MonkeyLips

Let us know how the sound compares to the stock exhaust system...wondering if I need to get a Nelson muffler with the 4040L???

Car_nut57

Monkey Lips,

Most folks say the system is quiet enough with just the 4040L with the cat in place. They do have a deeper sound and are a little louder than stock, but not a lot in the cab. You might try just the 4040L first and if you want it quieter later then cut in a muffler.

MonkeyLips

I think I'll end up doing just that...thanks!

Neil58

Ok, first 200 miles with the new aeroturbine 4040L with cat in front of it......no muffler. 2004.5 DRW, 4x4, CTD. Aeroturbine claims the following:

Reduced Temperatures
Increased Horsepower
Increased Torque
Increased Fuel Economy
Less Engine Wear & Tear

I have tested two so far. I will say it has more HP.....prior to installing the Aeroturbine, I floored it just to have a fresh sense of response in my mind.....after install, did the same thing and noticed a slight difference in pick up.

Drove 200 miles round trip to Seattle and back.....I did this about a month ago with cruise on, 70 mph most of the way.....never went over 70, slowed to 60 in spots and even a bit of stop and go once I reached the city.........17 MPH with and without the aeroturbine......so, I don't buy into the increased fuel economy claim.......more to follow as I add guages, etc.

Oh.............I do like the aeroturbine though......no drone at 70......just a tad bit louder than stock......nothing to even consider IMO.