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 Post subject: 2005 USDM LGT to EJ20x twinscroll manually retarded exh cams
PostPosted: Tue Feb 13, 2024 7:23 pm 
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Joined: Sat Jan 13, 2024 2:05 am
Posts: 1
Ok here goes
I have been working on my brother in laws USDM 2005 LGT that has been swapped to an ej20x. I have retarded the stock exhaust cam gears one tooth to tighten up the gap that normally exists down low. I have also retained the twin scroll setup by swapping over the cold side housing(so i could use the original intercooler) from the vf40 to the twin scroll vf38.

A little back story, had a different ej20x swapped in that retained the vf40 and no modification to the cams. it was a dog. even after being street tuned it was terrible down low. IDK if it was the tune or what.

Fast forward to now, that engine blew. I watched the Subie Sanctuary you tube video where they talk about retarding the exhaust cam to more closely mimic the non variable profile. I buy another ej20x and retard the cam. it pulls really hard down low now and breaks up over 35% throttle input. Knock sensor pulling timing.

I bought the Tatrix unit and downloaded ECU flash and Romraider. I have all that set up and working. I do not have a method to view the logs beyond excel so I would love suggestions on a log viewer. I have done a ton of homework here and I just might need a tutor to get through this course but I have not blown it up yet and have around 1k miles on the car of babying it around. Car runs on 93 in Michigan.

I pulled the rom that was on the ecu that rom can be found here.
https://drive.google.com/file/d/1EaWnz3 ... sp=sharing
IMHO there is WAAAAAYYY to much ignition advance in the ignition tables for a high compression turbo motor. Comparing it to the stock ej20x map it was wildly different.
so today I took that map and copied all the tables and data i could from the ej20x map to the LGT map. I dont need to set the world on fire I need this car to be a reliable daily. That map is here
https://drive.google.com/file/d/1aqu_G_ ... sp=sharing
Now it is a bit sluggish off the line(by comparison) but better. I am still getting knock at higher load and rpm.
Here is a log I took today. If I need to update parameters and log again I can. I am new to this so I don't know how long the logs should be really.
https://drive.google.com/file/d/1U3Epor ... sp=sharing


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 Post subject: Re: 2005 USDM LGT to EJ20x twinscroll manually retarded exh
PostPosted: Tue Feb 27, 2024 12:45 am 
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Joined: Sat Jan 06, 2024 5:13 am
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 Post subject: Re: 2005 USDM LGT to EJ20x twinscroll manually retarded exh
PostPosted: Thu Feb 29, 2024 6:23 am 
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Joined: Wed Nov 18, 2009 12:38 am
Posts: 185
Location: Vancouver WA, USA
What is your mods list other than the twin scroll vf40? and do you have a wideband?


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 Post subject: Re: 2005 USDM LGT to EJ20x twinscroll manually retarded exh
PostPosted: Mon Mar 04, 2024 6:25 am 
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Joined: Thu Dec 18, 2014 10:31 pm
Posts: 1529
Location: oregon
From what I've read from experienced engine tear down guys, the exhaust cams are locked with a pin to normal centerline, when the avcs solenoid is disconnected.

in either case, I felt that something was amiss with exhaust avcs, and told this guy to do an avcs delete on the exhaust cams. unnecessary? maybe. that's what the pros say anyways. he used a delete kit that you modify the camshaft with, I forget the manufacturer.

anyways, it's for a 2008 LGT which still has the oem TGVs, and thus because I can, have both cruise and off cruise (tgv closed/tgv open) tuned respectively.

total timing, and avcs for each TGV condition are different.

for you, you only have one set of timing and avcs, so I'd go with the cruise maps from my rom for inspiration. it's essentially derived from the 2014 USDM WRX, with the out of cruise area of the map matching what a derived 2007 STi style avcs would be.

ignore the per cylinder comps, it's because of the funky parallel dead-head feed system these 08+ EJ255/EJ257 have. per cylinder fuel injector comps are always to be VE per runner based corrections. use whatever comes with your intake manifold. in this case, the 2014 USDM WRX uses the most updated, and more correct, per cylinder fuel comps, when the fuel system is the same as 08 LGT at the rails/etc.

I'm going to do a whole new post for it in a bit, but here's a copy of the ROM for this post as well, since it's related.


Attachments:
File comment: 2008 USDM LGT 5EAT
EJ20X long block, exhaust avcs delete kit
cobb downpipe, 2014 WRX intake
air pump delete, all else stock 2008 LGT parts (tgvs/upper mani/injectors/rails/etc.)
93 octane

MP-Stage2-EJ20x-08LGT-v9.zip [424.09 KiB]
Downloaded 55 times

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