the dreaded exhaust question (again)

[The Radium King]

hi there, i'm asking the dreaded exhaust question (again). i've seached the forum but can't find what i'm looking for.

i'm new to the boxster and new to this forum - hello everyone ...

i have a 2000 boxster s. i am looking to increase power; i intend to do the chip/intake/plenum mods and was thinking about exhaust. sound is secondary and exhaust components (typically) expensive.

questions:

1) it makes sense to me that a freer-flowing exhuast will reduce torque at lower rpm (less back-pressure) but increase hp at higher rpms when more air is moving through; is this valid?

2) the boxster s has a more tuned exhaust, and aftermarket exhaust will yield a smaller (if any) hp increase; valid?

3) where is most power increase found - header, sport cats, test pipe (secondary cat delete) or muffler? i could see headers being most beneficial, as more power would be seen through efficiency (equal length pipes)?

4) if i am increasing/improving airflow at the intake with improvements to the intake and plenum, would these benefits be increased with a freer-flowing exhaust (more are in, more air out)?

i quess i'm trying to drill down to whether exhaust mods are worthwile and, if so, which ones give the best bang for buck. and finally, whether a $76 ebay header is just as good as a $500 tuner header ...

[Cloudsurfer]

Originally Posted by The Radium King

hi there, i'm asking the dreaded exhaust question (again). i've seached the forum but can't find what i'm looking for.

i'm new to the boxster and new to this forum - hello everyone ...

i have a 2000 boxster s. i am looking to increase power; i intend to do the chip/intake/plenum mods and was thinking about exhaust. sound is secondary and exhaust components (typically) expensive.

questions:

1) it makes sense to me that a freer-flowing exhuast will reduce torque at lower rpm (less back-pressure) but increase hp at higher rpms when more air is moving through; is this valid?

I'd say generally yes.

2) the boxster s has a more tuned exhaust, and aftermarket exhaust will yield a smaller (if any) hp increase; valid?

No, both cars use the same exhaust. 97-99 is one system, 00-02 is another, and 03-04 is different. Same from base to "S."

3) where is most power increase found - header, sport cats, test pipe (secondary cat delete) or muffler? i could see headers being most beneficial, as more power would be seen through efficiency (equal length pipes)?

Given how atrocious the stock headers are, I'd say the biggest gains are here.

4) if i am increasing/improving airflow at the intake with improvements to the intake and plenum, would these benefits be increased with a freer-flowing exhaust (more are in, more air out)?

Generally yes.

i quess i'm trying to drill down to whether exhaust mods are worthwile and, if so, which ones give the best bang for buck. and finally, whether a $76 ebay header is just as good as a $500 tuner header ...

Headers come in two varieties for these cars: "cheap" and "not cheap." Not cheap includes B&B, Supersprint, Cargraphic, Miltek, Tubi, FabSpeed, and a few others. Cheap includes the stuff on eBay for $100, and "discount" sites.

If you've ever wondered why good exhaust components cost so much, have a look at Burns Stainless (where most race teams and many exhaust manufacturers purchase components) and start pricing out what it takes to build a set of headers. Now add on R&D expenses, labor, and some mark-up so you can attempt to turn a profit, and there's your answer.

[jmatta]

Changing any of those items will likely yield little more than a lighter wallet. Most that have made the changes have only seen minimal HP gains, if any. If you wish to make your car quicker, you really have two options; increase displacement or lose mass.

Displacement is expensive, but so are add-ons that provide little payback...reducing weight is very cost effective, until you get into panel replacement.

[2K3_Boxster_S]

You can get 18hp if you do intake and full exhaust. see NHP exhaust thread.
Whether that's a minimal gain is dependent on what an individuals perception of expected results is compared to $$$ spent. It's not a cheap upgrade and it can't be done through ebay.

[Cloudsurfer]

Originally Posted by 2K3_Boxster_S

You can get 18hp if you do intake and full exhaust. see NHP exhaust thread.
Whether that's a minimal gain is dependent on what an individuals perception of expected results is compared to $$$ spent. It's not a cheap upgrade and it can't be done through ebay.

Hate to point it out to you, but the NHP is made in China "cheap" stuff.

[2K3_Boxster_S]

Originally Posted by Cloudsurfer

Hate to point it out to you, but the NHP is made in China "cheap" stuff.

Wrong. made in Canada. not even close to ebay cheap. Welds are beautiful, no fitment issues. China doesn't use T-304 stainless either. You got the wrong company.

