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Old 09-05-2007, 09:37 PM   #1
azscooby
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Default 2.0 WRX heads on Hybrid. Enough flow for 16G?

I've been doing a lot of research trying to get everything in order to eventually do a 2.5 hybrid swap into my 2002 WRX. It's got 135K and just won't die!!
I will probably go with a 16g, or a vf39/34. I'm quite sure I will not do anything bigger.

I've read a lot about how the 2.0 heads just don't flow enough....but what is enough?

Am I going to need cams to get this 2.5 enough air, or will the 2.0 heads be enough to feed those specific turbos (i.e. smaller turbos?)

I don't want to find out later that my weakest point is the flow from the 2.0 heads and kick myself for not putting in cams while I was in there.

If you think I do need cams, what lift/duration are we talking?

Any input would be greatly appreciated.
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Old 09-05-2007, 09:47 PM   #2
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If you put those heads on stock youll have a problem. If you have the heads ported and polished you could flow a gt30r.
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Old 09-05-2007, 09:50 PM   #3
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So you don't think those heads w/out PnP will flow enough for those turbos?

Do you think that with the PnP and w/out cams, it would be enough for a 16g?

I'm not worried about a gt30r, it's eventually going to be an auto-x car, so I really want more power down low vs. high end. No 1320's for me.

thanks...
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Old 09-05-2007, 09:56 PM   #4
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What are your goals? You can easily make 400whp off a gt35r and have a nice power band. The stock heads flow just like the STI heads only with a slightly smaller cam profile. So mild cams would get you there and more. Hell I could spool a gt40r at 4500 with the stock heads but the power band was just not there. You can really feel the difference that cams make when you really need them. A 16g probably wont matter but you could make a little more power with some head goodies.
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Old 09-05-2007, 10:00 PM   #5
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Yes, the powerband is not there ie port polish your heads you wont have a problem with a 34, 39 or any turbo bigger. You will be pleased with the difference.
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Old 09-05-2007, 10:04 PM   #6
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Only looking to be about 280 - 300 whp and a little more than that torque-wise.

Not looking for a monster, just whatever the 16g will get me. I want the spooling characteristics of the smaller turbos and am willing to sacrifice whatever up high, that's fine. I just don't want to find out later that the heads are what are holding me back.

I want it to be very driveable (read low-end), as well as a DD.

Just want to know if the heads are going to slow down a 16g. I want to do all the work inside at once, not find out later, "Shoulda done this/that."
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Old 09-05-2007, 11:14 PM   #7
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At least do sti cams. They are the same duration as your wrx cams but with higher lift.
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Old 09-05-2007, 11:26 PM   #8
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Originally Posted by jays05 View Post
At least do sti cams. They are the same duration as your wrx cams but with higher lift.
u'll be fine with wrx heads for your power levels. if you dont plan on going big. But yes STI cams is a must. WRX cams are junk for on the hybrid. It is recommended that you upgrade your springs for higher lift cams.
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Old 09-05-2007, 11:41 PM   #9
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I have found 420 peak whp and 325 whp at redline to be the max power the stock 02 wrx heads can make.

3 different turbos on my car with the same result at redline. I now have some ported heads and spicier cams but am waiting until my clutch is broken in before I get a tune.


I would recommend at a minimum get sti or 06 wrx cams so the power doesn't drop off as bad.



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Old 09-06-2007, 12:06 AM   #10
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well, you can look at it a few ways...pnp heads with 264 cams will help carry out ve's in the top end of the power band but would cause some loss in the low end...while the short rod ratio 2.5 motor mated to a "smaller" turbo and with higher CR; will bring up the low end torque (ve's) at least in comparison to an EJ20. I would pnp the heads as the 2.5 should cause enough demand to keep port velocities up in the ported wrx heads, helping to keep throttle/turbo response.

I'd pnp and do 264's with the ej257 bottom end and ej205 heads. Leave the CR in the low 9's as that will help reduce lag and will increase out of boost power for those real low speed corners.
What is your gearing and what are the max and min speeds you would expect to see on course? this is what will really dictate the desirable powerband for optimizing the car's desired motor. Short gears and a screamer motor can make for a faster set-up
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Old 09-06-2007, 09:04 AM   #11
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Quote:
Originally Posted by azscooby View Post
Only looking to be about 280 - 300 whp and a little more than that torque-wise.

