Who's actually running this set-up??
#31
I'm no expert but here is what I have gathered about the M8 Engine from posts here, on Facebook groups, and internet videos from DK Customs and others. Air filter only - No tune needed. The M8 can adjust for that.Slip-ons only - No tune needed. Same here for the M8.Air filter AND Slip-ons - No tune needed, but you could optimized with a with a tune. Many have done both with no issues. Full exhaust - Tune would most likely be needed to run optimally. Many have done this without a tune with good results (see above posts)Cam or other Engine change - Yes a tune is definitely needed. This is for M8 only. Older models are not as forgiving or have the ECM ability to adjust for minor changes.
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Calif Fat Bob (07-08-2024)
#32
Yes, I have - on multiple bikes. What I learned (especially on pre-2014 bikes) is this: -
For engine longivity, tuning is more important than sound. I now buy a programmable tuner first and no longer have to worry about whether I'm damaging the engine every time I ride. Modern tuners easily accommodate changes, so there is no need to wait until all upgrades are done until the bike is appropriately tuned.
I specified a greater need on pre-2014 bikes because emmisions regulations caused the MoCo to lean the bikes to the point that engine damage was likely without intervention. They aren't as bad now.
For engine longivity, tuning is more important than sound. I now buy a programmable tuner first and no longer have to worry about whether I'm damaging the engine every time I ride. Modern tuners easily accommodate changes, so there is no need to wait until all upgrades are done until the bike is appropriately tuned.
I specified a greater need on pre-2014 bikes because emmisions regulations caused the MoCo to lean the bikes to the point that engine damage was likely without intervention. They aren't as bad now.
I have wondered if worth tuning stock bike. My 2015 I left stock, because I really like the stereo on it.
I am curious why someone would change air cleaner and not tune. The pipes they do for noise.
It's an age old debate since forums started, do you need to tune for just slip ones. Probably the second thread, followed by which oil
#33
Join Date: Oct 2015
Location: Pine Flat Dam/South Bay Area, CA
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Curious why the last of twin cams were not as strictly leaned out by epa? What's the difference?
I have wondered if worth tuning stock bike. My 2015 I left stock, because I really like the stereo on it.
I am curious why someone would change air cleaner and not tune. The pipes they do for noise.
It's an age old debate since forums started, do you need to tune for just slip ones. Probably the second thread, followed by which oil
I have wondered if worth tuning stock bike. My 2015 I left stock, because I really like the stereo on it.
I am curious why someone would change air cleaner and not tune. The pipes they do for noise.
It's an age old debate since forums started, do you need to tune for just slip ones. Probably the second thread, followed by which oil
Last edited by Tommy C; 07-04-2024 at 09:50 PM.
#34
Interesting thread,I have a stock 2019 107 Electra Glide and a full S&S exhaust system with Grand National mufflers I'm planning to install.
Everything else is stock except a K&N air filter in the stock airbox.
It sounds like I may be able to ad the exhaust without a tune.
Having my local indy do a 30K service soon so I guess I'll have him put the exhaust on and see how she runs.
Everything else is stock except a K&N air filter in the stock airbox.
It sounds like I may be able to ad the exhaust without a tune.
Having my local indy do a 30K service soon so I guess I'll have him put the exhaust on and see how she runs.
Last edited by Y2K; 07-04-2024 at 10:14 PM.
#35
The M-8 has dual spark plugs, 4 valve heads, a more efficient combustion chamber, and I imagine the ports flow at higher velocity and mix the air and fuel better than the twin cam engine, so comparing the two engines is not the best way to find an answer for the OP's question. A few dyno runs before and after modifications using an exhaust gas analyzer is a more accurate point of reference.
I also realize M8 s are different,but is EPA? Mostly care about twin cams though
Also why add air? I get noise.
#36
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Last edited by Tommy C; 07-04-2024 at 11:05 PM.
#37
An engine is basically an air pump, Rounders. With less restrictions to get more air/fuel at the proper ratio in and exhaust out, the engine makes more power. The exhaust system needs to be tuned for the engine and any modifications it has. The wrong exhaust system will severely hamper performance. More noise doesn't automatically mean more power. That's why shops sell performance packages of parts that have been proven to work together. Randomly throwing different parts on a bike results in poor performance.
As I said I some just change pipes people just want noise. I didn't say if I agree with not tuning
So please spare me the air pump lecture.
I never said there was an advantage to just changing pipes, other than some just noise. I never have just changed pipes
Last edited by Rounders; 07-05-2024 at 09:30 AM.
#38
because the ac change is strictly cosmetic. the stock ac (on m8) is already a 'free flowing' ac, so technically not increasing the amount of airflow into the engine, ergo no tune needed.
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GPHDXLC (07-05-2024)
#39
#40
Just adding a little info on this subject. Concerning EFI bikes, the ECM will adjust the fuel trim to compensate for some modifications up to the point the fuel tables run outside the calibrated parameters. At this point a DTC will set and the ECM will go into open loop (default cal not looking at O2). A tune will refine the spark curve, fuel tables, and enrichment (accelerator pump if you will) to get the best performance out of your modifications.