[mdimant]

Just a note on Exhaust mods, I have 'cheap' Chinese 304-t stainless headers w/o cats and they work very well on my 00' S. They fit perfectly and use 2" tube & are mandrel bent. The welding is as good as i've seen on any custom boat or car parts. I extended & relocated the 02's to fore & aft of the rear cats and did a 'pedro diy' drill out of the exhaust outlets, drilling 2 5/8" holes in each side, basically deleting the 3rd baffle in the muffler. I complemented that on the intake side with 3 1/2" silicone tubing into a large conical filter (big & cheap from local AP store) & a plenum I built out of lightweight remnants from a local plastic supplier, reusing the stock MAF tube & sensor. I will do a Porsche ROW (rest of world) flash on the chip to handle the unavoidable cels, & will have less than a grand into it. It just flies, & it sounds like pissed off hornets. Very slight resonance btw 2k-2800 rpm (i don't run @ less than 3k often). The Chinese have copied the best pipes, not the worst (duh). Folks who disaprove of these cheap mods have already spent way too much and are usually unskilled @ doing anything themselves. I have nearly as much fun tweaking the car as I do driving it. I does not have to cost a fortune if you get a Bently book & study online what u want 2 do b4 u tear into it. This is roadster ownership at its best!

Originally Posted by The Radium King

hi there, i'm asking the dreaded exhaust question (again). i've seached the forum but can't find what i'm looking for.

i'm new to the boxster and new to this forum - hello everyone ...

i have a 2000 boxster s. i am looking to increase power; i intend to do the chip/intake/plenum mods and was thinking about exhaust. sound is secondary and exhaust components (typically) expensive.

questions:

1) it makes sense to me that a freer-flowing exhuast will reduce torque at lower rpm (less back-pressure) but increase hp at higher rpms when more air is moving through; is this valid?

2) the boxster s has a more tuned exhaust, and aftermarket exhaust will yield a smaller (if any) hp increase; valid?

3) where is most power increase found - header, sport cats, test pipe (secondary cat delete) or muffler? i could see headers being most beneficial, as more power would be seen through efficiency (equal length pipes)?

4) if i am increasing/improving airflow at the intake with improvements to the intake and plenum, would these benefits be increased with a freer-flowing exhaust (more are in, more air out)?

i quess i'm trying to drill down to whether exhaust mods are worthwile and, if so, which ones give the best bang for buck. and finally, whether a $76 ebay header is just as good as a $500 tuner header ...

[boxster_s_boy_34]

Take it from somebody who bought an NHP system and wishes that they would have bought a Fabspeed . The tips rusted through and cracked within 6 months of daily driving in nice weather. One of the rock guards on the mufflers has already come loose and I've only had the exhaust for a little over a year. Fabspeed may be a little more expensive, but you get what you pay for and I hate buying things twice. The headers are okay at best and the mid pipes are equally as mediocre. Fabspeed has been in the business for quite some time and all of their products that I have seen are just as top notch as say EvoMS.

[backman_z]

I am fairly new to the forum.
I have had my 04 Boxster 2.7 for less than a year.
I have not started tinkering yet, but plan to start this summer.

So I am not sure that I would take my word for it, but here is my 2 cents.

From what I have read here and on a couple other forums, the two things that most people seam to agree will give you the biggest bang for your buck:

1- Bypassing the secondary cats. This improves flow and decreases weight. Definate improvement in power, with the weight decrease, it is a combined big plus. Compred to some of the other exhaust mods, it costs less.

2- Underdive pulley. One of the cheapes mods available, and gains have been well proven. The stock pulley is 6 inches. Most of the underdrive pulleys available are 5", but there are a couple 4" one out there (Flat6).

This is where I am going to start; bypass cats and an undredrive pulley. Flat6 and his suppliers seam to be confident that the 4" pulley does not underdrive anything too much, so I will likely try their pulley. There is a guy near me with a dyno, so I am hoping to do a pre-mod dyno, and then on after each mod.

[The Radium King]

the underdrive pulley does appear to be a good solution - i'm watching the forums to see what people's long-term impressions of them are with respect to alternator operation; i've read that the battery light can come on at idle; ok for a race car, but i'm using mine as a daily driver/gt.

that's also an interesting idea of deleting the primary cats and using the secondary cats instead; if you get the secondary pipes for a previous year, they might even already come with the bungs? you mentioned CEL's; was that from the exhaust mods or the intake mods? i'm wondering how the engine management system would read across the secondary cats.

from everything i've seen, the best way to improve torque is with a 3.4 swap. such a swap apparently needs a better exhaust to really perform. so, to avoid redoing anything (and spending more $$$) i'm just looking at mods for my 3.2 that could eventually be reused with the 3.4. and if i put the $$$ into the swap, i would probably want to compliment it with a quality exhaust.

thanks all.