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Discussion Starter · #1 ·
Background:

Soon after I purchased my car I did the zip-tie and though I didn't notice any SOTP improvement I did however notice that my exhaust pipes were getting very sooty. That to me indicated that I was running richer, which made sense i.e. more air in the car compensates by adding more fuel.

After about 1500 miles I stopped by 21MC for a tune, thermostat, and minor exhaust. I also replaced the factory paper filter with a K&N. The initial dyno revealed that my car was running very rich and my initial numbers were 337.9rwhp and 324.6rwtq. After tuning my numbers improved to 369.7rwhp and 350.0rwtq. The real benefits were improved gas mileage and clean "soot free" tail pipes. I went a little further with mods by replacing the OEM airbridge with the Halltech Stinger airbridge so that I would have a place to install my nitrous nozzle but that produced no noticeable effect on the car.

Very recently I replaced the zip-tie modded air box with the Halltech Stinger filter however, once again my exhaust pipes are very sooty. :-?

So now for the question:

Is it possible that somehow my custom tune is being/has been overridden by some other computer tables within the car's ECM causing my car to add even more fuel due to the increase in airflow with the Halltech filter?
 

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Have you taken your car to the Dealer recently? If they re- flashed you computer your old tune is gone. :eek:o:
 

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It's just your PCM adjusting to yet another increase in air flow. Time for another tune if you want to have clean exhaust tips.
 

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Discussion Starter · #5 ·
IT L GO said:
Have you taken your car to the Dealer recently? If they re- flashed you computer your old tune is gone. :eek:o:
Fortunately I can rule that out, so far my car hasn't had any serious problems requiring dealer service.


jub jub said:
It's just your PCM adjusting to yet another increase in air flow. Time for another tune if you want to have clean exhaust tips.
That's what I was afraid of, no problem I'll be doing some big changes shortly that will require a tune update so I'll get it taken care of at that time. I just find it interesting that even after having a custom tune in place that specifically targets increased airflow that the PCM is still able to respond. I guess ultimately that means that the Halltech filter flows much more than my previous zip-tie modded airbox.

Ultimately I want to use this Blackwing that I have been sitting on so I guess I'll wait until I do my other mods so all can be tuned together.
 

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I had the Halltech Stinger and replaced it with the Tunnel Ram unit. Halltech claims 3 degree lower intake temperatures with the Tunnel vs the Stinger. The Z was tuned before changing intakes. I did the idle releard after installing the Tunnel and drove about 100 miles before dyno. I was at 387 before and went to 392 rwph after tuning again. My experince has been the PCM will make modest adjustments but tuning dials in finer adjustments.
 
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