otherotherbenz

Hi, I am wondering what is the different between downpipes with 200 cell cats vs. downpipes with cat bypass in terms of sound? which one is louder?

here is the link:
http://www.renntechmercedes.com/www/node/870
http://www.renntechmercedes.com/www/node/869

freefall

About $2000...

And the gains are the same so I'd like a little education here too especially now that I have been enjoying their ECU upgrade for a couple of weeks and already want "more"...

Rob@vividracing

Cat bypass will be louder they are basically straight 3 inch downpipes. You can't get a more direct exhaust route than this. They are louder but not really terrible. Its noticeable but just gives the car a deep growl when you put your foot in it.

If this gives you any comfort my wife still likes the car.

With the renntech software you can use either the only reason you would need to run 200 cell cats would our fellow ca residents or other very strict emission states that actually look for cats.

Zolivary75

I have 100's. Sounds like a beast.

otherotherbenz

If I install a cat less downpipes and also have my resonator deleted, will the sound be too loud and annoying?

Saeedg48

after much reasurch from aftermarket tuners they have come to realize downpipes don't give any additional power. because of the nature of the turbos. they're too small and run out of turbo efficiency. as you can see on dyno graphs the power tappers off at the end. if youve ever done a 4th gear pull you can tell the turbos slowly give way. use 5th gear and you feel a complete surge of power all the way though. with upgraded turbos, downpipes are a no brainer

Saeedg48

yes it will rattle everything in your cabin. I'd suggest a resonator delete

cfields2005

I recently installed Speedriven downpipes for myEurocharged tuned CL 65. The check engine light came on immediately, which I thought was odd because my tuner informed me he could turn it off. After many weeks, I finally thought to replace the 2nd o2 sensor. While doing this, the mechanic removed the 90 degree o2 extensions that were built in to the down pipes. He said that the sensors needed to be in the exhaust stream. So my question is this- considering I have a tune, why or why not do I need the 90 degree extension? Thanks.