Schnell Headers on 986 with Stock Exhaust - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Cloudsurfer · 08-20-2007, 08:03 PM

4 bungs in a non catted header do nothing for you. The engine ECU cares about the first set, as it uses that to control the fuel mixture going into the engine. The second set are there for OBD II diagnostics to detect catalytic failure (or in this case, cat removal). This is why you should get a CEL if you simply plug all 4 into the non catted header. You can possibly get by with a spark plug defouler, which moves the tip of the O2 sensor out of the exhaust flow somewhat and on some cars will cause the secondary O2s to read "normal" as if they are seeing catalyzed exhaust.

Relocating the secondary set to after the secondary cats may work, but you are going to change the impedance of the circuit with the added wiring. In my case, I also do not have secondary cats as I have the FabSpeed system.

I am VERY surprised you have not gotten a CEL on your car yet.

Patrick

08-20-2007, 08:12 PM

i have a 99, will i ever receive A CEL, from adding after market headers??

blinkwatt · 08-20-2007, 08:22 PM

Quote:

Originally Posted by blkboxster

i have a 99, will i ever receive A CEL, from adding after market headers??

Dude don't buy them yet,they just released the headers a couple of months ago and who knows what kind of issues you could have with them.

I don't like how they gave a 'one size fits all' idea for the headers,that's half assing it. Most vendors sell a non e-gas and e-gas set of headers separately.

08-20-2007, 08:27 PM

ok, thanks for the info, tell me whenever you find a good company that makes it for the 2.5's

thanks

blinkwatt · 08-20-2007, 09:22 PM

Quote:

Originally Posted by blkboxster

ok, thanks for the info, tell me whenever you find a good company that makes it for the 2.5's

thanks

The company Turbowerx has a header set up for the 2.5L that are supposed to be great!
I don't know if their dyno gains are accurate but if so them the headers are stupid good. Just on the 2.5L that gained +25hp,nothing to sneeze at!

Dyno Graph
http://turbowerx.com/external_pictures/986_Header_dyno_txt.jpg

2.5/2.7/3.2L headers
http://turbowerx.com/Products/986_Headers/986_Headers.html

I honestly think that they cheated on the dyno graph somehow. You would think if they can get a +25hp from them then someone else could get close to that range,perhaps Imagine Auto,Gemballa or Fabspeed, but those only gain around +10-13hp.

rule1 · 08-21-2007, 08:39 AM

You can be as suprised as you want!!! I honestly have not had a CEL.[Nello] the owner of maxspeed has had more than one not including me to report no CEL.

panameras · 08-22-2007, 12:34 AM

Quote:

Originally Posted by blinkwatt

Dude don't buy them yet,they just released the headers a couple of months ago and who knows what kind of issues you could have with them.

I don't like how they gave a 'one size fits all' idea for the headers,that's half assing it. Most vendors sell a non e-gas and e-gas set of headers separately.

I was hoping to get a little more midrange and slight top end increase from these headers. These definitely gains to be made by looking at the tiny unequal length factory pipes.

panameras · 08-22-2007, 05:47 AM

this was dynoed when the car was completely stock. done in 4th gear. didn't bother to open up the engine compartment thus 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. but interested to know what other explainations you may have for the "dips"? knocking?

panameras · 08-26-2007, 04:45 AM

Finally got these headers installed. Have to say I LIKE THEM

As far as fitment goes it was quite straight forwards sits perfectly underneath the engine and looks good too (like what the car should have had coming from Porsche, compare to the strange looking factory items). Not much hassle getting them aligned with the existing system so they were well designed but also thanks to the midship horizontal engine layout. I could have done it myself but got a workshop to do it anyway since it takes half the time on a hoist.

Let me know what you think

http://www.youtube.com/watch?v=NWysMofc5R4

Adam · 08-20-2007, 08:50 PM

Quote:

Originally Posted by bmwm750

4 bungs in a non catted header do nothing for you. The engine ECU cares about the first set, as it uses that to control the fuel mixture going into the engine. The second set are there for OBD II diagnostics to detect catalytic failure (or in this case, cat removal). This is why you should get a CEL if you simply plug all 4 into the non catted header. You can possibly get by with a spark plug defouler, which moves the tip of the O2 sensor out of the exhaust flow somewhat and on some cars will cause the secondary O2s to read "normal" as if they are seeing catalyzed exhaust.

Relocating the secondary set to after the secondary cats may work, but you are going to change the impedance of the circuit with the added wiring. In my case, I also do not have secondary cats as I have the FabSpeed system.

I am VERY surprised you have not gotten a CEL on your car yet.

Patrick

^ He is right on the $$$. The only header going on my car is the faspeed with the integrated cats. Hey, they are expensive, but I don't want to have to clear a code every other day either.