1970 911 with 993 engine - exhaust?

[rammstein]

Hey-

Normally I'm over in the 944 forum, but I am posting this question for someone else. There is a 1970 911 that somebody has put a 993 motor in. This person wants to keep the bodywork stock and does not want the setup to be loud (so no straight pipes). There are fitment issues for the exhaust based on these criteria. Any options out there? Ideas? Do I need to give more info?

TIA

[Kevin Stewart]

Do a search on 3.6 exhaust, you will find this is a pretty big issue, Kevin

[Bill Verburg]

You have several options
#1
what I did in a '76 C3

B&B headers/Fabiani(Flowmaster muff)

#2
What Rob Fusi did

Stock 993 headers/Triad

#3
What Mike Feinstein did

Stock 993headers/Magnaflow/ twin resonator tips

#4
What code7rpd did

Steve Timmons(MSD?) headers/Flowmaster

There are many others that I couldn't find

[Jack Olsen]

There have been some creative solutions to this, lately, but most of them have revolved around getting the car to work with smog laws.

On a 72, at least in California, that's not an issue. You can do 993 headers and a modified factory muffler, or a Flowmaster muffler, if you want to keep it cheap. Outside of that, you can do B&B headers with a B&B muffler ($$$ and resonance) or B&B headers with another type of muffler.

[Bill Verburg]

As Jack intimated what ever you do stay away from B&B mufflers

The headers are ok, the oil coolers are exc., the mufflers are cr**

[sc]

Bill and Jack,

Is their a muffler you can recommend that has low resonance and is not loud? I have looked at DYNOMAX and Flowmaster, but without trying each its hard to tell!

Thanks

[Bill Verburg]

The twin Coasts are great sounding and appear to have no resonance. The Fabiani/Flowmaster had little on a 3.6 even less w/ 3.8 but is loudish.

I am starting to suspect that the resonance is a product of mixing the 2 streams in one chamber as well as displacement related. Mike F and Rob's solution put further muffling after the mixing to address this. Mike seem's happy w/ the noise levels, Todd Embs has the same as Robb and seems happy.

[Bill Verburg]

Some other exhaust options can be found here

[tholyoak]

Keep in mind that if you are keeping heat that some of the above solutions will not work with the stock aluminum 993 heat tube

Todd

[Moses]

I am using the Dynomax Super Turbo muffler. It is the quietest one they make. It has a beautiful sound at idle. No problem with having a conversation while driving. When you put your foot in it, it screams like an F1. I have never heard a Porsche exhaust that I like as much as this one. Cheap and simple.

[Bill Verburg]

Todd is correct, I used the stock 964 heat tube and associated components.

If talking in the cockpit is the criteria I can as well, the fan whine can even be heard. It's still loud and boy racerish.

Hey Mark, did you know that you were famous? I was cruising some dyno sites and came across a pic of your car on the dyno.

Did you ever post your results?

[Moses]

Originally posted by Bill Verburg

Hey Mark, did you know that you were famous? I was cruising some dyno sites and came across a pic of your car on the dyno.

Did you ever post your results?

I haven't seen that. I'll have to look around. I posted the Dyno results. They were disappointing. Turns out the first exhaust was really restrictive. The new system is much better. I'll have it Dynoed again soon and post. The butt-dyno says I'm right where I want to be.

[jfpound]

I started with Bursch headers($350), ceramic coated($275), 2.5" tube from the collector to a pre-74 stock muffler ($300) modified to accept the 2.5" input. It's quiet and very fast. Welding required. If I had to do it again I'd probably use 993 headers, but my wallet and I are very happy with the current solution.

[rammstein]

Thank you everyone for your input. I'll see what these answers bring me tomorrow. Perhaps someday the dark side will pull me in.