1.8 n/a to 2.5 n/a

tony_0227 · 04-05-2009, 04:40 AM

i have a 93 L with a 1.8. i have a 98 2.5 dohc n/a. my question is how hard will it be to swap the 2.5 into my L. i have read that all i have to do is swap the throttle body over and i can use my 1.8 ecu to run the motor is this true thanks for the help

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Storm · 04-06-2009, 07:34 AM

I don't think you'll even have to swap the TB over. The IAC's wire up and run similar, even though they are physically different. Just swap the EJ18 engine harness over to the EJ25 and plug the sensors in, swapping over any of your original ones that aren't on the EJ25. The ECU for the EJ18 doesn't look for a knock sensor and I don't know if you have an EGR system on your current motor. The EJ25D will have the EGR system, which you can leave alone or remove and block off. Add in a tube between the intake (after the MAF) and the IAC, then motor on.

The ECU will run the motor fine, even though it's bigger. You may want to look into a piggyback fuel controller to dial it in a little better, but it's not necessary.

Jay Storm

gtu89rx7 · 04-06-2009, 10:15 AM

i believe you should be able to keep your 1.8 harness, just plug it into your 2.5 sensors. keep the 1.8 throttle body, you need it for idle control. the only parts you are changing are the 2.5 block and intake manifold.. not sure if the 1.8 exhaust manifold with bolt up. I believe the clutch is the same between 2.5 and 1.8 too

Storm · 04-06-2009, 05:27 PM

I used the EJ25D's external IAC with no problems. It's a 3 wire solenoid. I don't remember if I even had to change the plug end or not. I think it was plug and play on that sensor. There are a couple different sensors between the 2 motors....but it's been so long since I did that particular swap, my memory is a bit foggy. I know that it was an afternoon swap and I simply put the EJ18 harness on the EJ25, and dropped it in the car.

Both are sidefeed injectors, so the clips are the same, almost everything is identical....even the coil!

Jay

tony_0227 · 04-08-2009, 02:16 AM

very cool i was thinking of turboing it not shure though the head gaskets are blown so i have to change them anyway. what would i have to do to tubo the motor since it is a n/a motor to begin with thanks for the help

Storm · 04-08-2009, 06:59 AM

If you want to run more than 6psi, you'll need more than just headgaskets.

If you're going to go turbo, do it once and do it right. A basic WRX swap, including harness swap has been coming down in price over the years. It's your best, most reliable option.

Jay

tony_0227 · 04-08-2009, 11:25 PM

Quote:

Originally Posted by Storm

If you want to run more than 6psi, you'll need more than just headgaskets.

If you're going to go turbo, do it once and do it right. A basic WRX swap, including harness swap has been coming down in price over the years. It's your best, most reliable option.

Jay

yea i know but i allredy have a 2.5 what would i need to torbo it. new pistons, rods, ect, ect. thanks for the help

ballitch · 04-10-2009, 12:32 AM

I wouldnt suggest going from 1.8 liters of fury, to a turbo EJ25 motor. You go from 110 hp motor, to 165hp motor, 50% increase in power. I would swap in the EJ25 and get used to the car, then in a year or two, swap in (or make your own) a turbo motor.

But if you are adament that you "need" to have a turbo motor, there are many options. Some reading/searching will find you all the answers you need, as well as raise more.

Why isnt there a " turbo your car" FAQ? This comes up so often...

~Josh~

Storm · 04-10-2009, 11:22 AM

^^^ Because it's a GC body. No love here......

Jay

tony_0227 · 04-11-2009, 03:11 AM

thanks for the imput i am still looking at what i want to do. i know i want to turbo it i just want to do it right the first time. is there a diffrence from sti and forged parts. sorry for all the questions this is my first build i am doing myself thanks for all the help

19200 · 04-11-2009, 08:43 AM

I have a similar setup. Works well, except I have a flat spot at about 4500 rpm where it goes lean.

Anyone run into this issue?

