Welcome to the North American Subaru Impreza Owners Club Thursday July 2, 2015
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Built Motor Discussion

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 12-18-2013, 06:43 PM   #1
tomacGTi
Scooby Newbie
 
Member#: 297396
Join Date: Oct 2011
Default Dual avcs cams in a ej205 head

Searched high and low, but didn't find anything: would you just plug the exhaust cam the same as the intake? Also, are these the same duration and lift as in previous STis?

The gentleman who built my block and heads has a set of 2010 STi cams and since he's setting clearance for the valves, I thought why not?

Thanks for any advice.

-Randy
* Registered users of the site do not see these ads.
tomacGTi is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 12-18-2013, 07:41 PM   #2
25rsti
Scooby Guru
 
Member#: 166324
Join Date: Dec 2007
Chapter/Region: NESIC
Location: BLOD in BLOD out
Vehicle:
3 turbos &n NA
@DBlockSTi

Default

Yes you just plug them. No clue on their lift and duration.
25rsti is offline   Reply With Quote
Old 12-19-2013, 12:14 PM   #3
tomacGTi
Scooby Newbie
 
Member#: 297396
Join Date: Oct 2011
Default

Great!

I'm only ASSuming that duration and lift haven't changed in the course of the years and that the cams will hopefully be an improvement on the standard 03 WRX ones.

Thanks again!

-Randy
tomacGTi is offline   Reply With Quote
Old 12-19-2013, 12:38 PM   #4
verentchan
Scooby Newbie
 
Member#: 355749
Join Date: May 2013
Chapter/Region: SCIC
Location: San Luis Obispo, CA
Vehicle:
2008 WRX
Silver/Black

Default

From what I've read the STi cams have higher lift but same duration.
verentchan is offline   Reply With Quote
Old 12-19-2013, 12:40 PM   #5
Concillian
Scooby Guru
 
Member#: 4414
Join Date: Feb 2001
Location: Dublin, CA
Vehicle:
2002 WRX Sedan
Midnight Black

Default

Presumably the same lift / duration. Dunno if exhaust centerline is different, that's what I'd be most concerned about.

You can get a good deal of improvement in top end from stock cams just retarding the intake cam until the overlap is gone. WRX centerlines have some built in overlap that hurts top end some.
Concillian is offline   Reply With Quote
Old 12-19-2013, 09:39 PM   #6
tomacGTi
Scooby Newbie
 
Member#: 297396
Join Date: Oct 2011
Default

The STi cams are less expensive than cam gears at this point.

Once again, I'd only imagine that the centerlines would remain the same (I'll be using WRX gears) but I'll find out soon enough. I guess I'm stepping into untrodden territory.
tomacGTi is offline   Reply With Quote
Old 12-20-2013, 11:02 PM   #7
Concillian
Scooby Guru
 
Member#: 4414
Join Date: Feb 2001
Location: Dublin, CA
Vehicle:
2002 WRX Sedan
Midnight Black

Default

Just pointing out that the overlap will likely still be there. You'll still not have the full top end of STi cams normally have with AVCS, since they'll potentially have a bunch of overlap.

You also may want to degree them just to measure how much overlap you do have.
Concillian is offline   Reply With Quote
Old 12-21-2013, 12:20 AM   #8
tomacGTi
Scooby Newbie
 
Member#: 297396
Join Date: Oct 2011
Default

You're absolutely right Concillian.

I'm doing this primarily as a mild upgrade since my heads are being assembled and the builder had a set of cams for a very reasonable amount of money. I decided to go this direction since it seemed to be a proven low-buck upgrade without going too nuts.

I understand that I won't be extolling the full benefits of the swap with it the way it is but I also don't want to invest the money into the sprockets to be able to do it. I'm already spending more than I needed to on a "surprise" motor build. These are one of those "while you're in there" mods.

From the myriad of posts from people who have done the mod as-is, it seems as though there is still some gain over the WRX setup. I'm just in a different situation of having to plug four cams instead of two.

