Maybe the CBE isn't just an expensive noisemaker after all

[YoursTruly]

Originally Posted by JgamB Nitto Tire - Fueled by Enthusiasts 25.47 for 235/40/18 Neo Gen. My speedo is also off 1.5mph at 100. If Vdyno calculations aren't accurate for changing out the stock dunflops, I can't help that. Removing the Pu muffler is a good thing, that I will attest to. I was trapping ~109 on most passes at ENM on par with the other 330whp speeds that weren't running slicks with a TMIC as a handicap.

Weren't your logs taken with the same tires, just different exhausts? Even if the actual horsepower values are different than what would show on a real dyno, the difference in hp should still be valid because the tire diameter in vdyno was held constant.

I ran my pu without an axle-back for a couple days before I installed my ap and it was noticeably punchier, but I am sure that a tune would exaggerate this effect.

Also, don't run without an axle-back. It will melt the stuff in your trunk. FYI...

[JgamB]

Originally Posted by YoursTruly Weren't your logs taken with the same tires, just different exhausts? Even if the actual horsepower values are different than what would show on a real dyno, the difference in hp should still be valid because the tire diameter in vdyno was held constant. I ran my pu without an axle-back for a couple days before I installed my ap and it was noticeably punchier, but I am sure that a tune would exaggerate this effect. Also, don't run without an axle-back. It will melt the stuff in your trunk. FYI...

Yes they were - same tire. I plugged in the manufacturer's tire height for vdyno when I swapped and the gains appear to be largely valid. I did add a resonator to keep NVH within reason (holy shit so glad after 2K miles to ENM) but the losses from doing so appear to be negligible.

I'm going to agree that removal of the Pu muffler is probably the best bang for the buck, and then a person avoids resonators hitting the mid chassis brace or other fitment issues.