View Full Version : 03 Torque converter question
Would the installation of an 04 torque converter in my stock 03 cure the lag when I accelerate?
Or,should I just get a super tuneup.
Thanks for your help,
Dave
sailsmen
06-22-2007, 05:59 AM
I doubt the lag is due to TQ, more likely the shift points in the stock tune, which were set to met CAFE.
Stranger in the Black Sedan
06-22-2007, 05:59 AM
Define "LAG". The 04 converter will give you 300 rpms more stall, which will help launch significantly. I am probably going to do that swap, as I really don't need the super expensive aftermarket converters (yet).
If you really want the engine to get up in its powerband off the line, you need gears.
I have always stayed neutral to the 04 TC is better than the 03 TC.
You wanna make a difference is acceleration, get a smaller, lighter torque converter.
Doesnt even have to be a different stall.
Stranger in the Black Sedan
06-22-2007, 06:07 AM
Zack have you ever compared the 03 and 04 converters directly? I'm curious. 300 stall shouldn't be earth shattering but it also shouldn't be insignificant...
The "lag" is when driving at normal speed and punching the throttle to pass there is an annoying pause(2-3 seconds) until the foreward motion of the car catches up with the screaming whine of the engine.
This occurs with the trans in drive or overdrive.
Would the tune and shift point adjustment help correct this.
Stranger in the Black Sedan
06-22-2007, 06:22 AM
there is an annoying pause(2-3 seconds) until the foreward motion of the car catches up with the screaming whine of the engine
A 4.6L engine is trying to move 4200 lbs of steel! The 4.6 says, "hey, cut me some slack man, how quickly could you move this car if you had to push it!!"
Sooooo,
What's the solution,besides 4:11's or a Supercharger
magindat
06-22-2007, 06:51 AM
If the 'lag' is as you describe, tuning will greatly reduce it.
If you get a SCT XCAL2 and then have the vendor send you the tune, you can download the Extreme tune software and adjust shift points and TC lockup to your liking.
The lag is most likely the time it takes for the torque converter to unlock, then load with fluid pressure. If you ran in 1,2,3 unlocked, the lag would not exist, however your fuel economy around town would suffer.
Keep in mind, Ford programmed this car to be under the gas guzzler tax.
Also, you do not mention if you are footing it deep enough for a down shift. This would add even more time to the 'lag'.
A supercharger nor gears will stem your complaint. However, an Art Carr Level2 tranny build, a PI 3000 torque converter, and a custom tranny tune will give INSTANT response, hard gear switches (yes 'switch' since the word 'shift' implies it takes a little time), and the ability to control the car as if it were a stick shift by using only your right foot and knowledge of the shift points.
Mileage will suffer, and so will your wallet. However, the tranny WOULD be beefed for any future power mods including relatively high boost.
If the 'lag' is as you describe, tuning will greatly reduce it.
If you get a SCT XCAL2 and then have the vendor send you the tune, you can download the Extreme tune software and adjust shift points and TC lockup to your liking.
The lag is most likely the time it takes for the torque converter to unlock, then load with fluid pressure. If you ran in 1,2,3 unlocked, the lag would not exist, however your fuel economy around town would suffer.
Keep in mind, Ford programmed this car to be under the gas guzzler tax.
Also, you do not mention if you are footing it deep enough for a down shift. This would add even more time to the 'lag'.
A supercharger nor gears will stem your complaint. However, an Art Carr Level2 tranny build, a PI 3000 torque converter, and a custom tranny tune will give INSTANT response, hard gear switches (yes 'switch' since the word 'shift' implies it takes a little time), and the ability to control the car as if it were a stick shift by using only your right foot and knowledge of the shift points.
Mileage will suffer, and so will your wallet. However, the tranny WOULD be beefed for any future power mods including relatively high boost.
Thanks for the responses,and yes I am on the throttle hard enough to downshift which is why it's so annoying,and sometimes scary as in,I want the car to move now,fast,and we are still sitting here.
Some AH pulled out in front of me and I had to hard left and accelerate,close call !
The "lag" is when driving at normal speed and punching the throttle to pass there is an annoying pause(2-3 seconds) until the foreward motion of the car catches up with the screaming whine of the engine.
This occurs with the trans in drive or overdrive.
Would the tune and shift point adjustment help correct this.
Wow, I never experienced that before or after a tune NA. Mine would downshift pretty quick and then hang on! It is the best part about the 4 valve, it may not get off the line, but if you are moving and get it to downshift it will keep accelerating til you run out of road!
If you don't have a tune, get one. Pick an SCT or DS flasher and get a custom tune from the vendor. If you buy the flasher directly from Lidio or Dennis or Dagostino racing you can get it with a more recent tune then comes on the standard SW.
KillJoy
06-22-2007, 09:56 AM
This occurs with the trans in drive or overdrive.
Would the tune and shift point adjustment help correct this.
You should ALWAYS turn off OD before you punch it. That way, you do not need to downshift, your RPM's are in a better place, and it is not so hard on the Trans.
;)
KillJoy
88LTDCV351
06-22-2007, 02:43 PM
Mine also has this lag. Its disappointing. The light turned green, I was trying to get on the interstate going slightly uphill and this little Chevy Malibu kept up with me and his lane was ending and merging into mine. Thought I might have to give him the right of way since I couldn't blow the doors off of him..
Stranger in the Black Sedan
06-22-2007, 07:36 PM
A malibu? I have driven much much faster cars than my stock Marauder but it doesn't feel THAT slow to me. Were you towing a trailer at the time?
