Optimal Performance | Zipper’s ThunderMax With AutoTune

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.