Editor’s note: What we have here is Part 1 in a two-part series that’s intended to end the bitter brouhaha between proponents of carburetors and those who are ardent fans of fuel injection. Patrick Garvin dominates the discussion today, citing the wonders of fuel injection. Tomorrow, we’ll have Kody Wisner serve up his arguments in favor of old school carburetion. Like most of these pro/con blog posts, we’re probably not going to sway anybody’s opinion. But such musings can go a long way in confirming our right to be hardheaded about such things. And, if one of these blog entries changes your thinking about FI versus carburetion, for goodness sakes, write to us and tell us about it!
By Patrick Garvin
The motorcycles we see on the road today are a far cry from the machines of just a few years ago. The factories continue to produce a more efficient motorcycle — and many of these changes are nudged along by mandates from the Environmental Protections Agency. We get more emission restrictions every year. And with the air-cooled, pushrod motors built by Harley-Davidson, certain changes to the fuel system are unavoidable, including fuel injection.
In my travels to bike rallies and events all over the country I continually hear the complaints about fuel injection, even guys asking if there is a way to take the fuel injection systems off and retro fit carbs. I gotta tell you, that’s absolutely insane. There’s not a carb set-up on this planet that’s as efficient and tunable as fuel injection.
In the years I’ve been running a dyno, I’ve noticed that most of the complaints about fuel injection are based on a fear of the unknown. Guys went from being able to turn screws and replace jets to get their bikes running smoothly, to the mystery concept of plugging little boxes into ECU’s and then — horror of horrors — hooking their precious bike up to a computer! Most of the carbureted bikes I’ve seen on a dyno proved to be too rich (too much fuel). That makes for an inefficient motor that is bad for the environment, gets terrible fuel mileage and actually hurts horsepower output.
Fuel injection, on the other hand, offers a pantload of good reasons why it’s vastly superior to carburetion. Here’s the breakdown:
1) Basic Tuning—One of the great things about fuel injection is that you can get as complicated or as simple as you’d like. If you just want to have some basic adjustability, you can grab up a simple FI controller like the Arlen Ness Cheap Shot, which offers the same adjustability as your old carb set-up. Three dials — low, mid, and high — allow you to enrich or lean out the fuel mixture by simply turning the dials. This basic FI controller costs less than $150 and offers the same tuning characteristic of a $300 carb. Oh, and by the way, you don’t have to change any jets. Besides that, there’s no computers to hook up. Just plug it into the bike.
2) Advanced Tuning—Now here’s where the fuel injection absolutely blows the doors off the carbs set-ups. There are tons of ways to skin this cat, but we’ll just touch on a few. You can start with a device such as a Power Commander that simply plugs into the bike ECU. It allows you to use existing maps from Dynojet, have custom maps made at a dyno, or simply tinker with it yourself. The “maps” are grid layouts that enable you to choose how much fuel to send to the motor every 250 rpm. In addition, there are nine throttle positions that allow for razor-sharp tuning. With the FI controller you can change individual points in order get specific tunes for all the different parts of your rpm/throttle range.
3) The Ultimate Tune—Systems like the Power Commander V, Daytona Twin Tec TCFI and Thundermax systems take tuning to that absolute best-case scenario. Wide-band O2 sensors (factory HD’s come with narrow-band sensors) sample the exhaust from your machine and send that information to the FI unit where it automatically makes the desired changes to your air/fuel ratio. Let’s say you set the bike up for mileage and responsiveness in the mid and lower rpm ranges and you choose air/fuel ratios of 14.2 -14.8. On the top end of the rpm range at wide open throttle you want the bike to make big power, so you set it to run at 13.2. You get the best of both worlds. And no matter what the temperature or elevation, the system constantly reads the air/fuel and automatically makes the changes, maintaining a perfect tune-up within seconds. To quote Ron Popeil, “set it and forget it.”
With the availability of high-volume fuel pumps and injectors, there’s absolutely no limit to what can be achieved through tuning your fuel-injected ride. If you’re still questioning whether or not fuel injection is the best way to feed you bike fuel, just check out any top-level race team and see what they’re using. Look at the Screamin Eagle Pro Stock drag racing beasts and the road racing bikes — all of them use fuel injection. And think about this: Those folks could use whatever they want.
For an opposing view, don’t forget to read Kody Wisner’s response tomorrow.