Mar 17, 2015, 03:36 PM
Last edit by: IB Advertising
Issue: What is the best EFI tuner with no crazy modifications
When looking for a new EFI tuner there could be a lot of information out there that is difficult to wrap your head around. Users give their opinion of what is the best tuner out there that doesn't have too many bells and whistles for a decent price.
Read the full discussion below for more information
When looking for a new EFI tuner there could be a lot of information out there that is difficult to wrap your head around. Users give their opinion of what is the best tuner out there that doesn't have too many bells and whistles for a decent price.
Read the full discussion below for more information
Best tuner ?
Don't know if anyone completely addressed this but let me try (key word, "try").
Your bike is controled by the ECM, or computer. This computer has pre-porgrammed tables that use input from your various sensors to determin how much fuel and spark advance to command based on specific situations.
One of the inputs it uses under 80% of your driving conditions are your factory O2 sensors. They are not smart sensors (narrow band O2s) and can only tell the computer if it is lean or rich but not exactly how much to either side of correct it really is. However, the computer is smart enough to use this information to tweak fueling needs to get the fuel demands close to what it is programmed for.
Now, in the other 20% of the time the computer "guesses" based on what it has learned during that other 80% of the time as to what your fueling should be. When in this mode, it ignores the O2 sensors.
Knowing that, there are a couple different options out there.
1. The factory download. Harley downloads new tables into your ECM to overwrite the factory tables. This download is very basic and is the same for the particular model of bike you have, not the mods you have put on it. (ie, the download for a Fatboy Lo with SE slip ons and stage 1 A/C would be the same as the one for a Heritage with V&H Short Shots and an Arlen Ness A/C). While better than nothing, the general consensous is this option is only best if you use SE parts on your bike.
2. O2 Spoofs. These devices plug in between your O2 sensors and the ECM. They are designed to Spoof the ECM into seeing a leaner condition than actually exists. This causes the ECM to command more fuel. A very basic option and has no tunability but works for stage one mods for most people.
3. Piggy back system (non-adjustable). This is like the V&H fuelpac. It will act similar to the O2 spoofs but will go between the ECM and sensors/injectors/ignition to do more than just change what the ECM is seeing from the O2s. The benefit to this is that you are modifying the ECMs output in a more controlled fashion to get a more accurate result than with just O2 Spoofs. Downside is like option 1, this is just a "canned" tune and has no...or very very basic...adjustments. Again, works good for stage 1 upgrades (with V&H parts if you're using their fuelpac) but you'd need to go with another solution for further mods.
4. Piggy back system (Adjustable). This is like the PC3 and PCV systems. These systems go between the ECM and it's sensors/injectors/ignition to make adjustments to what the computer sees and what it commands. Two nice things about this solution is that you can always revert back to stock by just removing the device yet it gives you a great deal of customization if you expand your modifications later. Usually these come with just a "canned" tune for your modifications and require a Dyno tune to fine tweak the system. Because of their complexity, they will not use the stock O2 sensors to modify fueling needs. This means it is far more critical to get their settings (or their "map") just right for your modifications and riding conditions.
5. Piggy back system (Adjustable with Autotune). This is the PCV with the autotune feature. These now replace the stock "dumb" O2 sensors with Smart (wide band) O2 sensors. This is one reason why these systems are so expensive (wide band O2 sensors are about $125/each last time I priced them). These smart O2 sensors are what dyno shops use when they do their tunes. These sensors give very accurate feedback as to the air/fuel ratio that is coming out of the exhaust. This allows the Piggy Back system to actively adjust the tune as you drive. With this system, a dyno tune is not required to get better performance.
