Now, since we most of us are the members of the 20+:1 club of compression, I see that there is much interest in joining the 18:1 club with the promise of more numbers on the boost-o-meter.

So, here's my question: At 18:1, are you going to be crossing into the threshold of more difficulty in starting in cold weather?

Comeon' JD, I'd like to hear what's up with this.... :)

With 18:1's a manual glow switch and possibly the addition of an aux grid heater are the trick for cold weather. Mine started at -25f as long as long as the crankcase had synthetic oil.:cool2:

That's about all there is to it, kn, as D.Cam indicates - longer glow times and maybe some type of intake air heater.

As you know, heat of compression is lower at 18:1 than at 21:1, so some augmentation may be required in northern and winter climes.

'Quick-heat' plugs would be advantageous, as they burn hotter and do not burn out with extended glow times

I'm putting in new glows with the manual control on mine along with 2 block heaters. DAS said they put the glows on a over weekend burn with a couple of good batts and a charger for the weekend i believe. None burnt out and all were glowing pretty after the weekend! Hopefully that will keep me going in -40C

Do the other guys, like Navastar/cummins use this low of a compression in their engines? I was just wondering, because the old 7.3L (pre-Powerstroke) I used to drive for a company truck would hardly start in 70° weathter with 1 or 2 dead glow plugs.

Light truck idi engines - Navstar and GM - were designed around 21:1cr, specifically for smooth drive-away and ease of starting in cold.
They were specifically for entry into the highly Diesel-untrained, Diesel-unskilled, and Diesel-ignorant lite-truck consumer market - pick'em-up trucks.

That Ford\Navstar company truck - at 20.7:1cr - is definitely not a good comparison, kn. Also, the maintenance history and state of tune is unknown.

DI engines run 16 - 18:1cr and employ various methods of deep-cold starting - block-heaters, grid-wire intake heaters, etc.

The new breed - computer-control over mechanical injection, with 20,000psi inj pressures - are much easier-starting, using pilot-injection methods.

The entire injection cycle - start to finish - is under PCM control, so a small, very finely atomized - 20,000psi - quantity of fuel is injected to initiate combustion, with the remainder timed to coincide with flame-progress, as required.

Also is why the familiar Diesel-rattle is very subdued.