What is the best way to gut the stock cats?

MTU 50 · 09-11-2001, 09:32 AM

I was going to buy an aftermarket h-pipe w/o cats, but I just don't have the extra money to do that anymore.

I would leave them alone, but about a month ago I put on an A/C delete kit and I bought a smaller belt and bypassed the air pump. I know after a while this will clog my cats, so now the cheapest thing I can try to do is gut them out.

------------------
1991 GT, AOD, Moroso Cold Air, 3.73s, Pulleys,
3-chambers soon to be dumps after new h-pipe,
FMS c-springs, and KYBs, A/c delete,
190 LPH fuel pump, 3-row radiator

todd95GT · 09-11-2001, 11:02 AM

Call around to the hi-po shops in your area. Sometimes (like in my case), they will have many pipes laying around their shop and will give you one for a very good price. I got one from my shop that had some surface rust on it for next to nothing. I cleaned it up and bolted it in. Also check ebay motors and your local trader publications. Gutting those cats seems very difficult because of thier location in the center of the pipes. If there is a way to remove them, you can use a long screwdriver to drive out the material in the centers. I've done it before but it is easier to save a few bucks to buy an off road pipe; you could find a new one for just over a hundred dollars.

------------------
Todd
1995 GT/T-5
Pulleys; 65 mm TB; Flowmaster cat-back; Mac off road H-pipe; FMS aluminum driveshaft; short-throw shifter; HD clutch; Cobra R's; Cobra front and wing

Tony91LX · 09-11-2001, 12:45 PM

I wouldn't do it save up some money and get an off-road H pipe.

You will eventually have to go through emissions and will cost you a lot more in the long run to get cats then a H pipe.

Unit 5302 · 09-11-2001, 01:34 PM

Get a different H pipe. Try E-bay or the classifieds. I'm sure $50 will get you one.

MTU 50 · 09-11-2001, 08:30 PM

My college raised tuition 15% this year and because the school's budget is all f'ed up, I lost my job at the Library this year, so the bottom line is money is tight and $100 is far too precious to waste on an h-pipe.

My area is 2 towns next to each other in the Upper Peninsula of Michigan with a combined pop. of maybe 10,000. I highly doubt anybody is going to have old h-pipes laying around, but if I was back home(Detroit area) it would be a good idea.

Unit, you had a good idea too, but even $50 is too much. I was just wondering if there was a trick that could be done that was fairly inexpensive. My girlfriend's dad does have access to a welder, so maybe if I get the time I could just remove the damn things and weld pipe in their place. I just figured anything is better than clogged up convertors.

And I doubt I will have to deal with emissions any time soon so that is not a concern.

Thanks guys

------------------
1991 GT, AOD, Moroso Cold Air, 3.73s, Pulleys,
3-chambers soon to be dumps after new h-pipe,
FMS c-springs, and KYBs, A/c delete,
190 LPH fuel pump, 3-row radiator

Unit 5302 · 09-11-2001, 10:12 PM

The converters are very fragile. Harsh impacts will destroy them. Find a long metal tube, shove it in there band bust them up. Make sure you get all the chunks out. You can also give them a few jarring wacks with a hammer as long as you're not denting it up.

From what I've heard the gutted cats don't sound all that great, but yeah, they're better than plugged cats.

stevstum · 09-11-2001, 11:26 PM

I'm not sure this will work but get 4 m80s and put one in each end of the pipes. Light one at a time and run like hell. Thinking about it, if it holds up to this it will work on your car.

------------------
Steve Stumbaugh

89 LX 5.0 5sp.
Removed air silencer
Motorcraft 8mm wires
Autolite platinum plugs
BBK O/R h-pipe

Yan88gt · 09-15-2001, 10:45 AM

On some h-pipe there is metal screen that wrap the converters . Sometimes the converter is removed but the screen is still insinde. Be carefull!

