I don't thunk the main question should be if you need a tuner. It's just silly not to tune a bike if you invested in pipes and AC. If you tuned a bone stock bike, it would run better and make more power. Remember that Harley has to meet EPA requirements. The computer is not set to to give you optimal power and performance.

 

Over the long term the A/F ratio is not really something you can judge by the seat of the pants. It takes a bit of time to burn out an exhaust valve and recede the exhaust seat, by the seat of your pants you won't notice it until it starts running lumpy, too late......$$$$$
Heat is also bad for oil and bearings, the leaner it runs the more heat.
Figure out an acceptable exhaust gas temp for the given motor based on proper A/F mixes and run a plug in EGT on a hot day, bet you're running lean and hot
It will cut the the longetivity of the motor before replacement parts are needed.

 

I can say that my '07 ran much better after putting on the Fuel Moto PC, I run a full system, and not slip ons as well as stage 1 air. The bike popped way to much on decel, and did not idle like it should. To each their own but you cannot deny that running an engine cooler will prolong the life, there is just no way around it.

 

Wideglider...

I wondered about that exact thing... on our fuel injected cars, we always changed intake and exhaust without having to do mess with the computer. Why not my EFI Dyna FXDB? I decided to try only slipons (V&H 3" TwinSlash) knowing that if I encountered issues, I could easily reinstall the stock exhaust... No issues at all... In fact, getting more power (able to cruise in 6th at 50 mph) and better gas milage! I might try changing the Air Intake soon!

Thanks for your encouraging post.

 

Keep something in mind when you're talking about "changing exhaust" on a car. Most people don't change the exhaust, they change the part of the exhaust after the cat...a "cat back" system. The headers and cat are still factory and still restrictive. To me, that's the same as doing slip-ons on a motorcycle. When most car guys did a full exhaust, meaning headers, high flow cat, and cat back system, they would scan and tweak the tune a bit for it.

To understand why this works, you kind of have to know how your ECM works. In closed loop...when you're cruising and doing light acceleration...the ECM is constantly checking the AFR and making adjustments to keep it where it should be. In closed loop, your stage one modifications will be compensated for almost immediately. The main issue comes when the ECM enters open loop. In open loop the ECM has to make certain assumptions and guesses based on what it has "learned" in closed loop and the way it's VE tables are written.

If you do a stage one mod and then go out and make a bunch of Wide Open Throttle (WOT) runs, the engine is going to run really lean! This is because it's assumptions and "learned" data is based off the restrictive stock parts.

If you wipe your ECM clear then put about 100 miles on it in Closed Loop riding and THEN make some WOT runs, the bike will run closer to stock because it's learned information will be based off the new parts, not the old parts. If you DON'T wipe your ECM clear, it's going to take much longer for the computer to "unlearn" the stock info and "relearn" the new parts. (The "learning" is like an average. If you have 1,000 entries with your stock parts and then do your stage one without clearing these entries it will take about 1,000 entries with the new parts to even out the averages with the original parts.) However it's still going to be off since the VE tables are still for the stock parts.

If you re-write the VE tables, clear the ECM and let it relearn for 100 miles or so, your tune will be correct.

It isn't a matter of whether or not you NEED a tune, it's a question of how "right" do you want your tune to be? For me, I like it to be right. The PowerVision let's me do that and get it really close using real world data. It will rewite the VE tables for me so that the profile I have is right for my exact combination of parts. I like that. Do I need that much for a stage one WG? No...but it's nice to know it's spot on. Also, if (Okay...WHEN) I do other mods to the engine I now have a tool to tweak the ECM again when I need to.

This is why I hate "piggy back" systems. I'd rather rewrite the ECM itself like the PV allows you to do than have a go-between that can cause more issues.

 

Sorry, but your impression of what Stage 1 and 2 are, are wrong. Stage 1 is really just a "tune" in itself. Getting in more air and fuel. Stage 2 is when something is mechanically changed on the bike. I forget exactly to tell you the truth, but I believe Stage 2 is adding cams and/or headwork, Stage 3 is big bore kit. I could be wrong, as I don't follow what that the definition of "Stages" are that closely anymore, but I know that simply adding intake, exhaust, fuel management system and a dyno-tune isn't a Stage 2.

 

[QUOTE=ColdCase;9486176][quote=jeff.georgalas;9483525] The only way to truely prove your statement either correct or incorrect would be to take two of the exact same bikes off of the factory assembly line, do the full Stage 1 on one bike, and just intake and exhaust on the other, and run them at the track until one of them blew up or quit running.. Yes, I agree, you are 100% correct. A single example doesn't really prove anything in the big picture, you'd need 10 or 20 bikes to begin proving something, and even more would be even better.

 

Not sure why so many get so hung up on this issue. I don't think many that know what they are talking about say the you "have" to get a tuner, only that when properly applied it will improve the way the bike runs. If your happy running without one, more power to you. If you're happy with your tuner like I am, good for you too. End of story.

 

I know on my 08 Heritage when my PC III went south my bike had some serious popping going on. Bike ran like ****! When I got my replacement PC III all was well in the world again. Can't speak to others experiences but the PC's help my bikes run better & stronger. I think I'll stick with them & the support I get from FM. To each their own.....

 

Have run stage 1,slip ons and remap for years. No issues. Now went to full system 2:1 and am putting on XIEDS. Tuners not necessary for basic mods.