Milltek exhausts come highly recommended on here and by lots of vag owners etc.
Thay give a nice deep note when driven over 3k or "booted". Not too loud or over the top.
You can get two types : Resonated or Non Resonated.
A resonator is a chamber in the exhaust system that contains a specific volume of air which is designed to cancel out certain frequencies of sound (made by the engine) - making the exhaust noise quieter.
Therefore, a non-resonated exhaust system will give you extra performance and a louder exhaust note and the resonated system will give you extra performance without increasing the exhaust noise much.
Thay come with a few tailpipe options on the mk4 golf:
Descreet look: The same as your currant set up the exhaust is hidden under the rear bumper.
Twin 76.2mm jets (Same asV6 4 motion - Requires 4-Motion rear valance part number 1J6807521C from your VW dealer.):
Single 100mm jet (Same as anniversary)
Twin 100mm jets (Same as R32 - Requires R32 Rear Bumper or some mods!!)
4 motion rear valance install:
http://bambergvr6.50megs.com/golfivrear4mo.htmDont forget the High flow cat and downpipe which is a must.....
Standard cat is VERY restictive :
New milltek :
As you can see bit of a difference
A high flow cat will make the mid range so much better.
Milltek FTW
How does a catalyst combine with the engine management system?
It is essential that a catalyst works to its maximum potential or stoichiometric point. Therefore there needs to be a feedback mechanism between the catalyst and ECU to make sure this happens.
On most cars, a lamdba sensor (or Hot Oxygen Sensor) is positioned upstream of the catalyst to measure the amount of oxygen in the exhaust gas. The sensor develops a voltage of between 0.1V and 0.9V. A low voltage is measured in lean conditions (where the gas is high in oxygen and low in fuel) and a high voltage in rich conditions (where the gas is low in oxygen and high in fuel).
As the exhaust gas changes from rich to lean and vice versa this is called the switch point. As this point is passed the sensor tells the fuel injection system to increase or decrease fuel.
OBDII On-Board Diagnostics Exhausts that use only 1 lamdba sensor (AGU
) do not provide any way of determining the condition of the catalyst itself - you can use 100cpsi.
Therefore, a system was introduced called OBDII whereby a sensor is positioned upstream and downstream of the catalyst. The downstream sensor calculates the conversion efficiency of the upstream sensor by recording the ratio of switch rates of both sensors. The ratio should be below 75%. Above this and an error code is returned via the ECU to the dashboard indicating that the catalyst is under-performing.
Use 200cpsi for an engine using OBDII On-Board Diagnostics If a car has OBDII, it is necessary to use a catalyst that will convert the right percentage of harmful gases. Therefore, if a sports catalayst is used, you should use a 200cpsi substrate. This has more surface area and therefore more conversion capacity.
Sound clips :
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