Privacy Policy

A Little Information

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Motordyne USA knows that you care how information about you is used and shared, and we appreciate your trust that we will do so carefully and sensibly. This notice describes our privacy policy. By visiting Motordyne, you are accepting the practices described in this Privacy Policy.

What Personal Information About Customers Does Motordyne Gather?

The information we learn from customers helps us personalize and continually improve your shopping experience at Motordyne. Here are the types of information we gather. Information You Give Us: We receive and store any information you enter on our Web site or give us in any other way. You can choose not to provide certain information, but then you might not be able to take advantage of many of our features. We use the information that you provide for such purposes as responding to your requests, customizing future shopping for you, improving our stores, and communicating with you. Automatic Information: We receive and store certain types of information whenever you interact with us. For example, like many Web sites, we use “cookies,” and we obtain certain types of information when your Web browser accesses Motordyne . A number of companies offer utilities designed to help you visit Web sites anonymously. Although we will not be able to provide you with a personalized experience at Motordyne if we cannot recognize you, we want you to be aware that these tools exist. E-mail Communications: To help us make e-mails more useful and interesting, we often receive a confirmation when you open e-mail from Motordyne if your computer supports such capabilities. We also compare our customer list to lists received from other companies, in an effort to avoid sending unnecessary messages to our customers. If you do not want to receive e-mail or other mail from us, please adjust your Customer Communication Preferences. Information from Other Sources: We might receive information about you from other sources and add it to our account information.

What About Cookies?

Cookies are alphanumeric identifiers that we transfer to your computer’s hard drive through your Web browser to enable our systems to recognize your browser and to provide features such as personalized greetings, and storage of items in your Shopping Cart between visits. The Help portion of the toolbar on most browsers will tell you how to prevent your browser from accepting new cookies, how to have the browser notify you when you receive a new cookie, or how to disable cookies altogether. However, cookies allow you to take full advantage of some of Motordyne coolest features, and we recommend that you leave them turned on.

Does Motordyne Share the Information It Receives?

Information about our customers is an important part of our business, and we are not in the business of selling it to others. We share customer information only as described below and are subject to this Privacy Notice or follow practices at least as protective as those described in this Privacy Notice. Agents: We employ other companies and individuals to perform functions on our behalf. Examples include fulfilling orders, delivering packages, sending postal mail and e-mail, removing repetitive information from customer lists, analyzing data, providing marketing assistance, processing credit card payments, and providing customer service. They have access to personal information needed to perform their functions, but may not use it for other purposes. Promotional Offers: Sometimes we send offers to selected groups of Motordyne customers on behalf of other businesses. When we do this, we do not give that business your name and address. If you do not want to receive such offers, please adjust your Customer Communication Preferences. Business Transfers: As we continue to develop our business, we might sell or buy stores, subsidiaries, or business units. In such transactions, customer information generally is one of the transferred business assets but remains subject to the promises made in any pre-existing Privacy Notice (unless, of course, the customer consents otherwise). Also, in the unlikely event that Motordyne, or substantially all of its assets are acquired, customer information will of course be one of the transferred assets. Protection of Motordyne and Others: We release account and other personal information when we believe release is appropriate to comply with the law; enforce or apply our Conditions of Use and other agreements; or protect the rights, property, or safety of Motordyne, our users, or others. This includes exchanging information with other companies and organizations for fraud protection and credit risk reduction. Obviously, however, this does not include selling, renting, sharing, or otherwise disclosing personally identifiable information from customers for commercial purposes in violation of the commitments set forth in this Privacy Notice. With Your Consent: Other than as set out above, you will receive notice when information about you might go to third parties, and you will have an opportunity to choose not to share the information.

How Secure Is Information About Me?

We work to protect the security of your information during transmission by using Secure Sockets Layer (SSL) software, which encrypts information you input. We reveal only a fraction of your credit card numbers when confirming an order. Of course, we transmit the entire credit card number to the appropriate credit card company during order processing. It is important for you to protect against unauthorized access to your password and to your computer. Be sure to sign off when finished using a shared computer.

Which Information Can I Access?

Motordyne gives you access to a broad range of information about your account and your interactions with Motordyne for the limited purpose of viewing and, in certain cases, updating that information.

What Choices Do I Have?

