Time for an exhaust mod

Try Me · 10-23-2000, 09:33 AM

Fella's.. I'm ordering an H-Pipe for my '97 GT.

I've got a good idea what to expect. This topic has been covered over and over.

The last thing i need to know before i call the warehouse is do i need to worry about O2 sensors and check engine lights?

The H-Pipe i'm getting is MAC.

97snakedriver · 10-23-2000, 11:38 AM

If it has cats, no, everything should be fine. If its an off-road pipe then you need a set of MIL eliminators.

Try Me · 10-23-2000, 03:48 PM

Snake - what do you mean MIL illimenators?
Are these provided with the H-Pipe by MAC?
It's off-road by the way.

Thanks for your reply!

Stefan · 10-23-2000, 04:03 PM

Try Me,

Check down a couple of posts. 97ScottieGT kind of went through the same thing as you. The MIL eliminators fool the computer into thinking everything is ok in the absence of cats. I guess it has something to do with the difference in air velocity that the free flowing pipe provides. They most likely won't come with a new H or X pipe but previous posts will give you a couple of links were to purchase them. I think Hammer said www.DallasMustang.com has them.
You'll have to let me know how everything turns out with the new pipe. An H pipe is going to be one of next mods and our 4.6's are the first generation modulars so gains should be comparable.

Stefan

------------------
66 Standard coupe
200 inline 6 - Pertronix ignition, Flamethrower Coil, K&N, Clifford Perf. 6 into 2 headers, Holley carb, three row radiator, Firestone Firehawk 215/60R14's

96 GT Convertible
Bosch Platinum +4 plugs, B&M Ripper, Borla Side exhaust,
K&N, removed air silencer, Tokico struts/ shocks, BF Goodrich Comp T/A 245/50 16's
Next up: 3:73's, high flow H-Pipe

97snakedriver · 10-23-2000, 04:17 PM

Actually there are two sets of O2 sensors. 2 up stream from the cats, and 2 down stream. The upstream provide feedback for the air/fuel ratio. The ones downstream actually monitor the operation of the cats by comparing the amount of 02 before and after. In a properly operating cat almost all the 02 entering will end up as H2O.

If you have no cats, then the up and down stream sensors will read the same, and the computer throws a code. The MIL take care of that. Basically they're just two resistors and a cap which just gives a steady output of about .9V.

Try Me · 10-23-2000, 04:59 PM

Thanks a bunch guys. MIL's are on order when i stop at the shop.

97snakedriver · 10-23-2000, 05:01 PM

Oh yeah, you're right about the back preasure also. Its sort of a double wammy on the mod motors.

10-23-2000, 09:33 AM	#1
Try Me Registered Member Join Date: Jul 2000 Location: Ottawa, Ontario, Canada Posts: 465	Time for an exhaust mod Fella's.. I'm ordering an H-Pipe for my '97 GT. I've got a good idea what to expect. This topic has been covered over and over. The last thing i need to know before i call the warehouse is do i need to worry about O2 sensors and check engine lights? The H-Pipe i'm getting is MAC.

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10-23-2000, 11:38 AM	#2
97snakedriver Registered Member Join Date: May 1999 Location: Blacksburg, VA Posts: 1,526	If it has cats, no, everything should be fine. If its an off-road pipe then you need a set of MIL eliminators.

10-23-2000, 03:48 PM	#3
Try Me Registered Member Join Date: Jul 2000 Location: Ottawa, Ontario, Canada Posts: 465	Snake - what do you mean MIL illimenators? Are these provided with the H-Pipe by MAC? It's off-road by the way. Thanks for your reply!

10-23-2000, 04:03 PM	#4
Stefan Registered Member Join Date: Dec 1998 Location: Manhattan, KS 66502 Posts: 599	Try Me, Check down a couple of posts. 97ScottieGT kind of went through the same thing as you. The MIL eliminators fool the computer into thinking everything is ok in the absence of cats. I guess it has something to do with the difference in air velocity that the free flowing pipe provides. They most likely won't come with a new H or X pipe but previous posts will give you a couple of links were to purchase them. I think Hammer said www.DallasMustang.com has them. You'll have to let me know how everything turns out with the new pipe. An H pipe is going to be one of next mods and our 4.6's are the first generation modulars so gains should be comparable. Stefan ------------------ 66 Standard coupe 200 inline 6 - Pertronix ignition, Flamethrower Coil, K&N, Clifford Perf. 6 into 2 headers, Holley carb, three row radiator, Firestone Firehawk 215/60R14's 96 GT Convertible Bosch Platinum +4 plugs, B&M Ripper, Borla Side exhaust, K&N, removed air silencer, Tokico struts/ shocks, BF Goodrich Comp T/A 245/50 16's Next up: 3:73's, high flow H-Pipe

10-23-2000, 04:17 PM	#5
97snakedriver Registered Member Join Date: May 1999 Location: Blacksburg, VA Posts: 1,526	Actually there are two sets of O2 sensors. 2 up stream from the cats, and 2 down stream. The upstream provide feedback for the air/fuel ratio. The ones downstream actually monitor the operation of the cats by comparing the amount of 02 before and after. In a properly operating cat almost all the 02 entering will end up as H2O. If you have no cats, then the up and down stream sensors will read the same, and the computer throws a code. The MIL take care of that. Basically they're just two resistors and a cap which just gives a steady output of about .9V.

10-23-2000, 04:59 PM	#6
Try Me Registered Member Join Date: Jul 2000 Location: Ottawa, Ontario, Canada Posts: 465	Thanks a bunch guys. MIL's are on order when i stop at the shop.

10-23-2000, 05:01 PM	#7
97snakedriver Registered Member Join Date: May 1999 Location: Blacksburg, VA Posts: 1,526	Oh yeah, you're right about the back preasure also. Its sort of a double wammy on the mod motors.