94 Caprice Wagon 5.7L project--46 MPG so far

[funkhoss]

Originally Posted by ademonrower

Many thanks for those very useful pieces of advice.
Re (from funkhoss):

Aux. vacuum canister for servo brakes: great! that sounds quite simple. Where do I get one?

Here's one example--you can probably find them other places, too:

https://www.jegs.com/i/JEGS/555/63010/10002/-1#

Originally Posted by ademonrower

Sorry, I forgot to ask: re. the kill switch, does this have different implications for carburated engines compared with retro-fit EFI systems?

With EFI, it's pretty simple: all you need is a switch that momentarily interrupts power to the fuel injectors. Hold the switch until the engine stops running, then let go of the switch; you're then ready to bump or key-start the engine again whenever needed.

With a carburetor, it's more complicated. You can kill the engine by cutting power to the coil (and thus cutting spark; you could also do this with an EFI system, too) but every time you stop the engine this way the cylinder walls will get "washed" with unburned gasoline. This could lead to premature wear and oil dilution.

So, if you're going to do this with a carburetor, ideally you'd use an electric fuel cutoff solenoid. This is a little tricky if the carburetor in question doesn't have such a solenoid or provisions to install one.

Or, just go ahead and convert to EFI, and enjoy both a safer/simpler kill switch and a more efficient engine all around.

Originally Posted by ademonrower

Also, sorry if this sound stupidly obvious, but with the kill switch system operated as intended (i.e. not turning the ignition off), I assume that I bump-re-start the engine after every kill. Does that do the clutch, transmission, engine any harm in the long run? I suppose I'd have to develop a refined bump-start technique, so as to mimic the relatively mild impulse that the starter motor gives...

Am I right on any of this? Thanks!

I've been using P&G with EOC 100% of the time for over eight years and 170,000 miles on my daily driven Metro. It still has the original, un-rebuilt engine (with 305,000 miles), and the same transmission and clutch (I changed to a transmission with different gearing and preemptively replaced the clutch about the same time that I started using EOC).

The engine, clutch, and transmission all still operate flawlessly.

Of course, your mileage may vary--but that's my experience.

[ademonrower]

Very useful info! Thanks for answering so quickly :-)

[aerohead]

Originally Posted by ademonrower

Many thanks for those very useful pieces of advice.
Re (from funkhoss):

Aux. vacuum canister for servo brakes: great! that sounds quite simple. Where do I get one?

A kill switch (you don't want to use your keyed ignition switch to shut off the engine); >> OK, I'll look into that
a manual transmission (for bump starting); >>yup, I have a man.trans.
manual steering (for obvious reasons!); >> yup, I have man.steer.
a deep cycle battery (EOC will ruin a standard lead-acid starting battery pretty quickly); >> many thanks for that advice: I was on my way to destroying my lead acid battery; and
an electric pump for the heater core coolant circuit (if you like having consistent heat in the winter!). >> I'll try to weather that one (no pun intended), but perhaps my passengers won't like it, so advice gladly accepted :-)

From aerohead:

* How will you be driving the car? >> mainly highway and uncomplicated country roads, typical speeds between 40 and 70 mph.
* Overall driving speed may determine where to focus your resources.
* And there may be legal constraints in Germany for some body modifications, which would not be a consideration elsewhere. >> Yes, that IS a problem: it's a pity that one is allowed to do so little to one's car here in Germany, but with a bit of cunning, and making absolutely sure that it's rock-safe, I reckon I'm on the "good" side in terms of practical measures. If I'm caught, then I can turn it to our (eco-modders) advantage and call a journalist that I know: she'd probably love the story and its environmental implications :-) I can't be caught too much though, because the fines would ruin me...

Thanks!
Looks like we need to discuss aerodynamics, so I'm going to move my response over to the Aerodynamics Forum, where your 'flow extender' thread is.
See you there.