Turbo Magazine Homepage

Subaru WRX Tuning Attack: EJ20 Engine Build

WRX Tuning Attack
Built For Boost Part I
Can the EJ20 Handle Max Boost Pressure?
0305Tur Part1boost01 Z
Once the block was disassembled, RS Machine's Mike Coughtrie found the number three cylinder was out of round, but not enough to need a new sleeve. The two halves were cleaned and this was the end result.
0305Tur Part1boost02 Z
If this is your first look at an EJ20, your first impression would be, "Why was the block cut in half?" Enter the water boxer.
0305Tur Part1boost03 Z
In order to resurface the decks, the two halves need to be disassembled and resurfaced individually. Once the engine is squared, Mike machined a step deck on the surface. What this does is provide much tighter clamping around the combustion chamber area.
0305Tur Part1boost04 Z 0305Tur Part1boost05 Z
Looking at a close-up of this step deck, you can see how much of a difference there is. Mike wouldn't relate exact numbers, but they're minimal.
0305Tur Part1boost06 Z
The numbers on the side of the block (arrow) indicate main bearing sizes. Using the factory service manual, you can take these numbers and decipher the bearing codes.
0305Tur Part1boost07 Z
Once the step deck procedure was performed, the two halves were reassembled and ready to be bored out.
0305Tur Part1boost08 Z 0305Tur Part1boost09 Z
0305Tur Part1boost10 Z 0305Tur Part1boost11 Z
The engine was then bolted to the Sun cylinder boring machine to cut an additional .020 out of the cylinders. This was done to accommodate the .020-over Arias pistons. In the next article, we'll head to HKS for the engine assembly.
0305Tur Part1boost12 Z

Acura RL Research
Acura RL Car and Truck pricing can be complicated and sometimes confusing. As an authority on car buying needs we provide information about new cars, such as the Acura RL and all the features it comes with. The RL gets 16 mpg in the city and 22 on the highway, and it has a comparable warranty. The Ford Focus and the Honda Accord are other vehicles that might interest you.

Related Articles

 
Gear Set Solutions - 2002 Subaru Impreza WRX
Check out how to upgrade and replace your 2002 Subaru Impreza WRX's transmission gears.... more
 
WRX Turbo-Back Shootout - 2003 Subaru Impreza WRX
Check out the many different kinds of catback exhaust systems for your 2003 Subaru Impreza WRX and... more
 
2002-2008 Subaru WRX/Sti Buyer's Guide
This Buyer's Guide showcases some of the very best products from the most respected manufacturers... more

More Related Content