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Old 09-06-2019, 12:52 AM   #61
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Old subject, but.. What about 987 headers, would oem 987 headers fit? Would 987 equal length aftermarket headers be even better than the cheap 986 equal length headers?

I know I always have a lot of questions, but soon I hope to be providing answers also :-) The thing is that I really plan to do "the big bang" with intake, exhaust and custom tune.. I want to understand it all before I start. The roadmap looks like this:

1) ASAP: Headers, Im a bit afraid that the bolts are totally rusted/stuck and needs to be drilled out, you know.. So I will adress this first, while the car is still running so I can take it to a pro garage if I get stuck.
2) Midpipes with 200cel cats, when the headers are in place I do this.
3) During winter: Hope to be able to build my own "end system/cat back" I have some fun ideas I cant wait to try out.
During the winter I also plan to do the whole intake part, airbag, MAF, throttle, plenum 996 intake.
4 Springtime: Time for a custom tune and possible get some figures from the dyno.

So.. This is why I, all over the forum and asking things about intake AND exhaust.. bear with me..


Last edited by Robert986; 09-06-2019 at 03:58 AM.
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Old 09-06-2019, 01:26 PM   #62
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Originally Posted by Robert986 View Post
Old subject, but.. What about 987 headers, would oem 987 headers fit? Would 987 equal length aftermarket headers be even better than the cheap 986 equal length headers?

I know I always have a lot of questions, but soon I hope to be providing answers also :-) The thing is that I really plan to do "the big bang" with intake, exhaust and custom tune.. I want to understand it all before I start. The roadmap looks like this:

1) ASAP: Headers, Im a bit afraid that the bolts are totally rusted/stuck and needs to be drilled out, you know.. So I will adress this first, while the car is still running so I can take it to a pro garage if I get stuck.
2) Midpipes with 200cel cats, when the headers are in place I do this.
3) During winter: Hope to be able to build my own "end system/cat back" I have some fun ideas I cant wait to try out.
During the winter I also plan to do the whole intake part, airbag, MAF, throttle, plenum 996 intake.
4 Springtime: Time for a custom tune and possible get some figures from the dyno.

So.. This is why I, all over the forum and asking things about intake AND exhaust.. bear with me..


987 exhaust manifolds will bolt-on to the engine but it will require custom pipes to be fabricated to the muffler. I have a set of 987 Fabspeed manifolds with cats that I bought to install on my Box S but recently got a set of 986 Fabspeed manifolds & cat delete pipes for a good deal I am installing instead.
I will be selling the 987 Fabspeed manifolds soon.
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Old 09-06-2019, 02:44 PM   #63
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Bang for buck the eBay stuff is fine. I've used the eBay manifolds again on my 2nd 986. The latest configuration is with 200cell cats and Carnewal. I did plenty of Dyno runs on my previous car. You can spend plenty more on Cargraphic, FVD etc but will you really get that much more. Ditto the IPD kit. For a fraction of the price you can get the 996 throttle body and plenum and a couple of jubilee clips and silicone tube and you're done for very little outlay. Been there done that and would do it again the same way. My remap was a half day on the Dyno and cost me 350 back in 2013.
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Old 09-07-2019, 11:40 AM   #64
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Generally speaking installing most catless headers will decrease low RPM torque which is what gets the car moving & the headers increase power at high rpm. That's why I sold my headers & bought Fabspeed sport cat manifolds for my 3.6 litre.
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Old 09-07-2019, 01:46 PM   #65
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In Europe the OE headers are already catless. We only have the cats in the mid section. They're normally 400cell but most 'sport' cats are 200 or 100 cell. I've tried lots of permutations of exhaust set up on the 550 I now have but haven't bothered to Dyno test any as I did all that on my previous Boxster.
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Old 09-07-2019, 01:58 PM   #66
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Generally speaking installing most catless headers will decrease low RPM torque which is what gets the car moving & the headers increase power at high rpm. That's why I sold my headers & bought Fabspeed sport cat manifolds for my 3.6 litre.
I tend to agree there is a trade off with exhaust , I wonder if smaller tube straight headers ( no cats ) help with torque vs. larger diameter ? I made 252 lb ft of torque recently with mine and I have cheap Chinese headers , no cats , cat delete pipes and a stock muffler with PSE style bypass pipes . I also made over 282 hp at the wheels which would suggest my setup flows pretty well . Common sense tells me going with a larger diameter exhaust will yield more HP but " may " give up too much torque . It is a fine line . Have you dyno'd your setup ?
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Old 09-08-2019, 10:07 AM   #67
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Originally Posted by rfuerst911sc View Post
I tend to agree there is a trade off with exhaust , I wonder if smaller tube straight headers ( no cats ) help with torque vs. larger diameter ? I made 252 lb ft of torque recently with mine and I have cheap Chinese headers , no cats , cat delete pipes and a stock muffler with PSE style bypass pipes . I also made over 282 hp at the wheels which would suggest my setup flows pretty well . Common sense tells me going with a larger diameter exhaust will yield more HP but " may " give up too much torque . It is a fine line . Have you dyno'd your setup ?
It's all about what rpm you want max efficientcy & then optimize pipe diameter for that rpm. For street driving I shoot for 3000rpm. Your engine is so unique I would ask JR what you should use. I try to have everything ceramic coated to keep the heat inside also.
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Old 09-17-2019, 04:43 AM   #68
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It's all about what rpm you want max efficientcy & then optimize pipe diameter for that rpm. For street driving I shoot for 3000rpm. Your engine is so unique I would ask JR what you should use. I try to have everything ceramic coated to keep the heat inside also.
Is the 3000 rpm a typo or is there something I am missing?
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Old 09-17-2019, 08:17 AM   #69
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Is the 3000 rpm a typo or is there something I am missing?
I believe what BYP is suggesting is that for normal street driving you want to be maintaining at least 3,000 RPMs. That's what I try to practice when I'm local. I believe he's suggesting that you want to consider what should be the pipe diameter based upon that 3,000 RPM... not just some random eBay pipe.

