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#1
11-20-2004, 03:02 AM
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Yeah yeah yeah, I realize there's a million of these all over the web
 But this one not only calculates static compression ratio and displacement, but also dynamic compression ratio! I initially coded it to help me figure out where I was going with my own engine building project, and then I thought other Pontiac enthusiasts might get some use out of it too. So here it is:http://www.projectpontiac.com/ppsite...nt/view/11/43/ Feedback is always welcome, of course.
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1977 Trans Am SE W72 4sp, 95% original |
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#2
11-20-2004, 03:02 AM
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Yeah yeah yeah, I realize there's a million of these all over the web
But this one not only calculates static compression ratio and displacement, but also dynamic compression ratio! I initially coded it to help me figure out where I was going with my own engine building project, and then I thought other Pontiac enthusiasts might get some use out of it too. So here it is:http://www.projectpontiac.com/ppsite...nt/view/11/43/ Feedback is always welcome, of course.
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1977 Trans Am SE W72 4sp, 95% original |
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#3
11-20-2004, 04:47 AM
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I like it!
Thanks for the post
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Carburetor building & modification services Servicing the Pontiac community over 25 years |
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#4
11-20-2004, 06:13 AM
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Good one, only a few sites around that calculate dynamic CR and that one does both on the same page, very nice. Thanks, Rick
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'72 Formula 455HO TH400, Revere Silver, black deluxe '74 Trans Am SD 4 speed, Admiralty Blue, blue deluxe |
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#5
11-20-2004, 07:45 AM
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I like it, Thanks...
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1969 Firebird, Tx3-455/468 machined by CVMS E-heads by Dave Wilcox/Comp Cams 300B-6 flat solid 850DP on E-85 by Eric Niefert/T2 1" plastic spacer T-400/PTC 4000/390's/30x9 Hoosier radial slicks,#3400 1.38 60' 6.32 @ 108 MPH at Northeast Dragway NC 5/23/15 (9th pass on new engine) https://m.youtube.com/watch?v=ePCu2v...ature=youtu.be 1.37 60' 6.26 @ 109 half track, 9.86 @ 136 1/4 mile, #3350 11/26/16 at Richmond Dragway (125th pass on new engine) |
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#6
11-20-2004, 08:02 AM
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Wow, that is really neat. Works great for single pattern cams. Is there any way to add a field where you could just enter intake closing so it could be used with dual pattern cams? Not complaining, I appreciate all your hard work!! -Jim
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#7
11-20-2004, 10:18 AM
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Very nice!
So if we put in a negative number for valve reliefs, then we are entering dome cc, right? It would be nice to fit it on one page to avoid having to scroll down, but that may be hard to do. It would be interesting to hear if anyone has javascript turned off thus making program inoperative. I hear about 10% of users do, but don't know if that statistic is valid.
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http://www.pontiacpower.org/ |
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#8
11-20-2004, 11:16 AM
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Ok, this shows me at 9.49 (nine and a half, close enough) with my No. 96 heads and a zero deck. Ought to be ok on 93 octane.
7.43 Dynamic Compression with my 288R solid roller cam. What does this number mean? How is it useful to me?
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Badder than old King Kong And meaner than a junkyard dog -Jim Croce |
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#9
11-20-2004, 12:17 PM
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Here Ya go.
 Jim Click here
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#10
11-20-2004, 12:48 PM
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<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by DiamondJim:
Wow, that is really neat. Works great for single pattern cams. Is there any way to add a field where you could just enter intake closing so it could be used with dual pattern cams? Not complaining, I appreciate all your hard work!! -Jim <HR></BLOCKQUOTE> That was going to be the next thing I tackle. I initially set it up with cam duration and LSA because I'm too lazy to manually figure out closing angle for each cam I'm considering, but then I noticed that my formula for determining closing angle wasn't coming up with the right number for dual pattern cams. I figured I'd stick with duration and LSA for now anyways since a lot of people don't even know how to figure out closing angle in the first place. Giving users the option of using either duration/LSA or directly inputing closing angle themselves can get a bit more tricky, but I'll see if I can find an elegant way of doing it in the next few days.
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1977 Trans Am SE W72 4sp, 95% original |
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#11
11-20-2004, 12:55 PM
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<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by fiedlerh:
Very nice! So if we put in a negative number for valve reliefs, then we are entering dome cc, right? <HR></BLOCKQUOTE> Oops, forgot to make that distinction in the directions. I'll add that in to make it more clear. Thanks! <BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by fiedlerh: It would be nice to fit it on one page to avoid having to scroll down, but that may be hard to do. <HR></BLOCKQUOTE> I had to choose between just placing a bunch of fields on a page, or making a big table with instructions for those who might not understand what some of those numbers mean. I decided to include detailed instructions to make it useful to as broad an audience as possible. <BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by fiedlerh: It would be interesting to hear if anyone has javascript turned off thus making program inoperative. I hear about 10% of users do, but don't know if that statistic is valid. <HR></BLOCKQUOTE> I should probably put a note on there that javascript is required for the calculator to work. One of the reasons I did this in javascript is because the other dynamic compression ratio calculator I found on the web was written in Visual Basic, and that doesn't run on my Linux system (VB is a Windows-only thing). At least javascript is portable to all platforms.
