N/A to ej20g questions

[Hinano]

Okay so I'm set on going ej20g on my 90 5speed awd. A couple questions though..

1) my friend will give me his wrx crossmember for free, I need any impreza wagon control arms to run this?

2) how are the stock transmissions on the na? Will it take little over 200whp? Are the Japanese wrx transmissions stronger?

3) some engines being sold have coil plug thing on top of the engine while some have COP. Why is that?

4) how do i check the final drive ratio?

5) any advantages of jdm ecu v ej22t ecu?

6) what would be some things to replace while doing the swap?

7) I'll be getting a 04 wax exhaust for free too, but other than that and robtune, do I need anything else for this swap?

[mike-tracy]

1. You need 2002-2007 Impreza (sedan or wagon) non-turbo control arms, or 2002-2007 WRX Wagon control arms. The STI and WRX sedan control arms are different.

2. The trannies will last if you treat them right. The only thing significantly stronger is the 2004+ STI 6-speed, which usually goes for $3k or so for all the parts needed. The turbo trannies usually have better clutch selection. The ej20g transmission (both WRX and STI versions) takes 2002-2005 US WRX flywheels, clutches, etc.

3. Coil on plug is the coils go straight to the spark plugs. Wasted spark is where there is a coil pack on top of the manifold with spark plug wires. The EJ20g ecu expects you to run coil on plug, HOWEVER, Rob makes an ignition converter to let you run a coil pack aka "wasted spark" with that ecu.

4. Your final drive with the ej20g motor is going to be 4.11 as long as it's from a WRX. Most ej25 subarus with a manual have this, so finding a rear diff and its axles are easy. Before you buy, make sure to ask on the forum for confirmation.

5. The ej20g ecu is a 16 bit computer, the ej22t ecu is 8 bit. In simplified terms, the ej20g ecu can be programmed with much more detail and process information faster.

6. Replace any and all gaskets (except head gaskets), timing belt, water pump, new spark plugs. All the gaskets for that engine (except head gaskets) are the same as a 1996 (not 97-99) Subaru Legacy GT 2.5L, so you can get them at any parts store.

7. If you merge the ej20g wiring with your cars', and run coil-on-plug, there really shouldn't be much more that you need. I don't remember if your new engine is coming with the turbo MAP sensor and boost controller that goes on the passenger side strut tower. If it doesn't, you need it. One from an ej20g or ej22t will work. Also, you need a "plastic" maf from a 92-98 Subaru legacy, if your engine doesn't come with it.

[86BRATMAN]

One thing to note on the control arms, you can use your stock arms and use replacement bushings for the 02-07 control arms

[mike-tracy]

One thing to note on the control arms, you can use your stock arms and use replacement bushings for the 02-07 control arms

That's a good point.

[James614]

3) some engines being sold have coil plug thing on top of the engine while some have COP. Why is that?

5) any advantages of jdm ecu v ej22t ecu?

The engines with COP are 93-96 EJ20G engines. The ones with a central coil pack are 97-98 EJ20K, or Forester EJ20G (which is basically the same as the EJ20K and should never be confused with the WRX EJ20G, but are simply sold as EJ20G/JDM EJ20/EJ20T all the time). Theres pros and cons to each. And you can run either style ignition on either engine (you just need to find a way to secure the coil pack on the ej20g intake manifold).

Aside from being a better ECU, the EJ20G ECU can proper control the EJ20Gs bigger injectors out the box. Beyond that you can get a robtune which will let you run higher boost on 91 octane and also let you upgrade to 04 STI 550cc injectors if you want for even more boost. If you didnt already have the 22T ecu stock, theres really no reason to consider running one now. You would be significantly dowm on power, even if you did find a way for it to run the bigger injectors.

[Hinano]

Wow wow THANKS YA'll!

1) Since I might need a new rear, and the transmission sounds to be strong enough to handle the extra power, I think I'll buy just the engine.

2) Im really happy to hear I can just get new control arm bushings rather than the whole thing!

3) Can I just buy one of those cheap manual boost controllers?

4) for robtune, can I run it conservatively? Reason being, I will be taking trips from sea level to 14k feet elevation regularly and I don't want my motor to blow.

5) Okay so I'll also need a MAF, can do.

6) Does having the wrx transmission mean I can use axles from a wrx?

On another note, my friend who's building a 818 is thinking about picking up a JDM engine rather than rebuilding it also so looks like I might be saving on the shipping to Hawaii!

[James614]

3) Yes, that's actually recommended.

4) Yes, whether you get the 440 tune for stock injectors or the 550 tune, you can run any boost level below the tune's suggested Max and the tune maintains all the benefits of a factory tune. Drive ability and fuel economy remain excellent (unless you drive like a hoon, then fuel economy sucks balls, lol).

[Hinano]

1) do I have to get turbo front sway bar?

2) Do I have to run a turbo radiator?

3) can I run wrx axles on wrx trans?

[James614]

I don't believe a turbo sway bar is required. Turbo radiator is a good idea but not required. As for axles, if its a 93-96 WRX you will use the first gen Legacy axles.

[Hinano]

Thank you.

[mike-tracy]

Non turbo front swaybar rubs a bit in a turbo crossmember from my experience. So there is a knocking sound on sharp turns or sometimes on uneven pavement. But it fits...

[Legacy777]

I'd recommend getting a turbo sway bar. The WRX front sway bars also work.

[Hinano]

Okay cool. I think I can get the front wry for free so no worries.