If you have an EFI Harley Davidson then you might be confused as to what your options are when it comes to tuning your bike. The EFI model Harleys are notorious for being fairly finnicky and needing a lot of attention when it comes to the tune, so its no surprise that the massive Harley Davidson aftermarket has come up with some options.

My friend has an 07 Stage 1 Street Bob that he had tuned at the dealer using a couple of different methods. He tried just a Stage 1 PCM flash from the dealer but that did nothing for the way the bike ran. It ran extremely lean and hot from the factory and the addition of pipes and an AC simply made it worse.

After the PCM flash left him unhappy he purchased the infamous SERT option through Harley Davidson and had them install and dynotune it using the SERT. I wasn't there but the bike didn't seem to run any better or cooler when he got it back from the dealer. The SERT might be an ok option but its only as good as the dyno guy running the dyno, which in many cases, isn't that great from my experience.

Self Tuning Option

Zippers is a name you should know from the Harley Davidson world for many years. They have developed a number of products that have enhanced the way a Harley Davidson performs and are valuable asset to the aftermarket Harley Davidson community.

They have partnered with Thunderheart to develop the stand alone Thundermax EFI ECM with Autotune that will allow your bike to tune itself.

Yes, tune itself, you read that right.

The Thundermax Autotune EFI system uses wide band O2 sensors to take reading from your exhaust and then adjust the fuel mixture accordingly. Very similarly to the way most cars tune themselves these days.

This Thundermax EFI ECM is a dramatic improvement over the stock Harley EFI system for many reasons. It can adjust to changing conditions, temperature, altitude etc on the fly and keep your Harley Davidson in a much better state of tune than even when it came from the factory.

How it Works

I am no engineer so I cannot tell you about the specifics of the internals of the Thundermax EFI Tuner but I can tell you that you simply replace your existing ECM with the Thundermax ECM, which on most bikes is a snap. There is no cutting or splicing and we had my buddies bike up and running in about an two hours and we weren't pushing at all.

The bike uses wide band O2 sensors as opposed to the very limited stock O2 sensors to continuously monitor various components and then make adjustments to the fuel mixture and spark timing in order to optimize the way the bike runs.

Out of the box with very little "tuning" time his bike was running cooler and better than it ever had. The best part is that the Thundermax ECM will continually "learn" to fine tune for the various riding conditions and will simply get better and better the longer it is installed on the bike.

No need for dyno time, no need to pay a tuner, no need to put up with a bike that huffs and chuffs, surges and pings and doesn't run the way a 15-20k dollar motorcycle should run. This thing is great.

Thundermax Rideability

I was still a bit skeptical but after riding his Bob I can tell you that this little ECM has his bike purring like a kitten. It's a simple Stage 1 bike which is pretty representative of what most Harley riders are hammering around on but it rides better than most stock EFI Harley's that I have ridden.

I have ridden a number of EFI Harley bikes, including my own, and this Thundermax EFI ECM is one of the best riding bikes I have experienced. I am not surprised given Zippers reputation for quality but I had to see it for myself.

If you are considering the T-Max for your bike then I can tell you from first hand experience that you won't be disappointed.

Thundermax Brochure

I am including some of the literature from the Thundermax brochure for your enjoyment.
Easy Installation:
Simply replaces the factory Electronic Control Module (ECM). Modular construction is pre-assembled; no wire cutting or splicing, just bolt it on and plug it in. Loading a map is a breeze; initial set-up takes minutes, not hours.
Improved Rideability:
Your motorcycle starts better and runs noticeably better with the ThunderMax while optimizing power output.
Automatic Learned Tuning:
AutoTune automatically adjusts to the target air/fuel ratio as you ride the motorcycle with immediate "Per-Combustion Cycle" AFR analysis and correction. Wide-Band oxygen sensors provide real-time feedback at ALL rpm's and load, from key-on to key-off for full-time AFR correction.
Idle Control / Adjustable Rev Limit:
You choose your Rev Limit, Idle Speed, Ignition Timing, best Target Air/Fuel Ratio for power or economy and other settings you can't control with other tuning devices. You can read Diagnostic Codes and Running Statistics with included SmartLink software.
AutoTune for Power or Economy:
Allows 'live' tuning and settings adjustments. Monitors engine 'vitals', viewable all on one screen or through the creation of individual 'guages'. SmartLink software allows you to adjust air/fuel ratios for every speed and load condition. Tune for best power or economy or both!
hree Year Warranty:
Durable and reliable; manufactured in the USA with state-of-the-art electronic components. Excellent product support included.
Continually Upgradeable:
With ThunderMax, you get everything you need for future engine upgrades the first time you buy. Software, Firmware, and Map updates are free and available 24/7. Never outgrow it!
Self-Adjusting Fuel Maps:
Highly refined maps included with the SmartLink software disc. Easily choose the best map for your application, minimizing tuning time for most configurations.