the dreaded exhaust question (again)
 

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 ...

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.

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.

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.

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.
http://i80.photobucket.com/albums/j1...ey/header2.jpg

I think 18HP is pretty optimistic...there's no substitute for torque and you're not going to get appreciable increases with modifications. Gains will be at higher RPMs where it's mostly unused. I am not a technician, but have worked with my Porsche engine builder for years on track setups and know where dollars should or should not be spent.

NHP headers never look right in my eyes IMO, with the unequal length runners and side-entry high-flow cat. I've never seen any of the big companies use side-entry cats. You do get what you pay for really.

thanks everyone, i appreciate the information. also, thanks for the heads-up on maxspeed - good to have a canadian vendor available (less shipping and duty for us canadians).

i'm not made of money, but i like to tinker. i'd save up for a performance exhaust if it provided benefit without detriment (torque loss at lower rpm). looking at the dyno results on the maxspeed website (NHP vendor) there doesn't appear to be a reduction in torque or power except for a bit of torque at 1800 rpm. otherwise a net increase.

those with experience in these things please advise - can you feel the torque loss at lower rpm? can you feel the hp gain otherwise?

dyno

thanks again.

ps - 2k3 - how do you like the shifter? i've read that b&m are too stiff; how does the schnell feel? is it the same unit that maxspeed sells for $99?

1. first to clear up the NHP thing. Maxspeed (NHP) designs and specs the materials to be used. They are actually assembled overseas. do I care where it is assembled? no. The welds and materials are quality and my exhaust fit perfectly. and I wouldn't call $2400 for an exhaust system very cheap.

2. I would have to rip my entire exhaust off put stock back on and dyno to give you a definitive answer as to lower rpm TQ loss. at the end of the day car Dynoed with an overall increase in HP & TQ. 246 HP 218 TQ. The car felt nothing but faster to me.

3. Schnell feels fine to me. super short throws, if thats what you like. Have not missed a gear since installed. Needs a minor adjusment as the ball that fits into the selector (side to side movement) is a little sloppy. My cousin is a machinist, since this part is screwed into the shifter he is going to remake it with tighter tolerance.

Apparently anything that's not made in Germany is automatically considered crap to everybody on this forum.

Take a look at the OEM shifter that comes from the factory in your Boxster. It's garbage and has more plastic in it than a Toys R Us. The bottom linkage will eventually fail and the shifter will pop out leaving you stranded until it is upgraded.

Guess what they don't make Porshe's the way they used to. Lots of crap parts now a days. :eek:

I didn't really care for them either that's why

http://i80.photobucket.com/albums/j1...sey/header.jpg

These have been delivered and waiting to be installed. I am going completely catless and the sport Cat headers will be up on ebay soon.

Which brand are those?

Maybe I'm wrong about where they're made, but no one who knows anything about fluid dynamics, especially as it pertains to internal combustion exhaust design, would design a header that looks like that. Any decent headers you see will have merge collectors, and if catted, will have smooth transitions into and out of the cats- NOT a flat piece of metal welded to one side with a pipe on it (such that exhaust flow only goes through the middle of the grid) and then an exit on the side (so that whatever flow makes it through the middle of the grid has to now make a 90 degree (or tighter) turn in an extremely small radius.

Made in China or Canada or for all I care Nigeria, that's not the way to design a well flowing header.

I've experimented with several different exhaust configurations before choosing the final system for my 3.2 S. I found the following set-up produced the best results in terms of performance and reliability (keeping my vehicle OBD II compliant).
Here's my ditty:

1. A less restrictive, high quality after -market cat back exhaust.
2. By-passing/deleting the secondary cats (they're like having an extra set of thumbs).
3. Headers and cats that stick with the basic principles of the oem design, however, they incorporate longer, equal length primaries that flow into a merge collector, along with lower cell - high flow cats (something on the order of HJS 200 cell).

The final result yielded the following: No need to relocate O2 sensors, make bungs, chase CEL's, reprogram the ECU, or worry about emissions ! Excellent results in terms of improved power and performance. And perhaps equally important - great sound ! All this begs the question; who makes headers and cats that follow this design principle ? In all of my research and experimentation I discovered 2 companies that manufacture such a system. M&M exhaust in Germany ($$$$$$$$$$$$) who's products are imported exclusively by FVD/Brombacher and FabSpeed.

THEY ARE (drum roll........) NHP

2K3,

I know that I have since been taken off of your Christmas card list for some of my previous remarks regarding your choice of equipment. However, I can tell you from experience that going "catless" will prove to be a bad decision. I assure you that you will experience a significant loss of low end to mid range torque, not to mention CEL problems galore.

Yes, but it should sound really cool.

Your right no CATs is not good on NA engine, but for forced induction set-up's it's actually good. preparing for a DIY setup.

There's your answer. No one ever said it was going to be cheap.

Cheap Headers
 

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!

Nhp Is Junk!!!!!!!!!!
 

Take it from somebody who bought an NHP system and wishes that they would have bought a Fabspeed:o . 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.:cheers: