Vehicle Fuel Efficiency Booster (Fuel Doctor FD-47)

Hammacher Schlemmer has some cool things but the Vehicle Fuel Energy Booster I found on page 29 (December 2010 catalog) has claims that seem unsupported.

This is the device that improves a vehicles fuel efficiency by up to 18%. An independent automotive testing service showed the unit increased a vehicle’s average fuel efficiency from 23.8 to 28.1 miles per gallon in two weeks. The device plugs into a vehicles DC outlet and stabilizes the electrical current flowing to the computer that controls the engine’s fuel injection and ignition systems (ECU) optimizing engine efficiency and reducing fuel consumption. It also mitigates electrical interference from the stereo, lights or air conditioning to enhance the efficiency of these systems and improve gas mileage. Includes an adapter with two DC outlets that accommodate the fuel efficiency booster and another device. For use with vehicles that are at least two years old and have 12-volt systems; not for use with hybrid vehicles. 4″L x 1 1/2″W x 1″D (4oz). Product GU-78387. Price $79.95.

If such a device could increase fuel efficiency, it’s a puzzle that car engineers don’t add the functionality to the car in the first place. That is a bit of an alert for me.

The description says the Fuel Doctor isn’t for hybrids or new cars (less than 2y). Hybrids and newer vehicles have fuel consumption meters so on those it would be easy to verify if the device works. You could plug and unplug the device during constant conditions and see if the fuel meter changes. Perhaps the device doesn’t work on cars that have a means of verifying it. 🙂 The rest of the vehicles would need a Scan Gauge III to verify the device.

Hammacher says the product claims are backed by an independent automotive testing service so I decided I’d like to see their lab reports. I left a message with them and Trish got back to me right away:

Hello Darcy- I received your phone call from yesterday regarding The Vehicle Fuel Efficiency Booster. There is a listing of test results on our site and on the product page. Please see the Test Results tab above the sku number and price. Please see the link below and let me know if you need anything else. Thank you!

Trish Hammond, Senior Marketing Analyst, Phone: (847) 581-8987 Fax: (847) 581-8616,
Visit our web site at:, Hammacher Schlemmer, Offering the Best, the Only and the Unexpected since 1848,

Hammacher’s 5 documents aren’t convincing or scientific (not to mention disorganized and unclear). Hammacher’s a great company with lots of cool stuff but I’m concerned that this product may not have good scientific collateral supporting the claims. Hammacher hasn’t had any issues with product returns (according to Trish Hammond) so I’m suspecting those who bought it just think it works or they don’t sell many.

I tried to get more information about the documents from them but it appears they don’t know anything about them and they just refer me to the manufacturer. In fact, I think they probably just got them from the manufacturer.

So that leaves us with the manufacturer and the product testers.

Hammacher documents don’t have much in the way of contact information. One document has three names on it (Mr. Somsak Unjai, Mr. Pairat Meesakul, Mr. Banchop), three of the documents have the same name (Mr. Erez Mosafi) and one document has a link to the company involved ( So I sent Kett an email requesting details of these tests and a contact for questions. I also sent a note back to Hammacher to see if they know where these documents came from or who made them.

Jan Stoetzer ( of Kett got back to me but they won’t comment referring me to Fuel Doctor. I can’t even get them to admit they did the report. I wouldn’t admit it either.

I also found Tzvika Hershko ( on the internet who is apparently the person behind this product. So I sent him a note so he could help find out what’s going on here.

I came across your product in a catalog and was a little skeptical so I’m writing to find out more. Are you claiming that it keeps the voltage more stable by absorbing noise? Can you explain why it’s better than the voltage regulator that a car already has? Can you explain how much noise is in a car electrical and how it can hurt gas mileage? Can you explain why some sellers are saying not to use it in a hybrid? Why on cars that are more than 2 years old? If it’s because of alleged degradation of electrical components wont your product have the same characteristics?

I’m not the first person to question the product. When searching for where the product is from I found this analysis of the product. Tzvika Hershko has responded but hasn’t addressed any of the concerns of the reviewer. It will be interesting if he is able to deal with the concerns about the product.

I found a couple of videos on the device. One claims that Mark Soffa is the president of Fuel Doctor USA. Hmm, I guess I’ll need to send him a note too. I searched his name with the word fuel doctor and there is no contact information that I could see but I found another technical analysis of the product that shows that the product doesn’t work (here’s another). The Fuel Doctor’s Web site isn’t up so I went to contact page on the European site and sent a note via their contact page.

Sept 10 update: At this time, the Fuel Doctor does not have a Web site for this region and my emails sent from the European site and to Tzvika Hershko are unanswered.

So until I can get some reasonable reports on the product that show it works, I’m going to dismiss it as a junk product from a company with no Web site.

Sept 12 update: Here’s a note I received:

Dear Darcy,

Thank you for your e mail. I can understand that you are skeptical as many people are- having difficulties to connect between plugging something into your light socket that results in increase fuel economy.
Our fuel doctor is working on the degradation of the car’s electrical system and that is the main reason we are recommending that our product will be used on cars 2 years and older.
Here is a short explanation:
Fuel Doctor Platinum FD47 is just what we claim it to be: an automotive electrical system power conditioner. Think in terms of other electrical power conditioners used for homes, businesses and for computer systems. Each of these unique systems, conditions the power in a manner that either saves on a utility bill or sends a more uniform signal to the devices receiving the power. Most automobiles use the same circuitry on how a car’s electrical system is grounded. This similarity of structure is the common application for how the FD47P is able to condition the power of automobiles and other vehicles. Its placement within the wiring circuitry of the vehicle allows the device to condition the power going into the computer that controls most of the systems operating within the vehicle. Vehicle horsepower and fuel consumption are one of these systems. Depending on the efficiency or degradation of the electrical system within a particular vehicle, the degree of improvement resulting from the use of the Platinum FD47 can only be determined by physically testing it within a vehicle.
Then you be able to realize certain yields in speed, timing control and power resulting in increased fuel economy. Increased fuel economy constitutes less fuel burned which in turn equals reduced CO2 emissions. These are all by products of the FD-47.

I noticed that you are from Canada- we just started selling our product in Canadian tires shops- our office in USA is taking care of the Canadian market- you can contact with them Directly
Mr. Mark Soffa

Best regards,

Tzvika Hershko

So they’re answering email but still don’t have a Web site.

I replied to this with:

Thanks for the response.

You missed the following of my questions.

Why is it better than the system that’s already in the car?

How much noise is typical in a car electrical system and how does the noise interfere with a computer?

Why won’t it work in a hybrid?

Why on cars that are two or more years old?

If a car’s electrical deteriorates, then what stops the electrical in your device from deteriorating?

I got a reply right away referring me to Douglas at

Dear Darcy,

Please refer all these questions to our Chief engineer – Douglas
He will be able to answer you in the most accurate way