Re:164 L or S, and Speed

[C M Smith <cmsmith@domain.elided>]

Great debate we're having. Hope this is helping someone decide which
version of 164 to buy.

How fast do you guys like to drive down there?

I do agree that technically a gearbox should be set up to produce maximum
speed at maximum power output rather than maximum rpm, that's 500 rpm lower
for the 164 S and 700 rpm lower for the 164 L. However, for the real world,
redline top speed, although a bit lower, produces quicker acceleration and
allows a 5 speed box to be closer ratio. That's why 6 speeds are showing up
(and 7 speeds for GP cars). There is no perfect compromise. ( My factory
manual gives peak power rpm as 5600 for the L and 5800 for the S, the
brochure gives 5800 rpm for both models, adjust the math according to your
confidence in each source).

BTW, my factory manual figures states a road/engine speed ratio in top gear
for the S to be 23.03 mph/ 1000 rpm and for the L to be 25.62 mph/ 1000
rpm. So the loss in theoretical top speed for the S is 12.515 mph and for
the L is 17.934 mph, assuming the redline is 6200 rpm. This sacrifice is
desirable if you desire quicker acceleration. Also, the theoretical top
speed isn't as simple as gearing to match peak power to top speed,
apparently, although I confess I dunno the reason why.

Our freeway speed limit is 110 Km/hr or 68.35 mph which is achieved with an
engine speed of 2668 rpm for the L and 2968 rpm for the S, quite a
difference. The S could achieve a top speed of 133.6 mph at peak power rpm
and 142.8 mph at redline, with factory gearing. The L could achieve a top
speed of 140.91 at peak power rpm and 158.8 mph at redline, if it could
produce enough power. I suspect both versions would top out at about the
same speed, give or take, which for the S is a waste of the extra 17 horses
really.

I regret to advise I have not yet explored the top speed of my L. At 220
km/hr (136.7 mph) she's still pulling and I believe 142 mph is her probable
top speed, if the engine can make it's peak power. Trouble is, I drive at
an elevation in excess of 1000 metres (3400 ft) so my poor L is down on
power from those cars lucky enough to travel closer to sea level.

Where is this going? Well, seems to me Alfa designed the L to be more
relaxed at freeway speeds and more capable at top speed, kinda European
wouldn't you say? No wings or body mouldings etc,  are necessary for secure
road feel at 220 km/hr. The S on the other hand is geared (literally) for
the NA market. Busy at freeway speeds and short of legs at the top end. The
bodywork also suggests high speed capabilities the car doesn't possess.
Hence my opinion that the S is a poseur.

It's a rare road car that is properly sorted and needs significant aero
aids at speeds below 140 mph or so, My SAAB 9000 turbo tops out at 222
km/hr (at any sensible elevation, as the turbo keeps pumping more air in
when it gets a bit thin). The car is perfectly stable with its tiny rubber
lip spoiler on the hatch, stock suspension and 195/60 15 V rated Pirellis.
Ditto the Alfa 164 L. Both have a modest chin spoiler which is very
important. In fact a chin spoiler is so effective it's the best mod for
high speed motoring, even more important than stiffer springs and shocks.
The stiffer springs don't help much if your front end is unloading due to
air stuffing itself under the front of the car, I've never felt insecure
about the back end of a modern car travelling fast.

So, if you like low rpm at normal highway speeds and also feel the need to
stretch your legs a bit then the L is for you. If you plan to modify the
car for more power then the L is the only way to go, the gearing on the S
is just too short. Just like my 82 GTV6 which always felt a bit too tight,
topping out at around 205 km/hr, at peak power rpm come to think of it, so
maybe that's all she could be expected to do with a catalyst choking things
up.

All "actual" speeds given above are indicated not measured, although the
GTV6 appeared to have a speedo which read low!!!?!? unusual for an Alfa,
and the 164 seems to be about 3% optimistic.

 BTW, 80 mph is loafing unless you're in heavy traffic, that's only 130Km/hr! 

And to the guy getting 154 mph indicated at 6500 rpm, yes you did have a
perfect S. If your car will redline at the indicated redline of 6500 then
you're doing 150 mph, my fuel shut off kicks in at 6200 indicated on the
tach, in the lower gears, no hope of reaching redline in top. Just think
how fast your S would have been if it was geared for top speed i.e. a top
gear pulling only 5800 rpm. Every now and again an S should have come off
the assembly line with the engine just about perfect, and in perfect air
temp, humidity and elevation you might reach redline in top gear.  Why did
you let her go?

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