How To Modify S550 Mustang

How To Modify S550 Mustang


The success of the all new Ford Mustang has plenty of new owners scrambling to modify and tune their muscle car.  However that’s causing a problem for those who are having problems with their dealership. Knowing how to properly modify S550 Mustang will help you avoid problems with your warranty.

One of the most common issues for those who modify S550 Mustang is taking it to their dealership only to find that their warranty claim is being denied. Usually the stance taken by the dealership is that modifications are illegal and therefore voids any warranty with your new Mustang.

Although the new 2015+ S550 Mustang is one of the finest built by Ford, that’s not going to stop the mod bug from biting many of these new Mustang owners. What’s more when the dealership denies your warranty claim based on aftermarket parts, this is in fact illegal to do. That’s what this guide to modify S550 Mustang article is here to do, help you understand what’s legal and how to properly mod your Mustang.

Not everyone will modify their S550 Mustang, after all not everyone can afford to tinker with a $40,000 dollar car. Some may wait until well after the factory warranty passes, or simply pass on modifying their S550 Mustang. Either way, knowing the facts can help you make an informed decision.

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Tips to remember when you modify S550 Mustang

Legal concerns – Although the right to modify your car is something’s that protected, you’ll still need to adhere to the letter of the law. Making sure that your S550 Mustang exhaust system is legal or the modifications you are installing are not breaking any emissions laws is the first step. Making sure that your Ford Mustang mods are legal is one of the first steps to modify S550 Mustang properly.

Know your Rights – Just because your Ford Mustang is modified, doesn’t mean that the dealership can turn you down. Vehicle manufacturers are not allowed to void the vehicle warranty just because aftermarket parts are on the vehicle. So long as your emissions equipment is not affected or changed, your powertrain or car warranty is left intact.

Clean Air Act – The Clean Air Act is one of the biggest challenges to car enthusiasts everywhere. No where else does this make a difference than when you want to modify S550 Mustang exhaust parts. Your Ford dealership must adhere to two different kinds of emission warranties.

One is the defect emissions warranty and the other is a performance warranty. Let’s cover defect first as the front half of the emissions warranties that apply to your S550 Mustang. This defect warranty mandates that the manufacturer has to produce a vehicle which, at the time of sale, is free of defects that would cause it to not meet the required emission levels.

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The second type of emissions warranty is one that applies to the modified S550 Mustang. The performance side of the emissions warranty equation is in place to ensure that your S550 Mustang must maintain certain levels of emission performance over it’s life. This means that even though you modify S550 Mustang exhaust parts, your dealership cannot refuse the warranty.

What does this mean to modified Mustangs? – It simply means that your Mustang cannot be turned down for warranty, even if your aftermarket part is directly responsible for a warranty claim. To be specific your Ford dealer is obligated to make the repairs if your S550 Mustang fails to meet the performance warranty requirements.

This condition protects your rights and is mandated by the Environmental Protection Agency (EPA) in conjunction with the Specialty Equipment Market Association.


What if my part caused the failure? – If the installed part for your Mustang is directly responsible for the failure, your dealership must prove this legally. Not only that but this fact does not void the original new vehicle warranty. Any way you cut it however, your dealership cannot void an entire warranty simply because an an aftermarket equipment has been installed on a vehicle.

Magnuson-Moss Warranty Act – For anyone serious about the process to modify S550 Mustang performance, this legislation is vital. This act was created by Congress to protect consumers and clarify the limitations of automotive warranties.

Being able to answer questions about your warranty and make your Mustang warranty more readily understood helps to protect you. The act states that dealerships or auto manufacturers cannot limit warranties through the use of aftermarket parts.

You may have heard some people modify S550 Mustang performance, only to be told by their dealership that the aftermarket installed part is not registered or authorized by Ford. This is illegal and cannot be enforced, and the act protects you from having to follow this guideline. In simplest terms, the dealership cannot force you to buy branded parts that can be used with your car in order to retain the warranty.

This is commonly referred to as a “tie-in sales” provision, and it’s illegal. If you believe that you are being mistreated by your dealership, contact the FTC’s Bureau of Consumer Protection. You’ll want to apply as a waiver of the tie-in sales prohibition, to protect yourself.

How does this Act protect me? – The Magnuson-Moss Warranty Act protects you rights to sue for an unresolved warranty issue. It also encourages the dealership or the manufacturer to work with the consumer to reach an amicable solution. This is a far better resolution for the dealership than having worry about litigation and the costs associated with such litigation.

How To Take Action – If you’ve had a recent warranty claim denied by your dealership, here’s how to take action. After all, learning how to modify S550 Mustang performance won’t help unless you know how to fight back.

Warranty lawsuits – Being able to sue your dealership for a breach of warranty is easy to do once you have the information. Because a breach of warranty is a federal offense, it means that you can recover costs and fees.

You’ll need the right amount of professional help to represent your side of the argument. You will need to prove that the installed parts on your S550 Mustang did not cause the failure. The one area where the lines become a bit blurred is with engine computers, or when it comes to tuning your S550 Mustang.

Tuning Computers – One of the biggest factors to modify S550 Mustang horsepower is through aftermarket tuners. Because these computers can modify ignition values and fuel trims, it can cause serious problems with your warranty.

The first thing to remember when you plug in a tuner, is that Ford cannot dismiss your warranty simply because you’ve used one. If your Ford Mustang failure occurs because of a sensor failure, Ford will perform the testing and correct the issue. However if your Mustang fails due to a tune problem, the dealer must determine where the fault in the tune is.

In other words Ford must prove that your tune was the cause, and nothing else. This is the only way that they will deny your warranty claim. If you’ve gone with a mail order tune, and your S550 Mustang engine has failed, don’t be surprised to see a powertrain warranty cancellation tag when you come to pick it up.

FLASHEVNT ECU – Before you begin to modify S550 Mustang computer tuning, make sure you do the right amount of homework. Don’t flash your ECU too many times, because there’s a value in your S550 ECU called the FLASHEVNT value.

It reads how many times your factory engine computer has been flashed or programmed. This dispels the myth that many tuners have about a “no footprint” tune. There’s no way around this, even with a handheld programmer like the ones from SCT.

Have any questions about how to modify S550 Mustang performance? Leave us a comment below and let us know!