Philip1

this might sound crazy but has anyone rebuilt their muffler with 2" pipe? I am liking this idea because it looks stock but flows much better. I am thinking about doing this for my 2.7 boxster so that the entire exhaust is 2".


just a crazy idea

Macster

Crazy? That about covers it.

How do you know the exhaust will flow better?

The engine is an air pump. It is an air pump from its air intake opening (even where this is positioned for it has to pump air while the vehicle is moving at very high speeds) to the exhaust pipe tips (and where these are located for the same reason as I mentioned above regarding the intake's position).

To make a change like you are contemplating ignores the system's interdependencies. If the outcome is better and it won't it will be luck, or the inability to recognize and admit failure and spend considerable money to right the wrong.

extanker

you will lose torque [if they ever had any] but gain a bunch of neighbors that will hate you for the noise

Philip1

hmmm interesting so buying a fabspeed 2" catback is a stupid idea too.

terbiumactivated

If you want a mod that will actually make the car feel a bit quicker that isn't expensive try an under pulley. If you drive a lot with the top up you best think twice about ANY exhaust mods. If you simply crave a more powerful Boxster I would trade or sell, IMO buying the performance from Zuffenhausen is better.

ep3_lol

In general, a bigger more free flowing exhaust will gain you high-end power at the expense of low-end torque. So, basically, it'll be worse on the street but better on the track, noise aside. As for all the interdependencies, stock street motors are designed to work in a wide, wide range of atmospheric conditions and tend to do so quite well. People modify Boxster exhausts and intakes quite regularly with no problems. The motor is just not that delicate. Going too far to one extreme may cause problems, though, so you may want to see if anyone's tried what you want to do first, just to make sure.

Chris@Fabspeed

There is a lot going on in the 986 muffler. I can tell you if there is restriction in the exhaust it primarily comes from the catalytic converters. While the 986 multi-chambered muffler looks complex and backwards, there is very little backpressure created by it, and, this backpressure helps maintain low & mid range rpm cylinder filling.

986's, especially non S cars, also don't make a ton of power. A dual 2" system is PLENTY.

When testing our 981 system, we went to 2" over the axle pipes per my suggestion and picked up 10-15 hp, more torque, and better sound. The 981 makes anywhere from 50-100hp more than any 986.

Philip1

my 986 has a cracked LH manifold so I will be changing those out with headers. I figured while I was at it high flow cats and mid pipes. being under the car told me exactly where the restriction is located and the muffler isn't it. the stock headers and mid pipes are tiny (my 1.4l datsun had bigger exhaust) measuring 1.5 OD. my solution is 3-1 headers with 2" outlets and 2" mid pipes necking down to fit the stock 1.75 muffler. since I build race cars incorporating the new high flow cats into the headers wont be a big deal.

Philip1

something like this I think

extanker

good luck with your mods

Vonschmidt

Good luck and keep us posted. It's a real black Art but following the unit you show seems sound. However understand that for the street this may just end up so loud you might even get pulled over. Please email you final product and DYNO the car