Hi all I’m new here and I’m just about to start the build of turbocharging my Subaru Impreza RS wagon with the ej20 in it and I know the compression ratio was different to the ej20 used in the wrx.

does anyone know the actual physical differences between the ej20t and the na ej20?

thanks 

A turbocharger?

1 hour ago, Dr. Acula said:

A turbocharger?

Yes a turbocharger 

There are many differences, sensors / loom, intake manifold, ECU, exhaust manifoId, exhaust up pipe, exhaust down pipe, I believe the cams are also different. brakes are different, ARB's are different, shock springs are different.

3 hours ago, Jay762 said:

There are many differences, sensors / loom, intake manifold, ECU, exhaust manifoId, exhaust up pipe, exhaust down pipe, I believe the cams are also different. brakes are different, ARB's are different, shock springs are different.

I’ve got a new sub frame on it’s way and a blown wrx engine with good heads, I may use those heads and I’ll have to use the sub frame to fit the up pipe, speaking off I also have that and the down pipe aswell as a 2.5” Miltec exhaust system and UEL STI headers and the turbo and the intercooler off a wrx.

I also have the four pod brakes soon to be installed and some Coil-overs that are soon going on.

I think I can make this work with the engine if I swop the heads 

and tell your insurance company that its a turbo...which maybe classed as modified..not standard turbo version

Yh I’ve already looked at that, 

I’ve only got 1ncb as I was on my second year 7month in and moved to Scotland and it was cheeper to swop to a new Insurance. Long story short I’m almost on my 2ncb and my record has 2 years and 7months and with that and declaring a turbo and all the above aswell as bigger wheels etc it’s coming in at £1300 so I can’t complain.

however I own two cars and rent a shed so the Subaru is in storage witch I plan on taking it out November once the build is completed.  

Unsure if na heads have the oil feed and return for a turbo , so you'll probably need at least turbo heads.

Id imagine The na runs a higher compression  ratio due to not being boosted . Unsure if this is accomplished by different piston crown design,  head chamber sizes or gasket thickness. 

It would simplify things if you had a full turbo donor car engine, loom and ECU . As the stock na ECU and loom won't be able to control boost .

Inlet manifolds,engines looms and ecus in classics are different pending on "version". v1 to v4 are interchangeable but v5/v6 run a different inlet port pattern . So there's a few compatibility issues pending on year of car, loom and engine to consider too .Even when fitting another turbo engine to a turbo car , let alone a na 

Obviously it will be eaiser and cheaper to just buy a turbo version,  probably cheaper to insure a oe turbo version too (not modified)

I like the diy approach,  so will help if I can but unfortunately my na engine spec is pretty much non existent