My build is going to be quite mild: running a TD04HL-19t, I'll do a very mild clean up port on the heads when I get them back, EL header, the STi cams and a stock ej205 block. I'm not looking for all-out HP, just to maximize what I have now.

I'm only guessing that the AVCS exhaust cam centerline should theoretically be the same as the WRX one when the WRX cam gears are used. I should be able to figure that out when I lay my hands on them for assmembly when I have them side by said. I honestly don't know how to interpret the AVCS maps on here to assume where the cams naturally rest and where the advance/retard. I'm just hoping that zero is the same.

-Randy
tomacGTi is offline   Reply With Quote
Old 12-21-2013, 11:30 AM   #9
Concillian
Scooby Guru
 
Member#: 4414
Join Date: Feb 2001
Location: Dublin, CA
Vehicle:
2002 WRX Sedan
Midnight Black

Default

Zero is definitely not the same. AVCS cams naturally rest with no overlap in AVCS heads, but in non-AVCS heads they rest with significant overlap... somewhere around 15-20 degrees. As a result, a car with AVCS, but the table zero-ed or like an EJ207 with out AVCS wired will spool quite late but make great top end.

Then when AVCS works, spool fills in from the advance.

Here is an example of sAVCS zeroed vs. tuned AVCS:
http://forums.nasioc.com/forums/show....php?t=2167002

so the blue line is what happens when they're zero and the red is the spool and midrange gained by advancing the intake cam.
sAVCS cams with non-AVCS cam gears (WRX cam gears) have that 15-20 degrees overlap, so they'll perform somewhere in between the blue and the red at low RPM, but not as well as either at high RPM. In comparison to the WRX cams it should be about the same down low, but better up top, which sounds like what you're looking for... IF the exhaust centerline is the same.
Concillian is offline   Reply With Quote
Old 12-23-2013, 09:58 AM   #10
tomacGTi
Scooby Newbie
 
Member#: 297396
Join Date: Oct 2011
Default

Other thing that I noticed is that there is a lobe on the d/s exhaust cam nearest the sprocket end (I don't know if it's for timing or not) that interferes with the case slightly (VC bolt boss).

A minor clearancing and it spins freely.

I'll compare cams when I have the WRX set out of the car.
tomacGTi is offline   Reply With Quote
Old 12-23-2013, 10:06 AM   #11
Bad Noodle
Scooby Specialist
 
Member#: 174442
Join Date: Mar 2008
Chapter/Region: Tri-State
Location: NNJ
Vehicle:
2007 SuperWagon
I don't spell well

Default

I installed DAVCS cams on a sAVCS engine. Intake was same, but on the exhaust I plugged the holes and used solid wrx cam gears. Threw the timing belt on and rotated it a couple times with nothing hitting. From my research, if you use DAVCS cam gears, you will have retarded exhaust timing. If you use solid gears, you go back to 0. This is from dated research I did a few years ago, so take it with a grain of salt. But i'm throwing it up just for reference.
Bad Noodle is offline   Reply With Quote
Old 12-29-2013, 09:51 AM   #12
tomacGTi
Scooby Newbie
 
Member#: 297396
Join Date: Oct 2011
Default

Cams installed and engine running.

The car idles and runs as normal in the lower range but intake tone changes as you cross over 4k when the cams come on. Big difference from the WRX cams previously, they certainly do not fall off and the engine smooths out.

I'm still in break-in but from the couple of harder runs to seat the rings, the cams are an improvement to the stock 205 cams. Much smoother in the upper end of the powerband and they work great on the revvy 2.0L. I noticed little to no difference in the bottom end of the car.

My set up is very mild in comparison to the builds here and the tune is not yet set (waiting until 300 miles or so to log) but am happy so far with the difference that they made.

