11.3:1 434ci with <10psi twins. Thoughts?
11-02-2012, 09:53 PM
#21
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Ayousef....
Send me another nasty private message telling me i suck with the little puking avatar... i thought that was funny.
Everyone deserves a free lesson in life.... heres the one youll get from me.
Cylinder filling doesnt start in earnest untill you close the exhaust valve.... prior to that the air/flue can gladly walk right on past the exhaust valve.
Now... you are seriously gonna sit there with a straight face and tell me that changing the EVC event, which is 1/2 your overlap controlling events the other being IVO, will make NO difference to the DCR of an engine??? It might not change the number that calculator on Wallace Racing spits out for you... but it does change it.
Montgomery Ragland is a friend of mine who races X275 with a mod motor. We made an exhaust cam change in that engine and took 14 degrees of duration out of it. Overlap with the old cams...39... overlap with the new cams...24. The exhaust cam was degreed in with an identical EVO point as the old. This made all14 degrees of duration come out of the EVC event.
Cranking compression before...182-187
Cranking compression after....202-208.
Now jump up and down some more... tell me i suck again and send me some more nasty *** private messages.
Better yet... sit there and say cranking compression isnt a direct reflection of an engines DCR so we can REALLY laugh at you.
Class.....dismissed.
Send me another nasty private message telling me i suck with the little puking avatar... i thought that was funny.
Everyone deserves a free lesson in life.... heres the one youll get from me.
Cylinder filling doesnt start in earnest untill you close the exhaust valve.... prior to that the air/flue can gladly walk right on past the exhaust valve.
Now... you are seriously gonna sit there with a straight face and tell me that changing the EVC event, which is 1/2 your overlap controlling events the other being IVO, will make NO difference to the DCR of an engine??? It might not change the number that calculator on Wallace Racing spits out for you... but it does change it.
Montgomery Ragland is a friend of mine who races X275 with a mod motor. We made an exhaust cam change in that engine and took 14 degrees of duration out of it. Overlap with the old cams...39... overlap with the new cams...24. The exhaust cam was degreed in with an identical EVO point as the old. This made all14 degrees of duration come out of the EVC event.
Cranking compression before...182-187
Cranking compression after....202-208.
Now jump up and down some more... tell me i suck again and send me some more nasty *** private messages.
Better yet... sit there and say cranking compression isnt a direct reflection of an engines DCR so we can REALLY laugh at you.
Class.....dismissed.
On the other hand, overlap can effect cylinder filling, which you're probably confusing with DCR. In that case increasing overlap on a motor with little overlap will result in REDUCED cylinder filling at low RPM, and INCREASED cylinder filling at high-rpm, that might explain why you're getting a higher cranking compression with the cam with less overlap.
11-02-2012, 10:09 PM
#22
From what I understand is when you start your compression stroke and the exhaust valve isn't closed all the was your compression will be less. It your talking about what heads, stroke, pistons, head gasket thickness = CR thank will be different. Just thinking out loud and looking to learn.
11-02-2012, 11:44 PM
#24
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Ladies....CAN WE GET BACK ON TOPIC? Take your pissing contest elsewhere. 
If I go this route I will have a cam made better suited for my setup.
If I go this route I will have a cam made better suited for my setup.
