New EFI KLX250S performance testing needed.
#1
11-06-2019, 12:51 AM
Join Date: Jun 2013
Location: North Texas
Posts: 3,222
New EFI KLX250S performance testing needed.
There is much to learn regarding the new EFI KLX250S's. But someone needs to be the Pioneer.
1. A full dyno chart workup of the bike @ dead stock (but fully broken in). The stock fueling (AFR Chart) will give us a tremendous amount of data - allowing a vector for performance mods to be determined.
2. On a stock bike, the EJK should be dyno tested with the O2 sensor left intact. This will reveal how well the stock ECM (and its' closed loop fueling) and the EJK "get along" together. If they do indeed "play nice" with each other - Closed loop fueling via the ECM and open loop fueling via the EJK without the two of them constantly fighting each other - then we have the problem of performance fueling solved and further performance mods can ensue.
3. Next is Lidless airbox and O2 equipped full exhaust system testing. The Barker system with the optional O2 bung may be the "only way to go" for best performance. The FMF system with either the Power or Mega Bomb header should do very well also... Once the EJK is used to restore the fueling to the AFR curve found in #2, performance fueling can be explored. The charts will also indicate whether the MCM should be "looked at" for boosting TRQ in the lower half of the RPM range.
It may be that 25 or more HP is easily achieved with the new EFI's..
1. A full dyno chart workup of the bike @ dead stock (but fully broken in). The stock fueling (AFR Chart) will give us a tremendous amount of data - allowing a vector for performance mods to be determined.
2. On a stock bike, the EJK should be dyno tested with the O2 sensor left intact. This will reveal how well the stock ECM (and its' closed loop fueling) and the EJK "get along" together. If they do indeed "play nice" with each other - Closed loop fueling via the ECM and open loop fueling via the EJK without the two of them constantly fighting each other - then we have the problem of performance fueling solved and further performance mods can ensue.
3. Next is Lidless airbox and O2 equipped full exhaust system testing. The Barker system with the optional O2 bung may be the "only way to go" for best performance. The FMF system with either the Power or Mega Bomb header should do very well also... Once the EJK is used to restore the fueling to the AFR curve found in #2, performance fueling can be explored. The charts will also indicate whether the MCM should be "looked at" for boosting TRQ in the lower half of the RPM range.
It may be that 25 or more HP is easily achieved with the new EFI's..
Last edited by Klxster; 11-06-2019 at 06:51 PM.
#2
11-15-2019, 12:46 AM
Hello all, I just finished installing a 351 on a 2019 klx250 with an FMF slip on & air box lid on 26.53 HP 21.00 Torque with the EJK that I modified for the 351 kit. I also installed a Barker exhaust on this bike, didn't modify the tuning of the EJK; we got 29.0 HP 20.78 torque. Modified EJK for 351 kit now available, B&B Cycle Restoration.
#3
11-15-2019, 01:39 AM
Join Date: Jun 2013
Location: North Texas
Posts: 3,222
There yall have it !!
Straight from B&B Cycle Restorations - our premiere performance shop of many, many, years..
WIth 29/21 power available with the lid on the airbox, well over 30hp (likely 32-34 hp) would be available with a properly fueled lidless application !!!
Straight from B&B Cycle Restorations - our premiere performance shop of many, many, years..
WIth 29/21 power available with the lid on the airbox, well over 30hp (likely 32-34 hp) would be available with a properly fueled lidless application !!!
#5
11-20-2019, 08:16 AM
Hello all, I just finished installing a 351 on a 2019 klx250 with an FMF slip on & air box lid on 26.53 HP 21.00 Torque with the EJK that I modified for the 351 kit. I also installed a Barker exhaust on this bike, didn't modify the tuning of the EJK; we got 29.0 HP 20.78 torque. Modified EJK for 351 kit now available, B&B Cycle Restoration.
So do we have any modified EJK for the 331 kit? I have one from you, installed few months ago. All works nicely, but the current EJK doesn't play very well with it, especially at small RPM.
#6
04-04-2020, 08:36 PM
does this require any changes to fuel injectors? Not sure of the stock injectors capability
#7
04-05-2020, 12:09 AM
Join Date: Jun 2013
Location: North Texas
Posts: 3,222
#9
04-05-2020, 02:01 PM
I would be interested in the results with a fuel injector from a KLX 300 installed both with and without the EJK.
I believe there were comments regarding the duty cycle of the stock 250 injector and whether it was capable of providing enough fuel for the larger bores to make maximum power/torque.
I am a firm believer that the EJK is a band aide treating the symptom, not a cure for the problem. If an injector from a 300 would provide the added/necessary fuel and the EJK was no longer necessary it would be a no brainer, just one less electrical possible point of failure.
I am certainly no expert and am just throwing this out for discussion. Any comments or thoughts are welcome.
I believe there were comments regarding the duty cycle of the stock 250 injector and whether it was capable of providing enough fuel for the larger bores to make maximum power/torque.
I am a firm believer that the EJK is a band aide treating the symptom, not a cure for the problem. If an injector from a 300 would provide the added/necessary fuel and the EJK was no longer necessary it would be a no brainer, just one less electrical possible point of failure.
I am certainly no expert and am just throwing this out for discussion. Any comments or thoughts are welcome.
Last edited by Thunderbutt; 04-05-2020 at 03:26 PM.
#10
04-05-2020, 08:21 PM
Join Date: Jun 2013
Location: North Texas
Posts: 3,222
Thunderbutt..
ECM settings for the injector include scaling, voltage/injector output table, and basic injector capacity.. There can be more settings but those are the basic.. The ECM must know this data in order to operate the injector properly.
This means that simply replacing the stock injector with a different one (That has different values for each of the above data fields) does not create the results expected. The ECM will be attempting to operate the new injector with the old injectors' data. In some cases, causing total loss of idle, and unpredictable rideability.
Doing a "blind" injector replacement is purely experimental and would have to be dyno verified after passing DynoButt testing..
The issue I've mentioned before is that all injectors have a limit to the performance they can support. Generally, a huge increase in potential performance (such as a BB kit) will tax a stock injectors' capability. Regarding our KLX's, it is unknown how much HP the stock injector can support - so this must be a consideration and a concern when tuning ... After all, we are talking about taking a KLX from 20hp to 30hp..
The HP capability is an easy lookup once the details of the stock injector are known - anyone planning a BB + air flow mods should do the research on the injector.
ECM settings for the injector include scaling, voltage/injector output table, and basic injector capacity.. There can be more settings but those are the basic.. The ECM must know this data in order to operate the injector properly.
This means that simply replacing the stock injector with a different one (That has different values for each of the above data fields) does not create the results expected. The ECM will be attempting to operate the new injector with the old injectors' data. In some cases, causing total loss of idle, and unpredictable rideability.
Doing a "blind" injector replacement is purely experimental and would have to be dyno verified after passing DynoButt testing..
The issue I've mentioned before is that all injectors have a limit to the performance they can support. Generally, a huge increase in potential performance (such as a BB kit) will tax a stock injectors' capability. Regarding our KLX's, it is unknown how much HP the stock injector can support - so this must be a consideration and a concern when tuning ... After all, we are talking about taking a KLX from 20hp to 30hp..
The HP capability is an easy lookup once the details of the stock injector are known - anyone planning a BB + air flow mods should do the research on the injector.
Last edited by Klxster; 04-05-2020 at 08:26 PM.