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Dyno comparison, stock vs aftermarket headers


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Dynoed my 2000 Boxster S before and after with eBay 4 into 1 aftermarket headers. Here is the graph.

986SheadersHP1024.jpg

(I have posted this on 986forum as well)

The blue curve is the stock run, 4th gear. Didn't bother to open up the engine compartment so no rpm readings.

As you can see at higher speed(=rpm) there are many inconsistent dips on the graph this is where I expect an aftermarket headers would improve over stock headers. Im also interested to hear what do you think the cause of these "dips" might be?

Red is aftermarket headers with stock exhaust.

Other than the different room temperature and humidity, I tried my best to keep everything else constant. Same type of fuel, same set of tyres with the same tyre pressure. I don't drive the car much so there were minimal tyre wear (about 2000kms of 80% highway driving).

Let me know what you think.

Cheers.

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Down low below 65mph you had about a 5hp gain across the board, then it looks like at about 85mph variocam kicked in and there is a drop which is normal for any variable camed engine (VTEC MIVEC ETC), then the gains really started to pile on. You have an almost 25hp gain at 105mph which would be around the 6000-6300rpm mark by the looks of the graph. Pretty impressive. You got the power in the top of the band which is exactly where you want it if you like to go fast. The gains down low are pretty useless.

I'm actually surprised they did that well. The headers did quite well on the 2.5 because they don't have a collector built into the header, where the 2.7 and 3.2 both do. Even though there is a cat there, the existence of some type of collector is going to make more power vs. not having one. You still made great power on top of that.

I would be pretty happy with that thats great.

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it looks like at about 85mph variocam kicked in and there is a drop which is normal for any variable camed engine (VTEC MIVEC ETC),

Thanks I was wondering about why the irregular drop. This is actually my first N/A car with variable cams. The car definitely feels more alive above 4000rpm now. Do you know at what rpm does the variocam normally kick in?

I'm actually surprised they did that well. The headers did quite well on the 2.5 because they don't have a collector built into the header, where the 2.7 and 3.2 both do. Even though there is a cat there, the existence of some type of collector is going to make more power vs. not having one. You still made great power on top of that.

I've actually got the Euro spec Boxster S (Im in Australia BTW) which has no cats integrated in the headers so it made the job much simpler.

Overall Im quite surprised with the actual gain from these headers as you said "almost 25hp at 105mph". Very happy with it.

P.S. scheduled to get Giac next week :D

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............eBay 4 into 1 aftermarket headers. Let me know what you think.............

What do I think?...........I think.......you meant 6 into 2........... :P

Pretty impressive for a naturally aspirated piece that was already decently equipped!

NICE!..........Are those stainless?..........who makes them?...........how much?

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............eBay 4 into 1 aftermarket headers. Let me know what you think.............

What do I think?...........I think.......you meant 6 into 2........... :P

Pretty impressive for a naturally aspirated piece that was already decently equipped!

NICE!..........Are those stainless?..........who makes them?...........how much?

You are right! no idea where did the 4 into 1 came from?! :huh: :D

Yes stainless. Brand is Maxspeed. There are at least two vendors on eBay selling these under different brand names, as far as I can tell they are from the same manufacturer.

Here is a LINK

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If anyone is interested, I have an unused set of these headers that I could offer out for sale. PM me if you're interested.

Panameras, haha... maybe you got the 4-1 idea from... were you by chance, a former honda/acura/import enthusiast? I used to be, and when we thought headers, or I guess in that scene, 'header'... first thoughts to come to mind would be the 4-2-1 header vs. the 4-1 header.

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Panameras, haha... maybe you got the 4-1 idea from... were you by chance, a former honda/acura/import enthusiast? I used to be, and when we thought headers, or I guess in that scene, 'header'... first thoughts to come to mind would be the 4-2-1 header vs. the 4-1 header.

Actually I think it was because my previous car was a V8 and had an 4 into 1 header on each side :P so why are you"going towards a different route"? Turbo charging now are we? :D

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looks like another solid gain with the GIAC! did you consider any other programming options? was this program specifically made for your car and its modifications or just the year and model?

you've gotta be able to feel a solid 25hp increase throughout most of the upper rev range, eh? can you post driving impressions as well?

what did you notice most with the header addition, and what with the giac addition? have you payed any attention to fuel economy or range or other factors?

i've got an 01 S with evo intake that i've been considering adding either Che's or the headers you chose and some brand of programming this winter. thanks for providing info that makes my decision easier!

matt

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Matt. It's the standard Giac software for 2000-2004 Boxster S.

