Go Back   Corvette Forum > C4 Corvettes, 1984 - 1996 > C4 General Discussion
Sign in using an external account
Register Forgot Password?
Register Search Today's Posts Mark Forums Read FAQ Vendor Directory
Search
C4 General Discussion
General C4 Corvette Discussion not covered in Tech

Welcome to Corvetteforum.com!
Welcome to Corvetteforum.com.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join Corvetteforum.com today!


Corvette Store
 
 
C7 Parts & Accessories
C6 Parts & Accessories
C5 Parts & Accessories
C4 Parts & Accessories
C3 Parts & Accessories
C2 Parts & Accessories
C1 Parts & Accessories
Wheels & Tires
Sponsored Ads
 
 
Vendor Directory
  
Reply
 
 
 
 
Thread Tools Search this Thread
Old 02-03-2011, 05:37 AM   #1
91yellowfellow
CF Senior Member
 
91yellowfellow's Avatar
 
Member Since: Nov 2009
Location: Pittsburgh PA
Default I replaced my front Y pipe with one with out precats :)

Well like the title says I replaced my Front Y with one with out precats in it. I dont know if its just the extra noise or not but it does feel like she has a little extra pep in her step. Not a 50hp gain or anything crazy like some of them air foils and K&N air filters offer but it does feel like I picked up a handfull anyway. Anyone else remove theirs and notice a diffrence or is it all in my head.
91yellowfellow is offline   Reply With Quote
Old 02-03-2011, 10:21 AM   #2
ch@0s
CF Senior Member
Support Corvetteforum!
 
ch@0s's Avatar
 
Member Since: Oct 2008
Location: Houston Texas
Default

Quote:
Originally Posted by 91yellowfellow View Post
Well like the title says I replaced my Front Y with one with out precats in it. I dont know if its just the extra noise or not but it does feel like she has a little extra pep in her step. Not a 50hp gain or anything crazy like some of them air foils and K&N air filters offer but it does feel like I picked up a handfull anyway. Anyone else remove theirs and notice a diffrence or is it all in my head.
I does help, not as much as an airfoil.
Your SOTP meter is working correctly.
ch@0s is offline   Reply With Quote
Old 02-03-2011, 11:02 AM   #3
ggrassmid
CF Senior Member
 
ggrassmid's Avatar
 
Member Since: Jan 2008
Location: Coopersville MI
Send a message via AIM to ggrassmid
Default

I gutted my cat on my '85. Before stock tires 255 could go from stop/brake to WOT and spin tires. Gutted cat and now can spin 315's without thinking twice. Made a big difference in how my car ran and reacted
ggrassmid is offline   Reply With Quote
Old 02-03-2011, 11:27 AM   #4
eaglevision993
CF Senior Member
 
eaglevision993's Avatar
 
Member Since: Sep 2010
Location: Epfenbach BW
Send a message via ICQ to eaglevision993 Send a message via Skype™ to eaglevision993
Default

My pre-cats are also gutted. I did this when one broke into pieces and rattled.
I plan to install a new front Y pipe when I do the exhaust system this summer. The hollow cat chambers might cause resonances.

The car feels stronger without them, I felt that too. Noise level increases of course.
eaglevision993 is offline   Reply With Quote
Old 02-03-2011, 09:35 PM   #5
harrisr
Junior Member
 
Member Since: Jan 2007
Default

noticed a better response and of course more noise right away.
harrisr is offline   Reply With Quote
Old 02-03-2011, 10:09 PM   #6
redvetttes
CF Senior Member
 
redvetttes's Avatar
 
Member Since: Dec 2010
Default

Did you guys pick lots of drone
somebody said to cut the pre cats off and weld straight pieces of pipe on
Want to do that 1st thing when spring gets here
Just like to know what I will be getting into with the extra noise
redvetttes is offline   Reply With Quote
Old 02-03-2011, 10:20 PM   #7
CREWZIN
CF Senior Member
 
CREWZIN's Avatar
 
Member Since: Jan 2002
Location: Lecanto Florida
Default

I have the "Y" without the pre-cats, a gutted main CAT and the air foil. Goes like a scalded cat. No pun intended.
__________________

87 Dark Red Metallic Coupe. L98 Auto, 160,000 smilin miles.
Black 17" Z06 Motorsport Wheels, Muffler Eliminators, "Y" pipe w/o pre-cats, K&N with open lid, TB Flow Booster, Big Mouth Performance Air Dam, Vette Connection Stage II Chip.
CREWZIN is offline   Reply With Quote
Old 02-03-2011, 10:23 PM   #8
Sweeride39
CF Member
 
