Mild EJ25 Build

Trying to get some advice on a motor build. I have a mild built ej25 in my 98 Legacy GT. PnP stock heads and intake manifold, Borla headers, stainless 2.25" exhaust w/a Flowmaster super 10 and high flow cat, 8mm plug wires, injen cai, and stock internals. I drive it every day and it has 185k and a halfway decent body, especially for a Maine car where I live. It's probably the fastest car I've had yet, and I've gotten it up to 135 with a little to go on the highway. The car also has a stage 2 clutch and a ton of suspension parts and so now I wanna focus more on the engine. I want more power but it needs to be really reliable since I do have a loan on it for 2 more years and it can't break the bank, so no turbo swaps. I was thinking about getting a lightweight crank pulley, MSD ignition coil, getting my cams ground from Delta, a 180* thermostat, intake manifold spacers, and a lightweight flywheel. I've modified every vehicle I've owned at least a bit and am also currently building my 86 Camaro w/a 383 stroker, so I have no problems turning a wrench, although this is my first fuel injected vehicle I've really built, so I was just looking for feedback, ideas, advice, etc. on my build idea. I don't have a specific power goal in mind, just the biggest bang for my buck, and I'd like to get the car as close to a 150mph car as possible. I also would like to get some form of engine managment, but I've been told that that is pretty much nonexistent for those motors unless you go to a full standalone setup.

135 is nice. I've had my bone stonck 98 LGT 5MT wagon up to 126. It had a bit more to go but I had to hit the brakes. Speak of brakes, I suggest upgrading them as well. The Power Stop brake kit cost a bit over $300 with shipping and it yields great results. I know a few people who have installed it on their Subies and love it.

 

After that, continue with the engine upgrades. A lightweight pulley, MSD coil, and the Delta cams will yield the best gains for the money. Beyond those upgrades, personally, I don't think anything else is really worth the time and money.

 

Engine management is impossible unless you add a piggyback system or go full stand alone. The stock ECU is cannot retain a re-flash. So upgrades like injectors, fuel pump, etc. become pointless. One you get past the first few mods, everything else is just extreme unless you go turbo. Plus, the internals of the EJ25D are weak and will not handle a lot of power well. Especially if the motor has overheated at any point over it's lifespan.e

 

Stick all the extra into your Camaro. My 1986 Z28 Camaro is bone stock, though. I have no plans to upgrade anything at any point. But, if I were in your position, I'd take all my extra money and spend it restoring my Camaro and not worry about making my Subie especially fast.

Trying to get some advice on a motor build. I have a mild built ej25 in my 98 Legacy GT. PnP stock heads and intake manifold, Borla headers, stainless 2.25" exhaust w/a Flowmaster super 10 and high flow cat, 8mm plug wires, injen cai, and stock internals. I drive it every day and it has 185k and a halfway decent body, especially for a Maine car where I live. It's probably the fastest car I've had yet, and I've gotten it up to 135 with a little to go on the highway. The car also has a stage 2 clutch and a ton of suspension parts and so now I wanna focus more on the engine. I want more power but it needs to be really reliable since I do have a loan on it for 2 more years and it can't break the bank, so no turbo swaps. I was thinking about getting a lightweight crank pulley, MSD ignition coil, getting my cams ground from Delta, a 180* thermostat, intake manifold spacers, and a lightweight flywheel. I've modified every vehicle I've owned at least a bit and am also currently building my 86 Camaro w/a 383 stroker, so I have no problems turning a wrench, although this is my first fuel injected vehicle I've really built, so I was just looking for feedback, ideas, advice, etc. on my build idea. I don't have a specific power goal in mind, just the biggest bang for my buck, and I'd like to get the car as close to a 150mph car as possible. I also would like to get some form of engine managment, but I've been told that that is pretty much nonexistent for those motors unless you go to a full standalone setup.

 

96 25D heads would be a great start the direction of early peak TQ. Head work to that pair would restore any midrange power that you're used to. Intake manifold spacers, some NGK no resistance racing plugs & wiring, MSD 8239 coil, & heat wrapped header are all I can think of at the moment. If you're looking for more power in general, 22E heads on a 25D block will yield good low to midrange power with headwork done (about 185ish bhp).

The 96 25D heads were ported differently and had different cam profiles (I've compared my heads). That's why the torque peaked lower in the RPM band. It also peaked lower because it made lower power in general. Plus, the pistons on that motor were different. So, the fuel quench was different. There are a multitude of reasons the torque peaked lower. I'm not sure if any of them really make it a useful head...

 

If you went frankenmotor, I would port a set of 22T heads and an intake manifold and put them on top of the 25D lower end. That will probably yield you around 200 hp with the porting.

2.25" exhaust is going to be too restrictive, you'll need to go 2.5-2.75"

Turbo engine.