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Old 01-11-2006, 02:53 PM   #1
jaltman
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Default Want to switch from a blown stock 2.0 to an 2.5 sti short block

I Currently have a blown stock 04 Wrx (rod bearing) and am hopefully now taking the opportunity in having to rip the motor apart to upgrade to an 2.5 sti short block. But before I make this decision apparently its not as simple as taking a 2.5 block and throwing it in there and calling it a day. The only mods that I have done are TB exhaust, uppipe, boost controller and bov. Plan on sticking with the stock turbo for now but would really like to upgrade to 2.5. Any input from people who have done this swap before or know how to achieve this and have the car running right (like tuning needs or mechanical) please post. I'll take all the advise I can get, last thing I want is another thrown rod. Thanx
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Old 01-11-2006, 03:45 PM   #2
flwrx
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You will for sure need engine management.

If the car is not your daily driver and you can get by without it for a while, Id save up for some other parts. Stock wrx turbo will work with 2.5, but its a lousy combo. If you can, you should save up for at least a moderate upgrade turbo(vf30, vf39) and injectors and do it all at the same time. Plus youre gonna need a timing belt, head gaskets, oil/water pumps, etc.
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Old 01-11-2006, 03:56 PM   #3
SleepinCreppin02
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flwrx is right on with that i did the crawford performance s2 swap the top end from your 2.0 works perfectly it just changes out the whole bottom end but i have a vf39 and sti pinks plus youll need engine management i suggest going with the ecutek reflash and get rid of your bov and go back to stock it just a better unit good luck
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Old 01-11-2006, 05:24 PM   #4
the_colombian
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by just putting the stock sti block your compression ratio would rise making it harder to tune with pump gas and I think there are some other issues as well but Im not aware of exactly what they are. lower compression pistons will do the trick or you can just purchase a 2.5 hybrid ready block from someone like crawford or axxis or whoever you like.
Very good upgrade and I am very happy with mine.
Keep your stock turbo untill you save enough for something the size of a td06-20g or bigger if you like. The stock wrx turbo will work untill then. If you have money left, I would recommend upgrading your cams to at least STi cams. Wrx cams suck when you try to make over 300 whp on pump. Its do-able but not efficient. Wish I would have had enough for cams.
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Old 01-11-2006, 08:48 PM   #5
jaltman
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Quote:
Originally Posted by flwrx
You will for sure need engine management.

If the car is not your daily driver and you can get by without it for a while, Id save up for some other parts. Stock wrx turbo will work with 2.5, but its a lousy combo. If you can, you should save up for at least a moderate upgrade turbo(vf30, vf39) and injectors and do it all at the same time. Plus youre gonna need a timing belt, head gaskets, oil/water pumps, etc.

I already plan on replacing and upgrading the timing belt to either an sti or greddy unit just do to loss of timing and stretching from the stock unit, and the fact that I will just have to replace it in another 50,000 miles if I dont. The same goes for the water pump. But this is a daily driver that I wish I could invest more money on at this time, but the rod knocking was an unexpected event. Which is why my turbo, injector and tuning money is being dipped into just a bit. Wish I could binge on a turbo upgrade but its not practical at this time. But for some reason I'm thinking a larger bottom end is LOL. Just trying to go with the "If it aint broke dont fix it" philosophy as
much as possible right now.
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Old 01-11-2006, 09:02 PM   #6
jaltman
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Thanx, keep the input coming, im soaking it all in, and also if there are any ?'s or concerns on my plans in detail, please post.
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Old 01-11-2006, 09:20 PM   #7
dan240
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I second the headwork. Do what ever you can afford (port/polish and cams) because that's what will be limiting you later. The bolt on stuff is easy down the road, taking apart the engine again will be a bear.

