MGF/TF Exhaust differences

Does any exhaust for an MGF fit my car?

A very common question that is asked is "can I fit this exhaust to my car?" Before the year 2000, the answer would be very simple: yes! But the MGF/TF has its own 'millenium bug' - a problem brought upon us by new Europe-wide emissions legislation. From the 1st of January, 2001, all cars sold in Europe had to comply with new emission and on-board diagnostics requirements. As part of this rule change, an additional, post-catalytic converter Oxygen sensor had to be installed, to ensure that the catalyst was functioning properly.

In terms of day to day driving, this has absolutely no impact whatsoever upon engine performance or driving feel.

The problems only start when you start looking at non-standard parts, such as exhaust systems or catalytic converter replacement pips. If the second sensor does not return a signal, a fault is logged by your car's electronic management system - and the engine's performance is effectively de-tuned to a 'fail-safe' level until the percieved fault can be attended to. When this occurs, a Malfunction Indicator Light (MIL) illuminates on the dashboard...

Effectively, this rules out the use of catalyst-replacement pipes for cars built after 2000 (although a 'MIL eliminator' can be used to bypass the problem - see the ZX Tuner site - a solution successfully and cheaply employed by many Lotus Elise owners).

Note that the Trophy160SE is a special case - see notes under the Buying Rules of Thumb below...

For those wanting an exhaust system, they have to be very careful that the system that they are buying is suitable for their car.

So what are the differences?

Pictured opposite is a composite of the pre and post 2001 exhaust system as found on MGFs (the TF being identical to the post-2001 MGF system).

The items in black are areas that are identical between all cars - which is to say, not a lot. In red is the pre-2001 exhaust system, and in grey, the post-2001 pipe work.

Confusingly, the silencer box looks identical, but as one can see, the inlet pipe to the silencer is very different. The earlier system has an additional 90 degree bend that mates with a shorter catalyst. The earlier catalyst has a longer pipe after it (to accomodate that aforementioned additional oxygen sensor), and as a result, the inlet pipe into the silencer box is shorter.

Included here, but not directly relevant, is the remainder of the exhaust system. Surprisingly, the exhaust manifolds are of a different pattern. What this means with respect to gas flow and engine power is not known...

Therefore, if you are buying, take care to inspect your purchase to see if the pattern of the exhaust is suitable for your car.

The Buying Rules of Thumb:

1. It is NOT possible to install a pre-2001 exhaust onto a post-2001 car.
2. It IS possible to fit a post 2001 exhaust to an earlier car, so long as an adapter elbow is fitted between the standard catalyst and the new silencer box. Mike Satur sells a suitable adapter  -pictured opposite (my car).
3. It is possible to fit a TF exhaust on a late (post-2001) MGF and vice versa - so long as a centre exit design is avoided.
4. Early MGF Trophy 160SEs were homologated under low-volume SVA regulations for UK sale only. Therefore, a significant number of Trophy160s that were sold after 2001 were ACTUALLY fitted with a pre-2001 pattern exhaust system. Confusing eh? Well to make troubles worse, this model was properly type-approved and homologated later on (co-inciding with general release in Europe). These were fitted with 2001-pattern exhaust systems(!). These models can usually be identified by the presence of ABS brakes (these were not fitted to the early SVA-cars).