Hey all! I could really use some help with my sti swap! 98GT

[LegacSTI]

First of all, thanks to everyone on this site who has posted anything to help out a fellowsubatrooper. There are so many awesome posts here, and never (almost) any negativity or smack talkin'. I have searched the site to the best of my ability, and although there are many people/posts here about engine swaps, I still hope that there is someone willing to let me pm them back and fourth, or can make a guide for an STI/ 98 LGT swap. I have done a lot of engine work, and builds in the past- so the basics and inclinations are all there, i just know that the advice of someone who has done this before is invaluable. So, basically what ive got is a '98 legacy 2.5 gt with a blown head gasket. Instead of buying a new gasket set, i found myself a 2.5l STi motor with 35,000 on it. Ive got the motor, the stock sti ecu, the intercooler, etc.. everything i need (i think, like i said i could use a point in the right direction) except for: steering rack, lower crossmember, clamps hoses and all the little stuff. I also wasn't able to get the tranny. My plan is to make the swap with my existing tranny- after a rebuild kit done myself. i know i should bite the bullet and get the 6 spd. with dccd, since i plan to someday anyway and dont wanna go through the wiring twice- but im an idiot and am not going to at this time. So thats pretty much it, i just really want to get hooked up with somebody who has done this and can help me with the snags i know im going to hit. the wiring issue is going to kill me! If there is a schematic out there which lays out everything- like a post swap schematic i will pay for it! I also will trade parts, or buy a sli sweatshirt or whatever to those who can help me through this process. i plan to start in a week or so, and hope to hear from somebody, anybody!! i need to earn the name LegacSTI, so for now my name is Brady. Thanks for reading my lengthy post!!

[2000gtb]

If you have the right crossmember, everything else but the wiring is bolt on.. with that said, I had a guy named Zephyr do my wiring..

PS.. stock trans wont last long.. my third gear took a dump after 2 weeks.. wasnt even bangin the gears, just boosting..

[LegacSTI]

Thanks man, i think i'll be fine with the actual removal/ installation of the block and accesories- but the real help i am looking for is with the wiring. i would just really like to have a good understanding of how to tackle it before i dive right in. should i try to get an sti harness and go from there? or if somebody has a post installation schematic i will probably try to wire as i go and route on the fly. like i said, i am an idiot for only putting a rebuilt 5 speed in there, i am aware that its probably not going to last long. also, that particular tranny feels like garbage to me anyhow. its just so sloppy feeling! anybody who has performed this swap who can point me in the right direction with hints and tips would be really appreciated! and im serious about a sweatshirt too.

[2000gtb]

You will need the bulk harness that matches the ecu.. I think wiring from scratch will cost more..

[Bookem]

You can notch and reweld the crossmember to clear exhaust instead of sourcing one from a t-leg or retrofitting a wrx crossmember, and ppg the 5mt :grin: .

[mike-tracy]

What year STI motor/ecu? Swapping the mechanicals is easy, it's the wiring that's the main reason most people's swaps never get completed.

My suggestion is to contact shops that do this kind of swap (such as ECS), and ask them for their advice. Should you do a wiring harness merge? Should you do a complete wiring conversion? (you pretty much have to if you have a 2008+ STI). Is your sti swap out of a Canbus car? If so then you have a bioch of a swap, needing to redo every wire in your legacy.

I haven't done the swap, I have watched with interest people who have done them. Turns out 2004 STI swap is the simplest, with the 2005-07's being more difficult due to the engine immobilizer, to the 2008+'s with the aforementioned CANBUS being near impossible.

Also, I haven't seen anyone on here recently who has done the swap (kraziken's the only one that comes to mind). I hate to say it but you might need to do some research on rs25 or nasioc. Secondly, you'll need to download the "factory service manuals" for both cars so you can compare and decide what needs to be done wiring wise. Thirdly, good luck and keep us updated.

[LegacSTI]

Awesome, thanks Mr. mike-tracy! thats the kind of help i was looking for. i can do all the mechanical nuts and bolts stuff just fine, but i need a good old shove in the right direction as far as the wiring goes, and what to watch out for. As far as the year of the motor ive got, i tried all day to decode the engine identification number from the block. turns out, to the best of my knowledge, the year of manufacture can be found on the vin's on the car, but the engine number isnt the full 17 digits and lacks the number/letter for the year made. tomorrow i am going to call the guy who i got the motor from and ask him. the car now has a crawford engine pushing 930bhp! im not joking either, its a fully caged, tricked and tubbed out trailer only race car. ill try to get some pics of it, as its pretty much amazing. my best guess though, it that its a 2004. i know its newer than an '03, and before '06- and i heard him mention '04 before as well. i do not have the ecu, they kept it and re-flashed it for their race car, only to get another one later anyway. the re-flashed one is garbage so it turns out i am in the market. i know i mentioned i had one, but that was before i found out about the flash nonsense. i also think i will try to locate a wrecked sti and take as much of the harness as i can (maybe guages too!) along with its ecu. my first goal, of course, is to make the swap and produce a fast, daily driver that i can rely on. but a second goal, is to make a step by step, pictures included and diagrams a plenty, guide to performing this swap. from what ive read on this and another forum, many people would love to undertake this process but are leary to do so, and if i could somehow help with an "idiots guide", i think it could help a lot of people. but i can only do it if i can get help myself. so i will get the factory manuals, and maybe talk to a shop, and its good to know about the whole canbus thing- it never would have crossed my mind. thanks again! and please keep any hints, tips, and advice coming. i plan to start pulling next week- and will keep everyone posted as i go.

[LegacSTI]

Hello, so it turns out that it is indeed a 2004 sti motor. good news i suppose! only problem now is that the ecu and partial harness that i had a line on is from a 2007. i got ahead of myself, and assumed it would work out. so now im in the market for an '04 ecu and bulk harness. everything i can find online seems to be really expensive, so if anyone has any ideas or of any pick-n-pulls who may have subie stuff, and willing to sell a harness, please let me know. sorry to keep asking for information, but ive got no where else to turn! I would call up ecs and ask them what they would do, but hate to bother professionals making money for novice advice. Peace to all the suba-troopers.

[chuckthefuk]

Good news for you!

Since you bought a 04 EJ257 that means when you locate your ECU you don't have to mess with an immobilizer YAY pre 2005!

So thats one problem delt with.

Other then the basic wiring to your cluster this swap is going to be nightmare. I've gone this route spent countless hours trying to deal with what might and will happen.

Do yourself a favor! Find a COMPLETE harness from an 04 STi the best place to look for these things are Auctions where the entire car has been written off by insurance and the body is being sold for parts. You may need some dealer connections for this route.

You will run into 2 main issues with such an advanced swap:

1) Drive-by-wire. There is no cable throttle so the ECU has to handle throttle request and send it to the throttle body.
2) 2004+ STI's use very finicky throttle electronics which is all located in the damn pedal itself. Without the stock pedal sending the Drive-by-wire signal is difficult to overcome. And not to mention the electronics within the pedal have a range or threshold for the signal to operate properly.

-Chuck