compression ratio..come tell me

[howiechoo]

can any sifu tell me hoe can i increase compression retio? is higher cr in NA good? thanks..

 

[lozo]

change to high comp pistons
use thinner head metal gasket
skim the cylinder head
increase the stroke of the motor

as higher the cr, the higher the possibilities of knock

 

[Dino@Casper]

As u increase the compression ratio u should get more power, but ur risk the chances of getting knockin though

 

[howiechoo]

can explain more on knocking? btw, do pnp increase the cr ?

 

[lozo]

when cr is increased, temperature of the mixture is raised high enough for it to self-ignite without the need of spark plug. when self ignition occur, higher than desirable pressure pulses are created which could damage the components. this audible phenomenon is called knock or ping.

pnp does not increase cr, it only smoothen the flow in the head ports. IMHO, it only affects at full throttle or with a high revolution motor.

 

[Dino@Casper]

Yeah when the temperature rises to the flash point, where it self-ignite thats what we call pinging or knocking and thats seriously a big nono..

 

[Fluffy]

that will cause u to lose power and also in serious cases lead to detonation.

 

[howiechoo]

thanks for the info....
so if i pnp my head will not effect the cr rite? any1 had done pnp? wonder how many % can pnp increase the power of the engine

 

[rollakid]

i don't think you count pnp in % ler..

 

[Fluffy]

yeah.you can count the "%" of increase.just gives u better flow.

 

[howiechoo]

icic..thanks for info...so after pnp, i will only feel the engine is smoother and lighter rite?

 

[Fluffy]

something like that. :)

just a rule of thumb of increasing compression ratio,
every additional point increased will give approx 4% increase in power.

 

[donCityZ]

port and polish... not sure is it a good workmanship in Msia..???
In the overseas, they have specific CNC machine to grind and smoothens all intakes, valves etc. In Msia, i heard they do it BY HAND... mean grinding using sand papers etc. Each cyclinder must be balanced.. doing by hand with less precision, going to be balanceed????

Increase CR is good.. to avoid knocking, pls use high octane fuel.. but i heard our RON97 is good enough to cater around 12:1 CR. .. not sure tho.

 

[Dino@Casper]

We do have C&C machine in malaysia.. but i doubt anyone would send it to them .. its too dem expensive...

 

[rollakid]

powerzone ler?

 

[E3newbie]

C&C machine? Can someone tell me what it stands for?

 

[Freedom_Blue]

Powerzone do hand made not machine.But acc to my friend he said hand made is better then machine....Pro&Cons im not sure....

 

[donCityZ]

C&C machine is the Command & Conquer machine.. hahaha.. no no jk only.

CNC is a computerised drilling and grinding machine.. very precise.. i forget what it means..

some ppl also called it NC machine..

 

[E3newbie]

Oh! The machine that precision machinists use is called CNC machine. Thanks.

 

[jswong]

If you have any idea what sort of programming that needs to go into a CNC machine for it to do all the stuff that's required for PnP, you'll understand why hand-porting is still a more realistic way of doing things.. besides, there are some parts of the engine head that might require flexible attachments (like the short side radius and further up the ports), and these areas may not be accessible to the tooling heads on CNC machines... and you'll need to finish off the job by hand anyway.