planing on building a second motor

92.Legacy.SS · Post by **92.Legacy.SS** » Fri Sep 23, 2011 8:40 pm

so i know what kind of pistons and rods im going to get for my motor but i was thinking about a little bit bigger cams and a p&p for the heads lol but not sure on whats good for these motors and tuning setup would be nice to know also if anyone has done stuff to there cars for tuning let me know. thanks

Falken-18c · Post by **Falken-18c** » Fri Sep 23, 2011 9:43 pm

what motor the 22t if so just swap the heads

92.Legacy.SS · Post by **92.Legacy.SS** » Sat Sep 24, 2011 6:40 am

yes i might be getting another 22t motor.

your talking about the 20g heads right? lots of people tell me to just do that is there anything ill need to change beside using the 20g intake and maybe headers?

91legacyawdturbo · Post by **91legacyawdturbo** » Sat Sep 24, 2011 10:58 am

Coolant lines on the driver side head, sohc ones won't fit. Headers will fit you can reuse your ej22t's.
Check out the unspoken dohc swap http://bbs.legacycentral.org/viewtopic.php?t=38247

92.Legacy.SS · Post by **92.Legacy.SS** » Sat Sep 24, 2011 8:21 pm

WOW! okay ill have to read that thing more then twice lol but thanks for the info

91legacyawdturbo · Post by **91legacyawdturbo** » Sat Sep 24, 2011 11:50 pm

Your welcome, there is alot of useful info.

Falken-18c · Post by **Falken-18c** » Wed Sep 28, 2011 3:37 am

i also have a spare motor that im striping down to the shortblock 22t but im not sure what route i wanna go i might buy a 20tt and use the heads and intake manifold & ect are just get ej25 heads crank ect i also read on tsc that the 05-06 legacy na manifold has much longer intake plenum and longer and larger runners compared to any turbo manifold and also said on nasioc that this manifold outperforms almost all aftermarket manifold that run for alot of money and i guess you can buy this brand new for almost 200$ so i dont know what im gunna do.

fasterthanyou · Post by **fasterthanyou** » Thu Oct 06, 2011 4:52 pm

i am going to do a build as well. but instead of using a JDM motor or some crazy hybrid motor. i am just going to get a EJ25d long block and turbo it. swapping the intake manifold harness to my 22t components (injectors sensors and everything) and run it with the little VF11 and run 7 PSI. on a N/A motor this would be sweet i think

EDIT: plus the compression ration would be around 10 to 1. and there would be no issue of compression ratio drop when swapping heads. because 25d heads on a 22t has a compression ratio close to 7 to 1

92.Legacy.SS · Post by **92.Legacy.SS** » Thu Oct 13, 2011 2:36 am

so there is a guy in my area selling a wrx motor and my question is can i use the heads off that motor?

BoostedSubie · Post by **BoostedSubie** » Thu Oct 13, 2011 4:04 am

I'm also building a second ej22t i picked up for super cheap. I found a set of 25d heads also that i'll be using but will be getting the wiseco .20+ forged pistons cuz i don't want the low compression the hybrid brings. If i have the money i may end up using the phase 2 2.5 crank which requires either machining the block for #5 thrust bearing or machining the crank for the #3 spot. Gonna make my own rotated turbo setup using the Holset HX35. For managment, i'm either going Adaptronics or Mega Squirt. Just thought i'd give you some ideas. With my intended setup i'm shooting for 350hp which should be easy with the right tuning, anything more would be a bonus.

Grayguy · Post by **Grayguy** » Thu Oct 13, 2011 5:22 am

A little birdie told me that when using the 25d heads you need to swap in turbo cams (20g I think fit?) because else the duration is too much and you actually end up blowing boost out the exhaust valves...

I'll be building an ej255/25d/20k/22t hybrid this winter. 255short block, 25d heads, 20k intake Mani, 22t exhaust Mani...

