pre cats are off..
Original Founding Member!
Joined: Jul 1999
Posts: 9,037
Likes: 88
From: Granby, MA
Cruise-In 1, 3, 9. 10 & 11 Veteran
Re: pre cats are off.. (jackyy)
what year car....?.....any probs with codes or passing emissions.?...where do you live....how bout loudness...any change.....?....or torque curve....I have heard...that the curve moves further on up the line........please explain...thanks...cause i want to ....to my 1990 automatic
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: pre cats are off.. (jackyy)
I have no pre-cats, hi-flow cat (maybe 5hp loss) and hi-flow cat back. With intake, etc mods it was worth ~25HP at the crank. What you get despends on how restrive the rest of the exhaust is and if your L98 can gulp in enough air (I did some intake mods before exhaust).
Thread Starter
Instructor
Joined: Apr 2001
Posts: 134
Likes: 0
Re: pre cats are off..
ya i just took off the pre cats and replaced it with a y pipe from a 85 vette..the tubes are even larger than the 91...now i want to take off the main cat...oh ya the sound is better than before
thanx
thanx
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: pre cats are off.. (jackyy)
It makes a big difference in sound.
I had mine on a dyno last night; at about 10ft from the rt rear wheel at 5200rpm in 3rd gear she was realy mean!:yesnod:
I had mine on a dyno last night; at about 10ft from the rt rear wheel at 5200rpm in 3rd gear she was realy mean!:yesnod:
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Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: pre cats are off.. (KYVette90)
No codes, more HP to the rear wheels and latest trip mileage was 31mpg, up from 29+mpg last year.
If you don't like the throaty exhaust note you might not like it.
If you don't like the throaty exhaust note you might not like it.
Original Founding Member!
Joined: Jul 1999
Posts: 9,037
Likes: 88
From: Granby, MA
Cruise-In 1, 3, 9. 10 & 11 Veteran
Re: pre cats are off.. (XtremeVette)
throaty?....or boomy?...with lots of resonance...I like throaty nice gurgle noise...not a constant low bass resonance hum.....which would you describe it as..?....and did you throw any codes?....
Racer
Joined: Sep 2000
Posts: 337
Likes: 0
Re: pre cats are off.. (XtremeVette)
I did my pre-cats, and I really like the sound and feeling. It is like with headers.
I had no problems removing the old pipe except from the main cat, where it was stucked. But I cut the pipes just after the pre-cats and welded on new pipes. No problems!
I didn' t get any codes. Remember that you have the 02-sensor before the pre-cats and if you cut them off and replace them with pipes, like I did, you will have to put the 02-sensor back in the new pipes. Requires some welding.
I am also planning on changing my main cat to a freeflow race cat. Have anyone done this and did you gain any?
:D
I had no problems removing the old pipe except from the main cat, where it was stucked. But I cut the pipes just after the pre-cats and welded on new pipes. No problems!
I didn' t get any codes. Remember that you have the 02-sensor before the pre-cats and if you cut them off and replace them with pipes, like I did, you will have to put the 02-sensor back in the new pipes. Requires some welding.
I am also planning on changing my main cat to a freeflow race cat. Have anyone done this and did you gain any?
:D
Drifting
Joined: Aug 2001
Posts: 1,878
Likes: 0
From: EP Texas
St. Jude Contributor
Re: pre cats are off.. (Cratzy)
I removed mine also. Its a cheap mod. The car did not get much louder, and SOTP gains are little but there. Can't go wrong, no codes or problems. I left the main high flow cat and tested better on the sniffer then most new cars!!
