Frequently asked questions

Chip Tuning

What does chip tuning mean?

By chip tuning the software of the engine control unit (ECU) is aligned, for example to get more power, more torque, better mileage or even less fuel consumption.

Why does HMS-Tuning not offer additional (plug-in) control devices?

In order to achieve the most optimal and efficient performance increase, it is necessary to have all the different factors, which collude in the engine management, adapted perfectly to each other. This is only possible from within the engine control unit (ECU). Additional control devices only access the input and output signals of the ECU. Normally an optimal improvement cannot be achieved from this.

What does the engine control unit (ECU) do?

Modern vehicles are equipped with an engine control unit that is responsible for the entire engine management. It contains highly complex software, which controls, regulates and simultaneously monitors for example, the injection time, the fuel-air mixture and many other functions. Various factors such as the position of the accelerator pedal, the air mass, different temperatures and much more are included. These factors are calculated in the engine control unit, analyzed and tuned successive for optimum driving operation.

Why manufacturers don’t offer their engines at maximum power already?

Vehicle engines today need to withstand various stresses. Therefore, the manufacturers are designing vehicles to operate in regions with +50 ° C as reliable as at temperatures of -50 ° C. Concurrently the regional differences in fuels, exhaust emission limits and much more need to be considered. Sometimes there are only "internal political" decisions that lead to having one engine available with less power, just to keep the market open for another type.

Why does chip tuning of naturally aspirated engines not as much as for turbo engines?

An important factor to improve performance is to change the air flow. At naturally aspirated engines the air flow volume is preset and cannot be changed from software.

Is performance improvement possible even for vehicles with diesel particulate filter (DPF)?

Yes, even in vehicles with DPF performance increase is possible.

Does chip tuning also works for vehicles with automatic gear or dual-clutch transmission?

Tuning can be performed both in vehicles with automatic transmissions as well as vehicles with dual-clutch transmissions (like VW DSG). Depending on power deployment, it may be necessary to adapt the software of the transmission control unit to the new conditions.

Is fuel consumption increased from chip tuning?

Power depends on fuel. If you always would make use of the improved power after chip tuning, you surely would notice an increase of fuel consumption. Series cars also would consume more fuel, if more power is claimed. In general, fuel consumption even may decrease after tuning, if the vehicle is driven in a normal way. This because by increasing the torque, the accelerator must be depressed far less.

Does chip tuning need to be registered?

Yes, chip tuning must be registered at your appropriate authority. Because changing the vehicles performance invalidates the vehicles type approval and therefore the insurance coverage.

Will the vehicle run faster by chip tuning?

The top speed of a vehicle depends on the transmission design. Are there enough "reserves" available, the increase in top speed may be 5 to 10 km/h. Vehicles that are limited by software to certain speed (Vmax), will not get faster. In this case higher speeds way become achieved only by setting the software limit (Vmax) to a higher value.

Will the insurance contributions get expensive after chip tuning?

The vehicle insurance today depends not only on the performance of the vehicle. In many cases, therefore, the contributions remain the same. However, you should always report an increase in performance to your insurance company, so you do not lose your insurance coverage.

What happens to the manufacturer warranty after a chip tuning?

Modifications to the engine control unit will void the manufacturer warranty. This may be intercepted by an extended warranty we may offer to you.

Exhaust systems

What makes HMS-Tuning exhaust systems different?

Our exhaust systems are all fully self-developed based on the expertise of over 15 years of experience. The exhaust systems are made individually for each vehicle type and brought to series production stage. Even in series production our exhaust systems are all individually handmade and quality tested, which guarantees a constant, consistently high quality "Made in Germany". Our exhaust systems usually by design lead to a performance increase already. But what all our customers value most is: The incomparable sound of an original HMS-Tuning exhaust system!

What materials are used?

We only use high-quality materials like stainless steel 4301, which is welded in complex TIG welding processes having welding seams of at least 2mm. This guarantees the long life of our exhaust systems. Even for the exhaust valves, control electronics, the wiring and the pneumatic components, we only use quality products.

Which components are parts of an exhaust system?

An exhaust system consists of several components such as exhaust manifold, down pipe, catalytics, mufflers, tail pipes. HMS-Tuning exhaust systems usually begin after the catalytics (Cat back), include piping, pre-muffler or X-pipe (depending on the type), end-mufflers (with or without flap technique) and the tailpipes. Type and shape of the tailpipes in many cases you can choose yourself. On request and if technically feasible, we may offer other exhaust manifolds, downpipes, catalytics replacement, racing catalytics, X-Pipes etc. by additional charge.

What is an X-pipe?

An X-pipe is a special component of the exhaust pipes looking like an X. The usually separate exhaust streams of an engine with two banks of cylinders interact with each other through an opening in the X-pipe. This favors the exhaust flow, provides smoother, higher pitched sound and usually leads to performance gains.

What the sound level of the exhaust systems depends on?

For exhaust systems without flaps, the volume is determined solely by the design of the system and the installed mufflers. A subsequent change is possible only through conversion. The volume of a valve controlled exhaust additionally depends on the position of the exhaust valves. With open valves the system is louder, because the mufflers were bypassed. The position of the exhaust valves is controlled by our electronics and by a switch inside the vehicle as well. We may connect to an unused switch in the cockpit, or we will install a new switch after consultation with you. The electronic control keeps the valve closed between 50km/h and 70km/h to meet German regulations. For export trade different solutions are possible.

What about approval by a technical inspection authority?

All of our series exhaust systems, also with the flap technique, may get approval from the German technical inspection authority (TÜV) for use in Germany. We also may provide a data sheet that approves the exhaust system to meet regulations of the European Union for use in many other countries e.g. Switzerland or Austria. Our electronic valve control automatically ensures that these requirements are met. Outside Germany, however, you should inquire upfront from your local authority. In case of changes or modifications that affect the exhaust emissions, e.g. exchange or replacement of catalysts, an approval is not possible.

Who will install the exhaust system?

We would be happy to install your exhaust system in our garage including approval from the German technical inspection authority (TÜV). An appointment usually is done after your order. You may also have installation done by one of our retailers or every car repair shop of your choice. We then would provide you with the information necessary for installation.

To which countries we may ship?

We are able to ship to almost every country around the world. Please send us your detailed address for we may inquire the shipping costs and terms from the shipping company.

How does the exhaust valve control work?

The exhaust valves are generally controlled by electronics so that the HMS-Tuning exhaust systems are MOT (TÜV) compliant. Additionally this electronic provides the option to control the volume of the exhaust system by yourself. From a switch in the cockpit you may open or close the valves at any time. So you decide when your car sounds sporty or has more the classic sound. Either and existing, unused switch from the cockpit may be connected or an additional switch will be installed, even on demand a hidden one. For vehicles already equipped with a valves control from stock, the HMS-Tuning exhaust systems usually may become connected to the existing valve control.