Dynoed a stock Attack today!

[87gtNOS]

One more question for Freddie. Did you know the gear reduction Ratio is different in the Apex then the RX-1??

Gear ratio doesn't affect HP, it only changes torque. In the case of the 4 stroke Yammy's, it is a torque multipler!! Which is good!

 

[87gtNOS]

I was just looking at the Amsnow Dyno Sheet on the Apex. They claim it made 149.8 at 10100 RPM. If you take 149.8 * 5252 /10100 you get 77.8 which is exactly what they show for Torque.

So there numbers are correct by the calculation as well!!!!!!!!!!!!!!!!!!!!!!!!

Yes, they are, but because HP is a derivitive of torque. But to get that torque reading they enter a correction factor based on Baro, humidity, elavation, temp, etc...

 

[87gtNOS]

One question I've always had is why not correct the hp to riding temperatures (freezing or slightly below).

In reality our sleds are making more than the dyno numbers in the real world because the power goes up as the temperature goes down (assuming it's jetted correctly).

I seem to remember looking up the correction factors and finding 137 hp turns into a real 145 hp a little below freezing.

This is where the "correction factor" thats being discussed is used, Freddies numbers are after the math is done. HP is HP, it dont matter if its 10 deg or 100 degrees or at sea level or 10,000 feet, once corrected it all washes out.

I think the point is, not everyone corrects 'honestly'. Correction factors can be manipulated. Bikeman, I have heard can creat artificial pressure in his room be sealing it up and pumping in fresh air.

 

[87gtNOS]

This is where the "correction factor" thats being discussed is used, Freddies numbers are after the math is done. HP is HP, it dont matter if its 10 deg or 100 degrees or at sea level or 10,000 feet, once corrected it all washes out.

But it does matter to the rider. Since the actual output HP changes with temperature, the sled is quicker in colder weather. If we are riding a machine that produces 140 hp at 70°F, but we always ride it in conditions where it makes 145 hp we've actually got 145 hp on tap when we want it not 140 hp.

This is still something that mystifies me. Our sleds are fuel injected. They ECU knows temp, baro, mass of air(maybe), etc...so they should stay in a top state of tune no matter the weather.
Yes, I do know that air changes..but how it affects our EFI sleds, I dunno?

 

[dirkdiggler]

I was just looking at the Amsnow Dyno Sheet on the Apex. They claim it made 149.8 at 10100 RPM. If you take 149.8 * 5252 /10100 you get 77.8 which is exactly what they show for Torque.

So there numbers are correct by the calculation as well!!!!!!!!!!!!!!!!!!!!!!!!

Yes, they are, but because HP is a derivitive of torque. But to get that torque reading they enter a correction factor based on Baro, humidity, elavation, temp, etc...

HP = rpm x T(torque)
5252(constant

T = 5252 x HP
rpm

Period

Unless they didn't imput the Baro, humidity, elavation, temp, into the dyno prior to making there passes these formulas apply

 

[87gtNOS]

Dirk, I don't think you get it...those numbers are manipulated based on correction factors...of course the HP has to match the torque. Both numbers are elavated...the easiest calculation to see that is divide the fuel flow by the BSFC you get the actual "observed" hp.
This actuall observed hp was then calculated based on a actual observed torque, prior to correction factors being applied.

 

[cameljockey]

This topic went to #*$&@ in a hurry. The guy posts his numbers and all of a sudden we have to hear the sceptics. Why would he post results from mods to hear a bunch of #*$&@ like this????????

 

[87gtNOS]

This topic went to poop in a hurry. The guy posts his numbers and all of a sudden we have to hear the sceptics. Why would he post results from mods to hear a bunch of poop like this????????

I am not being skeptical of Freddie, I am honoured to have him helping us.
I hope some will learn about how a dyno works from all this.

 

[fourload]

The three things that I know of that can change hp on a sled are intake air temp,baro pressure and humidity assuming the same fuel is used.Iam pretty sure that I read in dynotech a long time ago that they correct to 60-degrees 0-humidity and I think a barometer of 30.13.[Not too sure on the barometer.]

