Turbo advice

I have a stock 2003 Legacy L Wagon 2.5L and after driving my friend's turbo wagon I want to look into installing a turbo on my car. I am looking for advice and tips on how to do it and what works the best. I am trying not to replace the sock ECU or internals. I am not going for a huge performance upgrade, just something that will give it a little more kick and that won't break the bank. Thanks.

I understand, a turbo will make a huge difference given the altitudes in Colorado. I saw your other post, saying you wanted a more off-road or rally look. Sorry to say this, but you won't find it easy or cheap to do this with the car you have, and in the end, it won't be worth it.

 

In this case it's better to buy a car that already has what you want.

That's what I figured, after looking around a bit it would be better to just buy a different car. Thanks for the input

 

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yeah cant just slap a turbo on a sohc. it will blow up fast. a engine swap is do-able but costly and the down time is a lot for the harness merge, unless you buy a 2nd harness so you don't have to take yours out.

That's what I figured, after looking around a bit it would be better to just buy a different car. Thanks for the input

 

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What fun is it buying a new car? You learn NOTHING from doing that!

 

yeah cant just slap a turbo on a sohc. it will blow up fast. a engine swap is do-able but costly and the down time is a lot for the harness merge, unless you buy a 2nd harness so you don't have to take yours out.

 

A friend of mine just boosted his 02 Impreza Wagon. Bone Stock EJ251, Stock ECU, stock 02 WRX turbo up/downpipe and wastegate, ebay BOV, 500cc injectors, and a walbro upgraded fuel pump for around $800. Runs 8 psi all day long. Granted it's not a speed wagon or sleeper by any means, but it's a fun car to drive and a nice surprise kick in the pants leaving you to plan your full turbo build.

 

It kind of irks me the wrong way when people say it's not worth it or never do it to a NA engine because it will blow up. If you understand the mechanical limitations of your engine and plan your setup right, you'll never blow it up. In fact, on the NA motors, your weak point is the rods. They'll grenade under boost pressure long before the sleeves will crack. The primary reason the sleeves crack is not from overboost (unless you're running ridiculous boost), it's from detonation.

 

Hell, there are completely open deck turbo motors from Subaru that are capable of decent boost pressure, take a look at the EJ20G, EJ20X, EJ20K, EJ20Y, EJ206, EJ208. All stock blocks, open deck, and turbocharged (the last two twin turbo).

What fun is it buying a new car? You learn NOTHING from doing that!

 

 

 

A friend of mine just boosted his 02 Impreza Wagon. Bone Stock EJ251, Stock ECU, stock 02 WRX turbo up/downpipe and wastegate, ebay BOV, 500cc injectors, and a walbro upgraded fuel pump for around $800. Runs 8 psi all day long. Granted it's not a speed wagon or sleeper by any means, but it's a fun car to drive and a nice surprise kick in the pants leaving you to plan your full turbo build.

 

True. I don't have the money to buy a different car anyway, so it would be great if I can boost this one. The main problem with big projects on the car is that it is my daily so it can't be down for too long, maybe a week.

 

What differences are there between the Impreza and Legacy in terms of boosting like that? I would think they would be very similar, but I don't know much about them.

A small boost like that is what I'm looking for so if I can I would like to do something similar to that.

i know a thing or two about a project on a daily. my daily has been off the road for 3 years and i been driving my antique truck. if you dont have reliable second vehicle don't do it!

You're going to learn when shopping for parts that Subarus are giant Legos.

 

The quickest way to do this is to use WRX take off parts, eBay, and salvage yard parts.

 

Parts List:

 

02-04 WRX or STI Engine Cradle (wrecked car, 05+ STI has a different mounting for the steering rack)

02-07 WRX TD04 Turbo

02-07 WRX Up Pipe

02-07 WRX Downpipe

02-07 WRX Turbo 1 piece headers (you can use a stock WRX exhaust manifold, but it may not clear your water pump outlet)

06-07 WRX or STI TMIC (02-05 will work but they're larger and may require modification to the top lip of your firewall)

Some assorted silicone hoses and reducers to plumb your boost pressure lines

Walbro Fuel Pump (optional, but needed if you upgrade your injectors)

WRX blue top injectors (optional. stock is 280cc, good for about 6 psi)

Any BOV of choice (space may be an issue)

 

The install:

 

It's pretty straightforward from here. Remember the bit about Legos, everything bolts on pretty easily with little modification. You may need to get creative to make things fit 100%.

