cat questions ??
Thread Starter
Instructor
Joined: Sep 2004
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From: peoria il
cat questions ??
i have 91 coupe. i put it up yesterday to see what i will have to do to put on my catback system (magnaflow) here is question 1 how do i get the bolts off of the cat to put the system on? question 2 will i get better performance if i gut the cat while i am under the car? question 3 are the two little cat looking things before the "main" cat. ,are they just smaller cats.? question 4 should they be gutted as well for performance? thanks for the help........jeff
Team Owner
Joined: Dec 2000
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From: SE NY
Cruise-In II Veteran
i have 91 coupe.
Q1 - how do i get the bolts off of the cat to put the system on?
A1 - Hit them with lots of PB Blaster, let stand overnight and hit em again the next day. If they still won't come off you should be able to twist em off or cut em off.
Q2 - will i get better performance if i gut the cat while i am under the car?
A2 - A gutted cat, absent cat or hi-flow cat will improve performance.
Q3 - are the two little cat looking things before the "main" cat. ,are they just smaller cats.?
A3 - Those are pre-cats to aid the main cat.
Q4 - should they be gutted as well for performance?
A4 - You will gain the most by replacing the stock front Y with a 2 1/2" mandrel-bent front Y.
An alternative to A4, for non left-coast residents, is to install full length headers and a new front Y w/o pre-cats.
Our L98s respond quite well to exhaust mods. Changind the front Y, cat and cat-back to hi-flow units will net around 18-20chp; installing FL headers will net another 15-20chp.
Q1 - how do i get the bolts off of the cat to put the system on?
A1 - Hit them with lots of PB Blaster, let stand overnight and hit em again the next day. If they still won't come off you should be able to twist em off or cut em off.
Q2 - will i get better performance if i gut the cat while i am under the car?
A2 - A gutted cat, absent cat or hi-flow cat will improve performance.
Q3 - are the two little cat looking things before the "main" cat. ,are they just smaller cats.?
A3 - Those are pre-cats to aid the main cat.
Q4 - should they be gutted as well for performance?
A4 - You will gain the most by replacing the stock front Y with a 2 1/2" mandrel-bent front Y.
An alternative to A4, for non left-coast residents, is to install full length headers and a new front Y w/o pre-cats.
Our L98s respond quite well to exhaust mods. Changind the front Y, cat and cat-back to hi-flow units will net around 18-20chp; installing FL headers will net another 15-20chp.
Race Director
Joined: May 2003
Posts: 10,749
Likes: 41
Originally Posted by rugby!
i have 91 coupe. i put it up yesterday to see what i will have to do to put on my catback system (magnaflow) here is question 1 how do i get the bolts off of the cat to put the system on? question 2 will i get better performance if i gut the cat while i am under the car? question 3 are the two little cat looking things before the "main" cat. ,are they just smaller cats.? question 4 should they be gutted as well for performance? thanks for the help........jeff
Thread Starter
Instructor
Joined: Sep 2004
Posts: 210
Likes: 0
From: peoria il
thanks for the help.....can i buy a y pipe w/o pre-cats from any place on line that sells catbacks or will i have to find a shop to make me some.
Last edited by rugby!; Oct 18, 2004 at 08:05 PM.
Melting Slicks
Joined: Jun 2004
Posts: 3,032
Likes: 4
www.ecklers.com
www.madvet.com
www.summitracing.com
they'll all have what you wanna look at...
I'd double check you're emmissions laws before you start ripping apart your exhaust.
www.madvet.com
www.summitracing.com
they'll all have what you wanna look at...
I'd double check you're emmissions laws before you start ripping apart your exhaust.
Thread Starter
Instructor
Joined: Sep 2004
Posts: 210
Likes: 0
From: peoria il
ok ecklers has a dynomax front y pipe w/o precats for $250 my question is has anyone replaced it and where is the o2 sensor located is it on the exhaust headers or on the front y pipe thanks.