92.Legacy.SS · Post by **92.Legacy.SS** » Thu Oct 13, 2011 3:57 pm

well right now my main goal would be to hit 300hp to the wheels but my dream would be 500 lol

but i know if i want more power i need DOHC which is why i asked if the heads from a wrx 02-03 would be able to work i know i need the intake manifold and possibly more then just that but just a thought.

Grayguy · Post by **Grayguy** » Thu Oct 13, 2011 4:23 pm

Yeah, all the Wrx stuff will bolt to any EJ block.

Post by **Legacy777** » Fri Oct 14, 2011 3:57 am

Grayguy wrote:Yeah, all the Wrx stuff will bolt to any EJ block.

Not necessarily. The newer WRX heads have some differences that don't make them ideal for use with the older ej22t short block. I don't recall if it is because it drops the compression very low and/or if there is issues with the headgasket and coolant passage alignment.

BoostedSubie · Post by **BoostedSubie** » Fri Oct 14, 2011 3:59 am

I planned on using ej20 cams for sure as that is true. I thought using the usdm wrx heads is a little more work than the jdm ej20 or ej25d heads as the sensors are different but don't really remember all the details. Remember too, when going bigger hp, how the factory tranny won't hold up long to that much power. Start planning on uprgrading the trannsmission as well.

fasterthanyou · Post by **fasterthanyou** » Fri Oct 14, 2011 1:36 pm

there is really no need to use ej20 cams. you will not "blow boost out of the exhaust" that is a misconception. the higher lobes actually aid in flow and you can run high boost as well. the 25d heads are the best flowing heads stock, and when you PnP and deshroud the valves, you can make some very high power.

the thing about car manufacturers in general is it is hella expensive to design new heads. so much of the same technology is used on thier heads. on the subaru motors w build for sand rails, we use the 2.5d heads and run as much as 30 PSI on an STI bottom end.

it would probably be the cheapest to just boost a 2.5d long block and use a 20k manifold, or get a turbo IAC and use the 2.5d manifold. then use some engine management. just a thought. compression would be around 10 to 1. and with even 7 or 8 PSI. that thing would screeeeem.

deffinately do wiseco or BC pistons, so you have a higher compression ratio. people dont realize how much power they lose when they drop the ratio below stock. you would be lucky to have 8 to 1 with a Stock 22t with wiseco's and 25d heads.

Post by **Legacy777** » Fri Oct 14, 2011 1:55 pm

The lobe height isn't the issue, it's the valve overlap. One of the members in Minnesota has experienced the issue first hand. Non-turbo cams have too much valve overlap. If you are planning to run higher boost, the problem gets worse.

BoostedSubie · Post by **BoostedSubie** » Fri Oct 14, 2011 3:26 pm

Thats what i thought, its the overlap that is the problem. I already have the block/heads and i've carefully thought out this build. I love the strenght of the 22t block and don't see myself straying from it. But yes, definately higher comp pistons. I'm gonna shoot for 8.5:1 but will see what wiseco can do. Their off the shelf pistons for the 22t are 8.5:1 but thats with the stock heads so like you said, with the 25d heads it probably would be more like stock 8:1. So, i'll see how much extra it would be to make a set for my needs.

fasterthanyou · Post by **fasterthanyou** » Sun Oct 16, 2011 5:04 am

overlap is not a problem. all valves overlap even on turbo applications, that is just how motors work. why would you change great flowing heads for cams that restrict flow. you will not boost past valves. the 2.5 d heads flow awesome. the only downside would be loss of compression, which is an issue, but you can run high boost.

My best friend works at a motor shop where they build sand rail motors from subaru motors. they have made 800 horsepower with 25d heads. they have a flow bench and everything. i have witnessed how well they flow, and they are durable as well. i will really try to get some of his printouts on head flow. we are making a website to help all the subaru people who are doing builds

Falken-18c · Post by **Falken-18c** » Sun Oct 16, 2011 5:10 am

fasterthanyou wrote:overlap is not a problem. all valves overlap even on turbo applications, that is just how motors work. why would you change great flowing heads for cams that restrict flow. you will not boost past valves. the 2.5 d heads flow awesome. the only downside would be loss of compression, which is an issue, but you can run high boost.

