Optimal Performance | Zipper’s ThunderMax With AutoTune

Tech Swap

01. The Zipper’s Performance ThunderMax with AutoTune will give the ’06 Softail the benefits of its closed loop system. Aiding in the performance department will be the Low Cat 2-into-1 exhaust from D&D; Performance, and this Zipper’s MaxFlow Air Cleaner with chrome backing plate and cleanable, pleated 2-3/4-inch-deep air filter element.

02. Trey started the install by removing the battery and the ECM fuse from the fuse box.

03. Trey then unplugged the main harness from the stock ECM and removed the stock ECM from the rear fender.

04. Trey positioned the ThunderMax onto the rear fender where the stock ECM was housed.

05. He had to fish the front and rear oxygen sensor wiring from the ThunderMax ECM to meet the sensors installed in the bungs on the D&D; pipe.

06. Next up, Trey installed the oxygen sensors to the bungs on the D&D; 2-into-1. He loaded the new oxygen sensor threads with anti-seize and installed them to the front and rear head pipes.

07. With the sensors hooked up to the pipe, Trey installed the Low Cat 2-into-1 to the cylinder heads and to the muffler bracket, which mounts to the frame where it meets the swingarm.

08. Trey connected the front and rear sensor wiring to their respective plugs leading to the ECM and zip-tied them in place.

09. Back to the ThunderMax system, Trey coated the main harness plug with dielectric grease and installed the main harness into the ThunderMax ECM.

10. The ThunderMax Datalink plug was then hooked up to the bike’s stock gray four-pin data link plug.

11. Moving on to the MaxFlow air cleaner kit, Trey removed the stock air cleaner assembly and hooked up the new Zipper’s backing plate with the factory breather bolts and the supplied hardware.

12. Trey then bolted the deeper, pleated air filter to the backing plate and re-installed the football-shaped air cleaner cover.

13. Going back to the ThunderMax, Trey installed the SmartLink software on the computer. This was a very simple procedure that even the computer illiterate can understand.

14. Trey plugged one end of the supplied communication cable into the ThunderMax ECM and the other end into the computer and began searching for the bike’s criteria—pipes, air cleaner, etc.—in order to load a base map. After the proper base map was loaded, we took the bike for a spin (about 5 miles) to see if the AutoTune feature did what it said it would do. At first, we noticed a much more crisp throttle response. Without the ThunderMax unit the bike was a tad sluggish, but the ThunderMax seemed to provide very positive results. After a few miles we brought the bike back to Ed to be put on the dyno to see what the final horsepower and torque results were as well as if the air/fuel ratio was on a more even keel.

15. We did a dyno run with the swapmeet pipes just for fun, and achieved 68.02 hp and 72.23 lb-ft of torque. The air/fuel ratio (blue line) wasn’t quite where Brad wanted it. Through the years we’ve done multiple dynos with a stock Twin Cam 88 and have found stock horsepower to be in the high 50s, with lb-ft of torque in the high 60s. After installing the new components, loading the base map, and simply taking the bike for a short spin, the bike reached 73 hp and 75.3 lb-ft of torque, which compared to stock is a substantial horsepower and torque gain. The air/fuel ratio was right where it should have been, around 13.7:1, and stayed smooth throughout the rpm range.

16. Here’s the Deuce with all the new components installed. We’d say the ThunderMax with AutoTune does exactly what it should, and Brad doesn’t have to listen to that annoying popping sound anymore when decelerating. hopefully we will follow this up with a more in-depth install of cams and pistons to see what gains we can get and how the ThunderMax AutoTune system responds to these changes.

In the quest for optimal performance, bikers constantly strive for the best results from their machines. Zipper’s Performance is synonymous with motorcycle performance and manufacturing top-quality components for Harley engines, transmissions, and more.

Zipper’s is also well known for developing the ThunderMax fuel tuning system in 2002 when the company teamed up with Thunder Heart Performance, eventually spawning the ThunderMax with AutoTune. The ThunderMax system we used for this bike fits ’01-later big twins with cable throttle and retails for $899.95 (throttle-by-wire is also available). It is a wide-band, closed-loop system that continually and automatically adjusts the air-fuel ratios whenever you ride, especially in ambient temperature or elevation changes. Working in the closed loop system is more advanced because the system continually measures the exhaust oxygen and adjusts the fuel mixture accordingly. Other benefits of the ThunderMax system are a quicker/snappier throttle response, increased power, and cooler operating temperatures, and it’s backed by a three-year warranty. But probably most important (especially for this particular bike) is the ability to continually make minor changes (high-flow air cleaner, pipes, etc.) or major changes (cams, heads, pistons, etc.) and the system will get the bike right in tune with a simple download of a base map from Zippers/ThunderMax’s huge library of engine mods/combinations. Once you load a good base map in, the AutoTune feature will further refine/adjust the map for even better performance/ridability.

The main reason a ThunderMax was decided on was that a buddy of ours, Brad, picked up an ’06 Softail Deuce for a good price but the bike wasn’t quite running right with the swapmeet pipes it came with. Brad knew he would eventually make internal changes, such as possibly adding new cams and pistons, and knew that the ThunderMax could easily handle and adjust with these changes. So to get off on the right foot, Brad picked up a high-flow air cleaner and a good-performing 2-into-1 exhaust. For the air cleaner, Brad went with the Zipper’s MaxFlow Air Cleaner kit ($139.95). The Zipper’s air cleaner includes a redesigned backing plate (available in chrome, black, or polished) and a larger filter element to flow more air. The MaxFlow kit fits all stock fuel-injected or carbureted Twin Cam football air cleaner covers.

For the pipe he picked up a D&D Performance Low Cat 2-into-1 exhaust system. The Low Cat 2-into-1 is a cool pipe with an upswept muffler design made for a lowered look to be used on ’00-later Softails, and is available in chrome or black with a starting retail price of $718.

We took the Softy to Huntington Beach Hogs and Choppers in Huntington Beach, California, where owner Ed Syer and his right-hand-man Trey Mills turned wrenches on the Deuce to get her up to speed. The ThunderMax installation is extremely easy. It took very little time to get the module hooked up and the oxygen sensors routed to the D&D pipe. We then installed the Zipper’s air cleaner, and the Deuce was back on track with some nice overall performance gains and more importantly, a proper air/fuel mixture. HB


**D&D Performance **
(817) 834-8961 | danddexhaust.com

Huntington Beach Hogs and Choppers
(714) 891-7207 | hbhogs.com

**ThunderMax **
(410) 579-2828 | thunder-max.com

**Zipper’s Performance **
(410) 579-2828 | zippersperformance.com