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2018 XT & 2010 X
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Discussion Starter · #1 · (Edited)
Has anyone else had this problem? I’ve installed a Cobb AP, OTS Stg1 (91oct) and WOW. My XT is much slower off the line (first several seconds of acceleration). I noticed it the first moment I left the shop, as I pulled out on the road, pressed the gas down, and the car just barely moved for 4-5 seconds. I seriously thought something was wrong with it. It’s gotten some better, but I’ve mainly adapted my driving style to hit 80%+ throttle off the line, then back off as boost comes on. I’m getting no errors, gauges look good, and the car definitely has more power when rolling.

Even tonight my wife said “the car USED to be fun to drive. It’s slow now. I get left by everything.” If she noticed, it’s definitely bad.

So I flashed back to stock tonight. And guess what? The car actually moved off the line well at 30-40% throttle. With the tune I have to hit 80-90% throttle to get the car to accelerate from a stop the same way. I’m really thinking about getting rid of this AP. Another option would be a pro-tune, but I don’t want to throw good money after bad at this point.

Anyone else?
 

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2018 XT & 2010 X
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Discussion Starter · #2 ·
Oh, and this isn’t because I’m just stomping the pedal. I’ve playing around with all kinds of different pedal positions. And this isn’t about launching it, it’s about just accelerating from a stop in a normal manner. Ugh, this is so frustrating.
 

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2017 Forester XT Touring
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452 Posts
Haven't noticed any issue like you describe, but I use the 93 octane OTS tune. Mine accelerates noticeably better with the Cobb tune than with the stock tune.

How long were you running with the tune?
Did you try disconnecting the battery to let the ECU relearn the pedal position? (After doing this, make sure you send it at WOT several times to let the car learn where WOT is!)
 

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2015 XT Touring CVT
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570 Posts
did you do an idle relearn? its will run strange until it learns idle speed. Also most tuners (not sure if cobb OTS is included) remove power at lower RPM because it bends rods on the FA20DIT. they give you more power up high where your less likely to lug the engine and its better utilized.
 

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Discussion Starter · #5 ·
I’ve been running the tune for about 3 weeks. I haven’t reset anything since loading it. Or since going back to stock.

You can really feel the power difference at WOT at 4k rpm with the tune on. But in all other situations it’s more fun with the stock tune!
 

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2001 Forester STi 6spd with MapDCCD and 535hp
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4,705 Posts
Is this the most up to date shelf tune? The reason I ask is because COBB updated their maps recently for all the FA20 models and they now take full advantage of the full time closed loop fueling feature, which is a huge improvement over a variability that would and could sometimes be a hit and miss issue for causing small but odd quirks. Using COBBs Accessport manager, the unit itself can be plugged in and updated.

Also, Check your DAM reading too. If the default (on the OTS map) is set to 0.50 (varies between maps / years) and isnt 1.00 , the full amount of possible power isn't being applied (by way of timing advance) , which would certainly lead to sluggish and reduced feelings of power and response. This is often the default on the first flash, and the car will "learn" it upward to 1.00, given it sees no significant issues or causes for keeping it down in the first place.

With all that said however, despite being far more advanced than EJ models, it is still very beneficial to do a proper and custom tune for these cars from a reputable tuner that has a strong focus on this particular platform.
 

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Discussion Starter · #7 ·
Thanks for the ideas. I double-checked and it’s the latest map (v401). I’ve loaded and unloaded it again to see if that made a difference. No dice.

DAM is sometimes up to 1.0, sometimes down to .6 something. Reading Cobb’s notes, it sounds like it’s ok to be below 1.0 with DIT engines. Looking at gauges, nothing seems amiss under WOT.

I’ll try to find some time to call Cobb tomorrow.
 

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2001 Forester STi 6spd with MapDCCD and 535hp
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@problemcat13 In older, EJ equipped models (even up to current STI) ... generally a DAM move is a cause for concern and further troubleshooting if it isnt related to its intention of "octane adjustment" for bad batches of gas in the tank.

With the FA equipped models, while it should be noted if you see significant drops that last longer than a drive or two, the knock logic is vastly changed and more sensitive with them, esp now that it has more data inputs for temps around the motor. The approach now is that the ECU can throw a DAM drop out there for even the slightest of what it perceives to be knock, even at low load cruise conditions.
 

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Discussion Starter · #9 ·
Talked to Cobb support today. They say it’s just how their map is, as they change the throttle mapping table to be a more linear experience. I assumed that would be a difference between stock and Cobb…but it’s terrible. (Having to go 80-90% throttle just to pull out in traffic every time, and then back way off the throttle to keep from hitting full boost, is not a natural driving experience). Anything less than 80-90% and the car just rolls, it doesn’t really accelerate.

At this time, I wouldn’t recommend an OTS stage 1 tune unless you like your 2018 XT to feel slower.
 
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