How to: 4r70w swap

Can you go into more detail about the adjustment to the PCM, to help cure this flare?


Anlo, I don't think your find will work, that one looks like it's for the 4.6 V8 motor.


-B

I know it can be done however I do not know the specifics, unfortunately I am just learning on the tuning changes.
Alan
 
Bryce,

It is my understanding that you can keep the same speedo gear and just adjust it in the tune.

The 4R70W transmission gear ratios are:

1st 2.84:1
2nd 1.55:1
3rd 1:1
4th .70:1

So, say you upgraded to 3.73 rear gear ratio, you get the increase in ratio by dividing the new gear into the stock ratio.
3.73/3.27 = 1.14

Then multiply the trans gear ratios by the increase in ratio:

2.84*1.14 = 2.238 new calculated 1st gear ratio.

Continue on with the rest of the gears.

Put your new values in the tables shown in the attached screenshot.

Now what I am not sure of his how this is accounted for in your '95 calibration with the 3.31 rear ratio.. If you could read the factory ROM it would be neat to see if it is compensated for in the tune, or what the deal is.

Maybe Dave Dalkie or Frasier could chime in?

Jeramie
 

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Also,

The 3-4 shift flare isn't that bad, but it is really noticable when cold. Once the trans warms up you hardly notice it.

It basically feels like the 3-4 shift slips a little at light throttle, when cold.

My old '94 with the '03 trans does this.

I bet it could be corrected in the attached table, but i am waiting for stephen to get his QH and software so we can play with it. Stephen bought my old '94.

Jeramie
 

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The gear must be adjusted in the tune but until you get the speedometer corrected the values the pcm is getting are not correct. The proper way is to do both as the computer does not control the speedometer, only a speedcal or dakota digital unit can fix this.
Alan
 
with all this talk of the 3-4 slip i took it upon myself to find out more, so i loaded in the stock tune and i too noticed the 3-4 slip

this is due to the ecu reducing the tv pressure on the 3-4 shift, it reduces so much that it doesn't have enough line pressure and for a moment you experience a neutral drop, i never noticed this before because i put a tune on my 95 auto the day i bought it and my 91 titanium doesn't have stock shift pressures either, i don't even think about the changes i make in the calibration its just second nature to me so i've never experienced this before today since i've never ran the stock tune

in any case you can resolve this issue rather easily. I recommend setting:

TVPMIN_ENG to 10 "tv pressure minimum engagement stall pressure"
TVPMINPT_ENG to 20 "tv pressure minimum engagement stall pressure at part throttle"

these scalars will clip the minimum tv pressure resulting in no neutral drop


hope this helps someone
 
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Bryce,

It is my understanding that you can keep the same speedo gear and just adjust it in the tune.

The 4R70W transmission gear ratios are:

1st 2.84:1
2nd 1.55:1
3rd 1:1
4th .70:1

So, say you upgraded to 3.73 rear gear ratio, you get the increase in ratio by dividing the new gear into the stock ratio.
3.73/3.27 = 1.14

Then multiply the trans gear ratios by the increase in ratio:

2.84*1.14 = 2.238 new calculated 1st gear ratio.

Continue on with the rest of the gears.

Put your new values in the tables shown in the attached screenshot.

Now what I am not sure of his how this is accounted for in your '95 calibration with the 3.31 rear ratio.. If you could read the factory ROM it would be neat to see if it is compensated for in the tune, or what the deal is.

Maybe Dave Dalkie or Frasier could chime in?

Jeramie


where did you get this utter ~~~~~~~~ from? who ever gave you that information needs to just give up on calibrating any engine management computer, simply logic will tell you that since the gear ratio in the transmission didn't change that the gear ratio's remain the same


the speedometer on the supercoupes are fed straight from the vehicle speed sensor, it DOES NOT GO THROUGH THE COMPUTER!!! therefore there is nothing you can do in the computer to change the speedometer.

unless the transmission gear ratio's have changed, DO NOT ADJUST THE TRANSMISSION GEAR RATIOS

the only thing the above will achieve is screwing up the computers calculations

if you change the rear end gear or tire size and the ecu isn't calculating vehicle speed correctly, you need to update the nvbase scalar, that value is rpm/mph in 3rd, then you'll need to update the constant, by multiplying nvbase by the update counter, which is usually 4.

now your ecu's calculated vehicle speed will be accurate for the new rear end gear, you'd probably want to reschedule the shift points now to compensate for the gear ratio change
 
I can agree to that on the 94/95 sc's not changing much related to the vss but the oss does make changes. Later cars if the vss is wrong they shift strange but i have never had that problem on a 94/95 sc. That tell you they must rely on the oss. It is actually dumb to have both since they both do the same thing in a different way. Ford got rid of the vss for all 99+ vehicles, they retained the mechanical function until sometime in 03. To me buying the 03/04 transmission is a better use of your money because cost to change them over even if you do have to pay labor isn't much, just making it work could easily be done for under $200 it is the improvements while you are in there that make it add up. If you add up the cost to ,ake a pre03 transmission as good as the 03 transmission you'll have about $500 in hard parts alone.
Alan
 
where did you get this utter ~~~~~~~~ from?