 

Get yourself some coolant hose and two 2-3/4" to 1/2" T connectors to fit the heater core hoses. You'll also need a 1/8" brass tee for the oil feed line. Use some good braided hose. This gets screwed into where the existing oil pressure switch is. For the oil return line you can either drill into the oil pan or valve cover or plumb it into the valve cover breather port (not recommended but works in a pinch if you can't drill or tap). It's recommended you return to the oil pan or valve cover as with going to the valve cover breather may cause the line to kink and will blow the seals in the turbo. If you go with the other return methods, use a 90 degree elbow for the same reason as before.

 

Afterthoughts:

 

This is a collective of the research I've done over the course of a year to find the best formula for boosting a NA motor. Many of sources of information came from threads on here, RS25, and NASIOC. The conversion can be done in two stages. First stage, Prep work, can be done in one weekend. This includes installing fittings, reworking vacuum lines, installing the engine cradle, etc. Once that is done, the second stage, the turbo bits can be installed. Like I said, people have boosted NA motors with great success. In stock form, your engine won't allow more than 6 psi on stock injectors. It'll fall flat on it's face due to running out of fuel, so you can adjust the wastegate to open around 6 psi. It's enough for a nice kick in the pants. The turbo is good for around 14-16 psi and over 10 you'll want a piggyback or standalone ECU which will probably set you back as much as you spent in total boosting your engine.

Alright thanks. I'll look more into that. I've also considered just doing an STI swap. It will probably come to time and money.

You're going to learn when shopping for parts that Subarus are giant Legos.

 

Parts List:

 

02-04 WRX or STI Engine Cradle (wrecked car, 05+ STI has a different mounting for the steering rack)

02-07 WRX TD04 Turbo

02-07 WRX Up Pipe

02-07 WRX Downpipe

02-07 WRX Turbo 1 piece headers (you can use a stock WRX exhaust manifold, but it may not clear your water pump outlet)

06-07 WRX or STI TMIC (02-05 will work but they're larger and may require modification to the top lip of your firewall)

Some assorted silicone hoses and reducers to plumb your boost pressure lines

Walbro Fuel Pump (optional, but needed if you upgrade your injectors)

WRX blue top injectors (optional. stock is 280cc, good for about 6 psi)

Any BOV of choice (space may be an issue)

 

 

You just made my day. Looking at two different project ideas for my son today, but you might have overshadowed them both....

You just made my day. Looking at two different project ideas for my son today, but you might have overshadowed them both....

 

You're welcome. I've been researching this for almost a year and have almost all of it down pat. Always finding out more things that can be done better. A year ago I pursued this avenue because I wanted boost but didn't want the hassle of rewiring my whole car to swap in a turbo motor. When I came across the EJ20G and EJ20X locally for less than a grand, that original plan went out the window. My original thought process with boosting the stock NA was that on the off chance I did blow up the motor due to my own dumbassery, I had a spare EJ25D sitting on the shelf waiting for a car to put it in and wouldn't have to undo any wiring. It would just work.

If you get an STI/WRX front crossmember, you need to shim your front control arms. WRX control arms have a 55mm front bushing, your stock NA control arms are 50mm IIRC. Or get the matching control arms and have a 20mm wider track in the front.

 

Mechanically, boosting any EJ motor is easy - it's the engine management at always becomes an issue. I have not seen an reliable piggyback solution - for some reason, the OEM ECU finds a way to screw it up (check RS25 and see all the old threads about this). By the time you get a good stand-alone engine management, you're well on your way to an engine harness merge and engine swap in terms of cost.

 

<--- guy who had a swapped 3rd gen legacy for 8 years.