Sweeride39's Avatar
 
Member Since: Dec 2009
Location: N. Little Rock Arkansas
Steve Sweere
Default

Does anyone produce a front Y pipe without the cats that mount to the stock headers?
Sweeride39 is offline   Reply With Quote
Old 02-03-2011, 10:48 PM   #9
CREWZIN
CF Senior Member
 
CREWZIN's Avatar
 
Member Since: Jan 2002
Location: Lecanto Florida
Default

Got mine from either Mid America or Ecklers and my headers are stock.
CREWZIN is offline   Reply With Quote
Old 02-04-2011, 09:10 AM   #10
coupeguy2001
CF Senior Member
 
coupeguy2001's Avatar
 
Member Since: Sep 2006
Location: Phoenix AZ
Send a message via AIM to coupeguy2001
Default

I bought an 85 front Y pipe out of a wrecking yard. It doesn't have precats. I could barely keep up with traffic on a major hill here in Phoenix, and when i got rid of the precats, wow, what a difference. I also ported the exhaust manifold flanges, and I really noticed some oomph when I did those two things. If you port the exhaust manifolds, grind away the material that chokes down the pipe weld at the flange, but don't get rid of all the discoloration on the flange. It will flow better, and be strong enough not to crack.
coupeguy2001 is offline   Reply With Quote
Old 02-04-2011, 12:10 PM   #11
ch@0s
CF Senior Member
Support Corvetteforum!
 
ch@0s's Avatar
 
Member Since: Oct 2008
Location: Houston Texas
Default

Quote:
Originally Posted by coupeguy2001 View Post
I bought an 85 front Y pipe out of a wrecking yard. It doesn't have precats. I could barely keep up with traffic on a major hill here in Phoenix, and when i got rid of the precats, wow, what a difference. I also ported the exhaust manifold flanges, and I really noticed some oomph when I did those two things. If you port the exhaust manifolds, grind away the material that chokes down the pipe weld at the flange, but don't get rid of all the discoloration on the flange. It will flow better, and be strong enough not to crack.
There is a lot of material there also gring the air tubes flush. On my 86 i cut the y right behind the cats gutted them then had it welded back together.
ch@0s is offline   Reply With Quote
Old 02-04-2011, 12:15 PM   #12
prinzSD455
CF Senior Member
 
prinzSD455's Avatar
 
Member Since: Mar 2006
Location: Antioch Ca
Default

Quote:
Originally Posted by CREWZIN View Post
I have the "Y" without the pre-cats, a gutted main CAT and the air foil. Goes like a scalded cat. No pun intended.
CREWZIN, who drew up your avatar? I am looking for someone to do a couple of carictures of my 3 cars.
__________________
1986 Corvette, Dark Red Metallic, 4-speed auto, graphite leather interior, 57,xxx miles

1985 Trans Am, Red and Silver, LG4 motor, 5-speed manual, dark and medium gray cloth interior, 74,xxx miles

1993 Trans Am, Dark Green, LT1, 4-speed auto, tan leather, 217,xxx miles on original motor and tranny.

2001 Lexus RX300, Silver Mist,
161,xxx miles
prinzSD455 is offline   Reply With Quote
Old 02-04-2011, 02:46 PM   #13
coupeguy2001
CF Senior Member
 
coupeguy2001's Avatar
 
Member Since: Sep 2006
Location: Phoenix AZ
Send a message via AIM to coupeguy2001
Default

Wel, I also did grind the air tubes flush. I bought small bullet cats to replace the precats and welded in a "test" tube instead of the main cat.
This is going on soon.
I am going to ditch my true dual setup soon. One of the bricks in the cats broke and part of it is banging around inside the muffler. Such an annoyance. The cats are too far back from the engine to lightoff properly so I will get the other setup installed.
The other thing wrong with it is the pipe welded right ahead of the cats isn't stainless, and the inside of the pipe is flaking off a little bit of metal. The flakes bunch up and choke off the cats then the next time i start it up, it runs fine, every start is different, and depends on where the flakes lay.

