I have a 1991 300SEL (European is one year ahead of US) with engine
I am trying to find out exactly what this engine is.
The reason why I am in doubt is because of this very interesting
article I found on the net(unfortunately in german):
The article says there is two development stages of the 104 engine:
1. stage, which is the 3,0 litres used for 300E-24 since spring ´89
2. stage, which is the 3,2 litres used for E320 since fall '92
Until now, I was quite confident, that I had a 3,2 litres version, but
according to the article, this can't be true.
As well as I know, the 3,0 litres is called M104.980 and uses the CIS-E
According to the article, the 3,2 litres uses resonance flap in the
intake system, and as well as I know, this comes with the M104.994
engine using the HFM-SFI injection system.
My M104.990 engine uses LH-SFI injection system and does not have
So, it is neither the first stage nor the second, but something in
Can anyone confirm whether it is 3.0 or 3,2 litres?
The reason why I am interested to find out the exact configuration is
one interesting part of the article (fig. 33 and 37), which indicates a
significant drop in torque between 2000 and 3500 rpm due to resonance
in the air intake system, if the resonance flap is not applied.
This is exactly what I feel by driving the car. It is quite lazy until
3500 rpm and at 4000 to 5000 rpm it drives very well. As I say, it does
not have a resonance flap, so this could be th explanation.
Does anyone have experience with driving both the 300SE (US '92-'93)
and the S320 (US '94 and later), thereby being able to tell the