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Old 05-01-2012, 09:58 AM   #626
khalonen
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Only thing I can't be sure about is what does my EJ207 camshafts triggers look like since it's never been opened.

My 2003 EDM EJ207 (in the car) has single avcs, and 3 (2wire) sensors at the intake cams.
1 Behind LH intake pulley, triggers in the pulley. to my knowledge this is the position sensor?
2 at rear of the heads, triggers on the camshaft. For avcs angle?

My 2008 EDM Dual Avcs EJ257 spare motor (disassebled at the garage) has 2 intake and 2 exhaust cam sensors, all 3 wire and triggering from the camshafts. No pulley sensor.

Here's pic that I believe the difference is between cams http://cosworthusa.com/store/pc/cata...04lowsmall.jpg

Guess I need to take the valve cover off to really see what's the EJ207 cam look like. The EJ257 cams I have is the left one.
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Old 05-01-2012, 10:03 AM   #627
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Hmmmmm.... Could it be a crossover type of CAMshaft signal method? Since 2003 is the first year AVCS was being used I believe it could be that they have kept the OE CAM trigger at the back of the CAMpulley like older models but adding the CAM position triggers on the pulleys and 2 additional sensors. Strange to say at best.

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Old 05-01-2012, 10:04 AM   #628
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Newer models use the same CAM position also as the CAM trigger.
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Old 05-04-2012, 10:04 AM   #629
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Quote:
Originally Posted by khalonen View Post
Only thing I can't be sure about is what does my EJ207 camshafts triggers look like since it's never been opened.

My 2003 EDM EJ207 (in the car) has single avcs, and 3 (2wire) sensors at the intake cams.
1 Behind LH intake pulley, triggers in the pulley. to my knowledge this is the position sensor?
2 at rear of the heads, triggers on the camshaft. For avcs angle?

My 2008 EDM Dual Avcs EJ257 spare motor (disassebled at the garage) has 2 intake and 2 exhaust cam sensors, all 3 wire and triggering from the camshafts. No pulley sensor.

Here's pic that I believe the difference is between cams http://cosworthusa.com/store/pc/cata...04lowsmall.jpg

Guess I need to take the valve cover off to really see what's the EJ207 cam look like. The EJ257 cams I have is the left one.
I would fit the existing Single AVCS heads and sell off the dual AVCS heads to someone who will 'use them'

The cams on the Dual AVCS are designed to work together, converting back to single AVCS with the D.AVCS cam specs would not give the results you want. A lot of effort for minimal gain
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Old 05-04-2012, 01:06 PM   #630
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The best thing to do is to ditch AVCS on both and get some real cams.

C
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Old 06-14-2012, 01:11 PM   #631
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Stock Standard S206 Dual AVCS Cam Timing(combined) less 20 degrees static separation
70 degrees of cam overlap until 3600rpm
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Old 06-14-2012, 05:50 PM   #632
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^^^^^^^^^^^^^And whats this thing run like? Is it torquey as hell or what?
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Old 06-14-2012, 06:28 PM   #633
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I would think there are improvements to be made on that. However I haven't tuned a dual avcs 2 liter. When I tune the avcs on the US 2.5's there's only so much overlap that helps before it hurts power. This is true with other peoples testing results too. Also a bunch of that overlap table is not even used. For example no way in hell is a 2 liter going to hit 3.0 load at 2000 rpm. That part of the table may have the overlap in it but it's not being used. An example of a time where too much overlap hurts power can be seen when you leave the avcs tables stock on a stage 2 tune. The 30 exhaust value in the high load area near 3200 dips the power near peak torque. Reducing the exhaust avcs to 20 eliminates the drop in power. Even the Cobb maps that first came out had that in there because they didn't fix the avcs maps. Apparently they changed the updated maps after that to get rid of the power dip. That's just an example, obviously just changing one table is not necessarily optimal.
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Old 06-15-2012, 08:33 AM   #634
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Quote:
Originally Posted by kakarot09 View Post
I would think there are improvements to be made on that. However I haven't tuned a dual avcs 2 liter. When I tune the avcs on the US 2.5's there's only so much overlap that helps before it hurts power. This is true with other peoples testing results too. Also a bunch of that overlap table is not even used. For example no way in hell is a 2 liter going to hit 3.0 load at 2000 rpm. That part of the table may have the overlap in it but it's not being used. An example of a time where too much overlap hurts power can be seen when you leave the avcs tables stock on a stage 2 tune. The 30 exhaust value in the high load area near 3200 dips the power near peak torque. Reducing the exhaust avcs to 20 eliminates the drop in power. Even the Cobb maps that first came out had that in there because they didn't fix the avcs maps. Apparently they changed the updated maps after that to get rid of the power dip. That's just an example, obviously just changing one table is not necessarily optimal.
Exactly.

