Anyone interested in Heffner building high flow/sound cats for the GT.


HOOKED ON GT

GT Owner
Oct 26, 2006
468
Orlando & Australia
Spoke to Jason today about looking into a new cat/sound set up.
He would probably use HJS cats and a ball socket set up like OE header/cat junction.
They would finish at same OE point so just bolt on whatever you current run.
He mentioned that getting a group of buyers together would water down the set up costs (building a jig and so on)

So any interest would potentially be a benefit for buyers.

Not sure when I'll find out what how his numbers turn out for just 1 and how a buy of 5+ would look..... but I'll get back here then with an idea.

Any thoughts would be appreciated.

Stuart A
 

nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
4,192
Based on past experience, I believe that it would be highly likely that an aftermarket cat would cause the CEL to trigger and for folks in California or any state having adopted CARB requirements, passing smog would be impossible.
 
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twobjshelbys

GT Owner
Jul 26, 2010
6,059
Las Vegas, NV
Based on past experience, I believe that it would be highly likely that an aftermarket cat would cause the CEL to trigger and for folks in California or any state having adopted CARB requirements, passing smog would be impossible.
My pulley/tune from the GT guys disabled the EGR, O2 and cat sensor monitors and caused me to fail the OBDII emissions test in Nevada (same as CA). His tuner was never able to get me a tune that would enable them. I took it all off and returned to factory.
 

nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
4,192
California is now looking at the bits and bytes of the tune when the smog station connects via the OBD2 port. If it detects an unauthorized tune, the car will fail AND you will be required to go to a referee who will typically be a lot more diligent in inspecting ANY changes on the car. The only way to pass smog in CA is to revert to an OEM tune.... drive enough to get the monitors to set and then go to a smog station. As long as the monitors are set (EVAP not set is OK), there are no active or pending codes, and it is an OEM tune - the car will pass. If history is any indication, other states will soon follow this new practice. Good 'ol California - doing its best to eliminate the ICE.
 
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HOOKED ON GT

GT Owner
Oct 26, 2006
468
Orlando & Australia
California is the reason why we cant have nice things...ha ha

Maybe we need a "quick connect" add/remove OE cat set up for the smog states.

I feel for you smogger states.
 

PeteK

GT Owner
Mark II Lifetime
Apr 18, 2014
2,283
Kalama, Free part of WA State
The cats are pretty easy to take off and put back on. The hard part is everything you have to remove to get to them. 😉
 
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twobjshelbys

GT Owner
Jul 26, 2010
6,059
Las Vegas, NV
California is now looking at the bits and bytes of the tune when the smog station connects via the OBD2 port. If it detects an unauthorized tune, the car will fail AND you will be required to go to a referee who will typically be a lot more diligent in inspecting ANY changes on the car. The only way to pass smog in CA is to revert to an OEM tune.... drive enough to get the monitors to set and then go to a smog station. As long as the monitors are set (EVAP not set is OK), there are no active or pending codes, and it is an OEM tune - the car will pass. If history is any indication, other states will soon follow this new practice. Good 'ol California - doing its best to eliminate the ICE.

Use abundant caution when putting the factory tune back. In my case the car wouldn't run. The "tune" package included a different Mass Air Flow unit which had to be replaced with the original in order to even start. Then the package included a different throttle body which due to the air flow over the EGR wouldn't the EGR test complete. At that stage I wished I'd simply gotten the Ford package instead. I reverted everything except the pulley at the time and eventually undid that (and sent the other one to you :) )

Yes, Nevada follows CA emissions regs by a few years. At that time we were allowed ONE not ready (not restricted to evap) and I couldn't get the Catalyst test to complete so when I got to one not ready I took it in. MA does also in lock step.
 

nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
4,192
Sorry for your experience, Tony. In contrast, we're batting 100% on dozens of GT's where we have restored the OEM tune, driven the cars to reset the monitors, and then successfully passing CA smog. As you noted, you cannot leave an aftermarket MAF scaling device on but thankfully the simple +100HP pulley tunes we used never required a scaler. I'm surprised that the Accufab throttle body caused you problems, but they're easy enough to swap on and off.
 

twobjshelbys

GT Owner
Jul 26, 2010
6,059
Las Vegas, NV
Sorry for your experience, Tony. In contrast, we're batting 100% on dozens of GT's where we have restored the OEM tune, driven the cars to reset the monitors, and then successfully passing CA smog. As you noted, you cannot leave an aftermarket MAF scaling device on but thankfully the simple +100HP pulley tunes we used never required a scaler. I'm surprised that the Accufab throttle body caused you problems, but they're easy enough to swap on and off.
Mine was not a MAF "scaler" (ie, MAFia) add on but a different MAF. As I recall the part number crossed to a Mercury that had a big engine (yes, that surprised me) but I don't remember all the details.