BYP, correct me if I'm wrong.
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Old 09-17-2019, 11:21 AM   #70
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I believe what BYP is suggesting is that for normal street driving you want to be maintaining at least 3,000 RPMs. That's what I try to practice when I'm local. I believe he's suggesting that you want to consider what should be the pipe diameter based upon that 3,000 RPM... not just some random eBay pipe.

BYP, correct me if I'm wrong.
So why would you tune your Porsche to drive it at 3000 rpm? I don't get it.
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Old 09-17-2019, 12:20 PM   #71
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So why would you tune your Porsche to drive it at 3000 rpm? I don't get it.
For a 986 "S" that is around the most efficent engine RPM & if you are installing headers you want the pipe size to be ideal for the intended rpm range. If you normally drive on public streets RPM range is 1,000-6000 so the best overall compromise is headers that give best exhaust velocity @ 3.000 rpm.
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Old 09-18-2019, 07:12 AM   #72
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For a 986 "S" that is around the most efficent engine RPM & if you are installing headers you want the pipe size to be ideal for the intended rpm range. If you normally drive on public streets RPM range is 1,000-6000 so the best overall compromise is headers that give best exhaust velocity @ 3.000 rpm.
Ok we must have very different cars and driving styles
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Old 09-18-2019, 07:28 AM   #73
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Do you drive your Boxster on the street at redline all the time, or do you use the entire rev range? Personally, I rarely ever go near redline when driving on the street in my car.

What BY is saying is that you want headers that will work over the expected rev range. Most people aren't flogging their cars at redline on the street, so the headers should be tuned to work well from 2K to 7K. You can tune an exhaust to make maximum power at redline, but then the car won't have much torque and will be a dog to drive in a normal manner.
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Old 09-18-2019, 08:25 AM   #74
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I think that best flow at 3k RPM is probably just about right. The last long trip I had in my S involved almost 15 hours at a bit over 3k RPM in 6th gear. I averaged almost 29 mpg, even with the top down most of the way. Not bad IMO considering the speed.
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Old 09-18-2019, 10:11 AM   #75
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I typed a very long reply to this yesterday.... but the internet God's saved you all from it, by it disappearing before I could post it.

Most people, when "tuning" (or modifying) a car for street use, look to get as much area "under the line" as possible. Think about a HP line on a graph, say from a dyno-run. You want to get that line as high as possible across the entire range, not simply shoot for a high peak hp. What's being suggested here, is that for street use, a 5% increase beginning at 3000rpm and moving up from there is worth more than a 10% increase at 7000rpm. Now certainly YMMV, depending on your own driving habits, and what the streets in your neighborhood look like.

And while we're at it; I'm sure BYP understands that talking only about diameter of the primary tube is like talking about a fraction with only a numerator, haha. The length of the primary and shape of the collector are part of that equation as well. It's amazing how much tuning can really happen with a header, though those benefits are rarely realized by a simple header change alone; the header shape should be part of the entire engine design from the start. (I'm sure that's why he suggested to the OP that he should refer to the engine builder for a recommendation)

I've built several headers over the years, from very high-revving in-line 4 cylinders, to big-inch V8's, to air-cooled-twin motorcycles..... etc etc. It's more art than science, when you suck at math like I do. hahaha.
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Old 09-18-2019, 02:47 PM   #76
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Do you drive your Boxster on the street at redline all the time, or do you use the entire rev range? Personally, I rarely ever go near redline when driving on the street in my car.

