2into2 vs 2into1 with Headers

[shaunmbenson]

Hey Gang

I have premuffler 91 octane SW Chip and LOVE it

according to this popular chart I would gain 11 hp down low and 14 up top by going headers and 2in2 out




My question is this - would my gains be significantly less with a 2in1 out?

I don't like loud exhaust as I do XCountry drives a lot

[Cory M]

If you do a lot of cross county drives you are probably better off keeping your stock manifolds (to retain heat) and getting a performance 1 in 1 out muffler to keep it sporty but not too loud. I have headers and a stock Dansk muffler on my driver (3.2SS) and it isn't quiet, but not too bad. It doesn't drone like a 2 out would, but I did have a coworker say it was loud in the parking lot the other day. It's definitely louder than the Carrera with the M&K test pipe and 1 in 1 out muffler that I used to drive. With the SW chip that was a solid combo and a healthy performance bump over stock.

[shaunmbenson]

Thanks Cory
Yeah my noise with premuffler and stock is quite nice
I sold and MandK 1 in 1 out cause it was a little droney on overrun
If I did headers tho I would do their headers with heater boxes so the stock heating would
Remain

[Duc Hunter]

Steve Wong told me that a second exhaust port was only worth about 3-4hp in the top end for my 3.6, and I would lose some low end. He also has some input on which headers were good, and which mufflers. His 3-4HP I believe was for a Dansk single vs dual outlet and he felt taht was a very good muffler from a performance perspective. I am pretty sure most of us would only notice the increased noise and drone, vs the HP.

As my car is a street car I chose the best of both worlds. I have 2 outlets and one is closed in the low end, then at 5,500RPM it is opened via a vacuum solenoid when the intakes valve opens. Was a pretty easy solution.