radride

Has anyone made any downpipes for the CL65's? Taking out the cats would really unleash some power on a car like this. Or does it screw up the ECU with the lack of cat in the system?

R.K.

AMGBOBBY

let me know when you find out brotha my cl65 will be here soon. thx

02cl55amg

ive got custom fabbed 3 1/2'' downpipes into 200 cell cats. also full 3" cat back into Burns mufflers. gained +2 mph. but was about $3k

freestylebiker3

if you get custom downpipes made from a really nice custom exhaust shop.. it would run you about 900-1100 dollars.. ( 3 inch mandrel bent 304 stainless steel) or call up speedriven and they have them in stock (MADE TO ORDER) around $1200 but now u need to find a local tuner to tune your computer to except the catless downpipes, for your o2 sensors.. i am on the same boat with you.. i am hoping speedriven gets a group buy going for 3 inch stainless mandrel bent one piece cat less downpipes for a good price becuase i would love to take my cats out...

radride

Just as I thought. You need to make changes to the ecu when you take out the cats...

R.K.

02cl55amg

i dont think you HAVE to make changes if you dont mind a permanant check engine light, but your going to have the ecu tuned either way im sure. maybe sppedriven will do a downpipe+ecu/tcu combo special???

AMGBOBBY

does the car sounds a lot different with the custom down pipe/exhaust?

freestylebiker3

if you install the o2 sensors with out tuning the computer for a catless downpipe... your o2 sensors will be trying to correct the fuel trim because the catless downpipe is not converting the gass to the standards.. so having the check engine light on for the o2 sensors could cause more trouble then we think.. it might even retard the timing and cut back on fuel and lower horsepower so the CO2 out the exhaust is not harmful, but who knows its just a guess

Malones Perf.

Your rear o2 Sensors just stare at the efficency of the catalyst and does not effect fuel trim at all. You can turn off the rear o2 sensors from any tuner or with developer software and you wont have a check engine light. I have put two catless exhaust on 275 engine vehicle and it sounds about the same just a little louder, deeper, and the turbos also sound louder. On the dyno without additional tunning we really only saw a 8-15 hp gain. Hope this helps.

freestylebiker3

yes i was refering to getting a tune so the rear o2 sensors read around 14.1 for the catless set up, the post o2 sensors compare oxygen contents based on the pre o2 and atmosphere. if you take a cat out, now your pre and post o2 sensors will read the same and the computer will think you have a bad cat converter.. people who put a post o2 sensors tune is just tricking the computer in thinking that the cat converter is working and doing its job... Using pre and post oxygen sensors allows the pcm to measure efficiency of both engine combustion and catalyst operation. so yes the post/rear o2 does not effect performance but messures catalyst efficiency

alx

the rear o2s can be replaced with sims... or shut down with dev sds

tuning the comp for bigger downpipes and no cats might or might not produce results if you already have an aggressive tune.

the stock downpipes and cats are not bad at all btw

freestylebiker3

your right the factory downpipe are not bad... in my oppinion they are one of the best factory exhaust system i have seen.... from my hole life in the automotive field i have only seen 2-3 cars that have a beautifull exhaust system.... and the cl65 is by far one of the best i have seen... full stainless system oval manderal bent tubing that is tig welded with no resonators just 2 cats and 2 mufflers with a big diameter straight pipe in between them ( i think 2.75 inch maybe 3.0 inch ) the exhaust system is a work of art.. but if you want that extra rumble out of the exhaust, catless would sound awsome... im sure this hole cl65 exhaust system retails near $10,000