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Has anyone eliminated their catalytic converter?

Joined
Nov 12, 2003
Messages
104
Location
York, Pa
Corvette
1988 convertible-blue pearl
I have an 88 with 87,000 miles. I have to replace my mufflers to pass the state inspection, but, since I have the classic registration it doesn't need the emission tested. My mechanic says I don't even need to keep my catalytic converter on. I am tempted to have it removed but I have read that it gives the engine a certain amount of back pressure and that is why they make hi-flow converters. A couple of motor heads at work tell me getting rid of the cat will not harm the engine, and I'm crazy if I don't do it since it is legal for my car. I just don't want to screw up the car. I am going to order a cat back system. The question is, has anyone actually done this and how did it work out. How about the hi flow cats?
Thanks for any opinions.
 
M

Moonunit 451

Guest
I have high flow cats and I like them, but if you don't require them, get rid of them, lots of folks do. It'll sound better and give you a few extra ponys:beer
 
G

grapeknutz

Guest
Moonunit 451 said:
I have high flow cats and I like them, but if you don't require them, get rid of them, lots of folks do. It'll sound better and give you a few extra ponys:beer

Sorry it's a federal requirement to keep cats on the car. Just be aware that a over zealous cop can still bust you because of that.
And on a side note it won't hurt performance on a STREET CAR as its duty cycle is low RPMs (not racing speed). Besides a good cat will not hurt a street engine unless is clogged or too small to handle the flow.
 
Joined
Jan 15, 2004
Messages
2,240
Location
Northern Indiana
Corvette
1987 Z52 Black Convertible
If you havent changed anything you have three cats. Two precats and the one main cat. If I were you I would get rid of the pre cats and get a high flow cat. That way you can stay legal.
 

Edmond

Well-known member
Joined
Aug 1, 2001
Messages
5,218
Location
Louisiana
Corvette
2003 Z06
You do need a certain amount of backpressure. But I think some mufflers would be enough.

If you don't need the cat, you can get rid of it. If it's not legal, I wouldn't mess with it because they fine people pretty severely.
 

ratorto

Well-known member
Joined
Nov 6, 2003
Messages
57
Location
Hilton Head, SC
Corvette
1987 Black Coupe
cats

I took mine off and no problem with anything.
I run true duals straight back to the Borlas on the end.
I use Hedman headers and bought the straight pipes from mid-america.
Great sound, great performance.............
 
T

Tanreall

Guest
I run true duels and straight pipes with no mufflers(EXTREMELY LOUD!) I suggest mufflers if you go this way or at least resonators.
 

Hrtbeat1

Well-known member
Joined
Nov 24, 2002
Messages
923
Location
MS Gulf Coast
Corvette
'90 coupe (gone) '96 CE LT4 Z51
One of the previous owners took out the main cat on my car. They put a Y in and it runs duals back to the Flowmasters. The only problem I've had is the EGR kept setting a code. (The Egr feed was just plugged, not removed) I have since removed the Feed tube and reburned a chip to turn off the EGR check engine light.


Hope this helps
 
Joined
Nov 12, 2003
Messages
104
Location
York, Pa
Corvette
1988 convertible-blue pearl
grapeknutz said:
Sorry it's a federal requirement to keep cats on the car. Just be aware that a over zealous cop can still bust you because of that.
And on a side note it won't hurt performance on a STREET CAR as its duty cycle is low RPMs (not racing speed). Besides a good cat will not hurt a street engine
unless is clogged or too small to handle the flow.
Most vehicles in Pennsylvania will be required to undergo some sort of check for tampering:
bullet.GIF
1996 and newer vehicles in 17 counties are required to have on-board diagnostics tests which by their nature will detect tampering;
bullet.GIF
1995 and older vehicles in 25 counties with separate emission inspections are required to have visual checks of the catalytic converter, exhaust gas recirculation (EGR) valve, positive crankcase ventilation (PCV) valve, fuel inlet restrictor, air pump and evaporative control system components. Inspectors will check for their presence, whether they are properly connected and whether they are the appropriate type for the vehicle.
bullet.GIF
a similar visual check will be performed as part of the safety inspection in the 42 other counties without emission inspections.

Classic, convertible and antique vehicles are not required to have visual inspections in any county.

The above is taken right from Pa DEP law which is consistant with Federal Law. I double checked with Pa DOT before I got the classic registration. No police officer can cite me for not having a cat and no inspection station can fail me for it either. I have decided to get a Hi flow converter anyway. Thanks for the comments. I always enjoy CAC. Its the best!
 

Edmond

Well-known member
Joined
Aug 1, 2001
Messages
5,218
Location
Louisiana
Corvette
2003 Z06
caninelver said:
Classic, convertible and antique vehicles are not required to have visual inspections in any county.

Why would convertibles be exempt? I could see classic and antique, but convertible?
 

vetteboy86

Well-known member
Joined
May 26, 2003
Messages
2,760
Location
IN
Corvette
1986 Black "Indy 500 Pace car replica"
I also want to know why verts are exempt. It seems to me that it wouldn't matter, but I have seen some weirder laws.

ratorto,

I assume you have short tube headers. Also did you get the headers with or without that EGR stuff?

