Re: Which automatic?

[Karl Henrik Peterson <karl@xxxxxxxx>]

> Im looking to buy an automatic. I want a 535I...540I...735I(L)...740I...etc.
> If I  stick with 89 or newer will I avoid the older automatic from the late 80's

> that wears out at 125k or so?

If you are thinking of 3.5l engine I suggest that you get a 3.0V8 instead. It has
the same amount of power that is 161kW and 400Nm@5600rpm (makes 224BHP)
The red line starts at 6500rpm and it does not loose its power even on 7000rpm.
The fuel consumption is 7.5l/100km@100km/h (62mph) and 8l/100km@120km/h
(74mph). City cycle is ca. 13.5l/100km. Besides for what I know, all the cars with
the V8 have the 5 (or 6) geared AT. (the sixth is the locked hydroclutch rezhime).
I have '93 730iA V8 and with a custom chip I have as mutch as 190kW and the fuel
consumption was lowered a bit with the exchange. A great car even in europe (let
me remind the fuel prices here! ca. $1 for a liter! => $3.78 for a gallon)

> What are the designations and which year model has what?
The V8 was introduced in 1992 and I think they all have the newer AT.
the engine is M60 3.0/4.0L DOHC 32valve V8

> Should I pay the extra for the 8cylinder and suffer the fuel mileage? Is
Yes. And I don't think that you would suffer mutch. If I compare my fuel mileage
with the 3.5l version, mine actually uses less fuel. And If U think about the 4.0L
V8 then I remind you that it has 210kW with the Motronic chip (factory standard)
and that the 5Liter V12 only has 220 kW and consumes at least 3L/100km more fuel
during the city cycle and 1 to 2 L more on the highway. Besides the V12 does not
support high RPM-s since it is SOHC not DOHC so You actually loose some driving
fun.

> Is the "8" much more expensive to maintain (other than 8 spark plugs instead of
6
I've had mine for 24months and all that I have done with the engine is some
diagnostics and changed spark plugs once and oil twice. It has cost me around
$200. Is that mutch in 2 years? I don't think so. The rest of the car is the same,
of  course. Oh yeah, the good news is that the 5(or6) geared Automatic is "service
free".

There is, unfortunately, a special concern with the early V8 (the one fitted on
E32 and early E38 up to 1996) that U should check before you buy it (specially if
you live in USA). It's the fuel! The early V8 was made from Nickel, Aluminium and
Silicon alloy (NikASil). the inner silicon coating of cylinders reacts with
Sulphur by S exchanging Si in the coating  (2Si + 2S + 4O =  2SiO2 + 2S - a
catalytic reaction, in a way). The end result is a corroded engine and pressure
leak which means that the engine is spoiled. This "effect" will occur usually when
some 'things' have a common area of probability. First you should make a query to
your primary fuel supplyer and check if the Sulphur concentration in the fuel is
less than 100PPM (parts per million). The fuel that I use has only 3PPM so, the
less the better. The other 'thing' is the weather. If you live somewhere where the
average temperature is low then it might be a bad sign. This is the case with me
(I have cold winters and not so warm summers). there may be some other
considerations with it. If U have them both (SUlphur concentration from 500 to
1000PPM and cold winters) you should check wether the engine (the short block) is
NikASil or not (the short block was exchanged by BMW).  If it is, consider the
risk of spoiled engine. The letter is getting too long now, therefore I'll stop
here. If U have questions (specially with the NIKASIL because there are some other
things to cover) or someone has found some mistakes I made, then let me know.

> Any help with these questions is greatly appreciated.
> Dan
I hope it helps a bit.

Karl Henrik Peterson
730iA V8 '93
from Estonia

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