As discussed above, you can always choose not to provide information, even though it might be needed to make a purchase or to take advantage of such Motordyne features as wish lists and customer reviews. You can add or update certain information on pages such as those listed in the “Which Information Can I Access?” section above. When you update information, we might keep a copy of the prior version for our records. If you do not want to receive e-mail or other mail from us, please adjust your Customer Communication Preferences. (If you do not want to receive Conditions of Use and other legal notices from us, such as this Privacy Policy, those notices will still govern your use of Motordyne, and it is your responsibility to review them for changes. The Help portion of the toolbar on most browsers will tell you how to prevent your browser from accepting new cookies, how to have the browser notify you when you receive a new cookie, or how to disable cookies altogether. However, you will not be able to use some important features if you do not use cookies. The Federal Trade Commission provides useful information about online privacy on its own Web site, Site Seeing on the Internet.

Related Practices and Information

Conditions of Use

Information You Give Us: You provide most information when you search, buy, bid, post, participate in a contest or questionnaire, or communicate with customer service. For example, you provide information when you search for a product; place an order through Motordyne or one of our third-party sellers; provide information in Your Account (and you might have more than one if you have used more than one e-mail address when shopping with us); communicate with us by phone, e-mail, or otherwise; complete a questionnaire or a contest entry form; compile a wish list or other gift registries; provide employer information when opening a corporate account; provide and rate reviews; specify a notification; and employ other Personal Notification Services, such as Motordyne Notifications. As a result of those actions, you might supply us with such information as your name, address, and phone numbers; credit card information; people to whom purchases have been shipped, including addresses and phone number; people (with addresses and phone numbers) listed in your address book; content of reviews and e-mails to us; and any other personal descriptions provided.

Automatic Information

Examples of the information we collect and analyze include the Internet protocol (IP) address used to connect your computer to the Internet; login; e-mail address; password; computer and connection information such as browser type and version, operating system, and platform; purchase history, which we sometimes aggregate with similar information from other customers to create features such a top sellers; the full Uniform Resource Locator (URL) clickstream to, through, and from our Web site, including date and time; cookie number; products you viewed or searched for; your purchase history; and the phone number you used to call our phone number. We collect the email addresses of consumers who communicate with us or through our authorized vendors via email. Any information or pictures provided becomes our property once received by us and may be used and disclosed as permitted in this Policy.  We may also aggregate your personal information with others’ information and prepare reports on site usage, purchase history or other factors for sale or distribution to others. Those reports are aggregated and include no personally identifying information. Finally, we may use your personal information to send you email or postal communications regarding products or services offered by us or by third parties with whom we have relationships in which we think you may be interested. We do not share, sell, trade or rent your personal information to third parties for unknown reasons. You may at any time choose not to receive promotional emails from us by contacting us at info@ Notwithstanding the foregoing, we may continue to contact you for the purpose of communicating information relating to this site, as well as to facilitate, complete, or confirm any transaction that you may enter into or responding to your inquiry or request.

Use of Forums

If you choose to transmit, submit or post information through the Site’s chat rooms, bulletin boards or other forums (the “Forums”), we will collect that information you provide. We retain this information as necessary to resolve disputes, provide customer support and troubleshoot problems as permitted by law and pursuant to our Policy.

Information from Other Sources

Examples of information we receive from other sources include updated delivery and address information from our carriers or other third parties, which we use to correct our records and deliver your next purchase or communication more easily; account information, purchase or redemption information, and page-view information from some merchants with which we operate co-branded businesses (such as or for which we provide technical, fulfillment, advertising, or other services; search term and search result information from some searches conducted through the Web search features; and credit history information from credit bureaus, which we use to help prevent and detect fraud and to offer certain credit or financial services to some customers.

Information You Can Access

Examples of information you can access easily at Motordyne include up-to-date information regarding recent orders; personally identifiable information (including name, e-mail, password, communications preferences, and address book); e-mail notification settings (including Alerts, Available to Order notifications, and newsletters); recommendations (including recent product view history, prior order history, and Favorites); shopping lists and gift registries (including Wish Lists); and your account (including your product Reviews, Requests, and Recommendations, personal profile, and address book).


