cylinder pressure +boost = what it is?

[SpoolingTurbo6]

When you do a compression check that is the cylinder pressure right...........
so if your @ 30 psi 0f boost and your cylinder pressure is 110psi.
It is what it is right 110+30=140psi.


T

.

 

[It's just a six]

Re: cylinder pressure +boost = what it is?

When you do a compression check that is the cylinder pressure right...........
so if your @ 30 psi 0f boost and your cylinder pressure is 110psi.
It is what it is right 110+30=140psi.

Your gonna see a lot more cylinder pressure than 140 psi w/30 psi boost pressure.
I am just quessing cause I'm too lazy to figure it out right now but more like 240-260 psi cranking compression?

 

[Black Knight]

Re: cylinder pressure +boost = what it is?

Isn't 110 psi pretty low to?
Well i'm assuming your talking about a SyTy, and mine was averaging 160 psi the other day.

 

[It's just a six]

Re: cylinder pressure +boost = what it is?

Yeah, it is low ,I think he just threw out a number ?

 

[Black Knight]

Re: cylinder pressure +boost = what it is?

KO :tup:

 

[SpoolingTurbo6]

Re: cylinder pressure +boost = what it is?

:tup: I just threw numbers out the. Thanks six, I knew it couldn't be that easy

 

[turbodig]

Re: cylinder pressure +boost = what it is?

When you do a compression check that is the cylinder pressure right...........
so if your @ 30 psi 0f boost and your cylinder pressure is 110psi.
It is what it is right 110+30=140psi.


T

.

Nope... actual cyl. pressure will be much, much higher.... like almost a factor of 10.

A compression check is really a go/no go kinda thing, it doesn't tell you much else.
Even a full leakdown will only tell you static pressures, which are pretty meaningless at
typical engine speeds.

 

[JSM]

Re: cylinder pressure +boost = what it is?

The 30psi is also before it is compressed by the piston. So instead of it drawing a vacuum up to 130psi, it is taking 30psi up.

 

[dgoodhue]

Re: cylinder pressure +boost = what it is?

Our stock cam (which is anemic by anyone standards) has 179 degree that the valve is open 0.050". That is 179 degrees of the 720 degree in a 4 stroke power cycle. The air is filled in time is during the exhuast stroke and compression stroke. Obviously it doesn't completely fill it up, but it will have the opportunity to fill a large area of the cylinder.