EMC - Adjustment of Air Fuel Ratio
Stellar HDF Member
Joined: Sep 2007
Posts: 2,452
Likes: 666
From: Vancouver Island B.C.
The Harley website says adding the 2 into 1 Screaming Eagle 2 into 1 exhaust requires and EMC update. Other manufacturers that offer a 2 into 1 exhaust for Harley bikes make no mention of an EMC update. I realize the EMC can make some degree of F/A mixture adjustment on its own (riding from sea level.to 5,000 feet probably requires some adjustment). Do the other manufacturers of 2 into 1 exhaust simple ignore and don't tell buyers an update is required or is Harley simply trying to force you to take the bike to them to swap out the exhaust?
Road Master
Joined: Feb 2021
Posts: 1,067
Likes: 469
From: Phoenix Arizona
@hattitude
"Again, IMHO, I always retune when I change the airflow through my engine. It gives the best, most efficient performance from the mods you make...."
Do you go to a dyno shop for retuning everytime? Do you have a add-on product supported system to flash maps?
Just curious.
FYI. I do agree and know a dyno tune is best. Not always practical or affordable.
IMHO
"Again, IMHO, I always retune when I change the airflow through my engine. It gives the best, most efficient performance from the mods you make...."
Do you go to a dyno shop for retuning everytime? Do you have a add-on product supported system to flash maps?
Just curious.
FYI. I do agree and know a dyno tune is best. Not always practical or affordable.
IMHO
Seasoned HDF Member
Joined: Sep 2008
Posts: 14,113
Likes: 11,160
From: San Diego, CA
@hattitude
"Again, IMHO, I always retune when I change the airflow through my engine. It gives the best, most efficient performance from the mods you make...."
Do you go to a dyno shop for retuning everytime? Do you have a add-on product supported system to flash maps?
Just curious.
FYI. I do agree and know a dyno tune is best. Not always practical or affordable.
As always, this is my opinion.
Short answer:
I use a flash tuner for all Stage I & II mods. The flashed maps from a good tuner, along with an auto tune session, work well on a street driven motorcycle. I have used a flash tune on a big bore but prefer a good dyno tuner. On anything above a big bore, I would go out of my way to get a good dyno tune.
Long answer:
I believe a dyno tune , by a knowledgable and competent tuner, is the best for any motorcycle tune. I emphasize the "knowledgable and competent" because it is my experience that not all people who own and run a dyno machine fall into that category.
Having said that, I live in SoCal. It is almost impossible to get performance parts shipped to CA anymore, and the last good dyno tuner I was aware of, worked for a shop that CARB went after. It almost had to close down. The shop barely survived the ordeal, and of course no longer has their "speed shop" or dyno machine.
I have and use a PowerVision full service tuner. I will rely on tune maps form FuelMoto or DynoJet for : Improved OEM tunes, Stage I tunes, and Stage II (bolt-in cam) tunes.
I did an HD big bore kit (95") on my '03 Heritage. It came with the HD download Stage III tune. It ran well. After buying my PowerVision tuner, I contacted DynoJet who "modified" the HD "Stage III" tune, and the bike ran excellent! I'm still riding that bike, with that tune, and it's a fun, good running bike. I can't argue with the success of a tune map on a Big Bore kit, but if i had a good dyno tuner nearby, I would rather go that route..
I put a 124" crate engine in my bagger. I was going install the engine, but couldn't find a close-by dyno tuner. I wasn't going to rely on tune map for that expensive mod.
So I went to plan B. I loaded my bike on a trailer and travelled to FuelMoto, 4 days each way. I had them do the install and dyno tune. I don't regret my choice...
Again, just my experiences and preferences.. If I had a local dyno tuner that I trusted, I am sure I would rely on them more often....
Road Master
Joined: Feb 2021
Posts: 1,067
Likes: 469
From: Phoenix Arizona
Technically, not really....
Both Twin Cam engines and M8 engines both have the partial closed loop & partial open loop OEM tunes. They both only make real time changes while in closed loop, the cruising rpm range, and they rely on algorithms in open loop for heavy load and high rpm operation. With increased airflow, you will still see a difference in AFRs in the open loop areas, but the M8s don't get lean to the point of being possibly dangerous to your engine like the Twin Cams did.
The difference is that the M8 OEM tunes are different and NOT as lean as the Twin Cam OEM tunes. Therefore, when you lean out in the open loop portions, their algorithms don't drop you into dangerous AFR conditions for the high load/rpm like the Twin Cams will.
As Dennis mentions in his video, with an M8 engine you DO NOT NEED a retune. You engine won't be in possible danger like a Twin Cam may be, but your M8 engine WILL RUN BETTER if you retune.
Again, IMHO, I always retune when I change the airflow through my engine. It gives the best, most efficient performance from the mods you make....
