zx14fan
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Posts: 547
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posted January 13, 2010 10:32 PM
Dyno manipulation
I post this question before but I guess I didnt make myself very clear.I understand static crank hp vs rear wheel hp.Can the dyno numbers be manipulated through gear changes?
  
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BobC
Pro
Posts: 1736
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posted January 14, 2010 12:16 AM
 Edited By: BobC on 14 Jan 2010 12:08
Isn't it the rate of change of the roller rpm that's being measured? Looking at the HP curve for my bike it's nearly the same in 4th, 5th and 6th. The roller speed is different in each gear for a particular engine rpm ( why the dyno needs a tacho input from the bike) and the dyno is calibrated taking this into account. Shoot me down if I'm wrong.
The map below was my bike when it was originally set up in 2006. The secondary 'flies were still in and it was geared 18/41 just before it's 205mph run at Woodbridge. Dyno run 2 below was with the exhaust and PC fitted but running a zero map, run 18 was the custom map after adjustments.
If you think about it, if what you asked was true then you could get more or less rear wheel HP by altering the final drive ratio, which you can't of course. The rear wheel speed will change with different gearing for a particular crankshaft rpm as will the acceleration but the power won't change.
____________
Candy Thunder Blue 2006 ZZR1400
Stock wheelbase
Max: 205.4 mph in 1.25 miles
2012 ZZR1400 in Golden Blazed Green
Brock CT Full System. etc
Max: 203.1 in 1 mile (so far)
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zx14fan
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posted January 14, 2010 01:02 PM
Ok that makes sence bob.
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Shane661
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posted January 14, 2010 01:11 PM
Edited By: Shane661 on 14 Jan 2010 21:25
Final gearing will affect hp #'s on the dyno, believe it or not:
http://www.hotbikeweb.com/tech/0808_hbkp_dyno_tuning_for_engine/dyno_testing_and_gear_ratios.html
I have personally found this to seemingly be true on my bike. I have several different dyno sets, with different gearing, and over 100 pulls.
Shane
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zx14fan
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posted January 14, 2010 02:12 PM
Shane could there be an equal between hp and gearing gain on a dyno to a certain point?
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Shane661
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posted January 14, 2010 02:15 PM
Do you mean like a formula to calculate the difference in hp based on a gearing change?
I have no idea.
It's really not significant since the power of the engine is not changing. It's just the way the machine is loaded and measuring the data. Don't get too caught up in chasing dyno #'s as they are not always indicative of performance.
Shane
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zx14fan
Zone Head
Posts: 547
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posted January 14, 2010 02:24 PM
That makes sence what I read.Im wondering say for example two teeth on a rear sprocket could be close to x amount of power on a dyno or if the difference isnt worth noting?
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Shane661
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posted January 14, 2010 02:27 PM
With all my dyno pulls and gearing changes, the output was within about 2%. The bike does always seem to put out a little more in a higher gear, with back-to-back pulls.
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zx14fan
Zone Head
Posts: 547
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posted January 14, 2010 02:34 PM
My point with this shane is to see if its worth changing gears for the street and the coastal roads here in cal.Based on what you think and have found I think Im better off leaving things the way they are?
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Shane661
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posted January 14, 2010 02:38 PM
Edited By: Shane661 on 14 Jan 2010 22:40
Ok, just to be clear:
Changing gearing does not affect the power output of the engine. What it does is increase or decrease the available power at any particular rpm.
As an example, if you put a couple of teeth on the rear sprocket, you will be turning a higher rpm at any given road speed. This puts more power on tap. It can be explained in more complex ways, but that is the simple explanation.
You are not going to see the true benefit of a gearing change on the dyno, but it will be very apparent on the street. Put a 16T sprocket up front, and see for yourself.
Shane
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gilberjj
Needs a job
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posted January 14, 2010 02:50 PM
One thing to think about, if the dyno in question feeds air dependent on speed, the faster you turn the drum, the more air the engine is going to get because of the simulated ram air.......
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zx14fan
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posted January 14, 2010 02:51 PM
Thanks for the time shane.I will try the 16.Its clear now what you explained.There seems to be some confusion on the subject.
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Shane661
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posted January 14, 2010 02:53 PM
A 16T front sprocket will be like getting a new bike. Try it. 
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08green
Expert Class
Posts: 188
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posted January 14, 2010 03:08 PM
i heard you get better numbers if you dyno in 4th vs 6th..
____________
2004 ZX10
2008 ZX14
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smokinZX14
Needs a life
Posts: 10197
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posted January 14, 2010 03:49 PM
quote:
i heard you get better numbers if you dyno in 4th vs 6th..
On my dyno 4th 5th or 6th allways makes the same HP ..
____________
Smokin Performance Cycles..
Tampa Bay , FL .. Brocks Performance Dealer ..
