X-Pipe 101: Deciding which formula is best.

Draff1 · 03-01-2011, 06:05 PM

There have been endless discussions about X-Pipes and tons of pictures and comments but I would like to see if I can understand all the facts related to the 3 major types:
1. Factory cats but delete secondary cats:
What are the actual HP gains?
What was / is the sound difference from stock
CEL or No CEL without software?

2. Hi Flow cats (street):
What are the actual HP gains?
What was / is the sound difference from stock?
Are some better than others? Ex. Akra uses 100 cell vs Challenge 200 cell
CEL or No CEL without software?

3. Catless (race):
What are the best full systems available for under 4k?
Downsides?
Do you feel a torque dip and if so how does it affect 1/4 mi times? Is the car actually faster in all phases?

Also for all 3 options, what is the Dyno telling us about the dreaded torque dip? I'd love to see some of the more knowledgeable guys including vendors weigh in. "Butt Dyno" is very subjective but I would love to hear from people that have done these mods but may not have had their car Dyno'd.

The goal of this thread is help determine which solution is best for different owners. Obviously for pure power option 3 is the best, but what you give up in terms of legality, smell, warranty etc. may not be the right direction for everyone.

Thanks for the comments.

jimmy ny · 03-01-2011, 07:36 PM

I am curretnly running Active Autowerke HFC x-pipe w/ resonators for 2ndary cats. NO CEL. NO software no disable CEL. They basically guarenteed over the phone but not in writing. NO issues as of yet. As a precaution my tuner installed elbow/reducers on the rear O2, just in case. I heard other companys are throwing CEL and they will tell you that if you ask them. A little louder at idle, great WOT running through a Borla sport exhaust. Has a exotic sound. Doesnt have alot of rasp or the big inch Mustang sound. Hope this helps. Good luck. They are 200cel German cats. The fit and finish of the system is FLAWLESS. They are suppose to make a solid 20-25 rear wheel on a set-up car. You will feel the difference in the mid to upper RPMs. I did not experience any torque dip. I think thats something the Akropovic guys are somewhat experiencing and they all get the CEL. Theres just no way not to with 100cel cats and they also change the location of them further toward the center of the car. I am also running Dinan 1 tune, Dinan intake and Dinan pulley.

03-01-2011, 06:05 PM	#1
Draff1 Private First Class 13 Rep 195 Posts Drives: 2009 Silverstone M3 Coupe Join Date: Aug 2009 Location: San Diego, CA iTrader: (0)	X-Pipe 101: Deciding which formula is best. There have been endless discussions about X-Pipes and tons of pictures and comments but I would like to see if I can understand all the facts related to the 3 major types: 1. Factory cats but delete secondary cats: What are the actual HP gains? What was / is the sound difference from stock CEL or No CEL without software? 2. Hi Flow cats (street): What are the actual HP gains? What was / is the sound difference from stock? Are some better than others? Ex. Akra uses 100 cell vs Challenge 200 cell CEL or No CEL without software? 3. Catless (race): What are the best full systems available for under 4k? Downsides? Do you feel a torque dip and if so how does it affect 1/4 mi times? Is the car actually faster in all phases? Also for all 3 options, what is the Dyno telling us about the dreaded torque dip? I'd love to see some of the more knowledgeable guys including vendors weigh in. "Butt Dyno" is very subjective but I would love to hear from people that have done these mods but may not have had their car Dyno'd. The goal of this thread is help determine which solution is best for different owners. Obviously for pure power option 3 is the best, but what you give up in terms of legality, smell, warranty etc. may not be the right direction for everyone. Thanks for the comments. __________________ 2009 Silverstone II E92 M3 Coupe - DCT Dinan Exhaust, RPi scoops, Dinan Tune, Dinan Pulley, BMC filter, LCI Taillights, MS 15mm spacers, Huper Optik tint.
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03-01-2011, 07:36 PM	#2
jimmy ny Second Lieutenant 17 Rep 246 Posts Drives: 2011 bmw m3 Join Date: Jun 2010 Location: new york iTrader: (0)	I am curretnly running Active Autowerke HFC x-pipe w/ resonators for 2ndary cats. NO CEL. NO software no disable CEL. They basically guarenteed over the phone but not in writing. NO issues as of yet. As a precaution my tuner installed elbow/reducers on the rear O2, just in case. I heard other companys are throwing CEL and they will tell you that if you ask them. A little louder at idle, great WOT running through a Borla sport exhaust. Has a exotic sound. Doesnt have alot of rasp or the big inch Mustang sound. Hope this helps. Good luck. They are 200cel German cats. The fit and finish of the system is FLAWLESS. They are suppose to make a solid 20-25 rear wheel on a set-up car. You will feel the difference in the mid to upper RPMs. I did not experience any torque dip. I think thats something the Akropovic guys are somewhat experiencing and they all get the CEL. Theres just no way not to with 100cel cats and they also change the location of them further toward the center of the car. I am also running Dinan 1 tune, Dinan intake and Dinan pulley. Last edited by jimmy ny; 03-01-2011 at 07:40 PM.. Reason: adding more stuff.
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