My best friend works at a motor shop where they build sand rail motors from subaru motors. they have made 800 horsepower with 25d heads. they have a flow bench and everything. i have witnessed how well they flow, and they are durable as well. i will really try to get some of his printouts on head flow. we are making a website to help all the subaru people who are doing builds

id like to see theese printouts

Post by **Legacy777** » Mon Oct 17, 2011 12:17 am

fasterthanyou wrote:overlap is not a problem. all valves overlap even on turbo applications, that is just how motors work.

The valve overlap for turbo cams is going to be different then non-turbo cams. With naturally aspirated cams the overlap is going to be larger to help scavenge the cylinder since the piston is having to suck air into the combustion chamber. Turbo cams will have less overlap since boost is forced into the combustion and helps in the scavenging.

For example, if you have a clear container filled with smoke and try and suck out the smoke with a low vacuum source, the smoke will be evacuated, but not too fast. If you take the same container and use 50 psi shop air, the smoke will be evacuated much quicker. The same principle holds true with your engine.

In the case of running the 25d non-turbo cams on the turbo motor, you will scavenge the cylinder and some of the air fuel mixture. This will reduce horsepower and cause higher EGT temps. If you're running lower boost applications, the issue shouldn't be as big a deal, but higher boost applications, it will be more noticable.

fasterthanyou · Post by **fasterthanyou** » Mon Oct 17, 2011 2:47 am

ok, turbo vs. non turbo cams. N/A has higher lobes, for more valve lift. but turbo have less lift and more duration.

oh yes, i agree that the overlap is for sure different but minimal. but if it were me personally i would be more concerned about flow. you may get some fuel going out the exhaust, on the exhuast stroke, but it is minimal. compared to the power gained from n/a cams. the lift of the cams will allow much more to flow through. and you wont hit like a max psi on the heads they will always build plenty of pressure. you will still be able to run high boost. like more than 30 pounds.

plus why would they make performance cams with higher lobes for the STI. its about flow.

the most flow restricion on the whole motor is at the valves. bigger plenums, knife edge, PNP of heads, gasket matching, PNP of intake, pnp of turbo, pnp of exhaust all help but in the end the valves restrict the most. so if you can minimize that flow restriction by deshrouding valves and having higher lift and a little longer duration, that will help the most. that is why variable valve timing works so well. or for subarus the AVCS.

i am not saying the 20g or 20k cams are a bad choice. they would perform great. but in my personal application i would stick with the 25d cams.

by the way if you could get some JDM avcs heads, that would be totally awesome.

hopefully i can post some pictures of turbo cams vs. na cams.

so i am not trying to argue, but trying to post the info that i know. please take all this with the best intentions. i tried to explain myself, but if i am wrong please correct me.

93forestpearl · Post by **93forestpearl** » Mon Oct 17, 2011 2:48 am

N/A cams really do handicap these engines. There have been several instances locally where N/A cams limited the engine to about 300whp, all with 30R+ sized turbos. Derek and I were at 28 psi and only making 300 whp, using a GT3782. AFR was in check, but the wideband was lying to us. The wideband was reading 11.5:1, yet the car still spewed black smoke. Timing was reasonable, is case you are wondering.

This is not an isolated issue. There have been several cars here that have ran into walls in regards to power and boost. EJ25D's, SOHC 2.5's, etc. Keep in mind that most people doing these hybrid setups are not pushing these engines enough to find these issues. I was making more power with my 22T heads and Delta cams than more boost and a larger turbo on 25D heads.

Notice the difference in overlap between the two cams. 25D on the left, and EJ20K on the right.

Grayguy · Post by **Grayguy** » Mon Oct 17, 2011 3:02 am

I was waiting for you to show up and explain what I couldn't haha.

fasterthanyou · Post by **fasterthanyou** » Mon Oct 17, 2011 3:15 am

93forestpearl wrote: I was making more power with my 22T heads and Delta cams than more boost and a larger turbo on 25D heads.

thats because your compression ratio took a huge hit

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