Gen 2 ZX14R Best ET 8.43 , Best MPH 164.95
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wrongway
Pro
Posts: 1078
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posted January 14, 2010 03:51 PM
quote:
Isn't it the rate of change of the roller rpm that's being measured? Looking at the HP curve for my bike it's nearly the same in 4th, 5th and 6th. The roller speed is different in each gear for a particular engine rpm ( why the dyno needs a tacho input from the bike) and the dyno is calibrated taking this into account. Shoot me down if I'm wrong.
The map below was my bike when it was originally set up in 2006. The secondary 'flies were still in and it was geared 18/41 just before it's 205mph run at Woodbridge. Dyno run 2 below was with the exhaust and PC fitted but running a zero map, run 18 was the custom map after adjustments.
If you think about it, if what you asked was true then you could get more or less rear wheel HP by altering the final drive ratio, which you can't of course. The rear wheel speed will change with different gearing for a particular crankshaft rpm as will the acceleration but the power won't change.
were you using a TRE or GIPro to set the gear position sensor to 5th or 6th gear ?
Roy
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Shane661
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Posts: 11494
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posted January 14, 2010 03:55 PM
quote:
quote:
i heard you get better numbers if you dyno in 4th vs 6th..
On my dyno 4th 5th or 6th allways makes the same HP ..
Your dyno is a special case, Lee. I heard that most 14's only make 129 hp on it! 
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smokinZX14
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posted January 14, 2010 03:57 PM
quote:
quote:
quote:
i heard you get better numbers if you dyno in 4th vs 6th..
On my dyno 4th 5th or 6th allways makes the same HP ..
Your dyno is a special case, Lee. I heard that most 14's only make 129 hp on it!
Your 14 will make 129 mine will make 170 ..Well it will look that way if we ever race each other ... 
____________
Smokin Performance Cycles..
Tampa Bay , FL .. Brocks Performance Dealer ..
Gen 2 ZX14R Best ET 8.43 , Best MPH 164.95
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Shane661
Needs a life
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posted January 14, 2010 04:02 PM
quote:
Your 14 will make 129 mine will make 170 ..Well it will look that way if we ever race each other ...
...You're going to eat those words one day, buddy!
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smokinZX14
Needs a life
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posted January 14, 2010 04:19 PM
quote:
quote:
Your 14 will make 129 mine will make 170 ..Well it will look that way if we ever race each other ...
...You're going to eat those words one day, buddy!
 
____________
Smokin Performance Cycles..
Tampa Bay , FL .. Brocks Performance Dealer ..
Gen 2 ZX14R Best ET 8.43 , Best MPH 164.95
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kingtramp
Expert Class
Posts: 121
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posted January 15, 2010 02:32 PM
quote:
Ok, just to be clear:
Changing gearing does not affect the power output of the engine. What it does is increase or decrease the available power at any particular rpm.
As an example, if you put a couple of teeth on the rear sprocket, you will be turning a higher rpm at any given road speed. This puts more power on tap. It can be explained in more complex ways, but that is the simple explanation.
You are not going to see the true benefit of a gearing change on the dyno, but it will be very apparent on the street. Put a 16T sprocket up front, and see for yourself.
Shane
CHange to time at X axis
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Shane661
Needs a life
Posts: 11494
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posted January 15, 2010 02:36 PM
quote:
CHange to time at X axis
Yeah, that should show it, actually.
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BobC
Pro
Posts: 1736
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posted January 16, 2010 02:27 AM
Edited By: BobC on 16 Jan 2010 10:31
quote:
were you using a TRE or GIPro to set the gear position sensor to 5th or 6th gear ?
Roy
No Roy, the only mods were the TiForce exhaust, a Speedo Healer and the Dynojet Power Commander. We did 19 dyno runs the first time in August 2006 to create the custom map and then another 17 runs in March 2007 to re-map it after I removed the secondary throttle butterflies. Thats 36 runs in all, a lot of time and patience on the part of Steve the Dyno' technician and a lot of $$ from me. There were no off-the-shelf maps available for TiForce then. Not like the Brock system I bought last year which came with 9 free maps.
____________
Candy Thunder Blue 2006 ZZR1400
Stock wheelbase
Max: 205.4 mph in 1.25 miles
2012 ZZR1400 in Golden Blazed Green
Brock CT Full System. etc
Max: 203.1 in 1 mile (so far)
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JDC
Zone Head
Posts: 570
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posted January 16, 2010 07:53 AM
Edited By: JDC on 16 Jan 2010 16:17
quote:
I post this question before but I guess I didnt make myself very clear.I understand static crank hp vs rear wheel hp.Can the dyno numbers be manipulated through gear changes?
If you change your sprockets your dyno ramp will look very different.
I had a few runs... I'll see if I can find them.
The HP/TQ will peak out at an earlier RPM if your are sizing up the rear/dropping the front.
Here u go.
45 on rear and 1 diff on front.
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wrongway
Pro
Posts: 1078
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posted January 16, 2010 11:16 AM
If you change the x axis to rpm instead of speed, they would line up ....
Roy
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