Langers

Well, having read every thread there is to read about exhaust mods, I'm still a little confused.

I'm looking to purchase a 1990 C4, but having driven it I know that it's a bit too quiet. I would like it to be a little louder under load and at idle, but not have a noticable increase in volume at cruising speed. It seems the G-Pipe would fit this description.

Seeing as the car comes with a primary muffler, secondary muffler and catalytic converter, what part exactly is the G-Pipe replacing?

What does the Cup pipe replace?

Thanks in advance,

Klaus Langbein

PC2

The secondary by-pass (sometimes refer to as the G pipe) replaces the secondary muffler (behind the passenger rear wheel arch) and the primary by-pass (sometimes refer to as the Cup pipe) replaces the primary muffler (Under the rear bumper).

Bill Gregory

Don't forget that you can make some nice additional tones, inexpensively, by drilling holes in the removeable cover of your air cleaner box. That, plus a cup pipe or G-pipe (not both) removed makes for a wonderful growl when the pedal goes to the floor, yet it's civil when idling and not pushing it. You can see pictures of a drilled airbox here. No need to spend $175 on a special cover which does little more than hold the airfilter in.

Langers

Ok thanks for the clarification guys. Sounds like I'll fit a G-Pipe.

Doesn't drilling the airbox increase intake air temps? Hot air rises off the engine...goes up through holes into airbox?

WilsonAnderson

Langer,

I have just installed the Fuch's G-Pipe on my 91 C4. It is one mod I would definately recomend. The Air box holes become useless (for added sound)with the G-Pipe. I have ran my C4 stock for three years and cannot believe I did not do this sooner! The increase in volume is only noticable at idle thru about REDLINE under load, but just commuting on the highway there is not much of an increase in noise, at least at 80-90 mph I do not need to turn up the radio any to compensate. Another added benefit is that when I let off the throttle "engine braking" does not occur with such force, I have the 5 speed and it seems like I am driving an auto almost when I let off of the throttle.

G-pipe is the way to go, and If you are lucky like I was to purchase one from a fellow rennlister like I did maybe you can get a Fuch's G-Pipe, the bends are much longer as well as smoother leading me to think that it may be more desireable that the Dansk unit. I am to say the least truly impressed with the g-pipe.

Take care,
Wil