Thanks!

tony_0227 · 04-12-2009, 07:03 PM

k i have decided to keep it n/a what are some good cams for the motor

Storm · 04-12-2009, 09:50 PM

Delta Cams are your cheapest option.

Jay

green00gt · 04-12-2009, 11:21 PM

i am also looking for a 2.5 na motor to give my DD some more power over stock where is the best place to look?

Shawn

tony_0227 · 04-14-2009, 01:17 AM

Quote:

Originally Posted by Storm

Delta Cams are your cheapest option.

Jay

was looking at those friend of mine said that they worked well for him. are has anyone used other brands

Storm · 04-14-2009, 06:51 AM

IMHO...."other brands" are way too expensive to even be considered. Nobody else has "off the shelf" grind profiles for an NA application....it's literally ALL for turbo motors. The only logical choice is Delta Cams. They are happy to make cams designed for NA Subarus.

Jay

tony_0227 · 04-14-2009, 06:45 PM

Quote:

Originally Posted by Storm

IMHO...."other brands" are way too expensive to even be considered. Nobody else has "off the shelf" grind profiles for an NA application....it's literally ALL for turbo motors. The only logical choice is Delta Cams. They are happy to make cams designed for NA Subarus.

Jay

cool thanks for the help

urabus555 · 05-01-2009, 08:13 AM

Quote:

Originally Posted by 19200

I have a similar setup. Works well, except I have a flat spot at about 4500 rpm where it goes lean.

I've done a fairly extensive search on this swap and it seems this 'lean' 'flat spot' is common.

Quote:

Originally Posted by Storm

You may want to look into a piggyback fuel controller to dial it in a little better, but it's not necessary.

Jay Storm

Is that the perpose of the piggyback fuel controller? Is there another way to address the issue? Larger injectors?

I'd like to do this swap with my rally car but don't want to have a lean spot...

Thanks

Storm · 05-04-2009, 11:01 AM

Quote:

Originally Posted by urabus555

I've done a fairly extensive search on this swap and it seems this 'lean' 'flat spot' is common.

Is that the perpose of the piggyback fuel controller? Is there another way to address the issue? Larger injectors?

I'd like to do this swap with my rally car but don't want to have a lean spot...

Thanks

That is what I did. I didn't have problems afterwords. YMMV....

Jay

urabus555 · 05-04-2009, 03:53 PM

Quote:

Originally Posted by Storm

That is what I did. I didn't have problems afterwords. YMMV....

Jay

Sorry about the way I asked the question...

I'm assuming that you went with the piggyback fuel controller (not the larger injectors). Which controller did you use?

Thanks

Storm · 05-04-2009, 05:40 PM

^^^ I used an SAFC to dial in the fuel a bit better. I had just come off a 13hr roadtrip, I didn't answer the way I was thinking.....

Jay

ciper · 05-04-2009, 07:09 PM

Quote:

Originally Posted by Storm

^^^ I used an SAFC to dial in the fuel a bit better. I had just come off a 13hr roadtrip, I didn't answer the way I was thinking.....

Care to give a rough idea of your S-AFC settings? This is a fairly common swap and the S-AFC can be had cheap from any number of Honda guys.

Storm · 05-04-2009, 10:45 PM

I can do one better.......I'm not using my SAFC anymore, and the settings should stay permanent during shipment. Make me a reasonable offer and I'll carefully remove the harness from the car.

Jay

lele · 05-14-2009, 09:46 AM

would installing 2.5 dohc n/a from 2004+ impreza be better or have the same issues as mentioned?

ciper · 05-27-2009, 02:11 PM

Quote:

Originally Posted by Storm

I can do one better.......I'm not using my SAFC anymore, and the settings should stay permanent during shipment. Make me a reasonable offer and I'll carefully remove the harness from the car.

Thank you for the offer. I wasn't asking for my direct benefit though,,, I am in the process of a ej22 to ej25 swap! The settings would probably help future swappers and I already have an S-AFC in my closet somewhere.