In addition, "just to find out" I tried a couple maps with AVCS leaning toward this input... didn't work, for me, at all.

Not only is the motor displacement, and cams, different here, but other things as well. This "information" does not directly correlate with our typical 2.5L applications.
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Old 06-15-2012, 08:06 PM   #635
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Quote:
Originally Posted by Paidfor
^^^^^^^^^^^^^And whats this thing run like? Is it torquey as hell or what?
No **** lol...
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Old 07-26-2012, 01:47 PM   #636
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I have spent ages reading all of the AVCS threads and learning the theory behind them and VE. I have seriously spent way too long on this topic considering the gains...

Anyhow. I have been conducting these tests on a 2011 STi with a Cobb 3" catted downpipe and stock catback running a modified Cobb 93 octane stage 2 map on 94 octane gas.

What I ended up with was a similar intake/exhaust overlap profile to what user 'sponaugle' came up with after his 70 dyno runs. I found that running slightly less overlap at spool was beneficial on the stock turbo, but that his high end gains were definitely there vs. the 10 degrees of intake advance the stock map runs.

Anyhow this is what I'm running right now.


I'm seeing full boost 19.5psi around 3300rpm. I also see on average an additional 5-7 g/s between 5500 - 6500rpm.

I tried quite a number of different approaches to the high rpm area, but adding in any more overlap always reduced the measured maf flow by some degree.

Frankly the stock AVCS tuning really is pretty good. There are only marginal gains to be had on the stock turbo.
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Old 07-26-2012, 04:28 PM   #637
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What kind of dyno did you use?

C
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Old 07-26-2012, 08:03 PM   #638
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Well, he's comparing g/s as opposed to whp, so I'd guess he's not using one. Not that you really need it for full throttle pulls anyway. Just need a road without dips and bumps, and then you make the pulls repeatable. The road dyno software works well so long as you are careful about it. I definitely wish I could spend some time with real time tuning and a dyno for the part throttle stuff and lower load areas though. It's far harder to make improvements there without it. Clark, want to lend me your dyno for a while? lol jk I'm sure I don't have the budget for that especially since I don't know how to operate it.
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Old 07-26-2012, 08:53 PM   #639
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Oh. Ok. I thought for a minute thats what he was doing. Thats not going to work for tuning. Just because there is more airflow through the maf sensor in no way means there is more power. When you alter the cam timing you are changing the running compression of the motor.

The only way to really tune AVCS is to use a dyno with steady state load for RPM. I am NOT suprised that he decided there where not much gains to be had in trying to flash, Then log, then flash, then log ect.

Its incredibly complex because you have intake, exhaust, overlap, ignition timing and fuel injection pulse all to be tuned in every load and rpm. There is an incredible amount of guessing going on here. The biggest pain is the fact that the timing curve will be very different when the map is altered.

