Is there a difference LGT vs WRX piston compression ratios?

[wintergreen]

I understand the my 2005 LGT has B25 heads on it and in later years they came with D25 heads that had higher compression ratios.

 

 

Will a short block from a 2007 WRX to replace my 2005 LGT block work? I will be putting the B25 heads on it. The block should be identical, I'm not sure about the piston dish or dome if there is a difference that would affect compression ratio.

[Max Capacity]

There isn't enough difference to worry about.

 

My 05 GT wagon has a ej257 from 2012, just buy the engine gasket set for your year car. When we did the street tune at 500 miles, the Tuner said there wasn't enough difference in the tune between the two blocks to make any difference, but he did a little clean up on the fueling or something, that was over 146,000 miles ago.

 

 

Read my click here link.

[silverton]

https://www.flatironstuning.com/blog/what-is-the-difference-between-an-ej255-and-an-ej257

[Max Capacity]

Thanks, I now remember seeing that in the past.

 

As I read that, I see the OP will be fine using his B25 heads on his 2007 short block

 

Seems having B25 heads makes it possible.

 

From the Flatironstuning link.

 

"Because of the difference in piston dish and combustion chamber volume, it is not recommended to pair a D25 head with an STI block, or one that was designed to work with B25 heads."

 

So the 07-09 GT's and OBXT's should select the ej255 shortblock.

Edited December 19, 2021 by Max Capacity