LX XLR8R · 09-15-2001, 11:56 AM

i second the m-80 thing..i know for a fats it works..if not you can only get to 3 of them with a pipe

------------------
1987 black notch(ex 4 banger)
DSS 306 w/ main support...Elderbrock 6028 heads..gt-40 intake..24# injectors...70 mm tb..77 pro-m...accel 300+..mac full legnth..tremec w/ pro5oh...full MAC exhaust,off road h-pipe,long tubes, catback...ron davis radiator..subframes, control arms...CFDF II..o yea holley FPR sucks..dont buy one..
AIM=onesillynotch

Five0 · 09-16-2001, 11:09 AM

It does not sound bad, I had it done on my 88gt because I could not afford the real thing and one of my cats went out and ruined one of my mufflers. It sent pieces of the material into my muffler so I pulled it off and took a piece of rebar and knocked all the material out; there are some screens in each cat and you will have to get all that out also.
It will however not sound as good as an off road H-pipe!

------------------
James Cox
nochevy@hotmail.com
1991 Mustang LX
No times with 347 stroker yet.

withamc · 09-17-2001, 12:44 AM

Years ago I cut my H-pipe apart right behind the cats, gutted them and welded them back together. I have heard that the turbulence caused by the empty cats actually costs you power though. Bottom line is I got a new BBK h-pipe with cats and it sounds much better and isn't any slower. Not sure why you're bypassing the air pump though. It hardly costs you any power - maybe 2-3 HP. The power steering is the killer.

09-11-2001, 09:32 AM	#1
MTU 50 GOT TORQUE ???? Join Date: Aug 1999 Location: New Hudson, Michigan, USA Posts: 689	What is the best way to gut the stock cats? I was going to buy an aftermarket h-pipe w/o cats, but I just don't have the extra money to do that anymore. I would leave them alone, but about a month ago I put on an A/C delete kit and I bought a smaller belt and bypassed the air pump. I know after a while this will clog my cats, so now the cheapest thing I can try to do is gut them out. ------------------ 1991 GT, AOD, Moroso Cold Air, 3.73s, Pulleys, 3-chambers soon to be dumps after new h-pipe, FMS c-springs, and KYBs, A/c delete, 190 LPH fuel pump, 3-row radiator

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09-11-2001, 11:02 AM	#2
todd95GT Registered Member Join Date: Aug 2001 Location: Palm Beach Gardens, Florida, USA Posts: 191	Call around to the hi-po shops in your area. Sometimes (like in my case), they will have many pipes laying around their shop and will give you one for a very good price. I got one from my shop that had some surface rust on it for next to nothing. I cleaned it up and bolted it in. Also check ebay motors and your local trader publications. Gutting those cats seems very difficult because of thier location in the center of the pipes. If there is a way to remove them, you can use a long screwdriver to drive out the material in the centers. I've done it before but it is easier to save a few bucks to buy an off road pipe; you could find a new one for just over a hundred dollars. ------------------ Todd 1995 GT/T-5 Pulleys; 65 mm TB; Flowmaster cat-back; Mac off road H-pipe; FMS aluminum driveshaft; short-throw shifter; HD clutch; Cobra R's; Cobra front and wing

09-11-2001, 12:45 PM	#3
Tony91LX Registered Member Join Date: Jan 2000 Location: Feeding Hills, MA Posts: 114	I wouldn't do it save up some money and get an off-road H pipe. You will eventually have to go through emissions and will cost you a lot more in the long run to get cats then a H pipe.

09-11-2001, 01:34 PM	#4
Unit 5302 Registered Member Join Date: May 1999 Posts: 5,246	Get a different H pipe. Try E-bay or the classifieds. I'm sure $50 will get you one.

