Making a 914-6 Conversion your own, The Quest for Quiet Options

[Root_Werks]

The Six Conversion:

2.7 CIS with 993 cams, 46/40 valves, 911S 8.5:1 CIS Pistons with Nikasil cylinders. Guessing it produces slightly more than stock 2.7S HP and has a much lower, broader TQ curve.

Current exhaust is stock 914-6 HE's and one of Ben's SS Quiet mufflers. Been very happy with the exhaust note the past few years, but always wondered if stock would be quieter.

Ben's Quiet Muffler ( I did have to reclock the tip as it was more for 1974-up 911):

[Root_Werks]

Ran the same tests as close as I could, same stretches of road and highway, windows up, same gears etc.

Dansk muffler results:

Idle outside - 80
Idle inside - 67
30mph - 77 4th gear
60mph - 85 5th gear
70mph - 87 5th gear

As the DB goes, not much of a difference by the numbers. Although I could tell on the freeway the note was toned down a bit.

Was it worth it? Eh, probably not. Not really much of a difference in overall cabin noise and I gained back that 5-6lbs right on the tail of the 914 (Dansk is heavier than SS).

Not sure if I'll swap back to the SS or not. I do like how the Dansk is hidden a little better.

Next steps to queit the cabin down:

Pull the rear window and swap out for safety glass version. I did this once many years ago on a 914-4 and was shocked how much engine noise was deadened.

Also noticed I need to adjust my rear trunk stop on the Left side.

[worn]

When I first got the 3.2 engine in the car I decided to cut up the 911 muffler that came with the motor using an article in Upfixing Der Porsche as a guide. Fit it to MSDS headers. Over time I had a loss in faith about my own handiwork and swapped out the homemade muffler for a very pretty Dansk sausage. Net result was, eh. I couldn’t hear or feel much of a difference. The only positive was that I no longer worry about doing it wrong.