'05 LGT 5MT - Tuning - Need help and insight from those educated in tuning.

[brok3n potates]

Feel free to message me for quicker conversation.

 

I picked up a 2005 Legacy GT last fall and I am finally getting around to working on it. At the moment I am beginning to tune the car from stock. I have done a hefty handful of research and have started changing some parameters. I would appreciate very much if someone could help me critique and explain what is wrong or right in my logs. Also, I'd really be interested to know exactly what parameters to look at or change for each of (or collectively) the installed mods. My biggest issue is that I don't know the 'correct' values for everything on the some of the tables, especially when there are changes made or to be made. I am using Romraider for logging, ECUFlash for editing and flashing, via an OpenPort 2.0.

 

Here is the mod list:

- Wiseco Forged Pistons (Full Stock Engine Rebuild 5-7k miles ago)

- VF52 Turbo

- 3" MAF Housing

- Cone Filter

- FMIC

- Unknown UEL Headers

- Unknown Up-Pipe

- Unknown 3" cat-less DP

- Forge BPV

- Grimmspeed EBCS

- AEM 320lph Fuel Pump

- AEM Wideband O2

- Boost/Vacuum Gauge

 

I am currently on stock injectors, as I need to have the other aftermarket set that came with the car cleaned and flow tested. I believe they are DW740cc but again I am not sure. Knowing the MAF needs proper scaling, I read that it is easier to scale with stock injectors so I am grateful for that. I am not looking for max power or anything crazy, just want to get it safely driving. I am aiming for about 18psi or whenever the stock injectors get near max IDC.

 

When I brought the car home, there was either no tune or an incorrect tune. It was in limp mode, I believe, though still boosted to about 15psi (had to try it once). It would dip RPM as soon as the throttle was depressed from resting, but come back up with increased throttle. Also, it would dip RPM when coming off the throttle, and letting the idle return, though it would come back up to proper idle. I have since adjusted the Tip In slightly richer to accomodate for the extra rush of air given from the mods, and it did seem to help smooth out that transition from resting. I do still have a slight stumble in that area, but there could be a number of factors causing that.

 

The first 2 logs are just idling with a couple different parameters

The last 3 logs are idling, then holding or slowly increasing revs to about 1000, 1600, 2000rpm. Thanks in advance.

romraiderlog_20220117_190411.csv

romraiderlog_20220117_190018.csv

romraiderlog_20220117_190041.csv

romraiderlog_20220117_190220.csv

romraiderlog_20220117_190421.csv

[Pleides]

Have you done a vacuum leak test before tuning your car?

We do have a tuning subforum and they may be able to help you more.

18 PSI is about the limit of the stock STi topfeeds on my car. LGT sidefeeds will be in ~5% of the range of my car.

 

Good luck. This is a topic I am not brave enough to tackle myself!

[Haze]

You've got a lot going on there. Fortunately a comprehensive guide has already been written. I suggest you read and re-read the "Subie newbie tuning guide" until you can recite it in your sleep.

https://sites.google.com/site/asubienewbietuningguide/

I did my own stage 2 w/ 3 port BCS tuning on my OBXT with no prior tuning experience and that write up as my main resource. Took me somewhere around 50 tune revisions and I'm sure I left a few HP on the table but it runs smooth and doesn't knock.

Getting your MAF scaling dialed in should definitely be a priority. I'd recommend zeroing out your WGDC tables until you get that sorted.

[NORULZleggy]

kudos to you for trying this out, just make sure you don't get to deep in and mess something up. Know when to get that pro-tune. I know it cost but better then boom town.

[brok3n potates]

Pleides, though I haven't done a pressurized boost leak test yet, I have gone around and checked all hoses. As far as I can see all are attached and I added zip ties on some vacuum lines. Also, I have gone around all the hoses and intake manifold area with starting fluid I believe, and noticed no change regardless of where I sprayed the fluid.

 

I should note that I have about 15inhg idling, yet if I barely hit the throttle to hold the rpms around 800+, I see a more proper 19inhg. Perhaps I have enough going on to warrant a slight idle speed increase as some would with larger injectors ? I'm not sure what would cause this otherwise. I have not done a compression test, but I don't seem to be burning oil or having major mechanically related issues.