I want to make my own purely mechanical tuning device. I will put a barbed fitting on the air filter box with a ball valve and then plumb that in after the MAF. This will let me induce a small "leak" and lean the system out as needed. I will be using slightly larger injectors than the ECU had. Unfortunately this system cannot richen the car but that can be done by putting a gob of JB weld into the MAF thereby reducing its diameter.

Yeah I'm ghetto like that

04-05-2009, 04:40 AM	#1
tony_0227 Scooby Newbie Member#: 177300 Join Date: Apr 2008 Chapter/Region: SWIC Location: Las Vegas Vehicle: 93 Subaru White	1.8 n/a to 2.5 n/a i have a 93 L with a 1.8. i have a 98 2.5 dohc n/a. my question is how hard will it be to swap the 2.5 into my L. i have read that all i have to do is swap the throttle body over and i can use my 1.8 ecu to run the motor is this true thanks for the help * Registered users of the site do not see these ads.

04-11-2009, 08:43 AM	#11
19200 Scooby Newbie Member#: 175371 Join Date: Mar 2008	Swap I have a similar setup. Works well, except I have a flat spot at about 4500 rpm where it goes lean. Anyone run into this issue? Thanks!

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04-06-2009, 07:34 AM	#2
Storm Scooby Guru Member#: 5218 Join Date: Mar 2001 Chapter/Region: MWSOC Location: SAUL'S Motorsports Vehicle: 96L Most Over- Developed Beater	I don't think you'll even have to swap the TB over. The IAC's wire up and run similar, even though they are physically different. Just swap the EJ18 engine harness over to the EJ25 and plug the sensors in, swapping over any of your original ones that aren't on the EJ25. The ECU for the EJ18 doesn't look for a knock sensor and I don't know if you have an EGR system on your current motor. The EJ25D will have the EGR system, which you can leave alone or remove and block off. Add in a tube between the intake (after the MAF) and the IAC, then motor on. The ECU will run the motor fine, even though it's bigger. You may want to look into a piggyback fuel controller to dial it in a little better, but it's not necessary. Jay Storm

04-06-2009, 10:15 AM	#3
gtu89rx7 Scooby Newbie Member#: 108029 Join Date: Feb 2006 Chapter/Region: South East Location: Charleston, SC Vehicle: 95 Impreza Outback EJ20G swapped	i believe you should be able to keep your 1.8 harness, just plug it into your 2.5 sensors. keep the 1.8 throttle body, you need it for idle control. the only parts you are changing are the 2.5 block and intake manifold.. not sure if the 1.8 exhaust manifold with bolt up. I believe the clutch is the same between 2.5 and 1.8 too

04-06-2009, 05:27 PM	#4
Storm Scooby Guru Member#: 5218 Join Date: Mar 2001 Chapter/Region: MWSOC Location: SAUL'S Motorsports Vehicle: 96L Most Over- Developed Beater	I used the EJ25D's external IAC with no problems. It's a 3 wire solenoid. I don't remember if I even had to change the plug end or not. I think it was plug and play on that sensor. There are a couple different sensors between the 2 motors....but it's been so long since I did that particular swap, my memory is a bit foggy. I know that it was an afternoon swap and I simply put the EJ18 harness on the EJ25, and dropped it in the car. Both are sidefeed injectors, so the clips are the same, almost everything is identical....even the coil! Jay

04-08-2009, 02:16 AM	#5
tony_0227 Scooby Newbie Member#: 177300 Join Date: Apr 2008 Chapter/Region: SWIC Location: Las Vegas Vehicle: 93 Subaru White	very cool i was thinking of turboing it not shure though the head gaskets are blown so i have to change them anyway. what would i have to do to tubo the motor since it is a n/a motor to begin with thanks for the help

04-08-2009, 06:59 AM	#6
Storm Scooby Guru Member#: 5218 Join Date: Mar 2001 Chapter/Region: MWSOC Location: SAUL'S Motorsports Vehicle: 96L Most Over- Developed Beater	If you want to run more than 6psi, you'll need more than just headgaskets. If you're going to go turbo, do it once and do it right. A basic WRX swap, including harness swap has been coming down in price over the years. It's your best, most reliable option. Jay

