The Exhaust System (Apr 07)

Another busy weekend with the 964 saw me removing the noisy G-pipe and replacing it with a standard final silencer. The new silencer was sourced from Porsch-apart for a third of the price that a new one would cost (£150 versus £450).

Fitting was fairly straight forward. It just took a couple of attempts to get the olive between the pre-silencer outlet and the inlet to the final silencer to seal nicely. The car is a lot more refined now at tick over and low revs and is both track and neighbour friendly in the noise stakes.

From what I've picked up the G-pipe does not give any bhp gains but saves a lot of weight compared to the standard silencer (about 10 kilos but don't quote me on that). The main reason people put a G-pipe on is for the aural pleasure it gives. Today on a long test drive since putting on the standard silencer, there was no perceptable difference in performance IMO.

Again, from what I've read about 964 exhausts, the silencers are very free flowing. It's the cat that has the greatest restrictions. Putting on a cat bypass can liberate a few more bhp.

There are quite a few combinations you can play with on the 964 because of there being a cat, pre-silencer and final silencer. These can all be replaced with a cat-bypass, cup pipe and G-pipe as appropriate.

From what I've gleaned from Rennlist; the standard set up (which I now have) is about 92 dba, change one component and you'll be between 97 and 100 dba, change two components and you'll be between 105 and 108 dba and if you change all three there will be blood coming out of your ears

BTW, all these meausurements are the standard 0.5 metres static test at 4,000 revs.

I didn't want to risk being on the limit on trackdays and having to start short shifting and the like to keep the noise down. And didn't want to annoy the neighbours too much . A happy side effect of putting a standard silencer on is that the overall balance/stability of the car seems a whole lot better. I guess that the silencer on the right is balancing the weight of the cat on the left (just how Porsche meant it to be).

I've stored the G-pipe for now in case I want to play with exhaust mods later. At the moment my future preference is to remove the heavy pre-silencer and put on a cup pipe. This will introduce a bit more growl (but should be below the magic 100 dba) but more importantly remove a chunk of weight from the car.