Dan
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Old 01-11-2006, 10:20 PM   #8
ipozestu
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I am currently in the middle of a hybrid swap. 12/15/05 I was diagnosed with rod knock, my motor only had 27k on it. Subaru said FU and I was on my own. I opted to go with a S2 shorty from Crawford. They are able to maintain the stock 2.0 compression ratio of 8:1. This make for a very nice transition to the 2.0 heads. I am trying to work with everyone involved on this project to a conservative, reliable, daily driver. That will be easily tunable and will put down impressive numbers.
EQ Tuning will be bringing this beast to life.
parts list:
Crawford S2 2.5L block
Stock WRX heads
APR head studs
OEM head gaskets
Gruppe-s V2 ceramic coated manifold
PDE Flex Uppipe
TD06-18g Deadbolt turbo
15lb Wastegate actuator
34mm Flapper
APS catless 3" TBE
JDM STI TMIC
APS TMIC BOV
RC Engineering 750cc custom injectors
Walbro 255 Fuel pump
here is a link to my thread on i-club (insert "www.")
i-club.com/forums/showthread.php?p=1341378#post1341378
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Old 01-11-2006, 10:39 PM   #9
the_colombian
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^ seems similar to my setup but I will be adding a td06-20g soon instead of the 18 to try and make up for the top end that my head wont make.
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Old 01-11-2006, 10:51 PM   #10
ipozestu
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I opted for the 18g instead due to posibility of excessive heat soak from the 20g. I don't have to dough for a FMIC. If later I decide to go with a 20g and FMIC or alky inject; I should have no problem with the DB turbo. It shouls be rolling with a base tune, on Mon or Tues next week. I can't wait. 1000-1200 miles and it'll be time see what that sucker will put down. Fingers are crossed for good numbers.
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Old 01-12-2006, 12:33 PM   #11
jaltman
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Default

bumpers
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Old 01-12-2006, 12:34 PM   #12
GTScoob
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*Subscribes.

I'd like to get an 18G for my car in another couple months and then if I ever blew the motor upgrade to a 2.5 and have a very similar setup.
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Old 01-12-2006, 12:56 PM   #13
bboy
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Quote:
Originally Posted by the_colombian
by just putting the stock sti block your compression ratio would rise making it harder to tune with pump gas and I think there are some other issues as well
The CR issues can be dealt with. Just don't raise it further by changing to pistons with a higher CR or decking your block/heads a lot.

Their are some ECU-wiring things to know about too. You'll have to find someone more in the know for that stuff.

Consider finding a used 6 speed (in fact I know of a whole used powertrain from a 2004 STI--not mine of course).
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Old 01-13-2006, 06:09 AM   #14
WRX2FFU
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My question for a future swap. Will the oil pan and windage tray swap over? which oil pump do you use? I think the 2.0 pump and 2.5 pump are the same.


BTW jaltman, did you find out why the rod bearing failed? was it oil starvation or some other cause?

You said it was stock?

I worry about mine sometimes...... 285whp/241tq 32,000 hard miles.
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Old 01-13-2006, 10:19 AM   #15
jaltman
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Was not oil starvation for sure because there was plenty of oil. I also drove the car very hard and was meticulous about my oil changes. I've this question myself to a couple of friends of mine, one being a subaru master tech and enthusiast and he said that it could have been me running to thick of an oil in my car. Me being a honda guy before purchasing my scooby two years ago always ran 20/50W in the summer time and 10/30W in the winter (if you want to call winter in florida winter) because of it being so hot in florida and never had any probs. But now Im hearing its bad to switch weights for one, and bad to run anything thicker than the 5/30W suggested. Was running synthetic also which is naturally thinner then reg., and I also did wait until about 18,000 miles before switching to synthetic. I never thought that this was going to happen, not yet anyways because for the most part it is stock and i never ran over 16 lbs of boost.
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Old 01-13-2006, 10:27 AM   #16
jaltman
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Even with me boost spiking if it ever had, which is very common with scoobies running boost controllers, I could understand a whole in the piston from leaning out, but not a rod failing. And in the two years of me owning the car i have hit fuel cut twice. Both times being over a year ago.
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Old 01-13-2006, 01:23 PM   #17
ipozestu
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Mine crapped out due to oil starvation during start. See, I installed a dual filter relocator, it is believed that while the oil was hot it filled all channels with the block and the hose connecting it to the filter. After cooling the oil shrank and drained out of the block into the filters. This caused a dry start condition. All of the products I was using were from AMSOIL. They are very concerned with the premature failure of my motor. I have to ship it out the them after I pick my car up. My fingers are crossed for warranty repair compensation from AMSOIL. They really stand by thier product. Chances are pretty good I'll have something funneled my way. One other conditon that may have caused it is was prolonged detonation. I had nothing major on my car prior to this. UP, TBE, Manifold. I did run it with those mods for probably 20k of the engines life without having it tuned. THe factory closed to open loop time delay coupled with my driving habits this senario also seems likely. IMO if you have any intent of "Driving" your car the way it should be driven. Regardless if you have mods, you have to have this blip tuned out. It will destroy your engine. The proof is in the pudding. That if why we are in this discussion.
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Old 01-14-2006, 05:16 AM   #18
cubuff
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You will not need engine management to swap the block. Your stock ecu will take care of the extra fuel needed. It would make everything more optimal but your not going to BLOW anything up by swaping the block. Bigger turbo and injectors will than require you to get EM. But until then have fun with a super fast spooling car with no topend.

