DynoTech on the Poo 800-Some thoughts

[thefullmonte]

When I purchased my '05 900, I was told that there were three different injectors that may come on the sleds. I was told that not all injectors flowed the same amount of fuel so they sorted the injectors into three groups; red, blue and yellow. Each color corresponded to a different flow rate of the injectors. In order for this to work the injectors had to match the right fuel map on the ECU. For example, if you had "red" injectors, you had to have the "red" fuel map in the ECU.

Assuming this is correct, could this show up on the dyno as a different fuel map? It would be good to know what injectors the Dragon and the SB that Jim dynoed had, red yellow or blue. As I recall the injector color was listed on a box under the clutch guard on the newer sleds.

Jim, let us know what you find for injectors on any 800's that you have come through your dyno shop.

Thanks

SpeedWobble

There was some mention of this last year as well. The possibility of different injectors flowing differently. This goes back to some poor running issues some were experiencing. Keep those wheels turning everyone. Everyday, one step closer to perfect running sleds.

 

[BigTruck]

So............



After reading through all of this great info, and getting really pissed at Indydan (im over it now).

What should I be clutching for? 7900 or 8300. Im currently running 10-64 weights and have no idea where that will put me (no snow yet).

Should I clutch for the 7900 or the 8300?

That seems to be the question.

Thanks.

Rob.

 

[R44guy]

This is great information but why is it so hard to get the correct information from Polaris's engineering department? I know the factory does not always approve of reengineering the wheel but this information can help everyonr including Polaris? Oh sorry I forgot about the federal emissions regulations or laws. What about all of these tuners besides the power commander? Like the BD, logic, attitude? or whatever they are can they help or are they just like starting over?

 

[hilinerider]

So............



After reading through all of this great info, and getting really pissed at Indydan (im over it now).

What should I be clutching for? 7900 or 8300. Im currently running 10-64 weights and have no idea where that will put me (no snow yet).

Should I clutch for the 7900 or the 8300?

That seems to be the question.

Thanks.

Rob.

fyi,

my setup for my d8 last year was 19/41 gearing, stock spring and helix with 10-64 weights, hps can, stock pipe no flash

ran good with no bog ran 6-8 elev.

pulled 7900 rev most all the time, top i seen was a little over 8,

could have been better imo,
going with carls clutch kit and 19-42 gears, going to see how that does, i want to see how it pulls at 82-83 then i will know and report

 

[dynotechjim]

the RPM where you will achieve your best acceleration with stock engine/ stock pipe is totally a function of the average gas temp in your pipe. I plan to provide that info, it has no bearing on altitude, just average temp of the exhaust gas in your pipe abd we can get that close by measuring EGT in the middle of the pipe center section, the fattest part of your pipe.

And for new good info on breakin/ HP improvement I just got this from Kevin Cameron:

http://www.dynotechresearch.com/blog/archives.asp?chosenMonth=11&chosenYear=2008#225

 

[AKSNOWRIDER]

the RPM where you will achieve your best acceleration with stock engine/ stock pipe is totally a function of the average gas temp in your pipe. I plan to provide that info, it has no bearing on altitude, just average temp of the exhaust gas in your pipe abd we can get that close by measuring EGT in the middle of the pipe center section, the fattest part of your pipe.

And for new good info on breakin/ HP improvement I just got this from Kevin Cameron:

http://www.dynotechresearch.com/blog/archives.asp?chosenMonth=11&chosenYear=2008#225

well jim, I can only comment on one of my big nitrous race motors from years back..but on this 440 CI. big block chevy it came off a dyno breakin..tune session went into the chassis made 6 passes on wet sand(200 ft ea)where the 2- 500 hp pro fogger kits were dialed in... then back on the dyno for full power pulls on both the motor and 1 fogger kit...it was then pulled down and reringed and put back on the dyno for more full power pulls...(these pulls were same day ..very close to same conditions...motor picked up 86 hp with a fresh re-ring on no re-hone...now we are talking a full on drag race custom race engine but I have had noticable seat of pants performance increases on other engines including 2 strokes by re-ringing without honing cylinders...my guess on a 800 sled you might gain 4-6 hp on a 2000 mile re-ring without honing. have never had a problem with ring seal either...