Not looking for a monster, just whatever the 16g will get me. I want the spooling characteristics of the smaller turbos and am willing to sacrifice whatever up high, that's fine. I just don't want to find out later that the heads are what are holding me back.

I want it to be very driveable (read low-end), as well as a DD.

Just want to know if the heads are going to slow down a 16g. I want to do all the work inside at once, not find out later, "Shoulda done this/that."
Just had Tim Bailey tune my hybrid. I have the FP 16GevoIII turbo with stock WRX heads and cams. On the most aggressive tune with meth I made 300whp/320wtq. Boost comes up around 3400 rpms. It is a low end torque monster. The heads and cams will not hold you back.
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Old 09-06-2007, 09:07 AM   #12
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This is a dyno of a hybrid before sti cams and after sti cams. No other head work was done.



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Old 09-06-2007, 11:10 AM   #13
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I just finished my hybrid yesterday. I ported my heads and put crower stage 2 cams in it with a complete valvetrain to support it and im running a 22. you wont be dissatisfied with this kinda build if your looking for more low end then you 2.0. I absolutely love it
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Old 09-06-2007, 10:21 PM   #14
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This is goooooood info.

rebos123 - this is the setup I'm looking at, but probably no meth, and I could certainly live with those numbers.

LiquidForce - awesome dyno, looks like 6K things really die off with the stock cams...which I could live with, though it is very telling as far as the improvement to be had over the WRX cams.

Homemade WRX -I'll be running stock gears, and I honestly don't know about the max/min speeds.

It sounds like from everyone that while the lower flowing 2.0 heads won't be a significant obstacle, I could definitely pull some top end hp out of the cams.

Question now is....Is the added cost, worth the extra breathing or is the money better spent elsewhere (i.e. better suspension upgrades.)

Thanks again all.
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Old 09-06-2007, 10:32 PM   #15
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Plan ahead my friend.

If you are like 99.99% of the people on this board you will not be satisfied with the 16g for very long. Not that the 16g is a bad turbo its just that power is addictive. Go ahead and put the cams in now and save yourself the expense of doing it later.

Even if you do your own work, the cost of all the gaskets and head bolts is about the same as cams. So waiting is going to cost you even more.
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Old 09-06-2007, 11:07 PM   #16
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well, if you plan on this car being a serious SM competitor you will need the cams and head work...you should also look at doing an EVO td05hr-16g (10.5 cm^2 hotside) twinscrool turbo...more top end and quicker spool...good for 400 and 400 on evo's with water injection on pump gas...it would require exhaust manifold change and a little fab/welding but nothing hard...would also be "pre-clocked" for a fmic too.
just a thought that I would love to do but am going bigger...much bigger
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Old 09-06-2007, 11:07 PM   #17
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Yeah, I understand about the desire for more power....but you could say that with just about any turbo, assuming there is something bigger/better out there then what you've just put on, lol.


Quote:
Even if you do your own work, the cost of all the gaskets and head bolts is about the same as cams. So waiting is going to cost you even more.
What did you mean by this? Why would it cost my more if I wait? Are you assuming that I would be able to re-use gaskets/head bolts if I do this sooner, rather than waiting for it to die on me?

Thanks
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Old 09-07-2007, 12:14 AM   #18
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Quote:
Originally Posted by azscooby View Post
Yeah, I understand about the desire for more power....but you could say that with just about any turbo, assuming there is something bigger/better out there then what you've just put on, lol.




What did you mean by this? Why would it cost my more if I wait? Are you assuming that I would be able to re-use gaskets/head bolts if I do this sooner, rather than waiting for it to die on me?

Thanks
At the time you pull the engine for the 2.5 swap do the cams. I am not saying do the cams now and the 2.5 swap later.

If you do all the engine work up front you will not have to pull it again if you decide to change turbos.

I have pulled my engine out 4 times from due to poor planning.
1. The 2.0 died
2. Cracked ringlands on #4 on the 2.5. All I did was swap a new piston in.
3. Cracked ringlands on #2. Swapped to built 2.5 instead of stock.
4. Installed a set of ported heads and upgraded cams.

