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More low end torque

> Subject: More Low-End Output
> From:	[email protected] (Andres)
> 
> The suggestions I got for increasing the low-end (2000-4000rpm) output 
> of my 1985 318i 5sp with 57k were:
> 
> 1. Get a different car:  I see this as my last option, but nevertheless 
>    a valid one.
> 
> 2. Drop in the engine from an E30 325e or 325i.
> 
> 3. Increase displacement to 2.0l, by replacing crankshaft, pistons, etc.  
>    Probable cost (done by a mechanic): $3,000-3,500.
> 
> In reference to 3., I believe it may be a good option for somebody with 
> a worn engine which is going to be rebuilt anyway.  In my case, it does 
> not seem worth to tear apart a 57k engine, spend that money, and 
> probably end up with only 11% more torque (assuming linearity to 
> increase in displacement).
>
	Yes, I suggested that to you as a possibility.  But at 57K your
old motor is just broken in.   Move on...  yes, the torque would increase
approximately 11%:  torque can be near linear to displacement, all things
being equal, for small changes. 

> With respect to 2., I wonder whether an increase from (max.) torque of 
> 103 lbs-ft that I have now to the 170 lbs-ft of the "e" engine or 164 
> lbs-ft of the "i" engine would also require to have to change clutch, 
> gearbox and differential.  With likely additional mods required like 
> larger radiator, switching battery to trunk, etc., I believe option 1. 
> may end up being more practical than dropping in a 325 engine.
> 
	Sadly, that's probably true.  A different cooling system is 
necessary, since the 4 and small-6 get their water from different places on
the radiator.  
	The transmission is different between the 4 and s-6 as well. The
nose of the input shaft is nearly flush with the bellhousing flange surface
on the s-6 motors, while the 4's and big-6 have a protruding nose.  Anyone
who's ever rebuilt, cleaned, kicked, whatever one of those trannies
knows they can't stand on the bellhousing end.  So you're getting the
motor AND transmission.  BTW, it's also stouter for the bigger motors.
	The rear end is likely to withstand gobs more power than the 4 can
dish out.  The gearing is great for the 325i motor and very sporty (short)
for the 325e motor.  
	You can get 'e motors cheaper, they provide more low-end punch and
gas mileage.  
	Or you can get the whole car.

> However, this made me think of dropping in a 16-valve 1.8 engine.  Max. 
> torque is 127 for the E30 version, 129 for the E36.  Sounds more likely 
> to be withstood by my drivetrain.  I presume things like heat 
> dissipation and others are also more likely to be handled with less
> problems compared to 325 engine requirements.
> 
> Does anybody know how feasible and easy it is to put a 1991 (E30) 1.8l 
> or an E36 1.8l engine into a 1985 car ?  Any advise on what would need 
> to be adapted/modified ?  What would be the best way to find a used but 
> good condition such engine ?
> 

	You'll replace the transmission with it since the Motronics uses
crank sensors attached to the bellhousing.  At least it did on our 325e.


			thi v.