 

[dynotechjim]

I had similar actual dyno results in a tech article you can see on my website archives (11/1/2004). We took a SkiDoo 600 twin with the infamous missing moly in the rings, leaked down 50% and 30%. Dynod 114hp, 209 CFM airflow. Fresh pistons/ rings and 30 min breakin netted [only] 3 HP with 117hp, 210 CFM [that agrees with your butt dyno!]. We really expected more because the blowby must have been severe. Kevin Cameron suspected that whatever escaped past the rings was mostly unburned fuel and air from the squish area, so no bad contamination could be occurring down below. So the poor ring seal was effectively dropping compression and increasing the squish area where fuel and air hide during peak combustion.

 

[BigBoreManiac]

Have I had it backwards all these years? Whenever mating two metals in a slip condition, whether linear or rotational, the materials should be dissimilar with one softer than the other. I always thought the ring were the harder material, thus the classic ridge that forms in the cylinder wall after service. The classic crosshatch honing forms a surface that can be machined smooth by the rings. The rings will loose some of their temper during service, thus softening and allowing more blow by. Thus, the power improvement achieved when re-ringing without honing. In todays engines, the cylinder walls are made much smoother whether by machine process, coatings, or both and therefore deliver the run-in performance out of the box.

So have I been wrong? Which is harder, ring or cylinder?

 

[Ron]

Here's a paste from an article on Nikasil. Looks like the rings are softest, so with Nikasil you "break in" the rings?

By Larry Carley
""Nickel is the “glue” that holds and supports the particles of silicon carbide on the cylinder wall surface. Silicon carbide is a very hard abrasive material with a hardness second only to diamond. According to one company who uses the process, the coating has a hardness rating of 600 on the Vickers scale, and a sliding hardness of 58 to 60 Rockwell C. The hardness combined with a tendency to attract and hold oil (“oleophilic”) makes these coatings highly wear resistant. To keep it from wearing the piston rings, though, the size of the silicon carbide particles must be very small, typically around 3 to 4 microns in diameter. The particles make up only about 4 percent of the coating.""

 

[BigBoreManiac]

Yeah, noticed that article after my post. Very informative. And to think it all started with the Vega?

 

[Ron]

Jim,

Good info on break in by Kevin Cameron but mostly about auto's and 4 strokes. You have no oil pan to catch metal so actual component wear is not apparent by that method on a 2 stroke. There are no iron cyclinders to wear....just rings on Nikasil.
This still doesn't answer the original question about the Polaris 8 break in vs dyno horsepower of a new engine.
There is a recommended process on the Polaris engine for break in....involves extra oil, a procedure & several hours to burn off the first tank of mix gas.
Break in includes seating rings and also includes other engine bearings/components.

Seems to me you need to dyno test an engine-
1. That has been through the break in procedure as recommended by the manufacturer.
2. With fuel that has been tested so that Octane rating is known.
3. With a sled that has been set up properly by a quality Polaris Dealer. (TPS setting)
Aren't there enough other variables without adding to the list? Maybe there would only be a small change in results but that is just guessing isn't it?

 

[dynotechjim]

Ron I still think the breakin provides little added HP. If there is any improvement in ring seal it likely is very little. As we saw with that SkiDoo 600, replacing defective rings with new ones (leakdown improved from 30/50% to 9/10%) only added a few HP. When we were bewildered by the low HP on the demo D8 (800 miles) we checked leakdown at less than 10%. We didn't check Casey's new D8 but after 10 gallons of gas through it on the dyno they are surely as good as they'll ever be. And Casey's brand new engine was nearly identical in HP to the demo sled on the first pull, with the same ECU (remember we did 30 minutes at varying RPM, light to heavy load on Casey's new engine before testing so that may have helped improve the already good ring seal).

Other than ring seal, there is the concept that poorly fitted or shaped bearings and rubbing parts (like the gear drive of the waterpump) eat some horsepower, and use energy to smooth those parts, and grind metal into hot particles like we used to see during breakin on our old 292 Fords. But as KC indicates, referring to modern engine design, "the energy argument disposes of the idea that [the HP improvement] could be a large amount. If much power was going into making metal particles you'd see the metal - lots of it."

