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Premium Member
2007 Forester XT 4EAT-VTD
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2,145 Posts
Discussion Starter #1
When I had my FXT tuned in August, Chris at EFI Logics mapped the throttle more aggressively. I think this more aggressive "throttle mapping" is standard fare with many tuners and I know many OTS maps include it.

To me at least, mapping so much throttle response early makes driving the car more difficult. So this past weekend I had Chris re-map the throttle.

The new map makes the car much more pleasureable to drive. As per my request, it's now mapped so the the first 40 to 50% of throttle pretty much stays out of boost, allowing for much better throttle modulation during normal driving. It's almost like driving a NA car in this range. Once more throttle is applied, wastegate duty is mapped to "bring it on" and the car performs just like before. The transition to boost seems much smoother now too.

The new mapping works really well for me. Since it has such a big effect on driveability, I think this is something to consider when having your car tuned.
 

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Premium Member
'09 STI
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4,212 Posts
IIRC most stage 1 tunes make the throttle plate mapping more linear as do most tuners. MY '04 XT was at full throttle at about 1/4 pedal travel stock. My '08 XT wasn't quite as aggressive but with the 4.44 it was still touchy. Can't imagine it any more aggressive than stock.
 

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Premium Member
2007 Forester XT 4EAT-VTD
Joined
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2,145 Posts
Discussion Starter #4
My post is based on observation/driving impressions only. Compared to the original tune done in August, the re-map is certainly far more "linear." Perhaps the original tune had already addressed this, but not far enough. When the TD04 kicked in with the factory mapping, it was pretty much a non-event. Not the case at all once I did the hardware upgrade and tune.

My only point is that by avoiding full boost in the initial range of throttle, the car is far more driveable under normal conditions. Discussing this point with the tuner is certainly something to consider as it has a pretty drastic effect. The combination of hardware/tuning I'm running still brings on boost fast and hard (at least compared to the stock TD04 with factory map), but now it's much further down in the range of throttle.

Sorry for any confusion my post may have caused. IMO it is a point that should be discussed when getting a tune.
 

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Premium Member
2017 VW Golf SportWagen 5MT
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10,887 Posts
Agreed. I have 3 versions of same map, throttle sensitivity being the only difference. If I drive on the most sensitive one (original version), my mileage will suffer and clutch will go alot sooner.

Stan
 

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The Sub kit guy
2005 Forester X & XT VF39
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13,100 Posts
I think the stock throttle mapping only uses 80% of the pedal travel. a Good tuner will utilize the entire pedal and smooth things out. After my tune, the car drove much nicer.
 

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Premium Member
'09 STI
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4,212 Posts
Sounds like your tuners are using shelf tunes at least for some things. No tuner who knows his stuff would look at the XT's stock throttle map and make it more aggressive. Now on a 2.0 WRX yes.
 

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Premium Member
2007 Forester XT 4EAT-VTD
Joined
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2,145 Posts
Discussion Starter #11
Tried cruise control this morning on the way to work and it is MUCH better! Set it to 65, disengaged and hit resume at 55 - nice, smooth response with no "over reaction." In fact, as stated in this thread, even the stock throttle mapping resulted in "over reaction" when using CC and going up a hill.

So, back to my original post and a few conclusions that can be drawn based on the info in this thread:

1. Stock throttle mapping is already sensitive
2. It's not uncommon to have tunes that make throttle mapping even more aggressive
3. Asking the tuner to make the throttle mapping "more linear" results in an easier-to-drive car with no sacrifice in all-out performance.
 

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9,011 Posts
My throttle mappng is way aggressie. If cruise is on, it will boost up to 8 psi to mantain speed on small uphills, but then it let's of the throtte, then boosts again. Kinda jerky.
Heh my stock 04 4eat does this too. With a catless uppipe and some new pipework, its even worse! If I have cruise control set and i'm going downhill, as it levels off it feels like i just floored it. Can't wait to eventually get a tune (and vf39.....oh how i wish college didn't cost so much!)
 
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