Fister iii with cat bypass
04-13-2011, 12:31 AM
#1
Drifting
Thread Starter
Fister iii with cat bypass
Ok I have them on and they are loud ... Obviously.
Observation....
The car seems to rev a lot faster. Has anybody else done this and noticed this?
Also, in seat the seat of pants test, it seems to have lost some torque. This may not be true, but only seem that way since it revs faster.
Thoughts?
Observation....
The car seems to rev a lot faster. Has anybody else done this and noticed this?
Also, in seat the seat of pants test, it seems to have lost some torque. This may not be true, but only seem that way since it revs faster.
Thoughts?
04-13-2011, 01:19 AM
#2
Rennlist Member
I don't doubt it's loud.
With cat bypass pipes and Stage IIIs you are eliminating a lot of backpressure in the exhaust. This may not be the best combo for a street engine as you will probably lose some mid-range torque. You may gain a little top end hp but for street use this is not ideal.
With cat bypass pipes and Stage IIIs you are eliminating a lot of backpressure in the exhaust. This may not be the best combo for a street engine as you will probably lose some mid-range torque. You may gain a little top end hp but for street use this is not ideal.
04-13-2011, 02:48 AM
#3
Burning Brakes
I had cat by-pass tubes for a while, but switched to AdlerFlow 200 cell sport cat's . Bypass was way too loud, triggering car alarms in parking houses etc. As Fister D told, street driveability was not so good.
04-13-2011, 02:02 PM
#4
Nordschleife Master
Yea, I also thing it lets the engine rev much faster. The low end doesn't seem as snappy. But midrange & top end SING! What I should do is have the car dyno tested again to see what's going on since the upgrades.
I have STG II's with Dach cat x-pipe. Don't think it's quite loud enough, & want STG III's.
I have STG II's with Dach cat x-pipe. Don't think it's quite loud enough, & want STG III's.
04-13-2011, 02:36 PM
#5
Advanced
I had the same issue but it is fixed now.
After a LPMM (semi-bypass on each side) the noise was great but engine lost some pull from apporx 2700-2900 revs. Shame on a varioram engine.
A year later, after somebody hit the back of me, I got a new exhaust , repeated the LPMM mod on the silencers but with new O2 sensors. the torque loss went away. The torque curve now feels smooth by the seat of my pants and the problem is solved.
I did also have a new CAT but I reckon new Oxygen sensors did the trick. How old are yours?
After a LPMM (semi-bypass on each side) the noise was great but engine lost some pull from apporx 2700-2900 revs. Shame on a varioram engine.
A year later, after somebody hit the back of me, I got a new exhaust , repeated the LPMM mod on the silencers but with new O2 sensors. the torque loss went away. The torque curve now feels smooth by the seat of my pants and the problem is solved.
I did also have a new CAT but I reckon new Oxygen sensors did the trick. How old are yours?
04-13-2011, 11:45 PM
#7
Drifting
Thread Starter
I owe you a sound clip... Will try this weekend.
I don't doubt it's loud.
With cat bypass pipes and Stage IIIs you are eliminating a lot of backpressure in the exhaust. This may not be the best combo for a street engine as you will probably lose some mid-range torque. You may gain a little top end hp but for street use this is not ideal.
With cat bypass pipes and Stage IIIs you are eliminating a lot of backpressure in the exhaust. This may not be the best combo for a street engine as you will probably lose some mid-range torque. You may gain a little top end hp but for street use this is not ideal.
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04-14-2011, 03:10 AM
#8
Rennlist Member
Been there, done that!!!
The sound is out of this world....I shant rave on too much or one might think I am on the Fabspeed/FD Motorsport payroll, NOT the case, just a very happy customer.
Note I have tried nearly combination of mufflers known to man...this is the best ever!