What BY is saying is that you want headers that will work over the expected rev range. Most people aren't flogging their cars at redline on the street, so the headers should be tuned to work well from 2K to 7K. You can tune an exhaust to make maximum power at redline, but then the car won't have much torque and will be a dog to drive in a normal manner.
Mine is not an every day car, when I drive it for fun (in the company of many other Boxsters) we would use the entire rev range from 3000 upwards all the way to the redline. but all in the lowers gears on what we call "B" roads. These are narrow, twisty and largely empty, perfect Boxster territory.

I certainly don't want to get into an online row but there seems to be an awful lot of work done to that car just to potter around. Like I say maybe it is just different driving styles and priorities, the idea that was put forward was so alien to the way we use our cars I thought it might be a typo
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Old 09-18-2019, 08:19 PM   #77
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Hmmm are we saying cat less headers reduce low end torque. Dont want anymore of that as my car is all street now. I had thought those and mid cats along the stock can was best in most regimes.

I was planning on creating an catless header experience thread so that performance, price, fit and finish could all be compiled.

I would not have considered FabS catted headers to be superior to the above set up especially when considering the price
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Old 09-19-2019, 01:05 AM   #78
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Hmmm are we saying cat less headers reduce low end torque. Dont want anymore of that as my car is all street now. I had thought those and mid cats along the stock can was best in most regimes.

I was planning on creating an catless header experience thread so that performance, price, fit and finish could all be compiled.

I would not have considered FabS catted headers to be superior to the above set up especially when considering the price
In Europe all the 986 are catless headers. A sample of one granted but based on my Dyno runs including a baseline there is no loss of torque anywhere once you layer up the mods like tubular manifolds, larger throttle body, remap. In fact the gains start just after 3.5k rpm and carry in right through to the redline.
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Old 09-19-2019, 08:20 AM   #79
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Hmmm are we saying cat less headers reduce low end torque. Dont want anymore of that as my car is all street now. I had thought those and mid cats along the stock can was best in most regimes.

I was planning on creating an catless header experience thread so that performance, price, fit and finish could all be compiled.

I would not have considered FabS catted headers to be superior to the above set up especially when considering the price
I'm installing FabS with sport cats because I got a new one from a forum member for $350 & Headers would be louder than what I want. This is the last piece of my Ideal Box once I get the sport seats installed.
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Old 09-19-2019, 01:07 PM   #80
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Well boys, the season is soon over so its about time for some wrenching..

I ordered those cats: They are cheaper than Circuit Werks, and no customs for me in Sweden, I hope they will be fine: https://www.ebay.com/itm/351973215955

So, next up are the headers: I found those now on eBay:

https://www.ebay.com/itm/Header-Stainless-Steel-Porsche-986-986S-Boxster-96-04-2-5-2-7-3-2-2-5-2-7-3-2/202683531546?fits=Model%3ABoxster&hash=item2f30e1411a:g:OV0AAOSw7PBTpCHo

https://www.ebay.com/itm/Stainless-Steel-Exhaust-Header-Manifold-for-97-04-Porsche-986-Boxster-2-7-3-2-H6/233239962851?fits=Model%3ABoxster&hash=item364e2f64e3:g:jiIAAOSw2YZc7Dx3

https://www.ebay.com/itm/OBX-Long-Tube-Header-for-97-04-Porsche-Boxster-986-2-5L-2-7L-3-2L-Stainless/162427660994?fits=Model%3ABoxster&hash=item25d1716ac2:g:hZwAAOxyZqhRhQGM

https://www.ebay.com/itm/T321-STAINLESS-RACING-HEADER-MANIFOLD-EXHAUST-97-04-PORSCHE-986-BOXSTER-BASE-S/401774979366?_trkparms=aid%3D555018%26algo%3DPL.SI M%26ao%3D1%26asc%3D20131003132420%26meid%3D63bcdcd f151840079ffddab060cf5092%26pid%3D100005%26rk%3D5% 26rkt%3D12%26sd%3D162427660994%26itm%3D40177497936 6%26pmt%3D1%26noa%3D0%26pg%3D2047675&_trksid=p2047675.c100005.m1851


Will I get away with the cheapest ones? They are SS 304, should I go for something better?
Id like to pull the plug tomorrow so if you have any ideas, please tell..


Last edited by Robert986; 09-19-2019 at 01:11 PM.
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