In your case, with your current riding style, you will be fine either way... Enjoy the new bike...!!!
Both Twin Cam engines and M8 engines both have the partial closed loop & partial open loop OEM tunes. They both only make real time changes while in closed loop, the cruising rpm range, and they rely on algorithms in open loop for heavy load and high rpm operation. With increased airflow, you will still see a difference in AFRs in the open loop areas, but the M8s don't get lean to the point of being possibly dangerous to your engine like the Twin Cams did.
The difference is that the M8 OEM tunes are different and NOT as lean as the Twin Cam OEM tunes. Therefore, when you lean out in the open loop portions, their algorithms don't drop you into dangerous AFR conditions for the high load/rpm like the Twin Cams will.
As Dennis mentions in his video, with an M8 engine you DO NOT NEED a retune. You engine won't be in possible danger like a Twin Cam may be, but your M8 engine WILL RUN BETTER if you retune.
Again, IMHO, I always retune when I change the airflow through my engine. It gives the best, most efficient performance from the mods you make....
In your case, with your current riding style, you will be fine either way... Enjoy the new bike...!!!
As always, this is my opinion.
Short answer:
I use a flash tuner for all Stage I & II mods. The flashed maps from a good tuner, along with an auto tune session, work well on a street driven motorcycle. I have used a flash tune on a big bore but prefer a good dyno tuner. On anything above a big bore, I would go out of my way to get a good dyno tune.
Long answer:
I believe a dyno tune , by a knowledgable and competent tuner, is the best for any motorcycle tune. I emphasize the "knowledgable and competent" because it is my experience that not all people who own and run a dyno machine fall into that category.
Having said that, I live in SoCal. It is almost impossible to get performance parts shipped to CA anymore, and the last good dyno tuner I was aware of, worked for a shop that CARB went after. It almost had to close down. The shop barely survived the ordeal, and of course no longer has their "speed shop" or dyno machine.
I have and use a PowerVision full service tuner. I will rely on tune maps form FuelMoto or DynoJet for : Improved OEM tunes, Stage I tunes, and Stage II (bolt-in cam) tunes.
I did an HD big bore kit (95") on my '03 Heritage. It came with the HD download Stage III tune. It ran well. After buying my PowerVision tuner, I contacted DynoJet who "modified" the HD "Stage III" tune, and the bike ran excellent! I'm still riding that bike, with that tune, and it's a fun, good running bike. I can't argue with the success of a tune map on a Big Bore kit, but if i had a good dyno tuner nearby, I would rather go that route..
I put a 124" crate engine in my bagger. I was going install the engine, but couldn't find a close-by dyno tuner. I wasn't going to rely on tune map for that expensive mod.
So I went to plan B. I loaded my bike on a trailer and travelled to FuelMoto, 4 days each way. I had them do the install and dyno tune. I don't regret my choice...
Again, just my experiences and preferences.. If I had a local dyno tuner that I trusted, I am sure I would rely on them more often....
Short answer:
I use a flash tuner for all Stage I & II mods. The flashed maps from a good tuner, along with an auto tune session, work well on a street driven motorcycle. I have used a flash tune on a big bore but prefer a good dyno tuner. On anything above a big bore, I would go out of my way to get a good dyno tune.
Long answer:
I believe a dyno tune , by a knowledgable and competent tuner, is the best for any motorcycle tune. I emphasize the "knowledgable and competent" because it is my experience that not all people who own and run a dyno machine fall into that category.
Having said that, I live in SoCal. It is almost impossible to get performance parts shipped to CA anymore, and the last good dyno tuner I was aware of, worked for a shop that CARB went after. It almost had to close down. The shop barely survived the ordeal, and of course no longer has their "speed shop" or dyno machine.
I have and use a PowerVision full service tuner. I will rely on tune maps form FuelMoto or DynoJet for : Improved OEM tunes, Stage I tunes, and Stage II (bolt-in cam) tunes.
I did an HD big bore kit (95") on my '03 Heritage. It came with the HD download Stage III tune. It ran well. After buying my PowerVision tuner, I contacted DynoJet who "modified" the HD "Stage III" tune, and the bike ran excellent! I'm still riding that bike, with that tune, and it's a fun, good running bike. I can't argue with the success of a tune map on a Big Bore kit, but if i had a good dyno tuner nearby, I would rather go that route..
I put a 124" crate engine in my bagger. I was going install the engine, but couldn't find a close-by dyno tuner. I wasn't going to rely on tune map for that expensive mod.
So I went to plan B. I loaded my bike on a trailer and travelled to FuelMoto, 4 days each way. I had them do the install and dyno tune. I don't regret my choice...
Again, just my experiences and preferences.. If I had a local dyno tuner that I trusted, I am sure I would rely on them more often....
Thank YOU .
A great answer and I completely agree.
Thread
Thread Starter
Forum
Replies
Last Post
