SSI or Mittelmotor header for a 3.2

[Seppo]

Happy New Year to everybody!

We have a 3.2 engine with 46 Weber, and DC21 camshaft
Now looking for a headers for the engines.
We have 2 choice Dansk 41mm SSI or Mittel motor 41mm
SSI


Mittelmotor

Which one do you recommend? Heating is not an issue.

[Arlo911]

If heating is definately not an issue go with the headers, less weight, easier to work on the engine and around it.

[Mark Henry]

Heat is nice on the cold mornings, taking the fog off the windshield and if you have a targa/cab it extends your top off time.
We had clear roads well into November this year, but it was pretty nippy in my 914 with no heat.

[HaroldMHedge]

Heat is also needed in heavy rain to clear condensation off the inside of the windshield.

[stephen1070]

Good afternoon - if you purchase the 41mm SSi from dansk please post pictures of them and comments on your experience. There has been no more information from Marek on these since his post a few months back.

If available, they appear to be great for people that like a little heat!

Regards
Steve

[MST0118]

I like Mittelmotor stuff, but if I were buying a set of headers, I would get them from William Knight. Good performance and value for the set I got from him.

[Seppo]

Finally we choose the SSI 41mm version.
The headers are arrived yesterday, they look really nice.
I was expecting a bit bigger hole on the head side (cca 40.5mm) to better match the 3.2 heads.

[Peter M]

I would of expected thicker flanges to avoid the need to replace the exhaust studs?

Can you also measure the OD of the primary tubes please?

Thanks!

[Seppo]

Originally Posted by Peter M

I would of expected thicker flanges to avoid the need to replace the exhaust studs?

Can you also measure the OD of the primary tubes please?

Thanks!

The primary tubes OD are 1 5/8".

[Marwil]

What is outside diameter of the secondaries?

[Seppo]

Originally Posted by Marwil

What is outside diameter of the secondaries?

The secondaries is OD 50mm.

[Jonny042]

Originally Posted by Seppo

The secondaries is OD 50mm.

This is typical of the eisenmann heat exchangers too - the research I did indicated that for a street-ish setup the secondary diameter is not a restriction and in fact might be best kept to that size for velocity/scavenging. Only 1 primary is feeding exhaust to the secondary at a time I guess.

[stephen1070]

Originally Posted by Jonny042

This is typical of the eisenmann heat exchangers too - the research I did indicated that for a street-ish setup the secondary diameter is not a restriction and in fact might be best kept to that size for velocity/scavenging. Only 1 primary is feeding exhaust to the secondary at a time I guess.

Regarding diameter of the secondaries - are most ‘2 in’ exhausts designed for a 50mm secondary?

and how much does the exhaust tip diameter restrict flow?

Thank you

[Jonny042]

Originally Posted by stephen1070

Regarding diameter of the secondaries - are most ‘2 in’ exhausts designed for a 50mm secondary?

and how much does the exhaust tip diameter restrict flow?

Thank you

Most are 50mm yes. Not sure about the other question.

[Marwil]

Thank you for the info on the secondaries, helpful in planning my next exhaust experiment.
Hoping this in not TMI but what I'm thinking about is - SSI's cut just behind the merge (install v-vand clamps on the ends to swap back if needed). Fabricate a 2" secondary feed into the upper ports of a 997 GT3 centre muffler(hoping to put a cat between the merge and the muffler). Cap the lower "loud" ports on the GT3.

My current SSI system feeds into 2.25" inlet/outlet cats then onto a 2.5" Magnaflow crossflow. I've fabricated a Helmholz on the left side the right out runs a vacuum operated valve than opens with the happy pedal. It works well but I think I've lost some torque on the bottom end, the top end pulls well but runs into the limitations of the stock cam at 5500 rpm. Hoping to regain some bottom end and perhaps know a few db off the output.