CovertRussian's 05 LGT Build Thread

Sprank told me to gap the plugs i got from him to .026-.028

to me, his info is pretty close up there to gospel, due to his experience. just another data point.

Excellent find! And yes, even with costly widebands we can still be blind in right situations. There is also the trend of wideband seeing a richer mixture as you get a more complete burn (because you burned more oxygen). So you start removing fuel and boom goes the engine.

 

Luckily Subaru's knock sensor and control is top notch. It's so good that you can actually tune by how much timing it pulled for you. Say you do a run and it feedback pulls 4* of timing, well now you know that your around 3-4* over advanced in that area, if you were 1-2* over advanced it would only pull 2* of timing.

 

With new spark plugs I was getting 2-4* of timing pulled via feedback, and in some cases my IAM dropped too. This is when I knew something wasn't right, so zoomed in on the AFR area and bam she's in 12.4-12.0 range.

 

Even with me richening the mixture way up (by 1 whole point), I'm still only hitting 87% duty cycle on my stock injectors and fuel pump. Makes me wonder if I can hit 300whp on stock fueling simply by keeping my PSI down.

This is making my head hurt... So with all of this, the standard method of adjusting a MAF curve using a wideband appears like it'd give bogus data if the rest of the tune wasn't perfect. It also sounds like this might be involved with my lean above 6000 RPM issue: maf and injector pulse width stay about the same, but wideband starts reading significantly leaner.

If you're going through the hassle of increasing the gap on your plugs to try and improve flame front propagation, have you considered using NGK SILFR6B8 or LFR6ARX-P plugs instead? The SILFR6B8 is stock in the '10+ Legacy GT and 3.6R and has a different ground electrode to expose more of the spark.

http://legacygt.com/forums/attachment.php?attachmentid=248718&d=1493920657

This is of course sales data so take it with a gain of salt, but it's sowing the propagation from time of spark with a highspeed camera. Top is the one with the projected platinum nub, middle is like our OEM iridium plug with a rounded ground, bottom is a standard copper plug with flat ground. This should produce an effect like you're going for while keeping the gap shorter.

Also not sure if making the gap larger alone incenses the spark energy. True voltage will go up, but the fatness/hotness of a spark is related to the current flowing through it and total energy has a time component. There is only so much energy in primary winding to generate the spark, so ether current or time is likely to decrease with an increase in gap. To keep these the same you may need to increase the coil dwell.

I've not done a lot of research into this though so could be off base.

Ignition dwell on A2WC522N (ecuflash def):

<table name="Ignition Dwell" address="cd70c">
	<table name="Engine Speed" address="cd6b8"/>
	<table name="Battery Volts" address="cd6f8"/>
</table>

Edit: I'd advise anyone else that runs across this to be extremely careful. A little bit goes a long way, and it's probably not needed unless you're messing with the gaps.

Edit2: Just FIY Subaru uses the same dwell calibration on the GroupN roms as our stock table

It's a known thing in the turbo world the to much spark gap...and your spark will get blown out. As we raised boost in the race car we tightened up the spark plug gap. That was even with a high output coil. At 35psi we were down to .018"

Correct with higher cylinder pressures (more boost) it becomes easier to blow the spark out, thus you need to reduce the gap. My general rule of thumb is, run the biggest gap you can without getting blow out (stutter at full boost).

My G20 would hesitate and shake if my gap was too big, so at .040 it would usually break up at 10psi. I'm amazed that Legacy wasn't breaking up at almost 0.060 at even 13psi.

Sprank told me to gap the plugs i got from him to .026-.028

 

to me, his info is pretty close up there to gospel, due to his experience. just another data point.

For how much boost is that, I might gap them down to factory spec (.031) but car feels great as is so not sure I'll bother.

This is making my head hurt... So with all of this, the standard method of adjusting a MAF curve using a wideband appears like it'd give bogus data if the rest of the tune wasn't perfect. It also sounds like this might be involved with my lean above 6000 RPM issue: maf and injector pulse width stay about the same, but wideband starts reading significantly leaner.

 

If you're going through the hassle of increasing the gap on your plugs to try and improve flame front propagation, have you considered using NGK SILFR6B8 or LFR6ARX-P plugs instead? The SILFR6B8 is stock in the '10+ Legacy GT and 3.6R and has a different ground electrode to expose more of the spark.

 

http://legacygt.com/forums/attachment.php?attachmentid=248718&d=1493920657

 

This is of course sales data so take it with a gain of salt, but it's sowing the propagation from time of spark with a highspeed camera. Top is the one with the projected platinum nub, middle is like our OEM iridium plug with a rounded ground, bottom is a standard copper plug with flat ground. This should produce an effect like you're going for while keeping the gap shorter.