C
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Old 07-27-2012, 01:50 AM   #640
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While I agree that you Cannot tell if power gains are there by using the maf, you don't really need to tune the full throttle areas of avcs by holding it at steady state. Just the lower areas. The full throttle stuff is easy to do with road dyno. You do it the same as on a chassis dyno. flash a map, measure the power of a pull flash another map and compare. Just repeat half a trillion times and you figure it out. Also your timing will be different but you can still see the power gains by changing the avcs anyway. Clark unless you're saying that there is more power to be had by running more overlap up top (which you disagreed with previously) then I think we probably agree on cam timing for full throttle. Also previous posts by you seem to indicate that even though I didn't have a dyno, I was doing the right stuff already with lower load areas as well. Lower load timing is the part that I can't really do much with without a dyno.
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Old 07-27-2012, 08:13 AM   #641
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I made roughly 45 pulls during my AVCS tuning. I kept AFR, Boost and timing constant through all of the tests. My only changes were to the AVCS tuning. My timing is on the conservative side and I noticed 0 knock events during all of the pulls. My MAF has been scaled so that the worst I see is about 1.5% out in all ranges.

I measured changes in power by monitoring not only the MAF, but the acceleration in 4th gear from 2500 - 6500 over the same dead straight, flat road in both directions and averaged the two runs. All runs were made on the same day, temp etc.. 3rd gear acceleration was a bit too short to gather really meaningful data.

I do not doubt Clark at all here. Perhaps my overlap values were not high enough in the high rpm area? I tested up to a combined 10 degree overlap up to 6500 rpm. I would taper the intake cam down from 10 degrees to roughly 5 degrees at 6500. The exhaust cam would stay at 22 degrees retard.

Perhaps I didn't try enough overlap? I just saw acceleration slow slightly and lower maf readings when I added that much overlap.

My methodology was the best I could do at the time. I have made a number of trips to the dyno, but I wasn't going to pay for a full day on the dyno just to fiddle around with AVCS.

Clark - If you want to suggest an approach to try I'll gladly give it a shot and post the results. You have worlds more experience here than I do.

If anyone wants screen shots of my AVCS/Timing/etc let me know and I'll post them up.
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Old 07-27-2012, 10:29 AM   #642
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I was just saying that trying to tune avcs based on an airflow graph is not going to work. In proper settings will allow the boost to blow through the motor and cause higher readings when that is exactly what you dont want. We want the air to be compressed and used.

If you change the avcs settings or overlap then you have to redo the ignition and fuel. Using constant settings is not going to tell you if your changes worked.

C
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Old 07-27-2012, 11:10 AM   #643
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snowsti2011 were you using any sort of road dyno? Or just airflow and the butt dyno?
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Old 07-28-2012, 09:31 AM   #644
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15 degrees of overlap in RPMs < 2K? There isn't enough flow in the exhaust to create scavenging. There's no value in running valve overlap in low RPMs. Try 0 and I think you'll see better results. It will do nothing for your peak numbers but you'll see better drivibility.

On a stage2 car, you should make more torque above 4800RPMs by running more overlap by reducing intake to 5 or maybe even 0 advance and retarding exhaust assuming your fuel will allow you to do that. The more you retard the exhaust side, the longer you allow it to burn which will raise your cylinder pressure.

Lastly, remember, valves do not open or close instantly. At the initial few degrees when valve opens or closes, it is still a major flow restriction. If you were to plot the lift, it is not linear. Keep that in mind.

Quote:
Originally Posted by SnowSTI2011 View Post
I have spent ages reading all of the AVCS threads and learning the theory behind them and VE. I have seriously spent way too long on this topic considering the gains...

Anyhow. I have been conducting these tests on a 2011 STi with a Cobb 3" catted downpipe and stock catback running a modified Cobb 93 octane stage 2 map on 94 octane gas.

What I ended up with was a similar intake/exhaust overlap profile to what user 'sponaugle' came up with after his 70 dyno runs. I found that running slightly less overlap at spool was beneficial on the stock turbo, but that his high end gains were definitely there vs. the 10 degrees of intake advance the stock map runs.

Anyhow this is what I'm running right now.


I'm seeing full boost 19.5psi around 3300rpm. I also see on average an additional 5-7 g/s between 5500 - 6500rpm.

I tried quite a number of different approaches to the high rpm area, but adding in any more overlap always reduced the measured maf flow by some degree.

Frankly the stock AVCS tuning really is pretty good. There are only marginal gains to be had on the stock turbo.