MENINBLK
06-22-2007, 08:13 PM
If the 'lag' is as you describe, tuning will greatly reduce it.
The lag is most likely the time it takes for the torque converter to unlock, then load with fluid pressure. If you ran in 1,2,3 unlocked, the lag would not exist, however your fuel economy around town would suffer.
Magindat,
You hit the nail on the head.
The Ford OEM Tune puts the Torque Converter into lockup for every gear except 1st.
If it were possible, Ford would lock the Torque Converter in first gear too...
If you shift the tranny manually, OD OFF selector in 1, you'd start off in First.
Move the selector to 2, the tranny shifts to 2nd and them almost IMMEDIATELY
locks the Torque Converter.
You can see this by tapping the brake pedal while you are driving in 2.
When you step on the brake the RPMs will rise because the PCM
unlocks theTorque Converter when you tap the brake pedal.
Now move the selector to 3. The tranny shifts to third and then immediately
locks the Torque Converter again.
Tap the brake and the RPMs will rise.
Now turn on the OD and the tranny shifts to 4
and the Torque converter will lock again.
Everytime you nail the accelerator, the PCM has to see the change in the
TPS (Throttle Position Sensor) and reacts by unlocking the Torque Converter
and adjusts the Engine Management System to adjust fuel, spark, and timing
for the increase in rpm, and it has to shift the transmission to a lower gear
before the Torque Converter is loaded up with pressure
from spinning around the transmission oil inside.
The lag comes from the high stall speed of the Torque Converter,
because when the tranny is in 4th and the Torque Converter is locked,
the inside of the Torque Converter has an RPM of ZERO.
In order for the Torque Converter to build pressure and multipy torque to 4th gear,
the Torque Convertter has to be unlocked and it has to INCREASE Engine RPM
at least 2500 RPM to begine to multiply torque.
When it is just about at that point, the PCM yanks out 4th gear and shifts down to 3rd
and the engine has to increase another 1000 rpm for the Torque Converter to match
the rotational input speed of third gear in order to start building RPMs and multiply torque.
As Zack said before, "A smaller and lighter Torque Converter
will decrease lag, rather than a Torque Converter with a higher stall speed."
This is because a smaller and lighter Torque Converter will increase your Engine RPM acceleration rate.
It works the same way a lighter flywheel works with a Manual transmission.
A Torque Converter with a higher stall speed and no tune will actually increase your lag time
because the engnine has to increase its RPM to match the new stall speed
in order to start multiplying torque.
A Performance tune will disable the Torque Converter from locking
until the tranny is in fourth gear and the vehicle is moving faster
than a threshold speed (65 mph for most).
This keeps the Torque converter loaded and the shifts can happen
faster and firmer. (thus chirping your tires on the 1-2 shift).
What does this do to your MPG ?
For me, absolutely NOTHING. I get the exact same mileage
whether I run the performance tune or I run the Ford OEM tune.
Even when I goose my Marauder, I burn just as much gas regardless of the tune.
My HIGHWAY MPG is slightly higher with the Performance tune than with the FORD OEM tune.
The benefits ?
I got a quicker Marauder, higher higway MPG, and a bigger SMILE. :D
MENINBLK
06-22-2007, 08:16 PM
Mine also has this lag. Its disappointing. The light turned green, I was trying to get on the interstate going slightly uphill and this little Chevy Malibu kept up with me and his lane was ending and merging into mine. Thought I might have to give him the right of way since I couldn't blow the doors off of him..
Naturally Aspirated, our engines aren't 2 valve Torque Monsters.
You have to think of them this way and respect this.
Once the RPMS climb, the 4 Valves allow the engine to breathe easier
and accelerate quicker than a 2 Valve engine does.
So for most cars, we don't have an immediate advantage off the line.
But once you get your RPMs going, there isn't much that can hold on...
Stranger in the Black Sedan
06-22-2007, 08:17 PM
Meninblk, that was a great answer. Thanks for the info! I tune some GM TPI era stuff w/ lockup converters but never really thought about what you are saying, about the converter basically having to spool up every time the converter unlocks. That just gives me another good reason to get a tune on the MM.
MENINBLK
06-22-2007, 08:22 PM
Meninblk, that was a great answer. Thanks for the info! I tune some GM TPI era stuff w/ lockup converters but never really thought about what you are saying, about the converter basically having to spool up every time the converter unlocks. That just gives me another good reason to get a tune on the MM.
I'm not an ASE CERTIFIED MASTER TECH for nothing....
Stranger in the Black Sedan
06-22-2007, 08:28 PM
Ok, thanks just the same
MM_BKK
06-23-2007, 04:59 AM
Don't forget about the Torque Modulation function of the EEC. It can reduce engine torque output by as much as 50% depending what the car is doing. For example, everytime the trans shifts up a gear it tells the EEC to reduce engine torque to act as shift accumulator and every time there's throttle tip-in, the EEC will reduce torque momentary and then put it back. When the TC is about to lock, the EEC will reduce torque. It does this by reducing timing and fuel. All this modulation can add to the "lag" feeling. You can have the Torque Modulation turn off with a custom tune, this has greatly improved throttle response for me and it made all the upshifts firmer with no lagging. And definitely only have the TC lock up in 4th gear will improved driveabilty.
OneBADLsE
06-23-2007, 10:22 PM
When i dont want to feel lag, im very agile with the way i handle the throttle. I know on my GM if i get back on the throttle quick, ill beat the Tc lockup, thus giving me a quick boost of power with zero ''lagg''. From what you guys are saying about the MM's, you dont have alot of time in between shifts and lockups. If, i'm understanding correctly.
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