 

Also not sure if making the gap larger alone incenses the spark energy. True voltage will go up, but the fatness/hotness of a spark is related to the current flowing through it and total energy has a time component. There is only so much energy in primary winding to generate the spark, so ether current or time is likely to decrease with an increase in gap. To keep these the same you may need to increase the coil dwell.

 

I've not done a lot of research into this though so could be off base.

Oh cool looks like spark plugs are finally catching up with the age old side gapping trick. I've been side gapping my plugs for almost a decade.

Very simple, 10 minutes with a dremel. Take a regular plug, mark the part that's covering the center electrode.

http://i160.photobucket.com/albums/t188/covertrussian/Cars/05%20LGT/Engine/Sparkplugs/Sidegap_002.jpg~original

And cut it off

http://i160.photobucket.com/albums/t188/covertrussian/Cars/05%20LGT/Engine/Sparkplugs/Sidegap_004.jpg~original

Another angle:

http://i160.photobucket.com/albums/t188/covertrussian/Cars/05%20LGT/Engine/Sparkplugs/Sidegap_001.jpg~original

http://i160.photobucket.com/albums/t188/covertrussian/Cars/05%20LGT/Engine/Sparkplugs/Sidegap_003.jpg~original

It works really well, on my old Nissan SR20DET I gained 7whp on the real dyno, doing side by side pulls. It also has usually gained me 1-2mpg. Since I've been doing it so long I did it right of way on the plugs for the legacy. Next time I buy new plugs I'll do a before and after test more properly.

Knowing that I can just buy the plugs for about same cost, I might have to finally stop using my dremel

true, i'm sure the tighter gap is for the 18 to 24 psi crowd.

i also couldn't find the same info on the ngk plugs. from their info, our regular plugs are the best. will keep digging as it sounds interesting.

utc_pyro just came across another post that might intrigue you related to AFR's not being read correctly by widebands. RomRaider sucks about direct post linking, so will just quote it. Here is the full thread.

Too much advance can hurt you're efficiency and have the same effect on a large cam that hasn't had injector timing tuned... What i think you're referring to is the natural scavenging effect hat happens... Your going to send unburned fuel out the exhaust before it has a chance to go through he combustion cycle.

What will happen when you push the advance too far; the ECU gives your injector a time to open to deliver the correct amount fuel. The fuel is injected and pulled into the combustion chamber... If the exhaust is open to long, that fuel will get pushed out. Now remember your o2 sensor is just that an o2 sensor, not a fuel sensor. So what will happen is the ecu will now see the car begin to lean out, so it will inject more fuel... This creates a problem where the car can smell rich but read lean. So the goal is to find the sweet spot that the motor isnt fighting itself but you're also not throwing off fuel trims.

Now mind you you would have to advance thigns a good amount to really see what im talking about above; but that doesn't mean it wont happen on a smaller scale... So you go too far your just wasting fuel that was injected and you compensate and end up using more fuel with the same air flow as before to stay in the commanded afr...

 

I agree that the bump in the low load is a replacement for egr systems. I have seen many many subarus run without that bump and do just fine. However I have not seen a gain in efficiency or gain in power from getting rid of it... So most of the time i just leave it...

What's interesting is, I've been smelling fuel when starting the car after header install, makes me wonder if this is happening with my EL header now.

Wow... So far the list of things that can screw up an O2 sensor reading AFTER air and fuel are metered:

Ignition Timing

Spark gap

AVCS/CAM advance/duration

Injector Timing

Based on the that logic I'd also expect if ones valves are out of adjustment to cause odd readings as well. Maybe the tech who did my airbag wasn't wrong about adjustment being off, even though my heads were refreshed 4000 miles ago.

I wonder if the ELH have an effect as well. Did you notice a direct change in your logs just from swapping the headers?

If you want a fun read the official does timing change afr debate thread over on romraider has some other theories.

With the fuel smell, I can tell you one area to check which is common with these years.

It's not quiet a raw smell, it might be simply from exhaust (maybe one of my gaskets is shot (had to reuse turbo to downpipe and downpipe primary to downpipe secondary).

Also thinking about, AVCS stays at 0 on cold starts until 140*F, so shouldn't be from overlap.

Wow... So far the list of things that can screw up an O2 sensor reading AFTER air and fuel are metered:

 

Ignition Timing

Spark gap

AVCS/CAM advance/duration

Injector Timing

 

Based on the that logic I'd also expect if ones valves are out of adjustment to cause odd readings as well. Maybe the tech who did my airbag wasn't wrong about adjustment being off, even though my heads were refreshed 4000 miles ago.

 

I wonder if the ELH have an effect as well. Did you notice a direct change in your logs just from swapping the headers?

 

If you want a fun read the official does timing change afr debate thread over on romraider has some other theories.