Had I just gone with the built block and heads after the 2.0 died I would have saved a ton of money and time.

I am just advocating doing it right the first time.

Don't be like Mike.
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Old 09-07-2007, 03:25 PM   #19
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Quote:
Originally Posted by azscooby View Post
Only looking to be about 280 - 300 whp and a little more than that torque-wise.

Not looking for a monster, just whatever the 16g will get me. I want the spooling characteristics of the smaller turbos and am willing to sacrifice whatever up high, that's fine. I just don't want to find out later that the heads are what are holding me back.

I want it to be very driveable (read low-end), as well as a DD.

Just want to know if the heads are going to slow down a 16g. I want to do all the work inside at once, not find out later, "Shoulda done this/that."
DrinkAV8 laid down 303 whp with his hybrid. Can't remember if he had cams in it though, but IIRC he did NOT port and polish. He went to cams later I believe after he started running into a performance wall in the upper rev ranges. He was on the stock TD04 at the time, now he's got something bigger, I think a VF39.
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Old 09-07-2007, 04:30 PM   #20
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I would suggest porting over cams if not doing both now as you can put in cams without having to tear everything down
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Old 09-07-2007, 05:36 PM   #21
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Originally Posted by Acostafan View Post
DrinkAV8 laid down 303 whp with his hybrid. Can't remember if he had cams in it though, but IIRC he did NOT port and polish. He went to cams later I believe after he started running into a performance wall in the upper rev ranges. He was on the stock TD04 at the time, now he's got something bigger, I think a VF39.
lol, your completely wrong.

He ran a td04 and upgraded to a perrin kit gt30r. I tuned both setups for him. We ran 22-23 psi on pump and was going to lower the boost and do more timing/fuel tuning. The car hauled ass it.

Unforunately, his car was totaled and Drinkav8 sold the complete engine/turbo set up to a local guy. It laid down 420 on race and 300 on pump. Stock wrx cams, heads, valves. According to the tuner Jorge. He said it kept power up pretty well.

However, if you do not plan on going over 300 whp then you do not need any head work except for a minimum of sti cams. It is recommended but not necessary to replace the valve springs.
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Old 09-07-2007, 05:40 PM   #22
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Originally Posted by azscooby View Post
I've been doing a lot of research trying to get everything in order to eventually do a 2.5 hybrid swap into my 2002 WRX. It's got 135K and just won't die!!
I will probably go with a 16g, or a vf39/34. I'm quite sure I will not do anything bigger.

I've read a lot about how the 2.0 heads just don't flow enough....but what is enough?

Am I going to need cams to get this 2.5 enough air, or will the 2.0 heads be enough to feed those specific turbos (i.e. smaller turbos?)

I don't want to find out later that my weakest point is the flow from the 2.0 heads and kick myself for not putting in cams while I was in there.

If you think I do need cams, what lift/duration are we talking?

Any input would be greatly appreciated.

Don't bother with those small turbo's the 2.5 needs more air. Go with an 18g 8cm^2 and you won't be upset.
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Old 09-07-2007, 08:47 PM   #23
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This is really good info and is helping me plan accordingly....

NITROS - I'm really concerned about lag with the larger turbos, what type of spool can I see with this setup and the 18g 8cm^2 on the 2.5l?

I'm thinking that from all the info I've seen it looks like I will at least port the heads, while I'm in there. I can replace cams with STI or bigger later, without a full teardown.
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Old 09-09-2007, 04:48 AM   #24
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Quote:
Originally Posted by LiquidForce View Post
I have found 420 peak whp and 325 whp at redline to be the max power the stock 02 wrx heads can make.

3 different turbos on my car with the same result at redline. I now have some ported heads and spicier cams but am waiting until my clutch is broken in before I get a tune.


I would recommend at a minimum get sti or 06 wrx cams so the power doesn't drop off as bad.
I don't understand this. This is a ej257 with 04 stock wrx heads. A gt35r .82ex lower is pump gas higher is c16. Nothing crazy just a fun day at the dyno.

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Old 09-09-2007, 08:51 AM   #25
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^^^^WTF is with that AFR? 12:1 on pump and the same on C16?
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