Last edited by Ziggyrama; 07-28-2012 at 09:43 AM.
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Old 07-29-2012, 06:51 PM   #645
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SnowSTI2011, thank-you for sharing your work with us. It is very informative.

If I may, I need to ask a question. Your graph of Overlap vs RPM does not account for engine load (g/sec). Is the data you have graphed for a particular Engine Load? Like 3.0 g/sec, or what?

Thank-you............. Frank
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Old 07-30-2012, 12:02 PM   #646
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Frank - Yes I am just graphing load 2.5 - 3 which are all the same in my maps.

Did a whole load more testing and fiddling over the weekend with various configurations including timing / fuel. Input from Ziggyrama was taken and the low rpm area no longer has much overlap. Drivability seems slightly better, but it's hard to tell. Input advance remains the same above 2400rpm, but 2 degrees was added to exhaust retard.

Acceleration times/Maf flow readings are the same as before, but the temperature and humidity has changed now so the basis for comparison is pretty much gone.

I will note that the car does seem more eager above 5000 rpm now, but that's hardly scientific.



Update - I have since updated the exhaust AVCS accel profile to 24 degrees of retard from 3200 - 4800 rpm. I'm going to leave it here I think.

Logs from the runs. No timing pull. However a small dip in my MAF flow around 4200 rpm which I can't quite figure out.

Last edited by SnowSTI2011; 07-30-2012 at 01:28 PM.
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Old 09-05-2012, 10:32 PM   #647
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Originally Posted by Paidfor View Post
^^^^^^^^^^^^^And whats this thing run like? Is it torquey as hell or what?
Torquey as fark... DBW remap, smoothed the boost curve, some fueling/timing adjustments and it ran a 12.1 1/4 mile mechanically stock.
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Old 09-07-2012, 02:17 PM   #648
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Torquey as fark... DBW remap, smoothed the boost curve, some fueling/timing adjustments and it ran a 12.1 1/4 mile mechanically stock.

http://www.motortrend.com/roadtests/...6_first_drive/

Apples to oranges, as I've pointed out before.

For years I've read and followed this thread. I've learned from it, and then relearned as time and testing gave me greater perspective. Some of the posters herein have provided clues for those who could hear, and corrected others when paths were taken in error. I can't thank them enough.

But, as far as I understand, this thread began and was evolving as an AVCS informational discussion about the USDM 2.5l motor. Later it also included the newer generation of that motor with Dual AVCS. There is precious little of this kind of information anywhere else. However, I see no relevence here for the input from a motor/ECU/platform that has no direct bearing on this thread... and worse, is misleading for those searching for help in understanding OUR cars just because it is called a Subaru and kind of looks the same. It is not.

I'd love to own an S206. Who wouldn't. But I think this thread is devalued and taken completely off course by the AVCS/performance information of that car here. May as well as include Hondas and Evos.

It is almost a moot point now anyway, the subject motor's end is near. Too bad the things that COULD have been said were not.
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Old 09-08-2012, 01:13 AM   #649
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Quote:
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Logs from the runs. No timing pull. However a small dip in my MAF flow around 4200 rpm which I can't quite figure out.
Notice how the 'dip' begins right where your boost stops climbing. Since boost levels off, load stops climbing as well - it's hard to see in that picture but I'm sure you'd see it clearly if you scaled up the load curve to be as tall as the others. MAF doesn't completely stop climbing (because MAF is basically load multiplied by RPM, and RPM is still climbing) but it does climb less steeply, which ends up looking like a dip. But it's not really a dip, it's just a reflection of the knee in your boost curve. In other words, you can't have a smooth MAF curve if your boost curve has a sharp knee in it.

You can smooth it out a bit by having the boost curve level off more gradually. That would leave you with a boost curve that's shaped very differently than most folks in the Subaru world - I'm not convinced it's a better approach, but I'm also not convinced that it's a worse approach.
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Old 09-08-2012, 01:49 AM   #650
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There is a a host of maf/load corrections and actions that are not available with that software. Those settings would adjust/ change how the load is reacting. Without access, Its going to be difficult to change that behavior.

C
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