89 x 95
1.218 compression height / +6 dome cc
5.572 rod length
53.8cc combustion chamber
8.643 deck height
.030" HG

total volume at bdc = 639.57 cc's
displacement = 590.31 cc's
volume at tdc = 49.26 cc's
639.57 / 49.26 = 12.98:1 static compression

this is NOT the compression that i had calculated the first time i had done it. I dont know what i did wrong the first time, but this compression is way to high. If i run a .051" HG, that will knock my compression down to 12.18:1 compression correct?

My first calculations showed a compression of 11.6-7:1 and that was perfect for me. I dont like that fact of running over 12:1 compression but i guess i can run some toluene mix if i find myself having to back off timing too much.

 

...anyone?

 

Your numbers are correct. 12.98-1. If you do not have the head gasket cc,s in the in the volume at TDC you will be lower.

 

yea, thats with the .030 hg included. I've talked to Belben and he believes that i will be fine with a .051 hg running around 12.2-12.3:1 compression. Jei at blacktrax also agrees that i will be ok and shouldnt have to retard the timing much to run on pump gas. As long as all the sharp edges are rounded off, i shouldnt have to worry about any hot spots.
This is also just static talk. Jei told me that my JUN3's should bleed some compression as well so it wont have such a high dynamic compression.
I found a really good article about mixing pump gas with toluene so if worst comes to worse and i find myself losing power because of the compression, i can just mix some with 93 and i should be good to go.
http://members.rennlist.com/95....html

 

You'll definitely be fine with 12.2 or .3 :1 on pump gas, I doubt you'll even need toulene w/that....

 

we'll see what happens on the dyno. Gonna retard the whole map and advance from there, hopefully it doesnt end up being heavily retarded.


Modified by 98vtec at 9:01 PM 4/3/2007