oh just get rip of your boost controller before and run the stock ecu boost settings.

If I were you though, why you have everything out if you can swing it. Buy a blown sti block with undamaged cylinder walls. Get forged pistons, Cobb rod bearings, cobb main bearings, crower stg2 cams (or wait for helix cams that come with springs and retainers), ARP headstuds, cometic headgaskets and then put your choice or bigger turbo injector combo with ABCD or E engine management tuned by the best toooner in your area. That would be an awesome setup which is ironically enough exactly what I have.. Have fun just do things right the first time so you dont have to spend more money later.

Last edited by cubuff; 01-14-2006 at 05:28 AM.
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Old 01-15-2006, 04:21 AM   #19
ka mano
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Default I checked your thread over there...

Nice pics on i-club, impozesto. Hope your tune goes well!

Last edited by ka mano; 01-15-2006 at 05:39 AM.
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Old 01-15-2006, 08:50 AM   #20
ScoobyNubieToo!
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PM swift2fly....he just swapped in an STI shortblock a few months ago.
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Old 01-15-2006, 10:16 AM   #21
sheikthin
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same thing happened to me, i spun a rod bearing and was forced to do the ej25 swap early. i already had ordered an fpgreen, 750cc injectors, front mount, wideband, etc before hand, so i had those to put on while the engine was out of the car. from what information i gathered, going with the stock oil pump and water pump was just fine, but i had low miles on mine. i wish i would have replaced the timing belt when i did it cause of course that just snapped last week, but thats the price you pay for having to cut some corners. i used the stock wrx heads with a light polish job, and they seemed to run just fine. i am making decent power, just passed break in not too long ago, and need to find a decent utec tuner thats relatively close to where i am. everything else bolts right up, including the oil pan. the blocks are basically the same, minus the semi-closed deck, larger displacement and an extra breather hole on top. its much easier to swap the injectors, turbo, etc with the engine out so if you can swing it, go for it.
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Old 01-15-2006, 12:50 PM   #22
jaltman
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Quote:
Originally Posted by jaltman
always ran 20/50W in the summer time and 10/30W in the winter (if you want to call winter in florida winter) because of it being so hot in florida and never had any probs. But now Im hearing its bad to switch weights for one, and bad to run anything thicker than the 5/30W suggested.

Any input on the oil issue?

And it sux that everybody thats done the swap upgraded the turbo and injectors, wish it were that easy for me
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Old 01-15-2006, 03:05 PM   #23
ka mano
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BTW, what boost controller you were using?
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Old 01-15-2006, 03:28 PM   #24
senortighto
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what is the approximate cost of doing all this? (block, cams, install)
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Old 01-15-2006, 11:12 PM   #25
TypeC
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Quote:
Originally Posted by senortighto
what is the approximate cost of doing all this? (block, cams, install)
If you can't do it yourself and are going to pay labor, you might as well sell your car and buy an STi. There are a LOT of man hours to do this.

It took me a good while and I've rebuild several EJ's. I dunno, for the whole thing I'm going to guess around 20-35 shop hours (depending on who is doing it).

Search the 2.0 forum as we've detailed the items needed for the swap in several threads. It's a pretty simple afair.

-C
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