09-11-2001, 08:30 PM	#5
MTU 50 GOT TORQUE ???? Join Date: Aug 1999 Location: New Hudson, Michigan, USA Posts: 689	My college raised tuition 15% this year and because the school's budget is all f'ed up, I lost my job at the Library this year, so the bottom line is money is tight and $100 is far too precious to waste on an h-pipe. My area is 2 towns next to each other in the Upper Peninsula of Michigan with a combined pop. of maybe 10,000. I highly doubt anybody is going to have old h-pipes laying around, but if I was back home(Detroit area) it would be a good idea. Unit, you had a good idea too, but even $50 is too much. I was just wondering if there was a trick that could be done that was fairly inexpensive. My girlfriend's dad does have access to a welder, so maybe if I get the time I could just remove the damn things and weld pipe in their place. I just figured anything is better than clogged up convertors. And I doubt I will have to deal with emissions any time soon so that is not a concern. Thanks guys ------------------ 1991 GT, AOD, Moroso Cold Air, 3.73s, Pulleys, 3-chambers soon to be dumps after new h-pipe, FMS c-springs, and KYBs, A/c delete, 190 LPH fuel pump, 3-row radiator

09-11-2001, 10:12 PM	#6
Unit 5302 Registered Member Join Date: May 1999 Posts: 5,246	The converters are very fragile. Harsh impacts will destroy them. Find a long metal tube, shove it in there band bust them up. Make sure you get all the chunks out. You can also give them a few jarring wacks with a hammer as long as you're not denting it up. From what I've heard the gutted cats don't sound all that great, but yeah, they're better than plugged cats.

09-11-2001, 11:26 PM	#7
stevstum Registered Member Join Date: Mar 2000 Location: Salem, Or. USA Posts: 233	I'm not sure this will work but get 4 m80s and put one in each end of the pipes. Light one at a time and run like hell. Thinking about it, if it holds up to this it will work on your car. ------------------ Steve Stumbaugh 89 LX 5.0 5sp. Removed air silencer Motorcraft 8mm wires Autolite platinum plugs BBK O/R h-pipe

09-15-2001, 10:45 AM	#8
Yan88gt Registered Member Join Date: Jun 2001 Location: Quebec canada Posts: 92	On some h-pipe there is metal screen that wrap the converters . Sometimes the converter is removed but the screen is still insinde. Be carefull!

09-15-2001, 11:56 AM	#9
LX XLR8R Dirk Diggler Join Date: Feb 1999 Location: SLOATSBURG, NY Posts: 1,931	i second the m-80 thing..i know for a fats it works..if not you can only get to 3 of them with a pipe ------------------ 1987 black notch(ex 4 banger) DSS 306 w/ main support...Elderbrock 6028 heads..gt-40 intake..24# injectors...70 mm tb..77 pro-m...accel 300+..mac full legnth..tremec w/ pro5oh...full MAC exhaust,off road h-pipe,long tubes, catback...ron davis radiator..subframes, control arms...CFDF II..o yea holley FPR sucks..dont buy one.. AIM=onesillynotch

09-16-2001, 11:09 AM	#10
Five0 Registered Member Join Date: Apr 2000 Location: middleburg, fl, usa Posts: 1,134	It does not sound bad, I had it done on my 88gt because I could not afford the real thing and one of my cats went out and ruined one of my mufflers. It sent pieces of the material into my muffler so I pulled it off and took a piece of rebar and knocked all the material out; there are some screens in each cat and you will have to get all that out also. It will however not sound as good as an off road H-pipe! ------------------ James Cox nochevy@hotmail.com 1991 Mustang LX No times with 347 stroker yet.

09-17-2001, 12:44 AM	#11
withamc Registered Member Join Date: Aug 2000 Location: Thousand Oaks, CA Posts: 396	Years ago I cut my H-pipe apart right behind the cats, gutted them and welded them back together. I have heard that the turbulence caused by the empty cats actually costs you power though. Bottom line is I got a new BBK h-pipe with cats and it sounds much better and isn't any slower. Not sure why you're bypassing the air pump though. It hardly costs you any power - maybe 2-3 HP. The power steering is the killer.