My 2006 Mustang GT 5-Speed is my daily driver. I log about 60 miles a day. The 4.6 litre 3-valve V8 is totally stock and I'm running 4.30 gears with MBRP muffler deletes.
I'm running a 91 octane race tune, custom written for combo. My average commute fuel economy is 20.5mpg with 23-25 highway when I'm not bumper-to-bumper traffic.
The throttle response is unreal and I've gotten good at getting the car rolling without losing traction.
Recently, we moved to a very nice neighborhood and I became self conscious about how loud my car was. So, last night, I swapped on a pair of Ford Racing 5230-GTA mufflers.
These are the same mufflers used on the Shelby's and at almost $800/pair retail, they are well made and embossed with Ford logo and part numbers.
They are considerably quieter but still sound nice. However, when I drove the car last night I was shocked - and not in a good way.
The car just felt sluggish. That self-accelerating pull right at 2,500 rpm isn't there and I noticed I'm pulling more RPM than I'm used to seeing. Since I drive this thing everyday, I notice all the little things.
So I did some research. MBRP said no tune is required when adding or removing mufflers. All the Mustang performance vendors all say that changing the mufflers on these late (2005-2009) Mustangs, with stock catalysts and H-pipe, will change nothing but the exhaust note.
I'm waiting for the word back from the tuner, but something has changed and its not just that the car is quieter.
Previously, I never get over 2,500 RPM when shifting. The exhaust resonance peaks at 2,500 and the car pulls very hard between 2,000-2500 RPM.
Last night, I noticed I was turning 3,000-3,500 and still wasn't getting the same pull I have been getting at 2,000-2,500.
Now, in the old days, "un-corking" our exhaust usually reduced our bottom end and improved midrange and top end, so this change has really puzzled me, but our mufflers were not under the rear bumper back then either, so its a totally different arrangement.
Doesn't make sense...but something changed.
I'm running a 91 octane race tune, custom written for combo. My average commute fuel economy is 20.5mpg with 23-25 highway when I'm not bumper-to-bumper traffic.
The throttle response is unreal and I've gotten good at getting the car rolling without losing traction.
Recently, we moved to a very nice neighborhood and I became self conscious about how loud my car was. So, last night, I swapped on a pair of Ford Racing 5230-GTA mufflers.
These are the same mufflers used on the Shelby's and at almost $800/pair retail, they are well made and embossed with Ford logo and part numbers.
They are considerably quieter but still sound nice. However, when I drove the car last night I was shocked - and not in a good way.
The car just felt sluggish. That self-accelerating pull right at 2,500 rpm isn't there and I noticed I'm pulling more RPM than I'm used to seeing. Since I drive this thing everyday, I notice all the little things.
So I did some research. MBRP said no tune is required when adding or removing mufflers. All the Mustang performance vendors all say that changing the mufflers on these late (2005-2009) Mustangs, with stock catalysts and H-pipe, will change nothing but the exhaust note.
I'm waiting for the word back from the tuner, but something has changed and its not just that the car is quieter.
Previously, I never get over 2,500 RPM when shifting. The exhaust resonance peaks at 2,500 and the car pulls very hard between 2,000-2500 RPM.
Last night, I noticed I was turning 3,000-3,500 and still wasn't getting the same pull I have been getting at 2,000-2,500.
Now, in the old days, "un-corking" our exhaust usually reduced our bottom end and improved midrange and top end, so this change has really puzzled me, but our mufflers were not under the rear bumper back then either, so its a totally different arrangement.
Doesn't make sense...but something changed.