Motordyne does not sell products for purchase by children. We sell children’s products for purchase by adults. If you are under 18, you may use Motordyne only with the involvement of a parent or guardian or visit our store in the Santa Clarita area. If you choose to visit Motordyne, your visit and any dispute over privacy is subject to this Notice and our Conditions of Use, including limitations on damages, arbitration of disputes, and application of the law of the state of California. If you have any concern about privacy at Motordyne, please send us a thorough description to info@, and we will try to resolve it. Our business changes constantly, and our Privacy Notice and the Conditions of Use will change also. We may e-mail periodic reminders of our notices and conditions, unless you have instructed us not to, but you should check our Web site frequently to see recent changes. Unless stated otherwise, our current Privacy Notice applies to all information that we have about you and your account. We stand behind the promises we make, however, and will never materially change our policies and practices to make them less protective of customer information collected in the past without the consent of affected customers.

back pressure rapidly reduces engine performance

The butterfly valve was attached at the end of the Y pipe and dyno tested at various levels of flow restriction.  From wide open to almost fully closed, as back pressure increased, dyno performance rapidly decreased.


This data set clearly demonstrates back pressure is not beneficial to power or torque in any way on our VQ engine.

6″ diameter parabolic diffuser (megaphone)

After that series of tests we performed another set of tests were performed.   Tests that decreased exhaust back pressure below that of a simple open ended 3″ pipe.   A 6″ diameter parabolic diffuser (megaphone) was clamped onto the end of the Y-pipe.  This was used to decrease flow resistance below that of an open pipe. Dyno tests show the diffuser produced an instant 4-6HP increase over that of a open Y-pipe.


back to back dyno testing

So while there are rapidly diminishing returns with going to larger and larger diameter tubing after the Y-pipe, significant gains can still be made by use of a diffuser.  The back to back dyno testing shown below was a simple open Y-pipe as the baseline and then with the diffuser attached.


To get an idea of how a diffuser works you need to consider all the kinetic energy being pumped out of the exhaust tail pipe.  For a normal exhaust system that uses 3″ tubing connected to a muffler with a normal 3″ outlet with a rapid expansion to a 4″ or 5″ tip, all the exhaust flow energy is wasted by shooting out all that exhaust gas at high velocity into the atmosphere.

If you have ever stood ~20 feet behind a car on the dyno you will see and feel the effects of all that energy being wasted. Standing behind a car on the dyno is like getting blasted by wind on a hot smoggy day.  All that wind is being blasted out of a 3″ tube!  So what is coming out of the tail pipe is quite intense.  It takes energy to move all that hot wind with such force and it’s all just wasted energy.  But if you were to connect a 5″ diffuser to a 3″ exhaust tube the exhaust gas velocity will be slowed down by a factor of almost 3X.

Pressure drop is determined by ρV2/2g. In this case ρ and 2g remain constant and V2 is the important variable.  Not only a diffuser brings the velocity down by a factor of nearly 3X, the total pressure recovery is determined by the square of the velocity 3X.  So the diffuser is recovering kinetic energy by converting Dynamic pressure into Static pressure.  This means your engine doesn’t have to waste energy by pumping out the exhaust gas so forcefully, it also makes it easier for a new fuel/air charge to get into the engine by means of scavenging.

Diffusers are commonly used in jet engines and rocket engines. They convert fluid motion into pressure or Dynamic pressure into Static pressure.  In the case of a VQ engine we only want to convert the dynamic pressure into static pressure before it is dumped into the atmosphere. One way to do this is with a diffuser. For a diffuser to be efficient, it must be designed with the proper expansion ratio and diffusion angle. Like the cone shown above.

If you were to take a common 5″ exhaust tip and bolt it onto a 3″ pipe, it won’t work. A regular exhaust tip has what is called a sudden expansion. A sudden expansion is unable to efficiently convert kinetic energy into static pressure. It just dumps it into the atmosphere and wastes the energy. But a diffuser organizes the flow and gradually slows it down (efficiently) and all that kinetic energy is conserved.  The engine is still pumping out a lot of exhaust gas but a diffuser makes it a lot easier to do.

In conclusion:

A wide range of testing was performed on a range of different diameters and lengths of exhaust pipes in varying locations of the exhaust system.   All of these tests demonstrated different ways of changing exhaust pulse scavenging and backpressure.  In all cases the results show scavenging is beneficial and back pressure is detrimental to engine performance.  Engine performance can be maximized by utilizing a continually expanding exhaust system design with the smallest (optimally sized) pipes closest to the engine and progressively expanding to larger and larger diameter pipes as the flow moves away from the engine.