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Impreza EJ20 N/A mods?


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Hi everyone, I just bought a GF (with naturaly aspirated EJ20) for really cheap, just to have fun, to start wrenching. I have NO experience with working on cars except things like changing oil, brake pads, calipers, discs, spark plugs..just the basic stuff. I bought the car to experiment, it was 200€, its not road legal, I expect Im gonna screw up at some point and blow the engine. So don't even go there - I know I don't have the experience, that's why I bought the car. Question is - what mods can I do to the engine that would actually increase its power? Something I could do at home, by myself I want to go the NA way, Im not gonna turbo it, not an option. Neither is a swap - I want to work on the engine, not swap it, even though that might be the best way to get more hp. Less restrictive exhaust? Improve the airflow to the engine? Better cams? Which ones? Bigger throttle body?

 

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Best thing to make your car fast is buy a binned wrx and transplant the engine

 

Subarus without turbos dont go much faster even piling loads of money into them.you need a turbo

If you must spend money focus on handling mate thats where you will notice improvements paying off

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What I would like to achieve is 100ish kW (134hp) or at least be in that area..95kW is good enough. It is 85kW (114hp) from factory, I think that should be achievable. It's not like I'm aiming for the big numbers like 150kW at the wheels, I'm just looking for a way in, start working on th engine.
100kW for a naturaly aspirated 2litre engine is something many manufacturers offer from factory.

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Well as with any n/a car you could look at

Exhaust system with decat

Induction kit

If you get borla headers you can make it sound like a proper turbo

Then things get expensive with options such as porting and polishing ect 

Ive had 3 sports and i loved them and they satisfied my urge untill i could get an sti

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Wotcha and welcome.

if you are looking to remain NA there are some interesting things you could do but they can be expensive.

Individual throttle bodies

oversize valves

ported inlet

skim the head then fit high comp pistons

polish / lighten and balance the rods and crank (possible knife edge grind crank?)

cams can vary in profile so dependant on what you want the engine power delivery to be lift and duration will vary - ultimately you could go for a bespoke profile to suit your requirements but if it doesn't have the variable valve timing sticks (AVCS) you could put that in place

My 2.0 NA RX allegedly has 156bhp from factory

As you are doing as a learning experience check and see if it has a rear thrust bearing fitted - if not that could be your first mod

What ever you decide keep a camera handy as we love a good project thread on here :thumbup:

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3 minutes ago, Jay762 said:

Wotcha and welcome.

if you are looking to remain NA there are some interesting things you could do but they can be expensive.

Individual throttle bodies

oversize valves

ported inlet

skim the head then fit high comp pistons

polish / lighten and balance the rods and crank (possible knife edge grind crank?)

cams can vary in profile so dependant on what you want the engine power delivery to be lift and duration will vary - ultimately you could go for a bespoke profile to suit your requirements but if it doesn't have the variable valve timing sticks (AVCS) you could put that in place

My 2.0 NA RX allegedly has 156bhp from factory

As you are doing as a learning experience check and see if it has a rear thrust bearing fitted - if not that could be your first mod

What ever you decide keep a camera handy as we love a good project thread on here :thumbup:

I would LOVE to do individual throttle bodies, but I couldnt find a lot of info on them - what throttle bodies should I get, how to get past MAF, can I run it on stock ECU? Probably not. I found ITBs made by OBX for example, Im not sure about the quality though. Or should I use some motorbike throttle bodies like VW and Honda  guys? Theres not much info on running itbs on EJ20 :/

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2 minutes ago, Drip94 said:

I would LOVE to do individual throttle bodies, but I couldnt find a lot of info on them - what throttle bodies should I get, how to get past MAF, can I run it on stock ECU? Probably not. I found ITBs made by OBX for example, Im not sure about the quality though. Or should I use some motorbike throttle bodies like VW and Honda  guys? Theres not much info on running itbs on EJ20 :/

The ITB's would be dependant on what your flow requirements are - at a basic thumb in wind check diameter of the existing manifold or an STI manifold (not sure if any difference) take into consideration any increase in size you would be making to the manifold with a porting tool and that gives you a size to start researching what is available. Yes I would suggest an after market ECU to translate x4 feeds from the ITB's, plus if it was me going for ITB's I would be modifying the exhaust manifold with additional wideband sensors to ensure each cylinder is getting the air fuel ratio spot on - otherwise why go to expense and trouble of ITB's?

Jenvey are a good make but are at the higher end of the price range.

The MAF will depend on how you modify the manifold to accept ITB's - if you integrate and retain a single air feed to the manifold you could keep the MAF 

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  • 3 years later...
On 2/9/2017 at 12:27 PM, Drip94 said:

I would LOVE to do individual throttle bodies, but I couldnt find a lot of info on them - what throttle bodies should I get, how to get past MAF, can I run it on stock ECU? Probably not. I found ITBs made by OBX for example, Im not sure about the quality though. Or should I use some motorbike throttle bodies like VW and Honda  guys? Theres not much info on running itbs on EJ20 😕

Hi Guys, has anyone using a n/a EJ20 swapped to a turbo crank? Wondering if it will run probably as long as its kept n/a? Any helpful ideas welcome. Please no undermining. dkanomi@hotmail.com

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