Higher Compression

[jcrx]

Originally Posted by civickiller

oh so i am wrong huh, ever heard of skunk2 high compression flat valves ? but thanks for clearing it up, im glad to find out that im wrong.

ok so valves have alittle dip in them, but with these valves, there is no dip and its all flat so therefore it raises your compression.

please dont talk if you dont know what your talking about.

Actually, I do know what I am talking about, the Skunk2 vavles raise compression 0.3-0.5 point<--note, not plural, as in you go from 10.2:1 to 10.5:1, and at over $400 a set, plus labor (and machining if you want to go oversized) they are hardly worth a look if you are just looking for a little more power instead of trying to squeeze every last ounce of power out of a build up, since the Hp to dollor ratio horrible. But ok, in all fairness yes, you can use valves to raise your compression.

[civickiller]

thats how you have to do it with a all motor car because as you know, you cant just get really high compression pistons because you inhibit flame travel so you want to get as high compression as you can before buying high compression pistons.

and when building an all motor trying to get as high compression as you can then $400 is nothing

[jcrx]

Pistons are one of the first steps in a all motor, motor. Actually, planning the whole is the first step, but to say the pistons are one of the last things is foolish.

[civickiller]

not really because say you got a ls motor 9.2cr, so you want higher compression so you go out and buy 12cr pistons, do you know how much that would hinder flame travel and you wouldnt get the full potential of the motor. yeah pistons shouldnt be the last thing but like you said you have to plan it all out so you know what kind of parts your gonna get and how it affect your cr so you can buy the lowests high compression pistons as possible to get max hp out of them without hindering flame travel

for example, you want a 12 cr on your all motor stock 9.2 cr so you can still drive it on the street, so you get the valves so 12 - .03 = 11.7, then you shave the head and the block so say that takes off 1 point ( dont quote me thats jsut a number) 11.7 - 1 = 10.7. so instead of having to get 12 cr pistons, you only gotta get 10.7 cr pistons which would help with the flame travel to get max hp. but of course the cr isnt the only variable in this whole thing but its one point of view, and there are alot of other factors

[jcrx]

Flame travel as in the path of the ignition spark from ionization at the plug to detonation? I understand the whole concept of combustion efficiency, hotspots blah, blah, blah, it's one of those things that is almost negligable since it is built into the design, as in, it's something that is just going to happen. The theory behind it, is mapping the path of the burned air fuel mixture in the combustion chamber to read effectivness, and there by being able to shape the chamber for a more efficient burn. Hardly something the average or even experianced engine builder can just do, also why many places that port don't just hand out info.

[jcrx]

Not that hotspots are negligable, wouldn't want you to read into what I said and have a shit fit, since they can cause detonation and damage motors. But more so that they come from damaged parts like nicks in pistons, poor port jobs, and other places in the chamber that can accumulate excess heat and cause the air/fuel to detonate before TDC, not usually from design flaws in high compression parts in general.

[civickiller]

as long as you dont say the wrong thing and misinform people it is all good.

yeah flame travel is more of a theory other then pure fact, thats why when i talk about hindering flame travel i just kind of talk about might be losing potential hp.

when i talk about flame travel i am talking about the way the air, fuel, and flame travel. with a piston that is domed too high when the flame is circulating through the comubstion chamber it get interferred with by hte pistons that is sticking up in its way. again all in theory, idk might have been proven fact but as far as i know its theory

hotspots can come from damaged parts but they can also come from new parts, thats why when you get new pistons you shave any sharp edges down so its all smooth because a sharp edge will cause a hotspot and maybe cause detention

[DeleriousZ]

again... jesus christ you guys argue more than kids in the 3rd grade! can't we just learn to get along and admit when we are wrong? you don't ALWAYS have to be right, or try and prove you are.. just take it easy!

[civickiller]

its not having to be right, its more of not misinforming people because if you tell someone who doesnt know something, you tell them something wrong and now they think what they know is right when they are really wrong.

like for example in that other post someone asked if you could put a gsr im on a ls, after i had said no it wont work, 2 or 3 other people who were misinformed, probably by other people, came on and said it would work, not trying to put a blame on them, i mean its not there fault they were misinformed. but they said it would work, when it wouldnt.

not trying to prove people wrong, just trying to get the right facts out so that people know what is right.

[DeleriousZ]

yeah yeah, i'm just talking about you and jcrx... seems like you guys hate eachother with a passion

[jcrx]

Who gives a shit, let it go.

[civickiller]

Originally Posted by Delerious93integra

yeah yeah, i'm just talking about you and jcrx... seems like you guys hate eachother with a passion

no i dont hate jcrx, he is very knowledgable, one of the few that are on this board

[jcrx]

Thanks, you're no slouch yourself.

[crxtacy]

wouldnt a mugen head gasket and ctr pistons net you a good compression? you can always change those out later if you wish. i would highly think over shaving the head before you do it, since you cant put it back to how it was.

im gonna throw a quick question in. how much compressoin on a street n/a car is too much on pump fuel? i would think anything over 11.1 or 11.5.1 woudl be a touch of overkill.

[civickiller]

dont type r's come 11.5 stock, so i woudl say 12 or 12.5, just make sure you tune it real good