Modern car engines come ready-to-go, with perfectly lapped rings. High performance models come with full synthetic oil in the sumps. I don't think the new sleds are much different.

 

[penguinpoo]

Jim,

Good info on break in by Kevin Cameron but mostly about auto's and 4 strokes. You have no oil pan to catch metal so actual component wear is not apparent by that method on a 2 stroke. There are no iron cyclinders to wear....just rings on Nikasil.
This still doesn't answer the original question about the Polaris 8 break in vs dyno horsepower of a new engine.
There is a recommended process on the Polaris engine for break in....involves extra oil, a procedure & several hours to burn off the first tank of mix gas.
Break in includes seating rings and also includes other engine bearings/components.

Seems to me you need to dyno test an engine-
1. That has been through the break in procedure as recommended by the manufacturer.
2. With fuel that has been tested so that Octane rating is known.
3. With a sled that has been set up properly by a quality Polaris Dealer. (TPS setting)
Aren't there enough other variables without adding to the list? Maybe there would only be a small change in results but that is just guessing isn't it?

I have checked the cylinder leakage of many engines, the best are around 2%. I have also experienced the dismal power of engines that have been rerung without cylinder glaze removal. I am with Ron, when dynoing engines for published results, some more care in selecting fuel and checking such things as tps setting would seem to be prudent. Look at the number of people who said they canceled their snocheked sleds on the results of the 08 1/2 dyno results.
How many times have we experienced the performance gain that comes with several hundred miles of breakin? Granted, more than just the engine is breaking in, but an engine with 2% leakage is going to make more power than one with 10%.

 

[rab]

check out this site for another perspective on the Break in procedure

http://www.mototuneusa.com/break_in_secrets.htm

 

[Ron]

check out this site for another perspective on the Break in procedure

http://www.mototuneusa.com/break_in_secrets.htm

Very interesting article, convincing too. But....does it apply to a 2 stroke with hard nikasil lined cyclinders? If it takes a diamond hone on nikasil seems like the cylinder wall "cross hatch" won't wear off anytime soon as rings seat themselves. Hmmmm!!!!

 

[dynotechjim]

"How many times have we experienced the performance gain that comes with several hundred miles of breakin? Granted, more than just the engine is breaking in, but an engine with 2% leakage is going to make more power than one with 10%."

Could it be the rubber track becoming more flexible? I'm not familiar with drivetrain breakin, but I respectfully disagree that an 8% difference in engine cylinder leakdown will result in any meaningful change in HP (though I've never seen a 2% engine here). I'm betting that performance increase from miles driven is more drivetrain related than engine HP increase.

 

[MARV1]

right on the money

I am with Ron, when dynoing engines for published results, some more care in selecting fuel and checking such things as tps setting would seem to be prudent. Look at the number of people who said they canceled their snocheked sleds on the results of the 08 1/2 dyno results.

It is sad but true. Wonder how many people out there cancelled because of DTR's poor fuel that made low power that was used in their dyno sessions? Higher performance engines like the new 800 need good fuel to make the power they can produce.

 

[voodoo]

It is sad but true. Wonder how many people out there cancelled because of DTR's poor fuel that made low power that was used in their dyno sessions? Higher performance engines like the new 800 need good fuel to make the power they can produce.

Who can get good gas these days? It's almost impossible to find non-ethanol anymore. I am glad they dyno with pump gas. Jim is honest with what he buys. If I remember right he bought 93 and it detonated right away indicating something was up. Most premium gas has some additive in it to bring up the octane. Usually it is some type of oxygenator that leans down the mixture. I have used what I like to call "dirty 87" for years. Rarely if ever burnd one down on it. I have burned more than 1 down on so called premium. What good would it do for Jim to find perfect gas or use 100 LL or some type of race gas to produce a good number then have the rest of us trying to figure out why our sleds never run that good. What you are suggesting is far worse than what happened. Why do you continue to discredit this company. Why don't you build a dyno in AK and prove to the world your vast internet knowledge.

 

[buckshot]

Is there a way to rig up a light on the dash to tell you that the computer has compensated for bad fuel?

 

[MARV1]

^^Yes, it is the DET sensor/check engine light. It blinks every second when you have a lean condition, usually from bad fuel.