Maybe that's why most people tune by EGT's primarily?

ELH did make the fuel leaner by about 0.4 AFR across the whole range.

Here is a screenshot from my back to back runs testing up to +4 of timing. Notice how AFR doesn't really change:

http://legacygt.com/forums/attachment.php?attachmentid=248781&stc=1&d=1494040185

My left AVCS is shot, I saw preliminary signs yesterday as I was doing 0-20* AVCS testing, for 15* and 20* it would spike up 5* more then settle back down. Today while driving the right one was doing fine, but left one would hunt from 0* to 40*, back to 0*.

I checked the OCV valve and it's not stuck, quickly searching on the phone I found a post mentioning that when AVCS gear it self starts leaking, OCV valve will start adding too much then reduce a bunch (hence the hunting).

The question is, does anyone know what inside the AVCS gear would cause oil to leak through it basically. Trying to figure out if I should try to rebuild it right now, or pull the timing belt and install a new gear.

EDIT: Looks like PhilT had the same issue here. He swapped over the valves and it made left side happier, then replacing vales fixed it.

At this point I'm glad I don't have dual AVCS, or this would be a $400 ordeal... Not sure Dual AVCS buys you enough to justify that either, 2010-12 LGT's even with 6 speeds are still rated for same gas mileage as our 05-09's.

This also made me think about these systems being used for improving gas mileage, first time you have to replace them it negates the gas mileage savings it might have made over the 100k miles ...

I've had this lip picking up dust in the garage for a while. After talking about aerodynamics last week, finally got a chance to get it installed.

With the under-tray removed you can see how the header starts interfering with aerodynamics. This could be why I only go 28.3mpg with the new header at first.

After trying to size the lip on the car, and not being able to find my clamps I decided to pull the bumper. Car's without bumpers just have that awesome raw look to them.

Bumper is off, the lip is a little longer then our bumpers no matter how I oriented it.

With the bumper upside down I started to see how far forward the lip should stick out. I believe most people mount it the furthest forward like this:

While I like it, I didn't want to scrape everywhere. Plus the pics that I have of legacies with actual JDM lip had it a little further back.

After probably an hour of trying to find the best location, drilling some holes, realizing it's not aligned and redoing, finally got it mounted:

Next up was cutting off the excess that goes past that bumper

One known issue is these gaps. I'll have to figure out a way to cover them up, started to use the heatgun and tightening it with a bolt, but looked very weird and stretched, so had to resort to having the gaps for now.

Ready to reinstall

It barely clears my drive on ramps, yay! As long as I don't lower the car I should be fine...

The lip does stretch far enough down to cover the header and other suspension components, this means that the under tray is no longer a must to have good aerodynamics.

Nevertheless installed the undertray, here is what it looks like before and after the lip. As you can see, the undertray is actually becoming more of restriction now (part of it is because it's been mauled by a deer).

Finally, here are some finished pics.

Love how angry the car looks from this angle

Ha! Not worth the effort though, I'm all about realistic and functional stuff. If it makes the car look better then I'm even more down for it.

I'm now waiting for the OCV's to ship out, so car is being parked until that happens, at some points AVCS was reading at 50*, I thought the max they could advance was 30*? Either way that much advance not good for the engine. If I had aftermarket pistons or cams, there is a good chance there would have been valve contact by now...

What kind of lip is that?

Sent from my iPhone using Tapatalk

One of my life goals is to get as comfortable tuning and tweaking as you, and a few others on here, are. I have a lot of real mechanic experience but would never attempt this kind of stuff without help. Hats off to you man...

Good shit, and thanks for the free lessons

What kind of lip is that?

 

 

Sent from my iPhone using Tapatalk

I got it from a friend, it should be the S204 ebay special lip

One of my life goals is to get as comfortable tuning and tweaking as you, and a few others on here, are. I have a lot of real mechanic experience but would never attempt this kind of stuff without help. Hats off to you man...

Good shit, and thanks for the free lessons

Thanks man! When you live where I live, in the middle of no where, there aren't many tuners or trusty import car mechanics. So necessity forced me to learn how to do all of this stuff .

I will be honest, when I got the car in 2013 I already had 5 years of tuning experience and I was terrified of tuning the legacy (knowing how expensive Subaru motors are).

Hey Covert, I noticed right away after installing the Tomei ELH + up pipe that wideband reading at idle had increased from 2.5v to 2.8v ,while the o2 is hollding at stoich 14.7 I properly recalibrated the wideband and went as far as replacing the sensor. Nothing changed

Any ideas? care to look at any logs prior to swapping out the header and current ?

This is the wideband That I'm using:http://legacygt.com/forums/showthread.php/tuning-alliances-wideband02-logging-kit-258451.html

Jason