This is a question I often get, so I thought I would share the most recent email asking it and my response.
I would like to learn more about tuners, how they work and how to tune my HD bikes. My wife and I each have newer touring Harleys. I put V&H Dresser Duals and Monster Ovals on mine, Dresser Duals and Monster Rounds on hers as well as a high flow AC on each. I currently Have a Thunder Max tuner on each bike and run the auto tune a couple times a year. They both seem to run well and we ride from home at 5700’ over passes that may be 10,000’ and down to sea level. I was looking at the Harley Forums and reading posts about tuners from riders and Professional tuners trying to find out what people think of the different types of tuners, ease of operation and end results. I found it confusing, some tuner was saying Thunder Max Alpha N platform for tuning was state of the art several years ago but not now. I wish I could find straight unbiased information or material that allows me to learn the different systems and make an informed decision. I’m thinking of buying a new Rushmore FLHTK and though I’ve been happy with the Tmax would I be happier with some thing else?
I was wondering if you could recommend any literature explaining tuning and tuners. I’m interested in learning how to read and interpret tuning tables and make an educated adjustment if possible, or to at least understand what the tuner is doing and why.
Any information you can give me is appreciated.
My reply to Bill’s email
I started writing a Harley EFI blog that I update about once a month or so. www.harleytuner.com you might find some interesting info there from time to time.
Not totally sure where to start to answer your questions and may have to elaborate on some of it in a later email.
First let’s talk about EFI.
The biggest advantage of OEM production EFI in your Harley is that it should correct for ever changing air conditions. Temperature, Pressure, Humidity. Properly set up/calibrated/tuned should never need “re-tuned” ever.
Alpha N is older technology and pretty much is only used on some race vehicles these days. FYI – Race parts are not necessarily better, especially for milder street engines.
As I’m sure you know, most modern vehicles including Harleys use Speed Density systems. Which is what I have used on race bikes I have been involved with including “The Rooster” 2003 Road King my buddy bought new and we played with. Just under 140HP and 150 ftlbs of torque. Actually very smooth and rideable.
The Thundermax is a good ECM, especially for what it was originally designed for: “aggressive Race bikes”. Big Cams, Exhausts… Race bikes that you would constantly be playing with the tuning at the track during a race.
As you know the best part about the Thundermax is its wide band auto tune add-on module.
Delpi (maker of H-D’s ECM) has been building EFI/ECMs for longer than almost any other company in the world. It is very sophisticated. Way more advanced than the Thundermax.
I have been playing this game (tuning EFI Harleys) pretty much longer than most people, which is why companies like Dynojet, Harley-Davidson Motor Co, Vance & Hines, Rinehart Racing, Speeds Performance Plus,… hire me for consulting and contract work.
I can run anything I want on my bike, and most manufacturers would give me their product to run if I asked.
For me it’s a no brainer. My daily/cross country ride runs an HD factory (delpi) ECM with a Flash Tuner.
Dynojet Power Vision, Screamin Eagle Super Tuner, TTS Master Tune…all basically do the same thing. The software interface is different, some have different features than others, some Dyno operators/tuners are only familiar with one or two, but the bottom line goal for all of them is to re-calibrate the air tables in the ECM to match your engines new airflow created by the new parts/modifications you have added/done. Pipes, Airbox, cams, heads,…
If you calibrate the ECM to the true airflow of your engine on your Harley and then set up the tune correctly (Calibrate first, Tune second), your bike will not only properly correct for ever changing air conditions caused by weather Altitude, and climate changes it will be able to correct for minor fuel blend changes (gas vs 10% or 15% ethanol) and even help protect your engine from damage that could be caused by an intake leak if you were to get one.
The best part is as long as you don’t change any parts affecting your airflow you should never have to mess with it again, just ride year after year with the ECM doing what it was designed to.
I don’t have time to hit all the details as to how and why this is right now, but the hows/whys will be trickling into this blog over time
The most efficient way to do this is on a Dyno of course. But if you want to attempt it the way you have with your Thundermax then I would recommend you buy the Dynojet Power Vision with their auto tune module. Pick a pipe with dual bungs (big and little) so you can use the wide band O2 sensors and keep the stock O2 sensors in tack.
It is near impossible to hit all the cells riding the bike around that’s why a Dyno is great for this. I can hit nearly every cell in 10 minutes.
I have been told that it doesn’t matter because you hit the cells you ride in. Fact is you hit the cells you were riding in today. When you go up or down in the mountains you will ride different cells. If you load your bike for a trip you will ride in different cells. On the Dyno you can hit all the cells needed for every riding condition very quickly.
In a follow up email Bill asked if I could recommend a dyno operator/tuner near him.
I have a list of shops I have trained on my website: http://www.danielsperformance.com/Customers.html. I plan on adding a recommended Dyno tuner list to my website in the near future.
If you go Power Vision or Super Tuner I might be able to help you find a good base map to start with. I have a blog post with some insight into picking a base map http://harleytuner.com/super_tuner_map_selection/ but I might be able to get you one with closer air tables if you like.
FYI – The Rushmore TK has been my favorite bike to borrow from Harley’s Demo fleet for the past year. Great bike.