Thursday, May 03, 2007

Ej20G varients.

to address the first thing people think of when EJ20G comes to mind;

Closed deck vs open deck.

I'm here to publicly state that closed deck is stupid. Sorry mike shields fanboys, sorry mike shields. closed deck is pointless. an open deck Ej20 can do 60 psi before the cylinder walls crack. Everyone knows that the person behind the closed deck theory has a EJ20g in his car, I know that he runs a stock ecu and dosn't go over stock 1 bar of boost. Car vs car, the WRX-RA we put together in 16 hours would beat his closed deck SPD special in a drag race.

closed deck has no advantage unless you are going over 600 AWHP. if you dont have a GT40R on your workbench, dont even think about debating with me that open deck is better than closed.

this being stated, lets go on to outline the differnt varients of EJ20g

All ej20G's have the same Forged crankshaft, Forged connecting rods, cylinderheads, Valves, Cams, exhaust manifold, up pipe, downpipe, throttlebody, fuel injectors and complete electrical system (ABS cars have abs added in, power windows, etc)

Ej20G wagons had td04 turbines. Ej20g wagon Sti-s had TD05-16g turbines
all wrx sedans had Td05-16g's. same turbine on sti, sti- ra, wrx-ra. all identical

the WRX-RA and Sti-RA have a 5th injector plumbed in the centre of the intake manifold. it dosnt do anything. it dosnt even work

Sti ej20g motors have a painted red intake manifold. only differance is the paint. sti-RA's have a non-painted manifold with a 5th injector

supposedly the STi engine ej20G and Sti-ra have forged pistons. I have yet to have a need to remove pistons to weight them, we'll verify this eventually sometime by comparing a normal wrx and sti piston

valvetrain on all EJ20G's with exception of the rare Sti-RA only are HLA under bucket. all cams are same duration and profile. only the sti-ra has mechanical valvetrain- little liter disc shims under the buckets.

Besides for these minor changes, the only major differance between any varient of ej20G (assuming sedan td05 turbine) is really the ECU. the ECU is everything in these cars, if you plug a sti-RA ecu into a normal WRX ej20g....... you get STi-RA performance. the td05 turbine is out of efficiency range by 7300rpm at best, HLA's will spin to 8500 before floating - you do the math. usually a shift is best performed by the time 7k rolls around


brian said...

Nice info for sure H,


snakeman said...

It's not always about cracking cylinder walls, it's about excessive boost causing the walls to flex and move, going out of round and causing rings to lose their seals.