headers for 2001 boxster?

[ryuujin]

Can anyone give me the real mail on headers for my 2001 2.7l? I've read a lot of stuff on the 'net' etc and I can't decide if i should outlay the dollars for an increase in HP that is questionable? Can fitting headers increase HP at the wheels of 10 to 20HP (quoted in some ads). If I fit headers should I then fit a full sports exhaust including cats and muffler to gain the maximum or can I just leave the exhaust standard? Will the fitting of the headers cause any problems such as CEL etc? I would appreciate any help with this.
Regards

[jwade]

Can fitting headers increase HP at the wheels of 10 to 20HP (quoted in some ads).

Ans: go with these headers..
http://www.turbowerx.com/Porsche_Products/Headers/986_Headers/986_Headers.html

Get rid of secondary cats and go with these bypass pipes:

http://www.fabspeed.com/Boxster.html

http://www.fabspeed.com/986Boxster_13.htm

Exhaust

I prefer the porsche sport exhaust but there are others available.

Since you are in australia, you most likely have the software already loaded that allows no CEL's.

All USA cars will get a CEL when the cats come off. That's why many here reflash their cars with RoW software, which you probably already have.

[Johnny Danger]

Originally Posted by ryuujin

Can anyone give me the real mail on headers for my 2001 2.7l? I've read a lot of stuff on the 'net' etc and I can't decide if i should outlay the dollars for an increase in HP that is questionable? Can fitting headers increase HP at the wheels of 10 to 20HP (quoted in some ads). If I fit headers should I then fit a full sports exhaust including cats and muffler to gain the maximum or can I just leave the exhaust standard? Will the fitting of the headers cause any problems such as CEL etc? I would appreciate any help with this.
Regards

Ryuujin,

Be advised, upgrading the exhaust system on your boxster (i.e. headers and cats) is a serious undertaking that requires a systematic approach. If I am not mistaken, the 2.7 engine has a similar exhaust system to the 3.2, wherein there are two sets of catalytic converters. These sets are commonly referred to as being the "secondary" and "pre" cats. Most would agree, that the "secondary" cats are for the most part extraneous, and, therefore, can be removed and bypassed. However, its the design of the "pre" cat and how it is integrated into the header that creates a challenge. A challenge in the sense, that it is a very delicate balance to increase increase air flow, at the same time maintain the necessary amount of back pressure, as well as keeping the vehicle OBD compliant ( refers to emissions, cel's ect.. ). In my experience, I found that going "catless" actually resulted in a loss of power. This was especially the case with regard a low end torque. Again, some degree of back pressure is necessary in order to maintain power. Next, I experimented with deleting the "secondary" cats and replacing the oem pre-cat/header configuration in favor of separate set of after market headers along with lower cell cats that were relocated further "downstream". Needless to say, this approach required that the O2 sensors via newly created "bungs" had be relocated, as well as the remapping of the vehicle's ecu in order to eliminate ongoing problems with cel's (check engine lights). Another problem with this application was finding high quality cats. There must be a million manufacturers with respect to headers, however, it was nearly impossible to find a real tri-metal 200 cat cell, say on the level of HJS. The third and final application, involved having a set of headers (along with the pre-cats) custom fabricated in a way that they followed the principles of the oem set-up, however, the newly designed ones involved longer, equal length primaries that flowed into a true merger collector and incorporated 200 cell tri-metal HJS cats. This design proved to be ideal. The installation was simply and straightforward. There was no need to retro fit or alter anything, the vehicle was completely OBD compliant, and most importantly, there was clear improvement in hp throughout.

[JTP]

Johnny, are you referring to the Fabspeed headers, are those what you are using on your car? They seem very nice but very expensive at over $2,200. Do they perform well and live up to the HP gains they claim?

[Johnny Danger]

Originally Posted by JTP

Johnny, are you referring to the Fabspeed headers, are those what you are using on your car? They seem very nice but very expensive at over $2,200. Do they perform well and live up to the HP gains they claim?

Mine were actually custom fabricated in Germany by M&M exhaust. They are the "big boys" behind most of the high-end exhaust products in Germany ( Gemballa, Speedart, Techart, Manthey ect..) They are very ex$$$$pensive, but unsurpassed as far as quality and performance. Fvd is the exclusive importer for the USA, and they are wonderful to deal with. On the other hand, the Fabspeed product seems to be very good as well. And by most accounts they perform well. However, there is nothing quite like the M&M product. There are several posts on 6Speed and Planet Porsche regarding their exhaust systems and how delighted the members who purchased them are.

[edevlin]

"Be advised, upgrading the exhaust system on your boxster (i.e. headers and cats) is a serious undertaking that requires a systematic approach."

Very good advice. Shortly after I got my 2000 base boxster (about 3 years ago) I started playing with exhaust upgrades. Just to throw another variable into my exhaust tale, the first mod I did was a high-flow intake and chip. I picked up maybe 15 hp on the dyno. The chip was optimized for both higher flow intake and exhaust, which is why I started messing around with the exhaust. So my experience with exhaust system is with a modified ECU.

I first added headers, then high-flow cats, then muffler. I used quality parts (TTP) and I ran dynos after each of the upgrades. I picked up about 5 hp with the headers, very little maybe 1-2 with the high-flow cats. With the mufflers I lost hp and torque with two that I tried (Gemballa and a Dansk-type), maybe picked up a little with the Dansk high-flow (looks like stock) that I currently have on the car.

BTW, folks ask if you can feel the difference in performance with the butt dyno, sometimes I sure can. I was convinced when I put the Gemballa muffler on the car would be faster. It sure sounded faster, but it sure felt slower, and the dyno showed a loss of several hp and a stinky torque curve.

I also spent close to a year dinking around with chasing the CEL that came from the header cat delete and high-flow cats. Ended up having to replace all the oxygen sensors and one of the cats with all the messing around that was done. Car has been running great for the last year or more, so exhaust issues have settled down.

As far as I can tell (half a dozen or so dyno runs), in my car I may have picked up maybe 7 hp on a full exhaust (headers, high-flow cats, muffler) on my 2.7L. With the wronge muffler, only 3-4 hp. This was a very expensive learning experience. I actually had a lot of fun doing it, learned a lot, and the car sounds great to my ear, but would not do it again unless I was swimming in disposable income. Have fun,


Ed

[Daniel R]

Some very good points have been raised by all members here, I will just add my 2c in regards to the Australian cars.

Here in Australia, perhaps due to less stringent emission laws, there are no primary cats in the Boxsters. We also have only one set of oxygen sensors which are located upstream of the secondary (and only) cats. What this means is that we can do more or less whatever we want to our exhaust system without risking a CEL.

My 2000 S is running Chinese ebay headers and 2" bypass pipes which I had custom made that connect to the stock exhaust. More power?? Maybe. Better sound?? It is definately louder and more raspy, depends on whether you like it or not.

In my opinion exhaust mods are seldom worth the effort unless you are chasing a different sound. I learnt this after going through the process myself. In retrospect I probably wouldn't do it again.