04-10-2009, 12:32 AM	#8
ballitch Scooby Specialist Member#: 74907 Join Date: Nov 2004 Chapter/Region: NWIC Location: salem, OR Vehicle: 98 cam'd EJ251 Wrx Tranny,slowr than ish	I wouldnt suggest going from 1.8 liters of fury, to a turbo EJ25 motor. You go from 110 hp motor, to 165hp motor, 50% increase in power. I would swap in the EJ25 and get used to the car, then in a year or two, swap in (or make your own) a turbo motor. But if you are adament that you "need" to have a turbo motor, there are many options. Some reading/searching will find you all the answers you need, as well as raise more. Why isnt there a " turbo your car" FAQ? This comes up so often... ~Josh~

04-10-2009, 11:22 AM	#9
Storm Scooby Guru Member#: 5218 Join Date: Mar 2001 Chapter/Region: MWSOC Location: SAUL'S Motorsports Vehicle: 96L Most Over- Developed Beater	^^^ Because it's a GC body. No love here...... Jay

04-11-2009, 03:11 AM	#10
tony_0227 Scooby Newbie Member#: 177300 Join Date: Apr 2008 Chapter/Region: SWIC Location: Las Vegas Vehicle: 93 Subaru White	thanks for the imput i am still looking at what i want to do. i know i want to turbo it i just want to do it right the first time. is there a diffrence from sti and forged parts. sorry for all the questions this is my first build i am doing myself thanks for all the help

04-12-2009, 07:03 PM	#12
tony_0227 Scooby Newbie Member#: 177300 Join Date: Apr 2008 Chapter/Region: SWIC Location: Las Vegas Vehicle: 93 Subaru White	k i have decided to keep it n/a what are some good cams for the motor

04-12-2009, 09:50 PM	#13
Storm Scooby Guru Member#: 5218 Join Date: Mar 2001 Chapter/Region: MWSOC Location: SAUL'S Motorsports Vehicle: 96L Most Over- Developed Beater	Delta Cams are your cheapest option. Jay

04-12-2009, 11:21 PM	#14
green00gt Scooby Newbie Member#: 94732 Join Date: Aug 2005	i am also looking for a 2.5 na motor to give my DD some more power over stock where is the best place to look? Shawn

04-14-2009, 06:51 AM	#16
Storm Scooby Guru Member#: 5218 Join Date: Mar 2001 Chapter/Region: MWSOC Location: SAUL'S Motorsports Vehicle: 96L Most Over- Developed Beater	IMHO...."other brands" are way too expensive to even be considered. Nobody else has "off the shelf" grind profiles for an NA application....it's literally ALL for turbo motors. The only logical choice is Delta Cams. They are happy to make cams designed for NA Subarus. Jay

05-04-2009, 05:40 PM	#21
Storm Scooby Guru Member#: 5218 Join Date: Mar 2001 Chapter/Region: MWSOC Location: SAUL'S Motorsports Vehicle: 96L Most Over- Developed Beater	^^^ I used an SAFC to dial in the fuel a bit better. I had just come off a 13hr roadtrip, I didn't answer the way I was thinking..... Jay

05-04-2009, 10:45 PM	#23
Storm Scooby Guru Member#: 5218 Join Date: Mar 2001 Chapter/Region: MWSOC Location: SAUL'S Motorsports Vehicle: 96L Most Over- Developed Beater	I can do one better.......I'm not using my SAFC anymore, and the settings should stay permanent during shipment. Make me a reasonable offer and I'll carefully remove the harness from the car. Jay

05-14-2009, 09:46 AM	#24
lele Scooby Newbie Member#: 156792 Join Date: Aug 2007 Chapter/Region: E. Canada Location: Toronto Vehicle: 94 Ver2 STI WRB	would installing 2.5 dohc n/a from 2004+ impreza be better or have the same issues as mentioned?