Read it somewhere on TCCoA a while back, i'll have to see if i can find it..

I've never messed with it, since i have not changed gears.

Jeramie
 
you need to update the nvbase scalar, that value is rpm/mph in 3rd, then you'll need to update the constant, by multiplying nvbase by the update counter, which is usually 4.

now your ecu's calculated vehicle speed will be accurate for the new rear end gear, you'd probably want to reschedule the shift points now to compensate for the gear ratio change


I found the nvbase scalar, where can I make sure this update counter is actually 4? Is this the NOVCNT scalar?

So if I change the rear gears, I should drive around in third, note the rpm and MPH, and then input the data into NVBASE? I'm a little foggy on this constant update?

Shift points, can you elaborate on this?

Update: I think I found the constant ... NVBASE_X_NVC
 
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yes novcnt is the update counter

correct, make sure your not getting torque multiplication from the converter I.E. make sure its locked

so if you cruise at 60mph and your engine speed is 2,760 rpm

2760/60=46 your new nvbase value

the constant is the value of nvbase x novcnt
in this example, 46 * 4 = 184

nvbase_x_nvc new value should then be set to 184

this is how the ecu calculates vehicle speed from the vss input
doing the aforementioned will have the ecu speed calculation correct

the shift points other than WOT are interpolated in the sealevel shift functions. I usually dummy it down to 2 points to make it easier to calculate, also reduces the chance of a mistake like having the downshift speed higher than the upshift speed which is a common mistake when folks try to reiterate the shift schedules.
 
Bump time, if I am understanding this correct somebody with an AOD Thunderbird can swap in a 4R70W without having to use a stand alone controller? You just have to do some things with the wiring harness and get a QH?
 
Bump time, if I am understanding this correct somebody with an AOD Thunderbird can swap in a 4R70W without having to use a stand alone controller? You just have to do some things with the wiring harness and get a QH?

No, that stuff is not in the AOD cars' computers. You would need to swap to a 94+ computer.
 
No, that stuff is not in the AOD cars' computers. You would need to swap to a 94+ computer.

Which requires, I believe matching '94 components, such as 94+ crank trigger, 94+ eDIS module etc. Also not sure how the '94 auto computer will react without the inputs and outputs for traction assist, which implements torque reduction, etc..

I think Dave Neibert looked into this and decided it was much simpler to use a stand alone system.

I had implemented a 4R70W into my '92 5 speed using a pretty advanced stand alone system from Powertrain Control Solutions (pricey).. But they now offer a simpler version that doesn't require a laptop. Just plug it in, and adjust dials for shift firmness and shift points. It is more affordable too.

Check out www.powertraincontrolsolutions.com

Jeramie
 
Did you solve your shift flaring when you had the 4R70W?

Well, the shift flare was on my old '94 SC when I put an '03 trans in it. I sold that car to a local friend who just got his QH.. We are going to try to tune it out with the QH.. Pretty sure it can be done without much effort.

I never had the flare problem with the stand alone in my '92. Nice thing about the stand alone is that it doesn't use a VSS sensor, so that means you can put even the latest/newest 4R70w's without regard to if they have vss teeth, or how many vss teeth they have. The stand alone simulates a vss signal for your speedo and EEC input, and the output is adjustable so you can recalibrate your speedometer and make it exact.

Jeramie
 
If you end up doing it, feel free to give me a call. Their new simple version is pretty cool, but I really liked having "full control" of everything on the full version.

That whole stand alone setup is on my best friend's '93 SC now, so I still get to tweak with it (when his car is running, LOL).. I have several calibration files I could share to get you started, and I can save you lots of time setting it up.

The full PCS controller like I had is extremely powerful, auxilary inputs, outputs, etc.. You can use it to control various other non-transmission related things too.. Like using an ACT input to turn on your intercooler fan at a certain ACT temp. It also can act like an RPM/WOT window switch for nitrous., you can use the outputs to illuminate an indicator light, or trigger a relay for various things, and control their operation with the software.

Very, very powerful.. Especially when you tap into the resistor based cruise control switches, and use them for manual shifting/manual tq converter locking, etc.. I could go on and on.. One guy used it on his Cobra, and used his ABS inputs to enable a boost-bypass solenoid controlled traction control, which opened the boost bypass valve a certain amount per % variation of wheel speeds comparing the front and rear axles. Outputs can be analog, digital, or PWM. