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Old 09-13-2007, 01:35 AM   #1
03SuBbYWrX
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Default STI cam or wrx cams in 2.5L swap. None AVCS...Please Help

Ok this might seem like a dumb question to some of you but i need to extra feedback. I recently melted a piston to the cylinder wall in cylinder #3 and snapped the rod and some other funky stuff. I am doing an Brand new EJ257 swap with stock 2.0L wrx heads but im wondering weather it's worth it or not to put in sti cams. I realize that if i don't do the sti cams my power band will be shifted way to the left and ill have mass torque but a loss in hp. I do not have the money to do AVCS right now. I guess my question is, is it worth it to put in sti cams to even out the power band. Will i see more improvement with leaving the stock wrx cams in there or spending the extra money to put sti cams in there and having my local shop modify the cams so they will work without AVCS. I have an APS SR30 turbo, turboback cat-less exhaust, cat-less uppipe, fuel pump, bigger injectors, GM boost silinoid, intake, turbo inlet hose, turboxs top mount IC, Turbosmart BOV, STI Type RA gearset, ACT Performance Street Clutch, and an ACT lightweight flywheel. Please help need to know quickly.
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Old 09-13-2007, 01:11 PM   #2
03SuBbYWrX
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please help i need some feedback quickly thanks
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Old 09-13-2007, 01:39 PM   #3
jays05
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The STI cams will give you more top end without any loss of low end. Somebody posted a great comparison graph recently.

http://forums.nasioc.com/forums/show...8&postcount=12
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Old 09-13-2007, 01:47 PM   #4
03SuBbYWrX
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ok well i have been reading a lot lately and people are making it seem like its dumb to put in them without doing anything else cause they say u will lose ur torque and have more hp or something. but i asked my tuner and he said that without them u will have a lot of torgue but a lose in hp. and he told me if i put them in then my powerband will shift up and to the right evening it out so i wanna do it but then i hear all this AVCS stuff but i don't have the money for that.
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Old 09-13-2007, 01:59 PM   #5
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The only difference between the STI and WRX cams (besides AVCS which is easily disabled) is lift. They have the same duration. I really don't see why people build hybrid motors using WRX cams.
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Old 09-13-2007, 02:05 PM   #6
ilivas
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you'll be very unhappy if you use stock cams. I threw in a set of 272 cams in my wrx heads.
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Old 09-13-2007, 02:53 PM   #7
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^^^^^ilivas: If it is running already, how do you like it? Did you lose much low end/ turbo spool with the 272's? Did you need to buy all new buckets to set up your valve lash? Are you still using the stock springs and retainers?

Sorry for all the questions, but I'm thinking of doing this soon. Thanks.
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Old 09-13-2007, 03:44 PM   #8
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I had the same kind of problem with my stock 2.0L engine about 18 months ago. I decided to do the ej257 swap as well, keeping the stock heads, and the stock turbo. After a bit of searching around, I found the general opinion was my car would pull real hard down low, but fall flat on its face at about 5300 rpms. This is because the 2.5L block flows more air then the stock heads can handle. There were three solutions to fix this. First i could do the AVACS heads as well. This was to pricey for me. Second was head work on my stock heads, which was a bit expensive also. The third option was to get cams that would increase the lift of the valves to let more air in and out of the heads. STI cams weren't too expensive or aggressive, and i could get them at my local dealership. It worked out well enough. You just have to have your mechanic tap and plug the holes in the cams used for AVACS.

I dyno at 226whp/248wtq and my car pulls hard all the way to redline.

Hope this helps.
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Old 09-13-2007, 03:45 PM   #9
intercoolerontop
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i have the 2.5 hybrid and the sti cams in the car. yes i would put the cams in, not only are they way lighter than the wrx ones but they make my car pull all the way to redline. BE SURE TO BLOCK OFF THE AVCS HOLES, they are on the intake cams, the two small holes in the front. i suggest welding them shut.
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Old 09-13-2007, 03:47 PM   #10
ilivas
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I dont have alot of lowend.... I have a BIG turbo. Larger than a GT35R. The lack of lowend is mainly the result of the turbo spooling late and low compression (8:1). Buckets were replaced also. I also have DPR valvesprings and retainers.
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Old 09-13-2007, 03:50 PM   #11
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^^^Thanks!
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Old 09-13-2007, 04:29 PM   #12
03SuBbYWrX
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ok guys thanks a lot. i def was gonna get sti cams so i bought a set for 300 from my shop and they are gonna mod the cams to disable the AVCS. for 300 bucks now i talked to my tuner and he said the same thing all of u are saying. the power def drops after about 5800 and ill be unhappy with leaving the stock cams in. so i went ahead and spend 300 plus an hours worth of labor to disable the AVCS on the intake cams. do any of you have a similar setup then me? how much power and torque do you make? thanks for all the help. Ive gonna through so many problems lately. with the trans shattering to not being able to get my turbo tuned for 3 weeks due to a whole bunch of leaks, to melting the piston.

nate02
I had the same kind of problem with my stock 2.0L engine about 18 months ago. I decided to do the ej257 swap as well, keeping the stock heads, and the stock turbo. After a bit of searching around, I found the general opinion was my car would pull real hard down low, but fall flat on its face at about 5300 rpms. This is because the 2.5L block flows more air then the stock heads can handle. There were three solutions to fix this. First i could do the AVACS heads as well. This was to pricey for me. Second was head work on my stock heads, which was a bit expensive also. The third option was to get cams that would increase the lift of the valves to let more air in and out of the heads. STI cams weren't too expensive or aggressive, and i could get them at my local dealership. It worked out well enough. You just have to have your mechanic tap and plug the holes in the cams used for AVACS.

I dyno at 226whp/248wtq and my car pulls hard all the way to redline.

Hope this helps.

did they ever figure out the cause of why it did this. i suspect that it was a failure with that fuel injector going into the #3 head or something along the lines of something to due with failure in just that one cylinder.
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Old 09-13-2007, 07:18 PM   #13
MindzeyeWRX02
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Quote:
Originally Posted by jays05 View Post
The only difference between the STI and WRX cams (besides AVCS which is easily disabled) is lift. They have the same duration. I really don't see why people build hybrid motors using WRX cams.
Because some of use spin a rod bearing and instead of doing a tear down we opt to have the STi SB dropped in and dont have enough $$ to do head work.

But you'll definitely want to upgrade your cams if you can.
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Old 09-14-2007, 12:17 PM   #14
naTe02
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Quote:
Originally Posted by 03SuBbYWrX View Post
did they ever figure out the cause of why it did this. i suspect that it was a failure with that fuel injector going into the #3 head or something along the lines of something to due with failure in just that one cylinder.
I think my engine problems were due to a spun bearing on the #3 cylinder due to oil starvation. Dealership said i was running too rich and there was fuel mixed in with the oil. I ended not using the dealership because everything would cost too much.
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Old 09-14-2007, 12:22 PM   #15
03SuBbYWrX
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ok well all i really know is that piston #3 melted to the cylinder wall due to a LEAN burn. so what i believe happened was the fuel injector failed causing no fuel to go to that particular cylinder and all that air cause it to run a really lean burn and melt the piton like it did. but either way it was pretty bad. i think it was due to me accelerating and once the fuel injector fail, the car went from rich all the way to really lean in that one cylinder. then shortly after the car died. but yea
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