 

[dirkdiggler]

I'm going to reserve my thoughts on these numbers until after I see the numbers Posted after there is something to sell to make better numbers Wink Wink!!!!!!!

 

[AIRWOLF]

Freddie,

if you need another Apex let me know I will donate mine for a couple of weeks

 

[SUPERTUNER]

Freddie the truth detector, please tell us your thoughts on a Ram Air kit, whether or not you think it might work?? A simple design like cutting open the air box lid giving air a straight shot to the throttle bodies.
Reading your various replies you note that once you placed a fan in front of the sled with no lid on the airbox you actually picked up a few horses. But you also mentioned lean spots that have you concerned.

Dyno's are indeed polygraph machines! But they will only tell the truth if they are not lied to about weather parameters. As I stated in my PM reply to you, we tested a ram air deal last summer on the asphalt and it failed miserably. I would have to pay Dynojet a fortune to develop a jet kit for it. I would much rather invest the money and time into my ECP billet throttle bodies and FI system.

Freddie

 

[SUPERTUNER]

Geez, I leave for an afternoon and all this! I am not going to get into a pissing match about other shops dynos. There are very few inertia ENGINE dynos on the planet. I know there are others but very few!

A quick lesson about dynamometers: On a Superflow, Schenck eddy current, Stutska, or any other water brake or eddy current style dynamometer, you have the choice of a computerized acclerator or a manaul accelertor. (throttle) Manual throttle style dynos are open to HUGE skepticism due to operator errors etc. Just sneeze once while the dynorun and you either bog the engine and possibly ruin the crank or allow the engine to over rev and break the crank. So everyone spends the extra bucks for a computer controlled accelerator. COOL! But the difference between an inertia load dyno versus a water brake or oil brake dyno is that the engine is in a more true environment through inertia testing. A dynorun at ECP sounbds a lot like a dragrace run except there is no doppler effect. Comperterized acclerators start at lets say 4000 RPM's. They accelerate to 4000 and gather and record the data, then depending on where you set the puter to gather data, it accelerates another lets say 250 RPM's and gathers and records data. I believe most modern water brake style dynos can go as low as 100 or 50 RPM increments. So picture this, the engine is started, the computer accelerator is deployed and the engine starts its ascent to peak RPM. It gathers data at 4000 and records, then again at lets say 4250, then again at 4500, then again at 4750 and so on. I don't know anyone who rides their snowmobile or motorcycle like that. An inertia dynorun at ECP sounds very similar to a dragrace run. We start gather data just below clutch engagement and literally have dta every single microsecond along the way. I get to view the graphs with 3 runs overlaying or print them out numerically.

This doesn't mean my customer made by me Dynojet dyno is better than other brands, it simply means that I could replate to the gathered data better and correlate to the real world easier due to the fact that I understand it better than accelerating, gathering data and accelerating and gathering data.

The true fact about dynamometers is that they are all worth the weight in gold! Does it really matter what the baseline numbers are on any engine? Big power number merely feed ones ego. My ego has been fed for so long from my racing exploits, it is no longer hungry. I just want work for my shop. Jim Czekala is a brilliant man and a good friend for many years. I admire and respect him highly.


No part of the writ could be reproduced with the express permission of George Schenck, Walter Stutska, Daniel Dyno or Jim Czekala... especially Jim Czekala!

Didn't get a chance to run Pauls sled today. Was real busy with walk-in customer and telephone rang off the hook all day. Hope to get another chance tomorrow.

Ciao!

Freddie

My back still hurts I am going home.

 

[RED800]

so instead i bought a 138 hp machine,so either some dyno's are lying,or #'s are being deflated so when they bring a product out they can inflate the #'s and say their product increased the hp.. this much.....not a bash to anyone but,numerous dyno's showed 150,so they are wrong...

 

[SUPERTUNER]

Freddie,

if you need another Apex let me know I will donate mine for a couple of weeks

Will do AIRWOLF. E-mail me at:

KliesECP@sbcglobal.net so I have your e-mail on file. Also give me your telephone number please. Make sure to put something in the subject line that will catch my eye so I don't delete it.

Freddie