Used a 10-32 tap and grub screws, teflon tape and VW oil pan gasket sealant on the threads in and on top of the heads. With the DAVCS I of course had to do all four and not two.
tomacGTi is offline   Reply With Quote
Old 01-13-2014, 09:59 PM   #13
tomacGTi
Scooby Newbie
 
Member#: 297396
Join Date: Oct 2011
Default

I spoke too soon on the cams: power is down everywhere. For reference sake: this is in a 2L with pocket ported heads, fresh rebuild.

After being retuned (etuned) by Eric at Torqued Performance, plugging the logs into Virtual dyno, torque is down 56 ft pounds (!!) in the midrange (3500) and HP is down all around, most noticeably at 3500. So Concillian, you were right. It felt as though there was more power because at 4k it was only barely catching up to where it was supposed to be before.



Though the curve is smooth, it's way down on power and I made a big mistake. My OTS Stage 2 setup made more torque and power at this point.

These cams are going to have to come out at some point and I'll have to locate stock ones and reshim. Again.

Last edited by tomacGTi; 01-15-2014 at 04:56 PM. Reason: photo
tomacGTi is offline   Reply With Quote
Old 01-14-2014, 08:14 AM   #14
Bad Noodle
Scooby Specialist
 
Member#: 174442
Join Date: Mar 2008
Chapter/Region: Tri-State
Location: NNJ
Vehicle:
2007 SuperWagon
I don't spell well

Default

^ good info. What did sprockets did you use?
Bad Noodle is offline   Reply With Quote
Old 01-14-2014, 08:49 AM   #15
tomacGTi
Scooby Newbie
 
Member#: 297396
Join Date: Oct 2011
Default

Stock EJ205 gears. 2010 dAVCS cams

I'm wondering if I can use a set of adjustable sprockets to avoid pulling and opening up the motor. The problem is that I don't know if it would ultimately help.

I am thinking there is significant overlap as the car isn't even building boost until 4k.
tomacGTi is offline   Reply With Quote
Old 01-14-2014, 10:56 AM   #16
Bad Noodle
Scooby Specialist
 
Member#: 174442
Join Date: Mar 2008
Chapter/Region: Tri-State
Location: NNJ
Vehicle:
2007 SuperWagon
I don't spell well

Default

good to know. I might be in the same boat then. What about using a set of stock 08 exhaust cam gears and possibly having them welded to position. Might be less expansive than buying adjustable cam gears...
Bad Noodle is offline   Reply With Quote
Old 01-14-2014, 11:00 AM   #17
tomacGTi
Scooby Newbie
 
Member#: 297396
Join Date: Oct 2011
Default

Honestly, if if I go that route, I'll just pull the cams entirely and run the WRX setup: cams, gears and all.

I don't mind a little experimenting but unless there is a simple solution, the only solution may be to swap cams.
tomacGTi is offline   Reply With Quote
Old 01-14-2014, 12:56 PM   #18
Bad Noodle
Scooby Specialist
 
Member#: 174442
Join Date: Mar 2008
Chapter/Region: Tri-State
Location: NNJ
Vehicle:
2007 SuperWagon
I don't spell well

Default

Wonder if you'll need all new buckets. That would suck as they're expensive little buggers.
Bad Noodle is offline   Reply With Quote
Old 01-14-2014, 01:21 PM   #19
2Fast4U1DAY
Scooby Specialist
 
Member#: 250152
Join Date: Jun 2010
Chapter/Region: MAIC
Location: Pennsylvania
Vehicle:
2006 WRX Limited
OBP

Default

Quote:
Originally Posted by Bad Noodle View Post
Wonder if you'll need all new buckets. That would suck as they're expensive little buggers.
Are the 205 buckets shimless? If not then yea that could suck, but IIRC arent they shimmed?
2Fast4U1DAY is offline   Reply With Quote
Old 01-14-2014, 01:32 PM   #20
tomacGTi
Scooby Newbie
 
Member#: 297396
Join Date: Oct 2011
Default

Shimless buckets.
tomacGTi is offline   Reply With Quote
Old 01-14-2014, 10:10 PM   #21
tomacGTi
Scooby Newbie
 
Member#: 297396
Join Date: Oct 2011
Default

Before I take everything apart, I'm going to try to advance the intake cams in the car one tooth to gain 7.5*. It is for free and much easier than pulling a motor or installing adjustable sprockets.

