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Nd4SpdSe wrote: Actually, the compression on a ZE is 10:1, DE is 9.2:1

Your right, a Millenia DE is just that, which adds the extra power over a regular DE.

DE's are only perfered for the valvetrain and the compression. People talk like the ZE valvetrain is brittle, but if you never go beyond redline, you'll never have a problem. If you do however plan on running boost or being aggressive, it doesn't hurt to put in a DE retainers. On the flipside, the DE has less flowing heads and intake manifold. As for compression and boost, as for Wytbishop said, there's a saying; low compression is a poor excuse for poor tunning.

I hope you're talking turbo, cause if you're sticking N/A, there's no way you're going to get 240-250bhp with jsut megasquirt. It takes quite the investment to get a KL to make that kind of power N/A. 200whp is realistic and had been done.

You're right. Sorry, my bad...

I was under the impression ZE was 9.5:1. Now I've been researching, and looks like I made a mistake. so here's the right info:

KL-DE = 9.2:1
KL-G4 = 9.5:1
KL-ZE = 10:1

I'm not talking turbo, but I also NEVER said I was gonna get there with "just" megasquirt. I will get there with megasquirt and a ton of work. There's a difference between adding only a megasquirt, and just slapping a MS and expecting a 40%+ power increase.

Wyt: I agree completely. The increase in thermal efficiency of using a higher compression ratio is actually what had me fall in love with ethanol as a fuel, with which you can run CR's over 16:1, therefore allowing for some HUGE power gains.
But my point is that you don't need a ZE to have a higher compression. Modifying the CR in an engine is as easy as decking the block, and eventually the heads. And that's actually part of what I'm planning to do.

Two corrections on the info you posted though:

10:1 is not 1% higher than 9:1. It's 11% higher.
In the table you pasted, it says a 9:1 CR requires a 96 octane rating, which we all know isn't right. You can run CRs up to 11.5:1 on 92 octane depending on, among many things, the heads and pistons operating temperature. And with the KL aluminum heads and floating cylinder sleeves design, I'm confident I can easily go over that number.

What I failed to post, because I thought it was getting a bit too wordy, is that table is based on somewhat dated hardware...older less efficient engines with less resistance to detonation. They themselves stated that modern engines would achieve higher values than that.

And according to that table, 10:1 is 1% more thermally efficient than 9:1 when compared to the baseline of 5:1. 33% vs. 32% increase. I am not comparing the change in compression from 10 to 9.

wytbishop wrote: And according to that table, 10:1 is 1% more thermally efficient than 9:1 when compared to the baseline of 5:1. 33% vs. 32% increase. I am not comparing the change in compression from 10 to 9.

Oh...! Didn't think of that... Sorry...

Odd, by that chart it would even mean a DE would need to run high-octane and a ZE on race gas.

That may be only 1%, but that's also N/A tune as well. Forced induction changes that dramatically where you get more hp-per-psi as you up the compression. It also helps for spooling the turbo quicker and you're less/not as dependant on the turbo for power since you're retaining N/A power as opposed to dropping the compression to run most boost, but there is a limit and a time where you will need to drop the compression to run high amounts of boost and gain more power.