bumper delete project


spartan

spartan

GT Owner
Mark II Lifetime
Feb 11, 2017
1,223
Bloomfield Hills MI
Started a bumper delete project. CDC rear panels with Heffner H pipes. Not sure If I will delete the stock cats or hollow out the Heffner cats.
 

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The Heffner cats are much lighter than the stock cats and I believe they are less restrictive too. Removing the stock cats with cat delete pipes will allow you to keep the stock units in your parts stash and will shave several pounds off your GT.

Chip
 
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Chip,

Will the sound be much louder with the Heffner cats ( removing the oem)?

Ill look for Cat straight pipes.
 
Are the heffner cats functional or do you have to disable rear o2 sensprs
 
Chip will know the answer. I bought them form him. I believe they are functional as he had them on his TT setup in order to pass emission.
 
Hey Fred, invest in a lift and you'll never regret it.
 
twobjshelbys said:
Are the Heffner cats functional or do you have to disable rear O2 sensors.
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They are functional and the O2 sensors for the stock cats should be disabled if those stock cats are removed.

Chip
 
Looking forward to seeing the finished project!
 
Will the Heffner cats pass smog in California?
 
SuperNova said:
Looking forward to seeing the finished project!
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I received the pipes from Chip yesterday. Thank you

Gutted the Heffner Cats and completed the install this evening. I'm running the OEM cats and 02 sensors.
 

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GTED said:
Will the Heffner cats pass smog in California?
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Technically no, unless it the pipes have a CARB exemption number. However if the tech isn't too picky and your OBDII monitors are all good you can still pass.

IMO the stock cats probably flow a lot better than those small cats in the Heffner pipe. The stock cats are a lot bigger and have a lot more cross sectional area. I wouldn't be surprised if the puny cats blew part under heavy use. Ask Ed Sims what his puny cats did during a mile run. Even the some OEM cats have failed under track use.
 
BlackICE said:
Technically no, unless it the pipes have a CARB exemption number. However if the tech isn't too picky and your OBDII monitors are all good you can still pass.

IMO the stock cats probably flow a lot better than those small cats in the Heffner pipe. The stock cats are a lot bigger and have a lot more cross sectional area. I wouldn't be surprised if the puny cats blew part under heavy use. Ask Ed Sims what his puny cats did during a mile run. Even the some OEM cats have failed under track use.
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How do they know what is different from the factory? Most of the inspectors have probably never seen a Ford GT before in their life so what would tell them that they are different? As I mentioned, in Colorado they knew about the Ford pipe kit, and must have had photos that showed the difference. But isn't CA using a drive-in service station inspection? (That is what is used in NV.) As you said, it's a few visual checks and the OBDII monitors.
 
twobjshelbys said:
How do they know what is different from the factory? Most of the inspectors have probably never seen a Ford GT before in their life so what would tell them that they are different? As I mentioned, in Colorado they knew about the Ford pipe kit, and must have had photos that showed the difference. But isn't CA using a drive-in service station inspection? (That is what is used in NV.) As you said, it's a few visual checks and the OBDII monitors.
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Most people know that stock cars come with mufflers and with cats mounted closer to the engine for faster warm up. It all depends on who checks the cars.

Do you feel lucky?

https://www.youtube.com/watch?v=8Xjr2hnOHiM
 
spartan said:
I received the pipes from Chip yesterday. Thank you

Gutted the Heffner Cats and completed the install this evening. I'm running the OEM cats and 02 sensors.
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Fred- that really looks great!! can't wait to hear it!
 
NorthwoodGT said:
Fred- that really looks great!! can't wait to hear it!
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Scott, Thanks for sourcing the CDC panels. I appreciate your help.
 
BlackICE said:
Technically no, unless it the pipes have a CARB exemption number. However if the tech isn't too picky and your OBDII monitors are all good you can still pass.

IMO the stock cats probably flow a lot better than those small cats in the Heffner pipe. The stock cats are a lot bigger and have a lot more cross sectional area. I wouldn't be surprised if the puny cats blew part under heavy use. Ask Ed Sims what his puny cats did during a mile run. Even the some OEM cats have failed under track use.
Click to expand...

I watched my aftermarket cats on my supercharged Viper exit the rear tips on a boost pull.
 
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