6. ECM Custom Reflash or replacement. This is what the SERT does and what the Thundermax allows you to do (but replaces the stock ECM completely). It allows you to physically change the tables within the ECM like the factory download (option 1) but now you can change all the values in those tables for any kind of modification you make to the engine. The benefit to this is that you are adding no additional devices to your bike or trying to "Spoof" the ECM in any way to get the right results and have direct control of the tables in your ECM. The drawback to this is you (or your tuner) MUST know what you're doing when modifying the tables and the SERT option REQUIRES a dyno tune to get the most out of it every time you make a modification to the engine. With the Thundermax ECM system, you physically replace your stock ECM with their system. If you get the Thundermax system with Autotune, it now will automatically tweak the base tune using Wide Band O2s. Coupled with the available table maps for different modifications, this eleminates the need to dyno tune the Thundermax ECM with Autotune like you would need to do if reflashing your stock ECM with the SERT.
Now, which is best for you...well, that's up for you to decide. There are pros and cons to each...and I've only outlined them...but this is a basic overview of the different types of tunning tools out there.
Your bike is controled by the ECM, or computer. This computer has pre-porgrammed tables that use input from your various sensors to determin how much fuel and spark advance to command based on specific situations.
One of the inputs it uses under 80% of your driving conditions are your factory O2 sensors. They are not smart sensors (narrow band O2s) and can only tell the computer if it is lean or rich but not exactly how much to either side of correct it really is. However, the computer is smart enough to use this information to tweak fueling needs to get the fuel demands close to what it is programmed for.
Now, in the other 20% of the time the computer "guesses" based on what it has learned during that other 80% of the time as to what your fueling should be. When in this mode, it ignores the O2 sensors.
Knowing that, there are a couple different options out there.
1. The factory download. Harley downloads new tables into your ECM to overwrite the factory tables. This download is very basic and is the same for the particular model of bike you have, not the mods you have put on it. (ie, the download for a Fatboy Lo with SE slip ons and stage 1 A/C would be the same as the one for a Heritage with V&H Short Shots and an Arlen Ness A/C). While better than nothing, the general consensous is this option is only best if you use SE parts on your bike.
2. O2 Spoofs. These devices plug in between your O2 sensors and the ECM. They are designed to Spoof the ECM into seeing a leaner condition than actually exists. This causes the ECM to command more fuel. A very basic option and has no tunability but works for stage one mods for most people.
3. Piggy back system (non-adjustable). This is like the V&H fuelpac. It will act similar to the O2 spoofs but will go between the ECM and sensors/injectors/ignition to do more than just change what the ECM is seeing from the O2s. The benefit to this is that you are modifying the ECMs output in a more controlled fashion to get a more accurate result than with just O2 Spoofs. Downside is like option 1, this is just a "canned" tune and has no...or very very basic...adjustments. Again, works good for stage 1 upgrades (with V&H parts if you're using their fuelpac) but you'd need to go with another solution for further mods.
4. Piggy back system (Adjustable). This is like the PC3 and PCV systems. These systems go between the ECM and it's sensors/injectors/ignition to make adjustments to what the computer sees and what it commands. Two nice things about this solution is that you can always revert back to stock by just removing the device yet it gives you a great deal of customization if you expand your modifications later. Usually these come with just a "canned" tune for your modifications and require a Dyno tune to fine tweak the system. Because of their complexity, they will not use the stock O2 sensors to modify fueling needs. This means it is far more critical to get their settings (or their "map") just right for your modifications and riding conditions.
5. Piggy back system (Adjustable with Autotune). This is the PCV with the autotune feature. These now replace the stock "dumb" O2 sensors with Smart (wide band) O2 sensors. This is one reason why these systems are so expensive (wide band O2 sensors are about $125/each last time I priced them). These smart O2 sensors are what dyno shops use when they do their tunes. These sensors give very accurate feedback as to the air/fuel ratio that is coming out of the exhaust. This allows the Piggy Back system to actively adjust the tune as you drive. With this system, a dyno tune is not required to get better performance.