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1977 Trans Am SE W72 4sp, 95% original |
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#12
11-20-2004, 12:58 PM
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Nice calculator!...I am a bit confused tho for a comp of 9.3:1 I am only getting a dcr of 6.32...Seems awful low for what kind of numbers i am running.My car should be a pig shouldnt it not?.Of course it isnt
..any input here?thanks
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Darby 74 Grandville 2Dr 455 c.i 4550# 2011 1.60 60 ft,[email protected]@117.74  2017, 74 firebird -3600 lbs (all bests) 1.33 60 ft, [email protected] [email protected] M/T 275/60 ET SS Drag Radial 2024(Pontiac 505) 1.25 60 ft, [email protected], [email protected].... 275/60 Radial Pro's |
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#13
11-20-2004, 01:21 PM
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nice calculator but javacrap is not welcome on a lot of computers
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  My Daddy bought me a car but all I got was this old Pontiac.
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#14
11-20-2004, 01:39 PM
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<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by BVR421:
nice calculator but javacrap is not welcome on a lot of computers <HR></BLOCKQUOTE> I've heard this from other people before. Can you explain to me why it's so evil? Is it due to pop-up windows? Because those are easily disabled and aren't necessarily due to javascript. Or is there some myth about a risk of virus infection from javascript? I've personally never had any issues with javascript on the web whatsoever. What else could I be using instead? Server-side is out of the question, way too slow, especially for dial-up users. VBscript is out of the question, that only runs on Windows and not Macs or Unixes. I'm no Java programmer, so that's out too. What exactly does that leave? Pen and paper? Kinda defeats the purpose... Criticism is good, but only if it comes with explanations.
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1977 Trans Am SE W72 4sp, 95% original |
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#15
11-20-2004, 01:50 PM
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<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by grandville455:
I am a bit confused tho for a comp of 9.3:1 I am only getting a dcr of 6.32...Seems awful low for what kind of numbers i am running.My car should be a pig shouldnt it not?.Of course it isnt ..any input here?thanks <HR></BLOCKQUOTE> Maybe you've found a bug in my formulas! It's always possible. It's hard to do extensive testing when you're correcting grammatical errors in the text all the time. What are the numbers you put in?
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1977 Trans Am SE W72 4sp, 95% original |
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#16
11-20-2004, 03:35 PM
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This one's from the Chevy guys, but it'll work just fine on our Pontiacs. Static and dynamic.
http://members.uia.net/pkelley2/DynamicCR.html GoreMaster: If you're determined to get yours working right, I'm fairly certain that Pat could be a big help. |
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#17
11-20-2004, 04:00 PM
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<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by GoreMaster:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by grandville455: I am a bit confused tho for a comp of 9.3:1 I am only getting a dcr of 6.32...Seems awful low for what kind of numbers i am running.My car should be a pig shouldnt it not?.Of course it isnt ..any input here?thanks <HR></BLOCKQUOTE> Maybe you've found a bug in my formulas! It's always possible. It's hard to do extensive testing when you're correcting grammatical errors in the text all the time. What are the numbers you put in? <HR></BLOCKQUOTE> As far as what numbers are you referring too?
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Darby 74 Grandville 2Dr 455 c.i 4550# 2011 1.60 60 ft,[email protected]@117.74 2017, 74 firebird -3600 lbs (all bests) 1.33 60 ft, [email protected] [email protected] M/T 275/60 ET SS Drag Radial 2024(Pontiac 505) 1.25 60 ft, [email protected], [email protected].... 275/60 Radial Pro's |
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#18
11-20-2004, 04:11 PM
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<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by grandville455:
As far as what numbers are you referring too? <HR></BLOCKQUOTE> What numbers did you enter into the fields to get those results for dynamic compression? I've gone over all my formulas meticulously, and I can't find any error. But the dynamic compression number you got as a result does seem awfully low.
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1977 Trans Am SE W72 4sp, 95% original |
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#19
11-20-2004, 04:13 PM
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<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by 242177P:
This one's from the Chevy guys, but it'll work just fine on our Pontiacs. Static and dynamic. http://members.uia.net/pkelley2/DynamicCR.html GoreMaster: If you're determined to get yours working right, I'm fairly certain that Pat could be a big help. <HR></BLOCKQUOTE> Actually, that's the Visual Basic calculator that I was referring to above. Doesn't work on anything but Windows, so it's useless for me. However I did base many of my own formulas off the ones listed on that page, so it was already a great help.
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1977 Trans Am SE W72 4sp, 95% original |
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#20
11-20-2004, 05:58 PM
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Nice 'cept the dramatic compression is coming up low. Why?
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