Last post on Jun 13, 2012 at 1:54 PM
You are in the Ford Crown Victoria/Mercury Grand Marquis
What is this discussion about?
Ford Crown Victoria, Mercury Grand Marquis, Performance Mods, Exhaust, Sedan
#2 of 46 Question about dual exhaust
Apr 04, 2006 (2:21 pm)
Hello to all! Totally new to all this. I own a 2005 Crown Vic P74. I recently had it tuned by SCT (computer flash Excal 2)and it runs really strong. I currently have single exhaust. I want to have duals put on it with Flowmasters. If I do this, does anyone know if it will throw the computer off and make it run like crap. ">
#3 of 46 Re: Question about dual exhaust [joe110]
Apr 04, 2006 (7:05 pm)
Very likely. Remember your on board computer is programed for one cat sensor and if duals are installed, then what?
#4 of 46 Re: Question about dual exhaust [euphonium]
Apr 05, 2006 (5:20 pm)
When did they change to a single cat? MY 84 Crown Vic had dual cats and then a "Y" pipe into a single exhaust. When I had the cats replaced under a recall in 1990, I had the dealer put on a dual system. No problems at all with it.
Haven't gotten underneath my 03 Grand Marquis yet to have a look-see.
#5 of 46 Re: Question about dual exhaust [euphonium]
Apr 07, 2006 (2:36 pm)
I spoke with SCT today. They said when you install the duals, you have to flash the computer to turn off the sensor. Sometimes you can get by without turning it off.
#6 of 46 Re: Question about dual exhaust [dekester]
Apr 07, 2006 (2:37 pm)
Don't forget, though, that it's much easier to change stuff like that on the old carbureted cars. With all of the computers and sensors on new cars, some traditional tricks may hurt performance rather than help, if they're not thought through very carefully.
On that note, though, I could have sworn that my '04 has dual cats, connected through a Y-pipe to the single exhaust. Did this change for '05?
#7 of 46 Re: Question about dual exhaust [euphonium]
Apr 08, 2006 (9:22 am)
I spoke to the SCT dealer and he told me if I put duals on my car, he could get me a stock tune for the Excal 2 that would disable the o2 sensor if needed. Its a standard procedure. But for me to see how the car runs first before changing anything.
#8 of 46 Re: Question about dual exhaust [turbo301]
Apr 08, 2006 (9:26 am)
My 05 crown has dual cats. I always thought they came with dual cats. I have duals into one pipe.
#9 of 46 Chrome differential cover
Apr 08, 2006 (9:38 am)
I just installed a chrome diff cover. For anyone else who wants one, go to Jegs.com. The rear of choice should be a 8.8 10 bolt. There is no listing for a crown vic. You have to match it up as a mustang GT. Looks nice too. Paid 33.98 delivered.
Apr 08, 2006 (5:48 pm)
It the rear diff cover just flat chrome, or is it cast with heat dispersing fins???