Edited January 24, 2022 by brok3n potates

[brok3n potates]

Haze, thank you very much for linking that guide to me. I don't believe I had seen it prior. It is very informative and comprehensible for someone getting into tuning, as I am. I have read through the entire guide, and will keep coming back to it for each different subject. I have made a few changes following the guide, but I have yet to log road time, or pulls. I haven't actually registered the car yet because I knew it would be sitting for a while. Guess it's about time.

 

It's good to hear you got yours settled from scratch in a similar manner. I kinda understand that you'd want to maximize timing and boost, to safely just under the limits of knock and fuel, but it's all the in-between that gets even more so confusing.

 

I do have WGDC at 0 for now. As far as the MAF goes, I did several flashes just getting the idling portion within reason. On the MAF graph tool on Romraider Logger, I am now seeing very close to 0 (+/- <1) at idle. This may be subject to change following other revisions as I move forward.

[brok3n potates]

I do have some new questions as well. I have no roughness at idle, except for an occasional count of 1-3 on cyl 2 and 3 which I have read is normal (similar to occasional 'knock'). I do however have a lot of roughness (40+ before it resets) on cyl 3 if I hold the rpms around 1-2k. It does seem to clear up a bit over that or under that. I wonder what that could tell me. I would think a mechanical issue or coil, spark plug etc. would cause the issue to be consistent throughout idle to redline, but again, I'm not sure.

 

Also I am seeing that there is a difference between Air/Fuel Sensor 1 (Estimated or calculated AFR) and my AEM AFR gauge. For example, the live AF1 will read about 14.2(+/- .4) at idle while the AEM reads 15.1 (+/- .4). Is there something wrong with my gauge/sensor potentially?

 

Should I set the initial IAM to .5 or 1 ? This could be preference but I don't know. If I set it at 1 (which I did), will it still swing lower if there is an issue ?

Edited January 24, 2022 by brok3n potates

[Pleides]

It sounds to me like you have a boost leak. You're not gonna be able to eyeball most of them. You're gonna need to pressurize the system to 10+ PSI.

 

Yes, your roughness count is odd, but that could be any number of things from bad plugs to engine mounts.

[need bb]

Roughness at 40 is an issue. Are all spark plugs recently changed? When I had high roughness values it was a coilpack going bad.

 

How are you trims in learning view? Step 1 is to get closed loop running well, before moving to open loop and boost.

[brok3n potates]

I have had issues with misfires, I believe due to coil pack(s). I changed a couple around and I have 2 extra ones from another car, one extra sti one ? (Shorter pink boot). There’s a cheap eBay one on there now but I don’t remember at this time which cylinder I put that on lol. Guess I will have to swap for one of the others and see what happens there. I haven’t changed the spark plugs but I assume they were replaced when the engine was rebuilt, but if the coil doesn’t change it, I’ll try plugs too. Maybe injector swapping as well. I wish there was a way to test these coils with a multimeter in the way you can test resistance of sensors etc. I have read there is no way except for trying a known working one, though I have no way of knowing about these ones without digging in and swapping them out. Not so fun on these H4’s lol.

 

I checked the ‘per cyl’ timing advance and there’s nothing awry there, only +2.11deg for cyl 2 and 4 above 3600rpm and 0 for cyl 1 and 3 (anyone know why ?) I haven’t changed it from stock.

 

I will have to hook up my boost leak tester and see how that goes. Haven’t done much of nothing in this cold NH weather. Changed the coil last fall and hardly touched it since.

 

Also, yes I am definitely going to start by getting closed loop operation sorted out before moving to open loop areas. Prior to that was getting afrs and compensations within reason during idle alone. Should I worry about the same closed loop parameters while just revving and holding rpms in neutral, or just while driving/cruising ?

Edited January 24, 2022 by brok3n potates

[Tehnation]

 

I am about to start learning how to tune as well, but I have an accessport now, so I am going to take the Cobb tuning class ($150), which is required to use the AccessTuner. Wish I was still was using opensource.

 

I would thoroughly read that scubynewbie tuning guide someone linked. I am reading it now myself, thanks for that whoever posted it!

 

For the A/F ratio stuff, I believe you use the ecu numbers versus your aem gauge. If your gauge is out of whack try calibrating it again!

Edited January 24, 2022 by Tehnation