Dyno Proven 231WHP 986 Boxster S.

[panameras]

Nick is spot on. First graph is showing figures in KW, all 4 runs were performed within minutes of each other, no variables been changed and 167kw was the best of them.

Second graph is showing in Horse Power. 224hp(167kw) vs 231hp. Only modification been a set of aftermarket headers.

Other than different room temperature and humidity, I tried my best to keep everything else constant. same type of fuel (BP Ultimate 98RON). 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).

Therefore there were indeed variables in test conditions, However the most important finding is what PAT mentioned "There's a difference of 25+ hp at 103 mph in the measured gear! Not to mention all the area under the curve throughout most of the range tested."

Now for the non believers, yes it is possible to get a few horse power gains here and there due to a cooler room temperature but looking at the graph how do you explain major gains of up to 25hp across the entire rev range. If you still think it was due to margins of error, well, you obviously know better than me and I have no reason to prove to you any further.

Im not going into too much details of the brand of headers I used as Im not promoting anyones business. What I can say is they are 4 into 1 design headers that you can buy off ebay for around $500US (I believe there are at least 3 different vendors that are selling them under their own brand names but are sourced from a same manufactorer) Again Im not associated with any of them, just trying share my findings with fellow boxster owners of a worthwhile performance "enhancement" that I would recommend.

[Pat]

Dyno graphs are great tools.
What I care about, however, is how the car drives. How much of a difference would you say this made in your car's seat-of-the-pants performance/feel?
Yes, I know this is subjective, but if you could expand on how the car feels before and after I would appreciate it.

[Topless]

Thank you again Panameras for posting your dyno results. Your curves do look promising and are consistent with others findings. This just adds another piece to the 986 knowledge base and raises even more questions about realistic performance gains on these cars.

The next step is for someone to test how much real world gain these headers produce by running some 1/8 mile, 1/4 mile, and lap times on a track they already have wired to get a good baseline. Then repeat the process after installing the headers. That is the kind of testing most racing teams are doing. A 1/2 sec. per lap over a day long race often is the difference between 1st and 20th place.

[edevlin]

Just my two cents, I tried to control as many variables as possiblw when I did before and after dyno runs with the addition of German-made TTP headers to my 2000 2.7L Boxster.

Depending on the run, I only saw a 3-5 hp increase at the wheels, less than I expected, but the headers sure make the exhaust system sing, at least to my ears. The downside is that I have been messing around with check engine light after the headers went on.

Ed

[panameras]

Originally Posted by Pat

Dyno graphs are great tools.
What I care about, however, is how the car drives. How much of a difference would you say this made in your car's seat-of-the-pants performance/feel?
Yes, I know this is subjective, but if you could expand on how the car feels before and after I would appreciate it.

Well, seat of the pants feels MORE SMOOTH is the best way to describe it. The engine feels more free-reving (especially from around 4000rpm) but not by much.

You can definitely feel the difference though 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. I wouldn't expect much more than that though it's not a magical mod like increase boost in a turbo car which would totally alter the behavior of the car.

In this case the car is smoother with a little bit quicker acceleration which is a nice cost effective enhancement consider the relative low cost and ease of installation compared to say, an evo cold air intake or an aftermarket muffler.

For those who like to talk numbers. $475/25whp= $19 per hp at the wheels!
Now you all know how much a performance software costs which typically "claims" 15-20hp at the engine.

However the point I'm trying to emphasize here is not how much more power it delivers but how it makes the engine breath just that little bit better everywhere in the rev range and how the car drives a little smoother.