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Old 08-28-2005, 11:17 AM   #1
Perdue
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Join Date: Mar 2004
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98 Legacy GT
04 Dakota QC 4x4

Default 1998 4EAT...how much HP will it hold?

I'm pondering a swap with some seriousness now that I have my brakes and suspension done. I'd like to get a STi block and put my heads and intake on it (from my EJ22), then use something like Rallitek's Perfect Power to tune it (Not sure that I'll be able to go to the engine's fullest abilities, but that's the plan at the moment). I'd like to keep my transmission though, which is the sluggish 4EAT, as for the moment, it'd seem more cost effective. I'm assuming I'd get maybe 270 crank with everything stock STi with the acception of my SOHC heads and my intake manifold, that is if the PP well let me dump enough fuel into the motor. Will a 4EAT hold that much power? What are my chances that I'll blow the poor little transmission to pieces?
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Old 08-28-2005, 04:38 PM   #2
Teh Legacy
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I'd highly suggest sourcing a different set of heads. The EJ22 will simply not flow enough. I'd suggest a set of SOHC EJ25 heads from a RS or MY0+ Legacy GT.

Jonathan
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Old 08-28-2005, 05:13 PM   #3
ballitch
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if you use the EJ22 heads your CR will be raised from the stock STI CR ,if you have Phase II heads, which you do. this will require you to use a higher grade of gas, it is also true that the SOHC EJ25 heads flow alot better than EJ22 heads, but if you are planning to turbo this motor you probably dont want the EJ22 heads on that block, they dont flow as well and you dont want to stack a high comp. motor with boost. unless you have a way to tune it. as far as your tranny goes, the 4EAT tranny is pretty stout, i dont know if would reliably hold 270 crank HP, but oyu can try to get a shift kit and tranny cooler as added insurance, but those might just prolong the inevitable.
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Old 08-28-2005, 06:23 PM   #4
Subietonic
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I've read several posters on here who reliably get the amount of HP you're looking from the engine to the ground through the 4EAT. That would not be a worry in my opinion. Getting that much HP with the block and the SOHC 2.2 heads would be a way-less than optimal route and probably won't generate that kind of power reliably.

Might as well source a set of 2.5 Phase I DOHC heads and put them on your engine, especially since you're building it out from an STI block. You will need a DOHC ECU and wiring to make the heads work as there are crank and cam sensor issues to deal with that are not present on the 2.2 SOHC. And you'll also need some engine management to handle the boosting process when it's running.

Good luck and keep us appraised.
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Old 08-28-2005, 08:30 PM   #5
xcntrk75
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My 4EAT couldn't even hold the stock 2.5 power. Went south with less than 100k miles on it... Must admit now however, I'm glad it did cuz the 5MT is soo much better...
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Old 08-28-2005, 09:02 PM   #6
Perdue
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I'd like to keep my heads so that I don't have to wire in a completely new ECU...that's sort of the point. Otherwise I'd just swap in the full motor: block, heads, intake and all. I'd like to be able to keep my heads and intake manifold in order to maintain the current wiring and simply use a Plug and Play Piggyback. I'd figure I'd have to run Premium grade gas to begin with, but just because I put on the SOHC EJ22 heads, I'd have to run even higher? I don't see how the compression ratios could be THAT different.
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Old 08-28-2005, 10:24 PM   #7
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If you are going to run Forced Induction on this engine i wouldn't run the 2.2 heads on that engine. It's probably not a good idea with the compression ratio you're going to have with the combination-it's going to be in the nieghborhood of 8.5:1 maybe even higher than that.

You would be able to have a lot more boost fun with the 2.5 heads on that block


~Mike
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Old 08-29-2005, 06:23 AM   #8
Perdue
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well, if I'm going to have to do all the rewiring to put in a new ECU, I'm probably not going to do a swap. I was looking for something where I could build and engine and then swap it in and tune it, as this is a daily driver. Guess if there's no way to lower the compression ration with these heads, I won't be doing a swap.
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Old 08-29-2005, 09:41 AM   #9
xcntrk75
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If you can do the wiring, then it opens your options up considerably including swapping out that 4EAT. The wiring is not bad at all given the proper preparation and research. Many have done it, the information is here, and any problem or issues get solved with the help of other forum swappers.

Most people say the wiring is more difficult then the mechanical aspect of a swap. In my experience, this was the exact opposite. The wiring was easier for me then swapping motors, crossmembers, transmissions, rear diffs, driveshafts, and everything to go AT -> MT. These mechanical tasks took me nearly 2-weeks to complete where the wiring was about 3 days.

If your only reservation is the wiring (which it is for everybody) then I say DO IT..!
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Old 08-29-2005, 10:28 AM   #10
Subietonic
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As others have indicated, if you're going to swap in the STI short block, go the whole route and get a balanced, sorted, FI "system". Cobbling together the bits that you're talking about will net you a hobbled engine/drivetrain that ultimately, you will not be satisfied with at all.

Realistically, if this is your daily driver and you can't take it down, out-of-commission, for a couple to several weeks, then this would be a non-starter IMHO. If you're looking to pop out the old block/heads and put the STI block and your 2.2 heads in on the weekend, that's probably doable, but not with FI on top of that. There's just too much in the mix to make that happen, especially if you want any sleep in there.

Since it sounds like you have the block already, do you have the whole engine? If you want to go the FI route, recommend that you spend some time planning, seriously laying out your pieces and the sequencing that you will need to do to implement the upgrade, including the electrical/electronics that need to go into it all. This may take you a few more months of prep work but you'll be much more content with the final result than with your initial approach.

Good luck on whichever route you choose and keep us appraised.

Dale
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Old 08-29-2005, 03:54 PM   #11
Perdue
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I don't have the block or anything yet. The wiring scares me a good bit though, and there's NO ONE in the area who's done a swap, much less rewired an ECU. I would basically be without much help, at least from anyone who's ever done this before. I'm thinking about just going with a cam regrind, pullies, and some EM and finishing out my preformance "upgrades" for the time being. I would like to do a full engine/drivetrain swap, but it looks like I'm simply not going to have the ability to do so.
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Old 08-29-2005, 06:28 PM   #12
xcntrk75
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You could always BUY a swap project. Seems to be a popular thing nowadays, to buy a swapped Subaru (typically GC for obvious reasons) They go for a pretty steep penny but even I would let mine go for the right price
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Old 08-30-2005, 05:36 PM   #13
Perdue
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I've got too much money in this car to turn around and put more into another "project"
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