Last edited by coupeguy2001; 02-04-2011 at 02:50 PM.
coupeguy2001 is offline   Reply With Quote
Old 02-04-2011, 03:56 PM   #14
TIMSTERS VETTE
CF Member
 
TIMSTERS VETTE's Avatar
 
Member Since: Jun 2010
Location: STEELER COUNTRY PA
Default

Please pardon my ignorance, I am just a shade tree mechanic. But when I hear gut the cat convertors, is it an easy thing to do?
TIMSTERS VETTE is offline   Reply With Quote
Old 02-04-2011, 04:30 PM   #15
pmihaltian
CF Senior Member
Support Corvetteforum!
 
pmihaltian's Avatar
 
Member Since: Dec 2001
Location: Charlotte NC
Send a message via AIM to pmihaltian
Default

Quote:
Originally Posted by Sweeride39 View Post
Does anyone produce a front Y pipe without the cats that mount to the stock headers?
You can get a cat-less front Y-pipe at most of the Corvette Parts houses. Here is one with a high output main cat:

http://www.ecklers.com/corvette-y-pi...1986-1991.html
pmihaltian is offline   Reply With Quote
Old 02-04-2011, 04:36 PM   #16
ggrassmid
CF Senior Member
 
ggrassmid's Avatar
 
Member Since: Jan 2008
Location: Coopersville MI
Send a message via AIM to ggrassmid
Default

Quote:
Originally Posted by TIMSTERS VETTE View Post
Please pardon my ignorance, I am just a shade tree mechanic. But when I hear gut the cat convertors, is it an easy thing to do?

I busted mine out with a piece of metal rebar I had laying around
ggrassmid is offline   Reply With Quote
Old 02-04-2011, 11:34 PM   #17
8valve
CF Senior Member
Support Corvetteforum!
 
8valve's Avatar
 
Member Since: May 2010
Default

WHen you replace the front Y pipe with one without Pre Cats, and also remove the Main Cat, will you have any problems with the Oxygen sensor operating correctly ? I am also considering running duals all the way back. Somewhere I think I read on the forum that removing the cats woudl cause Oxygen sensor problems. I have a 87 with only one Oxygen Sensor on the left pipe.

Thanks
8Valve
8valve is offline   Reply With Quote
Old 02-05-2011, 11:32 AM   #18
Casket86
CF Senior Member
 
Casket86's Avatar
 
Member Since: Apr 2010
Location: New Prague MN
Default

Quote:
Originally Posted by 8valve View Post
WHen you replace the front Y pipe with one without Pre Cats, and also remove the Main Cat, will you have any problems with the Oxygen sensor operating correctly ? I am also considering running duals all the way back. Somewhere I think I read on the forum that removing the cats woudl cause Oxygen sensor problems. I have a 87 with only one Oxygen Sensor on the left pipe.

Thanks
8Valve
Casket86 is offline   Reply With Quote
Old 02-05-2011, 11:52 AM   #19
ch@0s
CF Senior Member
Support Corvetteforum!
 
ch@0s's Avatar
 
Member Since: Oct 2008
Location: Houston Texas
Default

Quote:
Originally Posted by 8valve View Post
WHen you replace the front Y pipe with one without Pre Cats, and also remove the Main Cat, will you have any problems with the Oxygen sensor operating correctly ? I am also considering running duals all the way back. Somewhere I think I read on the forum that removing the cats woudl cause Oxygen sensor problems. I have a 87 with only one Oxygen Sensor on the left pipe.

Thanks
8Valve
No it won't.
ch@0s is offline   Reply With Quote
Old 02-05-2011, 02:14 PM   #20
GREGGPENN
CF Senior Member
 
GREGGPENN's Avatar
 
Member Since: Nov 2003
Location: Overland Park Kansas
greggpennington
Default

Quote:
Originally Posted by Sweeride39 View Post
Does anyone produce a front Y pipe without the cats that mount to the stock headers?
www.allencorvetteexhaustsystems.com

They are the only one I know of that makes a 2.5" front "Y" w/o cats. Not sure if the OP went 2.25 or 2.5. Either one would help.
GREGGPENN is offline   Reply With Quote
Old 02-05-2011, 02:14 PM
 
Go Back   Corvette Forum > C4 Corvettes, 1984 - 1996 > C4 General Discussion
Reload this Page I replaced my front Y pipe with one with out precats :)
 
 
 
Reply

Tags
1989, 1991, 89, c4, catless, corvette, coupon, ecklers, exhaust, long, manifold, metal, pipe, precats, remove, replace, ypipe


Thread Tools Search this Thread
Search this Thread:

Click for Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Questions about aftermarket exhaust Z01Vett C4 General Discussion 8 10-28-2013 02:36 PM
No precat y pipe 87droptop C4 Tech/Performance 17 09-04-2009 11:51 AM
ditched pre-cats! REDEVIL C4 General Discussion 6 02-23-2007 06:16 PM
89 Pre-cats, Do I need them??? jzvette C4 Tech/Performance 20 04-28-2005 04:43 AM
Will eliminating pre-cats on my '89 seriously affect emisions? TheCorvetteKid C4 Tech/Performance 16 04-12-2003 03:15 AM


All times are GMT -4. The time now is 06:02 PM.


Emails & Password Backup