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Equipment Name: F.A.S.T. System
Vendor: Hillbilly Motors (in 2003)
Contact: Jens
Address: Bleialferstr. 13 54597 Auw /Germany
Tele: 0049-6552-929046
Web site:


The FAST System comprises 3 parts;
a) A specifically shaped heat shield,
b) An aluminum stack that extends the throttle body inlet
c) A large K&N air cleaner plus securing clip.

The Hillybilly FAST system is unique in these tests in that it requires the complete removal of the stock inner air box. The heat shield fits to the frame where the air box mounts. The stack is used to extend the throttle body above the heat shield and then acts as the mount for the large K&N air filter.

Test bike: Buell XB9R (03 model) - Stock motor (just less than 1700 miles), Wileyco exhaust muffler (Basically straight through), Stock Induction system (Removed for this system), Buell Race ECM.

Theory of Operation
Jens at Hillbilly went to great lengths to explain how the FAST System came into being. Based on Hillybilly’s experience with the previous generation of Buells, they found that flowing heads was only part of the issue of getting the motor to breath easier. Getting enough air into the motor was another problem. When Hillbilly set about getting more out of an XB, they created the complete induction system on a flow rig suspecting the XB had similar air flow/demands to the previous models. They were able to determine that the stock XB air box/filter arrangement was a bottleneck restricting the air the motor needed (Twins have a large appetite for air). They then set about de-restricting the air induction equipment. The FAST System is the result.

The fit and quality of the parts are good, especially the heat shield or blanket, fitting the frame area perfectly. The stock rubber velocity stack and the complete inner air box are discarded.

The two crank case vents and the induction air temperature sensor that are installed to the inner air box lower, need to be removed and repositioned. The temperature sensor must be carefully removed from the air box and is the positioned under the heat shield between the 2 cylinders, held in place with a couple of zip or cable ties. The crankcase vents for the sake of this test were simply routed away from the air box area and allowed them to breath to atmosphere. Never block these pipes or you can pressurize your motor with potentially nasty results.


At the Dyno

I’m deliberately avoiding giving final HP/Torque values in this report. The reason for this is that there are many variances that can effect overall dyno results. To start with, everyone’s bike has different output characteristics as a function of build tolerances, wear and so on. Temperature, pressure, humidity and even the dyno itself all impact the final numbers. The important thing is the change in the relative performance values between the systems compared to the baseline stock set-up on the same dyno.

Although I have a basic understanding of German, I could not find any vendor claims for the system. This is likely due to European advertising law.

Looking for repeatability from the test method, my test criteria desired that the bike make 5 back-to-back dyno runs with less than 0.5 HP variation between all 5 runs if possible over the rpm range 3000 to rev limiter. The FAST system satisfied these criteria in 5 straight dyno pulls. The FAST System gave a 6.0 HP peek increase. This began as +3 HP at 3000 rpm to +6 HP at 7000 rpm. From 7000 to the rev limiter there is a discernable tail off in the power characteristic although the power is still rising, just not as quickly as before. The midrange hole is reduced considerably to a flat spot (Between 5500 to 6000 rpm) in the torque before the power kicks in from just under 6000 rpm.

The Ride Experience
What can you say about a 6HP increase (about 9% increase over stock), you notice it!! I have ridden the FAST system at 2 race meetings at different tracks and have found that my gear change and brake point markers had all moved. This is the confirmation to a racer that something tangible has changed. I was getting into corners significantly faster than previously experienced. From 6000 to 7000 rpm especially, the bike pulls like a freight train.

There is a significant increase in the induction noise at least in the riders ears. At idle and low rpm’s it sounds like….well just odd. At rpm’s above 6000 the motor sings as you can almost discern each breath of air that is being sucked in.


The FAST system has proved a couple of theories to me that have been bounced around the various Buell bulletin boards almost since the bikes introduction.

1) People have been putting holes in the inner air box to get more air to the motor – The FAST system is the ultimate in air box minimization and very effective!!
2) Other vendors offer methods to get cool air to the motor – The FAST system achieves this as well via the heat shield or blanket.

In my opinion, if you quest is for maximizing the HP gain and you regularly ride at high rpm’s, then this may be the system for you.

RamRaceCo will be retaining the FAST system for further development of our race XB9. This may be with alternative external air intakes directly on the outer air box cover and possibly with conditioning type velocity stacks.

Comments from Hillbilly Motors

First of all let us thank Mark that he took these work, and the discussion with the “non believers”
Full. Air. Supply. Technology. F.A.S.T. -the name is the program -feed the Beast !
In cooperation with M-TeK Engineering we developed that System with the understanding of the needs after hundreds of Flow Bench and Dynotest Hours.

We are very happy to get that confirmation of or work.

Have Fun!



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