6. ECM Custom Reflash or replacement. This is what the SERT does and what the Thundermax allows you to do (but replaces the stock ECM completely). It allows you to physically change the tables within the ECM like the factory download (option 1) but now you can change all the values in those tables for any kind of modification you make to the engine. The benefit to this is that you are adding no additional devices to your bike or trying to "Spoof" the ECM in any way to get the right results and have direct control of the tables in your ECM. The drawback to this is you (or your tuner) MUST know what you're doing when modifying the tables and the SERT option REQUIRES a dyno tune to get the most out of it every time you make a modification to the engine. With the Thundermax ECM system, you physically replace your stock ECM with their system. If you get the Thundermax system with Autotune, it now will automatically tweak the base tune using Wide Band O2s. Coupled with the available table maps for different modifications, this eleminates the need to dyno tune the Thundermax ECM with Autotune like you would need to do if reflashing your stock ECM with the SERT.
Now, which is best for you...well, that's up for you to decide. There are pros and cons to each...and I've only outlined them...but this is a basic overview of the different types of tunning tools out there.
Elite HDF Member
Joined: Apr 2008
Posts: 4,718
Likes: 11
From: Back in the Good Ole USA. South Carolina to be exact.
What "Harley ones" do you replace?
Elite HDF Member
Joined: Apr 2008
Posts: 4,718
Likes: 11
From: Back in the Good Ole USA. South Carolina to be exact.
That might be over-stating it a bit. The SERT & SEPST do come with canned maps (like a PC does) and the bike will run pretty good with these as long as the hardware is a reasonable match to the map, usually most likely if you have HD hardware of course. Some Autotuning with the SEPST afterwards is usually all that's needed to bed things down. A dyno tune is a good idea, of course, but then that's true of most of these fueling solutions.
Loading a base map simular to your configuration is likely to be an improvement. And Smart Tuning that is way easy.
Elite HDF Member
Joined: Apr 2007
Posts: 4,919
Likes: 23
From: Seattle, WA
I have seen numerous threads / posts about the PC being the culprit in electrical issues ....
R/
'Chop
I was very surprised NOT to see the TFI or Gen3 by Dobecks Performance mentioned.. I have a 09 with V&H slip-ons and HD's SE Air using a TFI... No More running Lean and runs Cooler too, it really works good..
I recently installed SE 255 Cams.. The TFI handled that very well.. TFI is a piggy Back and installs easily and also is adjustable like a carb...
It come with Suggested settings on its 4pots.. The adjustment I needed to do after the install of the Cams ,,, was to turn down on the Green light pot...Yes down as the Breathability of the SE 255's brought More Air and didn't need any More fuel but Less..
I get about 40/42 mpg...
No, I don't sell these. I only suggested you LOOK into them as I have and Save $$ over Other fuelers you don't need for the Light modifications like I (we) have done.. around 250$$ for either TFI or Gen3 by Dobecks..
The best thing is the easy install and It WORKs...
I would never go for the HD download for the stage one as it only gives More fuel at the WOT position and RPM that can damage the engine....
Who wants to rev a 4.375 stroke motor over 5600 RPM in the first place,,,, On the Street ?? maybe the track...
signed....REDHEAD
I recently installed SE 255 Cams.. The TFI handled that very well.. TFI is a piggy Back and installs easily and also is adjustable like a carb...
It come with Suggested settings on its 4pots.. The adjustment I needed to do after the install of the Cams ,,, was to turn down on the Green light pot...Yes down as the Breathability of the SE 255's brought More Air and didn't need any More fuel but Less..
I get about 40/42 mpg...
No, I don't sell these. I only suggested you LOOK into them as I have and Save $$ over Other fuelers you don't need for the Light modifications like I (we) have done.. around 250$$ for either TFI or Gen3 by Dobecks..
The best thing is the easy install and It WORKs...
I would never go for the HD download for the stage one as it only gives More fuel at the WOT position and RPM that can damage the engine....
Who wants to rev a 4.375 stroke motor over 5600 RPM in the first place,,,, On the Street ?? maybe the track...
signed....REDHEAD
Outstanding HDF Member
Joined: May 2008
Posts: 2,166
Likes: 4
From: la
Outstanding HDF Member
Joined: Dec 2010
Posts: 2,036
Likes: 8
From: Temecula, CA
Thanks for the points...will go back in and adjust where applicable. 