My driving imperssions are that the car feels smoother on acceleration and power delivery is more linear. The engine feels more free-reving (especially from around 4000rpm). I can definitely feel a big difference as I have already driven the car in stock from for a few years so it's easier for me to pick up any improvements. These two mods in my opinion are the most cost effective enhancements for a Boxster consider the relative low cost (headers) and ease of installation (both) compared to say, an evo cold air intake or an aftermarket muffler.

I have a sound file recorded as well if you are interested: http://www.youtube.com/watch?v=NWysMofc5R4...ted&search=

Edited by panameras
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Good results. I did extensive modifications to a Mustang years ago. 8 PSI Vortech blower, exhaust engine to tail, igniton, fuel, on and on. It was fun to see the gains once all had been done and dyno'd. There was an engine failure due to tuning but with money thrown at it, was fixed. Enough non-Porsche ramblings, I have a 2001 S. Great car, no problems as of 24K miles. Older model Boxsters can eek out modest gains with mods and money. But as an old player you'll get more out of your money by selling your car an upgrading. Be it a newer Boxster or 911.

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I have a sound file recorded as well if you are interested: http://www.youtube.com/watch?v=NWysMofc5R4...ted&search=

Nice clip. Why is there so much smoke? Was the engined already warm or still cold?

This video was recorded 30 minutes after I got home from work so the engine should still be warm at the time. But I hear Boxster engines do have a problem with white smokes very often.

Edited by panameras
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Good results. I did extensive modifications to a Mustang years ago. 8 PSI Vortech blower, exhaust engine to tail, igniton, fuel, on and on. It was fun to see the gains once all had been done and dyno'd. There was an engine failure due to tuning but with money thrown at it, was fixed. Enough non-Porsche ramblings, I have a 2001 S. Great car, no problems as of 24K miles. Older model Boxsters can eek out modest gains with mods and money. But as an old player you'll get more out of your money by selling your car an upgrading. Be it a newer Boxster or 911.

Yeah I get that a lot from fellow boxster owners advicing me to upgrade to an 911 instead. See my other is a R34 Skyline which has been tuned to 400WHP so I don't really need a faster car but I do have an addiction when it comes to modding cars hence doing a few things to the "already fine tuned" boxster. Muffler, bypass pipes, H&R sway bars, and spacers on the way :D

P.S. Engine failure from 8psi? I would think any factory engine nowadays should be able to withstand such relatively low boost. But I guess its as you say bad tuning.

Edited by panameras
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Good results. I did extensive modifications to a Mustang years ago. 8 PSI Vortech blower, exhaust engine to tail, igniton, fuel, on and on. It was fun to see the gains once all had been done and dyno'd. There was an engine failure due to tuning but with money thrown at it, was fixed. Enough non-Porsche ramblings, I have a 2001 S. Great car, no problems as of 24K miles. Older model Boxsters can eek out modest gains with mods and money. But as an old player you'll get more out of your money by selling your car an upgrading. Be it a newer Boxster or 911.

Yeah I get that a lot from fellow boxster owners advicing me to upgrade to an 911 instead. See my other is a R34 Skyline which has been tuned to 400WHP so I don't really need a faster car but I do have an addiction when it comes to modding cars hence doing a few things to the "already fine tuned" boxster. Muffler, bypass pipes, H&R sway bars, and spacers on the way :D

P.S. Engine failure from 8psi? I would think any factory engine nowadays should be able to withstand such relatively low boost. But I guess its as you say bad tuning.

It (Muskrat) was originally set up (timing) for pump gas 93. After a few more mods I wanted more, so up'd the timing to require 104. I had a MSD box where I could pare out timing at the top, where its really needed. Ran great for about a year, then started to puff smoke. Checked the compression ratio, one was half of all other. Engine out, taken apart, a ring landing was broke. New pistons (forged), con rods, so on and ran for another year. Good car, gobbs of power but not enjoyable on longer hauls. You had to watch it all the time. Then sold it. So I bought the '01 Boxster S. Had 13K miles in 03 when purchased.

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