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Old 09-02-2010, 02:28 PM   #1
blckout7
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Default Question about the 4eat

I came across a thread explaining all about the 4eat...it stated that "3" can be used on backroads or highways(getting on and picking up speed) instead of "d" because it changes the power band through gears 1,2,3. my question how bad is it switching from "3" to drive as your accelerating on a normal use...I've never done it before but would assume it can't be to good...I think
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Old 09-02-2010, 02:49 PM   #2
Gr3en
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This should be in the tranny section and it wont hurt anything if you downshift fron D to 3 when merging on the highway or climbing up a hill or whatever you need more torque for.
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Old 09-02-2010, 02:50 PM   #3
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Sorry about being in wrong section
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Old 09-02-2010, 03:41 PM   #4
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Change to 3 whenever you want, the 4EAT will automatically shift down when the conditions are deemed acceptable.

For example it won't shift down to 3 if you're going 125 in 4th.
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Old 09-02-2010, 04:06 PM   #5
IanB
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Being electronically controlled, there are failsafe's in place to prevent damage to the tranny. Shifting from "D" to "3" doesn't change the powerband in other gears, it just gets you into a gear better suited to accelerating than overdrive, and if it needs to downshift into "2" then it's one gear closer to start with, that's all.
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Old 09-02-2010, 04:11 PM   #6
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Ok thank you guys! My car modification is officially complete!!!
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Old 09-02-2010, 05:43 PM   #7
formula91
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Quote:
Originally Posted by IanB View Post
Being electronically controlled, there are failsafe's in place to prevent damage to the tranny. Shifting from "D" to "3" doesn't change the powerband in other gears, it just gets you into a gear better suited to accelerating than overdrive, and if it needs to downshift into "2" then it's one gear closer to start with, that's all.
This is only half true. It won't change the powerband, that's just dependent on the engine really.

However, having the gear selector in "3" loads different shifting tables. It will shift into 2 sooner and stay in 2 longer.
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Old 09-02-2010, 07:45 PM   #8
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I really wish those shifting tables were tunable...
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Old 09-02-2010, 08:38 PM   #9
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OK so all this being said.....if I hit WOT on the highway while in D and say at 4500 rpm's I drop into '3' RPMS increase like 2-300 and the car pulls even harder..........wtf causes that?
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Old 09-02-2010, 11:11 PM   #10
formula91
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Quote:
Originally Posted by Subyroo2.5 View Post
OK so all this being said.....if I hit WOT on the highway while in D and say at 4500 rpm's I drop into '3' RPMS increase like 2-300 and the car pulls even harder..........wtf causes that?
Because your peak torque and horsepower are around 5000-5500....

That's about when your car is producing the most power. So it would make sense. lol
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Old 09-03-2010, 02:25 AM   #11
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Quote:
Originally Posted by Subyroo2.5 View Post
OK so all this being said.....if I hit WOT on the highway while in D and say at 4500 rpm's I drop into '3' RPMS increase like 2-300 and the car pulls even harder..........wtf causes that?
That's the torque converter clutch unlocking. If you watch the tach carefully while climbing a long hill at steady state throttle, the tach will jump 200 rpms, then hold for a while, then downshift to the next gear. Unlocking the TC gets the engine further up in the powerband, and is the first step before commanding a downshift to really get it up in the powerband.

The TCU's on the pre-98 4eat's have been cracked and are tunable. People are doing paddleshifters, modifying the shift points, full manual, all with the stock TCU.
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Old 09-04-2010, 10:26 AM   #12
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Quote:
Originally Posted by formula91 View Post
Because your peak torque and horsepower are around 5000-5500....

That's about when your car is producing the most power. So it would make sense. lol
hahah who would have thought? Go read my post again.

Quote:
Originally Posted by WoodsWagon View Post
That's the torque converter clutch unlocking. If you watch the tach carefully while climbing a long hill at steady state throttle, the tach will jump 200 rpms, then hold for a while, then downshift to the next gear. Unlocking the TC gets the engine further up in the powerband, and is the first step before commanding a downshift to really get it up in the powerband.

The TCU's on the pre-98 4eat's have been cracked and are tunable. People are doing paddleshifters, modifying the shift points, full manual, all with the stock TCU.
Okay, but if im already at WOT and in the lowest gear possible, what makes a difference on my 4EAT when I shift to 3rd? My reasoning is that if im doing 110 and downshift to 1st nothing happens.....so why is it that I feel like im dropping a gear when I do this? Its almost like I feel 'vtec' kick in in a honda.
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Old 09-04-2010, 11:07 AM   #13
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Quote:
Originally Posted by formula91 View Post
This is only half true. It won't change the powerband, that's just dependent on the engine really.

However, having the gear selector in "3" loads different shifting tables. It will shift into 2 sooner and stay in 2 longer.
That may be true, my Suby is a Legacy and I've got "sport mode" if I want more aggressive TCU maps and manual mode if that's not good enough, I've never actually played around with 4 vs. 3 position for that reason. Sport mode is pretty decent though, I love how if you're hard on the gas and let off for a corner, it will hold the gear so you're still in the power when you hit the gas to exit the corner, pretty decent logic at play there really.
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