Thanks

Craig
 
M

Moonunit 451

Guest
Who friggin cares, ( no offense grapeknutz) you said you were exempt.

Regardless, unless you're a greenie,(and you believe human beings can and are destoying the earth), there are thousands of cars out there not running cats! Uh, and no one is going to jail!

Junk the cats :beer BTW how many gut their cats to get by the visual?

True duals -> Random Tech high flow metal matrix bullet cats 3" ($500 for two) -> Borla Chalenge 2 3/4 stainless :D
 

ratorto

Well-known member
Joined
Nov 6, 2003
Messages
57
Location
Hilton Head, SC
Corvette
1987 Black Coupe
for vetteboy66

The Hedman Headers are the long tube type.
I had them jet-coated and they included the egr adapters.
Like I said, it helps to have a lift when installing them.
 
G

goldeneye_vet

Guest
I have no cats and new hedman elite long tube headers with no problems. The fumes are a little strong when I start out in the garage but the sound is tremendous. I live in a cul-de-sac and all the neighbors love the car. In my state we don't have a sniffer test so we're safe there.
 

ratorto

Well-known member
Joined
Nov 6, 2003
Messages
57
Location
Hilton Head, SC
Corvette
1987 Black Coupe
codes

Goldeneye, thanks for your reply. I'll have a code check done as soon.
I did routinely replace the O2 sensor when we put the headers on so I'm not sure if it has anything to do with the headers. Perhaps its the throttle body bypass I did following the headers. Anyway, no sense guessing.
 

Mad-Mic

Gone but not forgotten
Joined
Feb 12, 2002
Messages
1,853
Location
Annapolis Maryland
Corvette
1987 Redskin Red Coupe
ratorto said:
Goldeneye, thanks for your reply. I'll have a code check done as soon.
I did routinely replace the O2 sensor when we put the headers on so I'm not sure if it has anything to do with the headers. Perhaps its the throttle body bypass I did following the headers. Anyway, no sense guessing.
clear the codes by unplugging the negative battery terminal for a few mins. this will clear the codes. with your mods on your 87 you shouldn't have no codes especially from the TB Bypass. drive it for awhile real hard. don't be a sissy Bob! in less than 100 miles the car "relearns" the calibrations and will run pretty strong.

i get a code every once in a while but it goes out after 10-20 mins and doesn't come back for months. it happened before i did my headers, deleted air, and deleted EGR. car still runs strong and am on the verge of cracking some high 12 second passes. :D

BTW i test fit my 11x17" rear ZR1 Amolds and they fit fine. they are on hold as i bought a set of 275/40/17" BFG DR's for the time being.
 

Mad-Mic

Gone but not forgotten
Joined
Feb 12, 2002
Messages
1,853
Location
Annapolis Maryland
Corvette
1987 Redskin Red Coupe
gutted cat, long tube headers, and no mufflers here. L98 TPI motors pick up alot of HP and TQ from this setup. i would guess about 30 rwhp and 50 lbs of rwtq. with a 20% loss in an A4 vette i pulled 240+ rwhp and 350+ rwtq in my 87 with only full exhaust done, alot of timing, TB Bypass, K&N filter, cut lid, descreened MAF, airfoil, and playing with plug gap with cut backs. the car was hot when i dynoed and only got 1 pass due to EGR hookup i rigged up blowing off and i thought it was a header gasket. water temp was 225 degrees. this equates to about 48 chp and 70 ctq over stock applications. if it was cooled down to race conditions and the EGR was properly capped, i think it would of made in the 260 rwhp and 370+ rwtq range

whats this mean? as it stood on the dyno being hot and blowing the EGR hookup off it still made a total of 288 chp total and 410 ctq. when you look at my numbers like that then you can see why i beat C5's pretty easily.

cooled down to 160 or less water temp the estimated #'s are 260 rwhp and 370+ rwtq. 52 more chp than stock. 74 more ctq over stock. with a total of 292 ctq and 414 ctq. i believe at the time these number were more accurate.

i will be dynoing the car again soon with some additional mods. AIR Elim pulley, Crank pulley, MAT relocation sensor, AFPR, fully ported TPI, Cut Back AC Delco Rapid Fire plugs, and a custom chip this fall. i'm hoping for 300+ rwhp and 400+ rwtq out of a light bolt on A4 Vette with 2.59 gears :D
 

BigRed

Well-known member
Joined
May 23, 2001
Messages
948
Location
Edmonton
Corvette
1985 Bright Red Rocket
Old man say what they don't know, don't hurt em.

Run your "true Dual" exhaust and in place of the Cat run your pipes. Now GUT the cat entirely and slip it over your fancy exhaust and weld it into place. It Looks like its there and with resonators in it sounds like its there....But it ain't there.

As long as your state or province isn't picky with emissions away you go.
 

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