Swiss Eco Special - The Unofficial BMW M5 Messageboard (m5board.com)

Passmore · 7th April 2006, 15:00

Gents,

I have a 1994 3.8 6 speeder. and love it.

However the Swiss 3.8 pushes out 327 bhp as opposed to 347bhp (DIN).

Apparently this is because the intake was fitted with a helmholtz resonator to tune the intake noise frequencies to meet strict Swiss pass-by noise regs. However, I have also heard that for the Swiss market smaller exhaust manifolds from the S38B36 engine were fitted (80mm vs. 90mm).

Anyone know as to if the above info is true - esp regarding manifold. Obviously I would prefer the extra 20bhp that have been taken from me by the over zealous Swiss.

Can I bin the helmholtz intake easily? i.e. will the DME be affected etc.?

any advice appreciated!

Passmore

illjah · 7th April 2006, 15:49

I believe there is at least one other swiss member who have removed this, I'm sure a search will bring some stuff up (although I can't seem to find it at the mo!)

unesential · 7th April 2006, 15:58

I believe if you can obtain the standard air box you should have no difficulty. The DME should not be affected as it gets its info from the MAF which is the same. You will only be reduceing the restriction forward of the sensor allowing more airflow which the sesor is already capable of monitoring.

unesential · 7th April 2006, 16:06

There are 3.6 exhaust manifolds listed for several areas, Japan, Commonwealth, and Austria. IMHO there is not much difference in them as the Commonwealth people would be complaining if it robbed them of power. The RHD must require a different configuration of the plumbing than that afforded by the standard 3.8 manifold.

Is this so Farrel?

Sebring NL · 7th April 2006, 16:52

LOL I searched for the thread I replied to at a swiss member for I recalled Illjah's story..:

Hubcentric rings

The swiss member was..Passmore!!

Obviously not much use in that!

I have a book on the S38b38 with a special section about the eco-stuff..Will look it up as soon as I can leave the office

Passmore · 7th April 2006, 17:02

I have searched the board, can't find much info on it.....a little here:

Intake Horn

If I look at this pic from realoem:

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Am I right in thinking I have items 11, 15, 16, 17, 18

and the standard setup is just item 10.

Or is the standard setup 10, 15, 16, 17, 18?

As to the exhaust setup, looks like the 3.6 manifolds were used in Switz. 'Commonwealth' is a strange term for BMW to use, the UK is head of the commonwealth - but they get the 3.8 manifolds!

Passmore

unesential · 7th April 2006, 18:03

YEs you have all the added plumbing.

AlexA · 7th April 2006, 18:08

Passmore,
I think the Swiss 3.8 also looses some of its power due to it using the more restrictive ceramic catalysts from the 3.6, rather than the ones from the regular 3.8.

raymondw · 7th April 2006, 18:25

[1] Yes,the Swiss version of the S38B38 only has 327hp. This due to the application of the S38B36 exhaust and S38B36 ceramic cats.

[2] All the B38's have the helmholz resonator. Principle of operation is that oscilations with a certain frequency can be attenuated by a cube with two holes. The resonance frequency can be tuned by the diameter of these holes. It doesn't affect flow-through as it isn't connected in series to the air-intake. You can find the helmoholz resonator underneath the air intake with which it is connected through a small pipe

[3] The Swiss version of the S38B36 has a bended intake nozzle that does affect flow through at high air-speeds. The ETK doesn't mention such a part for the S38B38 though.

Simonal · 7th April 2006, 22:12

I think these changes were also applied to the Austrian version too.