I've heard that you can run 18psi on stock engine with decompression plate. This would put me roughly around 300hp.. does this seem legit? On a t3t4 turbo..

 

You can do that on a 100% stock engine with no decomp plate, AND a good tune. The decomp plate just allows you more leeway by lowering the compression and destroying the quench area.

 

What do you mean by destroying the quench area?

 

it means you have a lot of learning to do before you spend money on your car. Unless you like to learn the hard way and pay three times as much, buying the parts you think you want until you get what you actually wanted in the first place.

 

Other options i've heard are a thicker head gasket like shark racing sell, be adventuous and use 2head gaskets, or just use 1.8 rods and pistons if you got the 2.0l beta



P.S

are you talking about 300hp at the wheels or at the fly wheel ?

 

At the wheels

 

a decomp plate and thicker head gasket is the same thing

 

What I mean is every engine has a specific combustion chamber design to provide for proper flame front propagation to make sure your air fuel mix burns properly. The quench or 'squish' area is the area where the piston comes up close to the top of the block and bottom of the head and pushes the air fuel mix towards the middle of the combustion chamber near the spark plug. Take two flat pieces of glass with a drop of water in the middle and you get the idea. The air fuel mix is squished between the piston and edge of combustion chamber and pushed towards the center.



Now take a decomp plate or thicker head gasket and see what happens. You've moved the top of the piston away from the cylinder head and combustion chamber. Those two places of glass no longer touch now so the air fuel mix is no longer pushed towards the middle of the combustion chamber ruining the proper flow of the flame from the spark plug.