1 month update:
As some may remember, when I had this exhaust installed, some modifications were needed. Mainly, the extension of the tips and about an 8" extension to the mid-pipe.
When I first drove the car, it was quieter than stock. Of course, the first thing that came to mind was, "$hit, the muffler must really be restrictive if the sound if this quiet."
First impressions with part-throttle driving was that it felt 'smoother' and more relaxed. I noticed I could do highway speed passes without the trans kicking down a gear at roughly the same acceleration rate.
I then went to the drag strip to confirm any gains. Unfortunately, the car had about 3/4 tankful, compared to my baselline runs which were done at 1/8 tankful. To top it off, the temperatures differed by 20 degrees.
So to compensate, I removed the spare tire and tools to minimize the weight difference. I also added 1 mph to my base times to help equalize the temperature difference.
So my baseline traps were corrected to 91 mph. After the catback install, I trapped at 92.5 mph on average. So at first glance, it looks like I did pick up about 10-15 HP.
Since my 'correction factors' are NOT scientific. I measured gas mileage as a back up ( I do this anyways with all my cars).
If the exhaust makes more HP, it does so by increasing exhaust flow, thus increasing engine efficiency. If my catback did make more HP, I should see an INCREASE in mpg.
After one month, my average went up to 18.3 mpg. Before this, I averaged 17.5 mpg (using data from similar temperatures).
This equates to a 4.5 % increase. The HP improvement should be similar in terms of %. Using a baseline of 315 HP, this comes out to 14 HP. This number backs up the mph gain I saw at the track.
Again, this is NOT scientific at all. But at least the increase in gas mileage and the increase in trap speeds do correlate with one another.
As some may remember, when I had this exhaust installed, some modifications were needed. Mainly, the extension of the tips and about an 8" extension to the mid-pipe.
When I first drove the car, it was quieter than stock. Of course, the first thing that came to mind was, "$hit, the muffler must really be restrictive if the sound if this quiet."
First impressions with part-throttle driving was that it felt 'smoother' and more relaxed. I noticed I could do highway speed passes without the trans kicking down a gear at roughly the same acceleration rate.
I then went to the drag strip to confirm any gains. Unfortunately, the car had about 3/4 tankful, compared to my baselline runs which were done at 1/8 tankful. To top it off, the temperatures differed by 20 degrees.
So to compensate, I removed the spare tire and tools to minimize the weight difference. I also added 1 mph to my base times to help equalize the temperature difference.
So my baseline traps were corrected to 91 mph. After the catback install, I trapped at 92.5 mph on average. So at first glance, it looks like I did pick up about 10-15 HP.
Since my 'correction factors' are NOT scientific. I measured gas mileage as a back up ( I do this anyways with all my cars).
If the exhaust makes more HP, it does so by increasing exhaust flow, thus increasing engine efficiency. If my catback did make more HP, I should see an INCREASE in mpg.
After one month, my average went up to 18.3 mpg. Before this, I averaged 17.5 mpg (using data from similar temperatures).
This equates to a 4.5 % increase. The HP improvement should be similar in terms of %. Using a baseline of 315 HP, this comes out to 14 HP. This number backs up the mph gain I saw at the track.
Again, this is NOT scientific at all. But at least the increase in gas mileage and the increase in trap speeds do correlate with one another.
