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Re: 745i questions

> From: [email protected]
> >>1.  What's the displacement of the engine?  Is it the<<
> >>same block as the 733/533's 3.2 liters?<<  
> 
> Displacement is 3430cc, same as the 735i.

This is only true of examples built after 5/83.  745s built prior
to that had the 3210cc motor, same as the 733i.  5/83 onward
cars gained the larger motor, as well as Motronics, knock control,
and the 4HP22-EH transmission.  Previous cars had standard L-Jetronic
injection and the 3HP-22 transmission.

> >>2.  What's the boost in psi for the turbo?<<
> 
> 35.6 psi

Uh, I think it's more like 6-7 psi or so.

> >>3.  Horsepower/torque figures?<<
> 
> 252 bhp, 280 lbft or torque compared to 735s'  218/310.
> Mine is kind of doggy out of the hole but once the turbo 
> winds it takes your breathe away!

252 bhp is correct for all 745s, but the torque number varies
depending on if it's a 3.2 or 3.5 motor.  It's somewhere around
270 lb-ft for the former, around 290 for the latter.

> >>4.  Is the automatic transmission unique in its application<< 
> >>or does it share it with other 7-series?<<
> 
> It uses the  ZF 4 HP 22 EH trans, shared with many other 
> BMW's (according to my owners manual)  My dealer claims
> otherwise.  Be sure to read the FAQ's on this trans.

The 4HP22-EH transmission is basically the same as the other models,
but it is a specific version for the 745i.  It uses a larger bellhousing
and torque converter.... (don't ask how I found this out.)  I believe
the 3HP22 is basically standard.

> >>Also what are the common  problems?<<
 
The motor tends to suffer from cylinder head and head gasket problems.
Heads crack, and head gaskets leak.  Turbochargers die, usually from
improper care/usage and a dead turbo cooling fan (blows cool air on 
the turbo for about 5 minutes after shutting off the engine).  
Transmissions tend to fail sooner than on the regular big-6 cars,
and the transmission control portion of the Motronic unit (post-5/83 cars)
can fail too.  The rear self levelling suspension leaks, and the
exhaust system is pretty expensive.  Other than that, it shares
the regular E23 problem areas (climate control, etc.).

However, when everything is working right, they're nice cars.
Great on the highway, and lots of fun on the unsuspecting.

Hope this helps,
Ben