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'89 CRX HF
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Discussion Starter · #1 ·
why is it that every site that sells SRP pistons, the compression ratio doesnt match the actual SRP site. everywhere i look the part #149195 say that the slugs are 8.5:1-8.8:1 compression in an a6, but on the SRP site it says 9.0:1 with a .040 hg?
http://www.jepistons.com/cat/srp/sc/honda/d16a6.shtml9.0:1
http://tunertoys.zoovy.com/category/srp_pistons.d16a6/8.5:1
http://www.prostreetonline.com/buy/srp_pistons/sr-149195/8.8:1
http://www.9secondracing.com/cgi-bin/search.cgi?partnum=141028.5:1
http://www.jegs.com/webapp/wcs/stores/servlet/productitem_10001_10002_759329_-1_6615468.8:1


im guessing that i should trust SRP's site, but i just dont understand how every other vendor lists them at a lower c/r... :confused:

if i follow SRP's site, my c/r of my motor comes out to about 9.35:1, while if i follow every other vendor's listing its about 8.85:1-9.05:1. thats quite a difference...
 

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I'm pretty sure one measurment is witha stock head gasket which I think is ".048, so if you use the ".040 headgasket, thats probably what gets you the extra compression, although, 8 thou isn't alot, but thats all I can come up with
 

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Useing the information from JE's website and the Zeal Autoworks calculator I came up with 8.8:1 for the low compression and 9.5:1 for the mid compression pistons. And that was with a .037 Z6/Y8 HG.
 

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'89 CRX HF
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Discussion Starter · #4 ·
I'm pretty sure one measurment is witha stock head gasket which I think is ".048, so if you use the ".040 headgasket, thats probably what gets you the extra compression, although, 8 thou isn't alot, but thats all I can come up with
ya but the .7 difference in HG isnt going to make that much of a change in compression...

if the ratio is what SRP says, my compression is a little higher than i figured :sad:
 

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ya but the .7 difference in HG isnt going to make that much of a change in compression...

if the ratio is what SRP says, my compression is a little higher than i figured :sad:
ya I know thats not alot of difference, but, it depends on whos entering what information into what c/r calculator, I was just theorizing! :)
 

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'89 CRX HF
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Discussion Starter · #6 ·
using the dish measurements from SRP's site in the knology comp calc, i get about 8.6:1 in a 100% stock a6, with stock a6 HG thickness...
 

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hmm this makes me wonder also. i will be using those A6 SRPs in my z6 build. before, i was assuming 9.6:1 but if the pistons actually make 9:1 in an a6, my compression will be around 10
 

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that sucks.
 

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Discussion Starter · #10 ·
well im hoping that the knology calc is right, because then i would be around 8.9-9:1 compression. PERFECT!
 

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well if the knology is right i will be at 9.7. which is ok with me.
 
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