Equipment Name: SVVS and Vortex Cone
The SVVS comes potentially in 2 parts;
a) A reshaped, short, aluminum velocity stack that fits in to the stock throttle body and,
b) A clear Vortex Cone is worked into the stock XB9 inner air box top. The vendor also suggests that a stock XB12 air-box top works almost as well. Tests would be conducted to confirm this.
The vendor claims performance gains of 3-7 rear wheel HP with this kit on a stock XB9R/S. They further emphasize the importance of a smoother torque curves in eliminating the midrange hole in the power/torque characteristic.
Test bike: Buell XB9R (03 model) - Stock motor (just less than 1700 miles), Wileyco exhaust muffler (Basically straight through), Stock Induction system, Buell Race ECM.
Theory of Operation
According to Corey James at 2Win Induction Technologies, the shorter the stack and the more open the radius in relation to the height of the stack, the better its performance should be. "Height in a velocity stacks kills your low-mid range and does nothing for the top-end". A large open radius in a short stack improves velocity and volume intake and reduces air reversion within the air box.
Side Note: When the SVVS and Vortex Cone air box upper are installed on the bike, it appears that the cone is not centered on the stack. I called the vendor to make sure I had not fitted it incorrectly. Corey James confirmed that the cone should not be centered on the stack. On later reflection this appears logical. In the stock arrangement the stack is not centered on the air box or the air cleaner. This would set up preferential air flows around the stack probably at the front. As the Vortex Cone is to all intents, a flow conditioner, it would therefore be entirely appropriate to position the cone/conditioner I such a way to ensure uniform flow into stack and throttle body.
The fit and quality of the parts are very good (the stack itself it quite beautiful to look at)
The stock rubber velocity stack gets re-used. It must be cut (or trimmed!) at both top and bottom to leave just the sealing ring to form the new seal between the SVVS stack and the stock inner air-box lower. I had sent both my stock rubber stack and air box top to 2Win Technologies for them to fit so that I could eliminate as much as possible, fitting errors from the test results. This is a service that they would perform for any customer and I would suggest any future customer to consider this, particularly the fitting of the Vortex Cone. (I you don’t want you bike off the street for the few days it takes to turn this pieces round, then perhaps consider buying a new stock Rubber stack and air box. They are around $35 (US) each.)
The kit comes with good fitting instructions. The only comment I had on these was that for customers that are going to trim the stock rubber stack themselves, that perhaps a couple of pictures could help tell the story better than several paragraphs to text. To be fair, there are such pictures on the vendors web site, but my comment was a well received.
Like all other systems tested, the vendor instructs you to then ride the bike between 3000 and 4000 rpm for at least 20 minutes to allow the ECM to adjust the air/fuel value for the new conditions you have just fitted. Personally, I would give it more time especially if the bike has not been used recently and there are big ambient (Temperature, humidity etc) differences between now and the last time you rode it.
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 slightly 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.
The vendor claims an increase 3 to 7 HP at the back wheel and filling the mid-range hole on a stock XB9. Based on my testing, I found these claims to be accurate.
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. The SVVS system satisfied these criteria. The SVVS System gave me 3.4 HP peek increase and all but eliminated the midrange hole to just a slight decrease in the overall rate of increase in the power/torque characteristic. That’s to say the curve no longer went south for 750-1000 rpm like it used to.
The test was then repeated with the stock XB12 inner air box top replacing the XB9 Vortex Cone modified air box top. In my testing I found minimal difference between the 2 air box configurations. Again based on 5 repeatable back-to-back dyno runs, the difference between the Vortex cone and the XB12 air box top was less than 0.5 HP.
For the average street rider where most of the ride takes place in the midrange, the fix to the midrange characteristic should be most satisfying and arguably worth the money alone for the modification.
The Ride Experience
I rode with the SVVS System at Texas World Speedway at a track-day. Using the midrange to pull the bike out of a slow to medium speed corners, there is a noticeable difference to the ride and you truly feel the XB pick-up rather than bog down like it sometimes used to feel like. Overall, my lap times did drop over the day. Some of the drop was down to the easier ride the SVVS gave me…….Oh, and another 3 HP didn’t hurt either.
In discussions with the vendor, they were very open and honest with me. They did tell me that even in their own controlled tests between bikes, stacks, air boxes etc, that they could not establish a regular HP gain over many tests and bikes. Hence their +3 to 7HP claim. I believe that this may be down to the alignment of many pieces; the final position of the motor dictates the position of the throttle body. Then the Vortex cone is effectively positioned by the securing holes in the air box and those on the frame. I have other theories based on testing other systems in these tests that will probably help the power output of an SVVS system. I will discuss these further in a summary of all the tests.
RamRaceCo will be retaining the SVVS system for further development of my race XB9.
Comments from 2Win Induction Technologies LLC
Excellent summation, well done! Thank you for the validation of our claims of mid-range performance. More important than a top-end HP gain in our design was targeting this “mid-range hole” for correction. We were delighted that the results of “mid-range correction” were also achieved during your testing. Additionally, we were pleased you achieved a +3.4 hp gain as we found that we had gains of anywhere from 3-7 rwhp. However as we discussed earlier on the phone, our gains of 6-7 were achieved only when we designed an “open-air” design similar to the Force Motor Company Air Intake System and that of the Hillbilly design. Basically, we created a vortex cone plate that mounted over the Buell Race Air Filter and bolted down in the same way the Force Unit does by 2 mounting bolts that penetrate both the upper air filter cover and the lower air box cover on the XB9R/S.
The Hillbilly Stack is an excellent design for top-end performance and was our motivation for also developing an “open-air”, air box eliminating SVVS System which we also have available giving the additional +3-4rwHP while still terminating the mid-range hole.
For the sake of the Buell Community, we are also very pleased that you tested our SVVS with the XB12 Air Box. We also found that this worked equally as well as our Clear Vortex Cone and allows our customers to have a choice. My personal preference also went to the XB12 Air Box Cover for most all of our customers as it reduced our labor and time and allowed the average person to simply purchase our SVVS and our supplied XB12 Air Box, or purchase an XB12 Air Box from their local dealer if they did not already have one mounted.
Thank you for all your hard efforts on behalf of the Buell Community, your work is much appreciated by many.
Corey B. James
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