Benefits of SmartCarb Float Bowl Pressurization Circuit

Posted by Scot Wilson on

Our winter here in the desert is almost over and soon I will be getting back on the bikes for participation in more SmartCarb test rides at the track as well as on Ducati Club rides. We are extremely excited at the successes that we have experienced with using the SmartCarbs with our different Ducati Bevel Drive & TT Racers. The purpose of this blog post is to discuss our findings as to the superiority of the SmartCarb design and specifically the benefits of the pressurized float bowl. This technology truly puts the SC in an entirely different category and a quantum leap above other brands. I would like to share several significant benefits of our SC that should be seriously considered by anyone who is searching for a new fuel delivery system for their engine, whether 4 stroke or 2 stroke, vintage or modern. 


As discussed previously and covered in my other blog posts, the SmartCarb is the only “True” single circuit system that utilizes an internally vented and pressurized float bowl and a precision flat ground metering rod. This design has evolved over the past 50 years of development. No additional circuitry, such as a pilot system, nozzle jet, or main jet is ever needed. The superior efficiency of the SmartCarb’s single circuit system delivers all of the fuel in a plume of fine vapor and in a precise mixtured state, completely unlike other carburetors that use overlapping circuitry. These other carburetors deliver fuel inconsistently from liquid to vapor states and an imprecision of air/fuel mixture control. In this blog post, I will be discussing the significant gains in performance, safety benefits and fuel economy that we have achieved as a result of the design of our SmartCarb flat-slide carbs. Most notably I will also discuss how the Float Bowl Pressurization Circuit does its job.


All of these benefits listed above have allowed us to use smaller SmartCarb flat-slide carbs where our engines benefit from the improved velocity when more effectively matching the venturi of the SC with the inlet tract of our engine. This "injection-like" precision of the fuel mixture has been demonstrated time and time again on the dyno as superior to other brands. Due to the technological advantages of our SmartCarbs, we know that like fuel injection, that these flat-slide carbs can sustain this superior linear velocity of the fuel mixture efficiently through the entire rev range of our Ducati 1000 DS Monster engine as shown in the picture above. It is due to the design of the "pressurized" float bowls of our 36 mm SmartCarbs that we achieve, in part, this linear "injection" of the fuel mixture into our engines without the need for fuel mapping from an ECU or other expensive electronics!! It has been further determined through our analysis that in most applications, that neither larger carburetors nor fuel injection are necessary for the majority of our vintage or modern Ducati engines.

As shown in the diagram above, air travels into the Float Bowl Pressurization Scoop (just above the venturi opening in the body of the carburetor) as well as into the venturi. The float bowl "pressurization" comes from this "ram effect" where only air enters the float bowl to maintain constant pressure and works in conjunction with a one-way check valve. In this way, the constant pressure allows a steady, linear injection of the fuel mixture regardless of the altitude. Please also find the mechanical drawing below that very effectivley illustrates the position of the vent scoop, vent passage, and the check valve. 

These benefits from the design of the pressurized float bowl was experienced when I took my 1981 Ducati 900 ss MHR with SmartCarbs to the top of Mt Lemmon (10,000 ft). There was no loss of power during the entire ride starting at 2500 ft. There was also no need to adjust the carbs along the way as they were automatically adjusting to changes in altitiude and any other atmospheric changes, by "design". Smart Carbs have also been put to the test at the Pikes Peak International Hill Climb which is a grueling road race that starts at 9300 feet in altitude and climbs up to 14,110 feet in less than 13 miles!! Two racing quads were outfitted with SmartCarbs and they achieved a 1st and 2nd Place Finishes respectively!! SmartCarbs can also claim 1st Place finishes at Pikes Peak with 250 cc motorcycles!!

As mentioned in earlier blog posts, the technical benefits of the SmartCarbs are a 30% saving in fuel consumption, 6 to 14% improvement in HP, adaptability to altitude and other atmospheric changes, ease of adjustment and 80% less hydrocarbon emissions. We have confirmed achieving all of these benefits regardless of the year, model or engine size of our Ducati twin cylinder engines. In addition, it has also been proven that carbs have an intrinsic "qualitative" advantage in their design that creates a proactive or pre-atomization of the fuel mixture into our race engines unlike fuel injection as discussed in my previous blog posts from 12 Oct and 16 Nov 2019. These benefits in addition to the other technical advantages in design of the SmartCarb provides a further competitive advantage over fuel injection and other brands of carbs. 

Safety when racing or traveling down-hill on steep mountain roads is another benefit of the "pressurized" float bowl design. Fuel in the SmartCarb’s float bowl stays in the float bowl. One-way check valves in the vent passages allow air to flow into the bowl but they do not allow fuel to flow out or vent to the atmosphere as discussed earlier. The SmartCarb is a "sealed fuel system" with zero fuel spillage that has been EPA certified with the lowest evaporative emissions ever tested by a carburetor fuel system according to the engineers at Technology Elevated . Zero fuel spillage and superior, single circuit metering rod atomization through the entire rev range provides the user of our SmartCarb unparalleled performance, safety, and fuel economy gains that combine to create a significant value proposition when entertaining the purchase of your next fuel delivery system. Seen below is Technology Elevated CEO, Corey Dyess at Evan Steel Performance in Tucson, Arizona when we were "dialing" our 36 mm SmartCarbs on our TT 1000 racer. 


In conclusion, an additional benefit of the design of our SmartCarb flat-slides  according to the engineers at Technology Elevated, is that "the SC’s flow more cubic feet per minute(CFM's of fuel mixture) per size than our round venturi counterparts, and due to the fact that they are a single circuit, they appreciate the increased velocity that a slightly smaller throat size affords. They still make more peak power than the stock carbs, but the bottom to mid is where the real improvements are". We are getting better performance from a 36 mm SmartCarb over a 41 mm Keihin FCR for example. I highly recommend visiting the Technology Elevated website to review the multitudes of tests that have been performed on many different engines and by numerous motorcycle manufacturers. 


We are also excited at the opportunity to do research and development on potential performance improvements that we can achieve using our SmartCarbs with our Norton twin cylinder racers through our sister company, BritIron Classics. 2020 is shaping up to be another exciting year!! Feel free to contact us at, or call 520-730-7576 (WhatsApp enabled for international calls) for inquiries on our SmartCarbDucati, TT & Norton offerings!!


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  • SmartCarbs are being used very successfully in the marine engine and snow mobile engine world. I would recommend going to the Technology Elevated site for information on those applications. All the best

    Scot P Wilson on
  • there are lots of snowmobiles owners waiting for an simple carb that adjust to different temperatures….

    Ronald Bourdages on

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