Dynatec CDI and Jetting


9 replies to this topic
  • Parx_400

Posted June 14, 2013 - 06:33 AM

#1

Two Questions,

1. FOr the more advanced two settings on the Dynatec should I rejet and aprox how much more? I use Indy 450's chart as a baseline. Bike has a yz cam, relocaed battery/ completed open top airbox and a full open exhaust.

2. Is it possible to use the differnt maps as a way to adjust your jettings? For example lets say I jet the bike for setting one that is more advanced than stock. I go on a super long ride where my altitude goes from 4K to 11K depending on the area. could you the stock map effectivly richen the bike and then the setting 2 that is more advanced than setting one to lean the bike. I have never played around with ignition before some im just wondering.

  • beezer

Posted June 14, 2013 - 09:36 AM

#2

What kind of graphics do you have?

  • Parx_400

Posted June 14, 2013 - 10:03 AM

#3

Stock :)

  • beezer

Posted June 14, 2013 - 10:06 AM

#4

Me too.

My Dynatec ignition should show up today or Monday.

I'll let you know how it works. I'm at sea level.

  • mywr4504stroker

Posted June 16, 2013 - 01:15 AM

#5

hi guys
im new to this site just wondering does anyone no how to adjust a votex on a wr450 2005

thank you

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  • Krannie McKranface

Posted June 16, 2013 - 07:39 AM

#6

Two Questions,

1. FOr the more advanced two settings on the Dynatec should I rejet and aprox how much more? I use Indy 450's chart as a baseline. Bike has a yz cam, relocaed battery/ completed open top airbox and a full open exhaust.

2. Is it possible to use the differnt maps as a way to adjust your jettings? For example lets say I jet the bike for setting one that is more advanced than stock. I go on a super long ride where my altitude goes from 4K to 11K depending on the area. could you the stock map effectivly richen the bike and then the setting 2 that is more advanced than setting one to lean the bike. I have never played around with ignition before some im just wondering.


Jetting means air/fuel ratio. It only needs to be correct. You cannot 'jet for more power'. When you substantially change air-pressure (or humidity), you alter your jetting to suit. That's it.

Ignition curves means when the spark occurs, and for how long (dwell), in relation to the piston/crank position.

The two are not directly related, but can be used to change motors characteristics.
You do not alter jetting for 'tuning', unless the air/fuel ratio is way off. When it's right, it's at it's best.
You do alter the ignition curve as tuning, EG: to create a 'soft' map for difficult traction conditions, or other.

If the spark is 'retarded' (sparks too early) you get less power. If the spark is 'advanced' (sparks as late as possible) then you can get more power. If it is too far advanced, it will detonate (pre-ignite; 'ping').
So, the trick is to advance it in the right places to match load, jetting, riding type, and the state of the motor's tuning.
That is why there is a 'curve' instead of a straight 'line' of spark advance/retard, because the motor does not have linear characteristics.
The stock WR ECU curve #1 and curve #2 are very different, and some bikes get 'stuck' in curve #1 (like mine), and many bikes 'toggle' between the curves, causing the stutter.
The Vortex does not have 'auto-switching' curves. You pick from one of (4) pre-made curves, and go. Or, you create your own, using the programming tool.



You might be confusing the Vortex discussed here for the pre2012 WR's with a FI ECU programming box for the '12/'13 models, which alters both.

Now, having said that, if you have a high compression piston, porting, and are running race gas, you can now advance your timing substantially, for more HP,
without also getting detonation (pre-ignition).

Edited by Krannie, June 16, 2013 - 07:44 AM.


  • tomerb

Posted June 16, 2013 - 08:55 AM

#7

"If the spark is 'retarded' (sparks too early) you get less power. If the spark is 'advanced' (sparks as late as possible) then you can get more power"


I don't understand what your saying.

  • Krannie McKranface

Posted June 16, 2013 - 11:19 AM

#8

"If the spark is 'retarded' (sparks too early) you get less power. If the spark is 'advanced' (sparks as late as possible) then you can get more power"


I don't understand what your saying.


....and I don't understand what you are asking......

You, as a motor designer, have to choose when the spark occurs.....anywhere from before, during, or after Top Dead Center on the compression cycle (not literally after....)
You can't pick one timing....because the motor does not have a linear power curve. So you have to match the curve to the motor, or against motor, or whatever, to achieve the desired power band and throttle response.
Hense, the mapping curve choices (handle bar map switch) or auto curves (WR450) or gear dependent curve mapping (CRF450R), etc.

  • grayracer513

Posted June 16, 2013 - 11:22 AM

#9

"If the spark is 'retarded' (sparks too early) you get less power. If the spark is 'advanced' (sparks as late as possible) then you can get more power"


I don't understand what your saying.


One reason might be that the quoted statement is backward; advanced is early, retarded is late.

Another consideration is that there is an optimum ignition timing point for every situation. The purpose of spark timing is simple; the spark occurs in advance of the piston's down stroke so that the burning fuel will have time to build the necessary pressure in the combustion chamber to drive the piston down on the power stroke. If the spark happened at TDC, the piston would be halfway down the bore before there was any significant pressure applied to the crown, and by then it would not be possible to translate that pressure into any useful output mechanical force.

If the spark is too early, the pressure will rise too soon and attempt to reverse the piston before it reaches TDC, which will cost power, and can cause the fuel to begin to detonate (ping, knock) rather than burn smoothly.

  • Krannie McKranface

Posted June 16, 2013 - 11:34 AM

#10

"If the spark is 'retarded' (sparks too early) you get less power. If the spark is 'advanced' (sparks as late as possible) then you can get more power"


I don't understand what your saying.


Oh yeah, I wrote it backwards.......... :naughty:[size=4] [/size]




 
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