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From what you're showing for the ECR calculations, I believe it's is the same formulas the "DCR" calculators common online (or spreadsheets) are using. This one for example: http://www.wallaceracing.com/dynamic-cr.php. They are simply using incorrect terminology (albeit a pretty common misnomer) that's proliferated in the automotive hobby world. In other words as you said, they are not stating true DCR, but rather ECR; and then referring to it as "dynamic" if though it's not taking the true dynamic responses of the system.
I applaud your idea of correctly the terminology. Alas, I think it's gone on unchecked for so many years, that just like when people started referring to every displacement GENIII as an "LS," you'll never get enough traction to make it go away.
Thanks for the feedback.
This hits the nail on the head. It’s simply incorrect use of terminology. If you look into it much further, like I have, you’ll find others out there that use the correct terms. You’ll even find the formulas to calculate it yourself, and me being me, I actually built my own excel calculator that matches up with great accuracy to anything you can find online.
I think it’s even posted in this section somewhere. I uploaded it a long time ago, few years back. The password on it is “1” if you want to dig into how the numbers are actually calculated. If I find time later, maybe I’ll just repost it again if anyone is interested.
I know I’m not the only one that likes to dig into things to a ridiculous level of understanding. As I get older, I find curiosity drives me to some interesting places in my quest for knowledge. And with engines, the old saying of “knowledge is power” becomes quite literal, and is part of the fun of building things and doing guy stuff lol.
Here I found that thread… This was before I made my engine physics video. It’s long, but in reality saves a lot of time doing all the digging through the forums and specific sites, articles and so on. I spent days reading and researching trying to find appropriate general rules, with as many examples as I could find. Here’s the link…
Update: My motor is done. Dropped it in last week. It was engine dyno'd at 525hp around 6k rpms~ This was just a break-in time on the dyno, and it ran with a carb intake. I'll be running fuel injected and a ported LS2 TB and FAST 92 on my ‘04 C5. Planning to get it all back together and dyno tuned this summer.
I made some slight changes to the build, I decided to go with the Wiseco pistons -9.7cc, K1 rods at 6.098 length, and the LS9 Gasket. Pretty happy with the results. I achieved my SCR and DCR range I was looking for:
10-15-2021, 01:40 PM
