14bar!

[apeng]

hi frens!
i really need help here
few months ago my foremen changed my piston...all the job done and my car already running smoothly...
as now i want to boost slightly higher...
my frens ask me to do 'static compression test' so i go to his shop since he said he has the gauges....
so he open my plug and ask me to crank...
and he got some reading at his gauges...
all reading form my 4 cylinder is 14bar or 200psi..
so he said that in need to lower my compression in order to boost higher...

can i know what test is actually done?
what is the reading show?

 

[speed2horizon]

hi frens!
i really need help here
few months ago my foremen changed my piston...all the job done and my car already running smoothly...
as now i want to boost slightly higher...
my frens ask me to do 'static compression test' so i go to his shop since he said he has the gauges....
so he open my plug and ask me to crank...
and he got some reading at his gauges...
all reading form my 4 cylinder is 14bar or 200psi..
so he said that in need to lower my compression in order to boost higher...

can i know what test is actually done?
what is the reading show?

This is what happened. when your piston is at BDC air trapped in the cylinder assumed to be at atmospheric pressure. P absolute = 0psi = 0 bar

in a compression stroke, As the piston goes up, the trapped air is compressed. When piston reached the TDC, air is fully pressurized according to your engine specification. The gauge takes teh highest pressure read during the cranking process.

Healthy turbo engine should land at around 10-13bar. If i'm not mistaken...

The figure shows the highest pressure achieved by the engine during the compression stroke.

 

[kelvins3281]

14bar i think a bit higher for turbo rite or not?

 

[apeng]

i m not sure...
btw anyone has the www for me to read at least...
or someone can detailed...?

 

[speed2horizon]

14bar i think a bit higher for turbo rite or not?

Yeap... A little too high....
So, GOOD TUNNING and. DON'T BOOST TOO HIGH lor..

 

[lavodo]

wut piston r u using?.. my engine comp 4g63t 19+psi.. boost around 1.7 - 1.8.. no prob.. just to remembered, make sure ur piston + conrod is good enuff (forged) if want to live long ur engine with hi comp..

 

[speed2horizon]

wut piston r u using?.. my engine comp 4g63t 19+psi.. boost around 1.7 - 1.8.. no prob.. just to remembered, make sure ur piston + conrod is good enuff (forged) if want to live long ur engine with hi comp..

Stock evo engine also can stand that boost if tuned properly with bigger injectors. If u use methanol injection can even go higher....

BTW, 190psi is only 13bar... Which was what We've discussed earlier...
Haiz...

 

[kelvins3281]

Owh i thought 19bar.huhu...

 

[apeng]

can i lower the compression with adding thick metal gasket?
currently i have 2 pcs of metal head gasket...
my foremen suggest for another 1 but thicker metal head gasket..
can this be the solution?

 

[kelvins3281]

Huh wanna use 2pcs gasket??can mehh??:hmmmm:

 

[lozo]

apeng,

your static compression pressure is on the high side for forced induction. usually stock motors have compression pressure around 8 to 10 bars and boost at merely 0.5 to 0.7 bars. however if you tuned it right..say really retarding the timing under boost and have strong internals plus low boost levels, i've doubt it has any problem. e.g vw polo gti

 

[apeng]

can i still lower the compression?
as for me i m using td04 at kancil turbo engine...i really need to boost 1.5-1.8bar to have better torque...
so far i can boost at 1.25bar happily with my emanage tuned by gt auto...

 

[xtremeleo]

mine is 200psi across all pistons, no biggy pun. d 1.3 motor is churning out an excess of 180hp wit no problem, tuned to perfection by joshua of millennium motorsports. havent had any problems since the last 4years i last let him tuned it

 

[HKS-GT2835R]

d 1.3 motor is churning out an excess of 180hp wit no problem

 

[consonar]

hmmmm... hi compression there for L2 engine... btw, what piston do u use? kelisa? 2e? 2e turbo? 3e?

and did your foremen skim the piston before put in the block?

shoot!!! in the 1st post u said that 4piston!?? JBJL? what piston u put?? :hmmmm:


btw, rugi if use 2 metal gasket rather than skim the piston...

last time im using 2e piston in L2 can stand 2.6bar with skimmed the piston a bit...

 

[kenzo]

errr, my advice would get a thicker metal head gasket or methanol injection or e85 hohoho

and plz dont ever skimmed the piston head, im pretty sure head gasket are way cheaper and easier to change rather then blowing a hole in the piston...

 

[apeng]

hmmmm... hi compression there for L2 engine... btw, what piston do u use? kelisa? 2e? 2e turbo? 3e?

and did your foremen skim the piston before put in the block?

shoot!!! in the 1st post u said that 4piston!?? JBJL? what piston u put?? :hmmmm:


btw, rugi if use 2 metal gasket rather than skim the piston...

last time im using 2e piston in L2 can stand 2.6bar with skimmed the piston a bit...

yup JBJL...

errr, my advice would get a thicker metal head gasket or methanol injection or e85 hohoho

and plz dont ever skimmed the piston head, im pretty sure head gasket are way cheaper and easier to change rather then blowing a hole in the piston...

noted...

 

[HKS-GT2835R]

btw, rugi if use 2 metal gasket rather than skim the piston...

care to explain why?
cuz i'd rather stack gaskets, or put block spacer than skim the pistons.

 

[kenzo]

care to explain why?
cuz i'd rather stack gaskets, or put block spacer than skim the pistons.

correct! i have no idea why corona rather skim his pistons lol :stupid:

 

[speed2horizon]

Pistons are normally overdesigned to take more than it suppose to take. Up to a certain extend of course. Double metal gasket can be risky as there are more possibility for the water and oil to mix due to increased chances of uneven head tightening problem.

If skimming pistons are done nicely, problem can be less than a double metal gasket. I've seen ppl using double carbon gasket. But carbon gasket are compressible and metal gasket aren't.