedwerx 1000, ZR900 mod) then dynoing two more on Sunday (both SLP ported ProX800's).

Spiders build fancy mosquito-catching webs on my dyno all summer. But in the fall the cool air sets in, and the spiders flee as the hordes of blue, yellow, green, red, black, and orange sleds converge here to dyno tune, having great fun optimizing whatever they have.

Also there is a new Fusion sitting at Cooper Sales and Service waiting for me to have two days to test and tune. Maybe next week. Plus the new MachZ's hare on their way, we need to dyno one of those before the Old Forge Shootout.
 

2005 DynoTechResearch $ cost to tune

Weekdays $125/ hr from overhead door opening to overhead door closing.
Saturday/ Sunday add $25/hr.

Setup time on F7s is usually 30-45 minutes if sled arrives w/o clutches and w/o hood, breakdown is 15 minutes. Max setup/ breakdown is one hour (in case I'm fumbling for wires, bolts, etc).

Minimum cost per sled  $250 weekdays $300 Sat/ Sun.






'10 sled testing, and Power Commander V

Scheduled this week--Thursday AM Casey Mulkins is bringing a new 2010 Polaris Rush 600 for stock evaluation with temps in the 30's F. If it's rich as we expect we will lean out mixture with a new power Commander V Autotune. Then we'll have Casey's own D8, upgraded with lots of stuff.

Friday AM, our first production 2010 Arctic Cat F8. Let's see how the production sled compares with the preproduction 800 we tested last February. 160? If not, we have our new PCVs for the Cats to get the fuel flow back where it was with the prepro 800.

We've got Power Commander Vs for all makes now--Yamaha, Skidoo 4 tek, Dragon 6,7,8 and just received the first Cat 800/1000 boxes that can be Autotuned. $369 free shipping. Autotune unit for self tuning $249 free shipping. PCV maps will be posted on this website as acquired. Canadian sledders contact Sledwerx in Ontario because I just shipped him a batch of PCVs to have in stock. So get it quickly from Spenc and save the weeks of customs delays.



 

"Turbo" Crankshafts, once more

Email from Jim C to Kevin Cameron:

http://parrisracingconcepts.com/Home_Page.php

This is the latest "turbo crank" deal, being aggressively marketed to snowmobile people now. Turbo crank mods are cicada-like, coming around, being promoted and talked about every few years, then going away.

Is this like the deal that [then TX highschool roadracer Colin Edwards' race team manager] David Herold tested here at DynoTech with you [as team performance consultant] 20 years ago on the [90 HP Yamaha roadrace bike] TZ250? I recall you saying at some point [prior to the dyno test] it couldn't possibly provide meaningful power or airflow boost because the  crank wheels were traveling well below the speed of sound [even at 12,000 RPM]. [The stock crank and "turbo" crank as you predicted delivered identical airflow CFM and HP]. 

Jim C
========================================================================

KC's response:

The important variable in the design of a centrifugal compressor is its tip speed - the velocity of the impeller tips. The impeller accelerates the air molecules to tip speed, and compression takes place as this energy of motion is converted in the diffuser into the energy of pressure. There is a strict elationship between the two.
 
Compute the "tip speed" of the crank-become-a-crude-centrifugal impeller as circumference in feet times revolutions per second. If the flywheels are 5" diameter the circumference is about 16 inches, or 1 1/3 feet. If crank rpm is 8500 then revolutions per second are 142. Multiplying the two together gives us a "tip speed" of under 190 feet per second.
 
Referring to my handy little table "Pressure of Air on Coming to Rest from Various Speeds" I find that an adiabatic pressure rise (adiabatic means with no exchange of heat) of 2% results from 100% efficient operation. Since the crank flywheels are not equipped with a diffuser as centrifugal compressors are, it is unlikely that much of this 2% would appear at the bottoms of the transfer ducts.
 
To get one atmosphere of compression requires 100% efficient recovery from a wheel with a tip speed of 1200 fps.
 
If these things have any effect at all, it's most likely on fuel vaporization.
 
KC

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