If i put a 2.0 evo x versus a 2.5 sti. Assuming both horsepower and torque are the same, will the 2.5 sti be pulling ahead of the evo x since the engine is a bigger capacity.

Hope this dont sounds too dumb.

 

theoretically if they are producing the same horsepower and torque... it then becomes weight of the car and gear ratios that make the difference... Assuming drivers are the same/similar.

I would also think that since an evo motor is a 2 litre inline 4 that it would be much lighter than the subaru, which is a opposed 4 cylinder of 2.5 liters. This being said the smaller motor would be more responsive due to physics.
But i guess This isn't always the case, seeing as how The motor that yamaha made for the LFA revs from idle to redline in under a second... and it is a v10 a little under 5 liters... but thats a whole different thing.
but to answer the question: no. The sti will not be accelerating faster simply due to having larger displacement when other things are the same.

 

Many other factors to consider including vehicle weights, drivetrain losses, gear ratios, total power curves, etc... A larger displacement motor alone is not enough to justify an advantage. Although, power curves will be different on each motor. A 2.5 certainly has some advantages. But so does a smaller motor with a larger turbo.

 

The larger displacement engine has the theoretical ability to make more power because it has a larger combustion chamber and can burn mor gas and air. There are a lot of factors, tho, especially since these are turbo cars. The larger engine should have more torque but the hp could be made up for with a larger turbo. The more air you can get into the engine the more gas you can burn and te more power you can make.