PM'ing Concillian about this, he pointed out a chart (post 9 here) that showed AVCS functioning and not functioning. I am pretty sure this is what I am dealing with as well even though I am running WRX cam gears. My chart looks eerily the same and even though I would give up some one top, hopefully it will offset the ridiculous amount I lost on the bottom.

I don't know if one tooth is enough to throw a CEL or throw things completely haywire, but I have heard of motors running two teeth off and being fine despite being way down on power. If this does work but triggers a CEL, I guess I'll be investing in some cam gears or at the very least Crawford's eccentric pulley to get some swing in timing.

Fingers crossed.
tomacGTi is offline   Reply With Quote
Old 01-15-2014, 04:41 PM   #22
tomacGTi
Scooby Newbie
 
Member#: 297396
Join Date: Oct 2011
Default



Today I advanced both intake cams one tooth. Timing was dead nuts on with WRX gears before I started and they are now with the exception of the advanced cams.

This is a VD screenshot of advanced and not advanced. I gained torque and a bit of spool but lost HP. These cams are going to come out and factory 02-05 WRX ones are going in. Nothing like doing a job twice.

I think the problem may lie with the dAVCS cams but I'm tired of being the guinea pig. Noone has ever posted any results of before and after doing this and hopefully my experimentation will clear some air.

Talking with different people about this, I think the key is that these cams work well in hybrids because the extra half-litre of displacement makes up for the loss in bottom end. The cams then gain it back up top with breathing. For a EJ205, I don't think it's worth the trouble.

-Randy

Last edited by tomacGTi; 01-15-2014 at 04:46 PM.
tomacGTi is offline   Reply With Quote
Old 01-15-2014, 04:45 PM   #23
Strider327
Scooby Specialist
 
Member#: 131280
Join Date: Nov 2006
Chapter/Region: BAIC
Location: Northern California Hayward
Vehicle:
2004 Impreza WRX
WRB

Default

I remember thinking about going this route as well. However, a lot of people talk me out of it and good thing I wasn't stubborn and listened. Still interesting to see the results no doubt. I went ahead and got BC 272 cams instead at the time.
Strider327 is offline   Reply With Quote
Old 01-15-2014, 05:00 PM   #24
tomacGTi
Scooby Newbie
 
Member#: 297396
Join Date: Oct 2011
Default

Trust me, I have no desire to pull out a motor that just went in. Not to mention that: the additional cost of seals, buckets, oil, coolant.....

I do have a problem with it not being right. I intended this to be a one and done and upon diligent internet surfing, these cams should have worked. I was wrong.

Caveat emptor.

-Randy
tomacGTi is offline   Reply With Quote
Old 01-15-2014, 05:05 PM   #25
Strider327
Scooby Specialist
 
Member#: 131280
Join Date: Nov 2006
Chapter/Region: BAIC
Location: Northern California Hayward
Vehicle:
2004 Impreza WRX
WRB

Default

Quote:
Originally Posted by tomacGTi View Post
Trust me, I have no desire to pull out a motor that just went in. Not to mention that: the additional cost of seals, buckets, oil, coolant.....

I do have a problem with it not being right. I intended this to be a one and done and upon diligent internet surfing, these cams should have worked. I was wrong.

Caveat emptor.

-Randy
I hear ya Randy. So what are your plans now? Are you going back with WRX Cams or are you gonna do something BC Cams?
Strider327 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -4. The time now is 05:43 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2015 Axivo Inc.
Copyright ©1999 - 2015, North American Subaru Impreza Owners Club, Inc.