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Old 06-06-2006, 01:55 PM   #1
traction issuez
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Member#: 86559
Join Date: May 2005
Chapter/Region: BAIC
Location: Bay Area
2005 RS Wagon

Default Flat Foot Shifting or Anti-Lag

they basically do the same thing, but for someone whose more drag and less autox/rally. is flat foot better?

i would think anti-lag will be harsher on the turbo and has the same result as flat foot.

what do you guys perfer for drag?

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Old 06-06-2006, 02:02 PM   #2
Scooby Specialist
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Join Date: Jun 2005
Chapter/Region: MWSOC
Location: Indianapolis, IN
2009 BMW 135i


Using the UTEC's FFS, I only lose 2-3 psi on shifts. It seems to be more than adequate.
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Old 06-06-2006, 02:08 PM   #3
traction issuez
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Join Date: May 2005
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2005 RS Wagon


interesting, thanks for the facts. i have hydra so i have to buy extra harness for my flat foot shifting so i'm wondering should i get it or not.
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Old 06-06-2006, 03:27 PM   #4
Element Tuning
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673 WHP Element
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If you own a Hydra then the Element Accessory Wiring harness does both. Anti-lag is totally different from flat-foot shift. The Anti-lag doesn't have to be enabled but it allows the Hydra to switch into the Anti-lag fuel and spark maps based on TPS, Speed, and clutch position. This isn't setup for "Rally" anti-lag but instead for drag racing to spool the turbocharger for higher boost levels. Once the vehicle is in motion the anti-lag is disabled.

Just using the launch control will net only about 8 so on some larger turbo setups anti-lag is desirable.

Flat-foot shifting is just like launch control but it is not disabled when the vehicle is in motion. Using this feature keeps the throttle plate open so you don't loose hardly any boost between gear changes.

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Old 07-03-2006, 11:27 PM   #5
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2001 V7 sti


Just to add, on my ecu. The flat foot feature requires a switch on the clutch pedal mechanism. As soon as the clutch is pressed to the point where it releases the ecu switches to a form of anti lag where the ignition/fuel misfires and keeps the turbo spooled. Of course accelerator is kept on the floor.
As soon as you release the clutch pedal enough it goes back to normal mode and instant power. This is typically whats used for drag as it's used for launch and shifting down the track. Normally an extra switch is fitted within easy reach so the flat shift mode can be disabled for normal driving.
Proper anti-lag (as per WRC cars), is a mode that switches to anto lag mode based on engine factors such as rpms, throttle position, manifold pressure etc. If your into drag racing this is not the mode you want.
If you want to see an example of flat foot shift mode you will find a video on nasioc. Look for threads started by "explicit" he has posted an in-car video of a 11.2sec 1/4 mile run. In that video you can clearly see the car switching to FF mode while at the start line.
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