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WHATEVER
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Discussion Starter · #1 ·
I would like to understand how a dyno is used to tune a V-rod using the SERT, does anybody have any good links to info or knowledge they would share.

I have no idea how a dyno works so the more info, the better.

Thanks!
 

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RICK
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648 Posts
The User Manual In Your Race Tuner Software Gives A Lot Of Info--131 Pages Front To Back. That Gives You All The Basics, After That It Is In The Tuner And Experience Knowing The Changes To Make And Where To Make Them.
 

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WHATEVER
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Discussion Starter · #3 ·
I am very familiar with the SERT Manual, I tune extensively with a Twin Scan and dual channel wego, what are the basics of tunning on a dyno, are you doing the same runs to redline in different gears?, how do you know what adjustments to make to the VE tables once you have your commanded AFR set?, is there a specific software that does these calculations? etc.
 

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RICK
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648 Posts
No, The Af Ratio Table Has Limits. When Those Limits Are Reached, You Must Change The Amount Of Calculated Air(ve) Entering The Cylinder To Alow Adjustment With Af Ratio Table. Each Cylinder Uses Its Own Ve Table, Allowing For Single Cylider Tuning. There Is No Software That Calculates It For You. You Must Use An O2 Sensor And Load Adjustments. For A New Custum Built Map From Scracth, You Use All Gears, All Rpms. If You Are Just Fine Tuning, You Don't Need To Go Through All The Headaches Of A Custom Map. A Custom Built Map From Scratch Can Take Days!

On The 07 Tc's With O2 Sensors, You Don't Tune With The Af Table, You Have To Use The Ve Tables(except Under Full Throttle)
 

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WHATEVER
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Discussion Starter · #5 ·
Rick, thanks for the info. one more question, once you have your VE tables set to where the meassured AFR is consistant with the commanded AFR can you change the AFR tables to fine tune without having to re-adjust the VE tables?
 

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RICK
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648 Posts
Thats Correct! Once They Are Set, The Af Table Is Simple And Easy, As Long As You Can Get Your Measured Air Fuel Ratio(o2 Sensor In Exhaust) To The Correct Ratio Without Reaching Your Table Limits In The Race Tuner. Its Relativly Simple Once You Understand How It Works. Are You Tuning Each Cylinder Individually?
 

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WHATEVER
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Discussion Starter · #7 ·
Yes I tune them individually. I have learned a couple of tricks from SROD as far as reaching table limits you can change the injector size in the tuning constraints (smaller will give more fuel due to increased PW) or you can change the CI and then recalibrate the VE tables with O2 monitoring equip.
 

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SNAFU
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13,094 Posts
Another thing to note, tuning an EFI on an inertial dyno is pretty close to guess work. There are ways to sweep the pulls using partial throttle and if you use a fast reacting wideband sensor instead of a true 4 or 5 gas probe you can get close.

If you really want to tune an EFI system you need a brake dyno. With a brake dyno you can maintain a constant RPM and sweep through the throttle positions to adjust complete rows of the VE table per pass. With these you can use a true 4 gas analyzer since you stop on each TPS/RPM cell for a few seconds thus allowing the 4 gas to lock into a reading.

BUT, since the dyno cannot simulate all of the riding variables such as wind drag and airflow into the motor you are doing just that, simulating the road experience. That's why a device like the Twinscan2+ is so great. It records live data in a real world situation so all variables are taken into account.

In the best situation I would use the TS2+ to get the base map then use a dyno WITH the TS2+ to fine tune WOT and other areas that have less data points in normal riding.

The factory does exactly that. They use the dyno to get a rough baseline then ride the bike thousands of miles using data acquisition then fine tune any gaps back on the dyno. It's a real scientific process, that's why I get a kick out of Bubba in his trailer at these rallies who purports to be able to do "what the factory can't" :rofl:
 

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Jay Johnston
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You guys are great, thanks for explaining all of this, I never post in this section because I simply don't know enough, I guess I just don't know what I don't know, but I read and re-read everything. It is making more sense with each new post.
So for whatever it's worth THANKS I appreciate the detailed explanations!
 

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spit happens
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RNTRACING said:
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On The 07 Tc's With O2 Sensors, You Don't Tune With The Af Table, You Have To Use The Ve Tables(except Under Full Throttle)
Now don't quote me on this,but I thought with the '07's and newer you had to somehow turn off the O2 sensors with the SERT to get a more accurate tune on the dyno.Correct me if I'm wrong.
 

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SNAFU
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Vinny said:
Now don't quote me on this,but I thought with the '07's and newer you had to somehow turn off the O2 sensors with the SERT to get a more accurate tune on the dyno.Correct me if I'm wrong.
On the closed loop bikes you put it in open loop and load a "normal" AFR table into the map so you can calibrate the VE table. Then, after you get the VE tables cleaned up, you turn close loop back on and reload the closed loop AFR table.

You do the same thing when you retune a car ECM, they have been closed loop for a long time. If you leave it in closed loop the BLM tables mask what's really happening. Going open loop lets you see the base calibration.
 

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Registered
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Closed loop tuning

Like mjw said tuning must be done in open loop to get a good map'
HD closed loop will try to correct AFRs +or - half to one full AFR so if you are running a measured 12-1 AFR at cruise on the dyno or your scanner it cannot make it 14.6-1 as indicated in the Air fuel table.it can only correct to about about 13-1.
When tuning first take all the Red cells in the AFR table (14.6-1)and make them 13.1 (my preference)This disables the closed loop function- Closed loop is only enabled when Desired AFR is 14.6-1.
Then tune the bike to about 14-1 Measured AFR using the VE tables and then put all the AFR table cells you changed back to 14.6 (red).
Closed loop will then be enabled again.
Note Closed loop is primarly used for normal riding conditions Not WOT /Heavy Load--ETC
These areas should be tuned using VEs only with a richer desired AFR.
Hope this makes sense(probably not)
Stu
 

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Premium Member
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Oh man, I just got my SERT today, and they're tuning it next tuesday. I hope they know all this crap
 

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PeytonVRSCD said:
Oh man, I just got my SERT today, and they're tuning it next tuesday. I hope they know all this crap
All that sounded like Chinese to me. Glad I'm dropping mine off with Srod this week.
 
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