Not sure that needing to remove the stock O2 sensors is due to 'their complexity'. Rather its because otherwise the stock ECU will read the AFR as rich or lean (as set by the PC) and try to override this and so undo the tune applied on the PC i.e. its more about overcoming a limitation of the PC+stock ECU combination than because its a good thing to remove the O2 sensors.
That's kind of what I meant by 'Complexity'. Was trying to keep the deffinitions as simple as possible and not throw too much at someone. I tend to do that ANYWAY. LOL
Since I have not used the SERT first hand I was taking what I knew from tuning ECMs in cars and painting this with a broad, slightly tinted, brush. But yes, the canned maps that come with these will get you close. I mainly mentioned the two drawbacks because, for many, the importance with having the more "robust" tuning options will be for future modifications and for that knowing what you're doing and dyno tuning are a must if you're spending that kind of cash on the motor anyway.
They've come down quite a bit then. Use to be a good Narrow band would be $50. At the time, few cars came with wide bands stock but you were starting to see more and more come with them from the factory. Must have driven the prices down. Then again, I know there was a reason why we stayed away from replacing our factory Bosch O2s in our Grand Prix's with Denso units...can't remember why that was though...hate getting old.
EDIT: NOW I remember...the Bosch units have a small slit in the side of the pickup...that part which is actually in your exhaust stream... and had a tendancy to allow for a larger margin of error at determining af ratio if the slits weren't possitioned just right in the stream. The Denso units looked more like swiss cheese so that no matter which way they seated they would always have the same exposure to the exhaust stream and read very accurately from one to the next. So when we would price Wide Band O2s, we would price the Denso units which run $90-$160...
Not sure that needing to remove the stock O2 sensors is due to 'their complexity'. Rather its because otherwise the stock ECU will read the AFR as rich or lean (as set by the PC) and try to override this and so undo the tune applied on the PC i.e. its more about overcoming a limitation of the PC+stock ECU combination than because its a good thing to remove the O2 sensors.
That might be over-stating it a bit. The SERT & SEPST do come with canned maps (like a PC does) and the bike will run pretty good with these as long as the hardware is a reasonable match to the map, usually most likely if you have HD hardware of course. Some Autotuning with the SEPST afterwards is usually all that's needed to bed things down. A dyno tune is a good idea, of course, but then that's true of most of these fueling solutions.
http://shop.advanceautoparts.com/web...487-_-10720525 You can get O2 sensors cheaper than $125.
EDIT: NOW I remember...the Bosch units have a small slit in the side of the pickup...that part which is actually in your exhaust stream... and had a tendancy to allow for a larger margin of error at determining af ratio if the slits weren't possitioned just right in the stream. The Denso units looked more like swiss cheese so that no matter which way they seated they would always have the same exposure to the exhaust stream and read very accurately from one to the next. So when we would price Wide Band O2s, we would price the Denso units which run $90-$160...
Last edited by Robotech; Apr 14, 2011 at 05:33 PM.
Stellar HDF Member
Joined: Feb 2011
Posts: 2,023
Likes: 457
Thanks Robotech for explainning each type system. Now I have a better idea of how I want to mod my bike. After reading everyones advice on tunners over the 6 months my head is spinning.
Just have to find a job to support my habbit.
Just have to find a job to support my habbit.
Tourer
Joined: Apr 2007
Posts: 311
Likes: 0
From: DE
I went with the Thundermax. I LOVE it. Bike starts quicker, runs smoother, cooler, and better then stock. Added a cam, uploaded a new tune and I was OFF! I actually had them tune it in Daytona last year. Great guys, great company, and a great product. Pricey, but I found it to be worth it.
Road Captain
Joined: Feb 2007
Posts: 684
Likes: 1
From: Colorado
Scott is a good guy, and if / when you choose to tune your bike, he is the MAN.. actually S&S flew him in to tune their Xwedge when they were getting ready to release it to the public.
It might not hurt to tell him "Ken from Colorado" referred you.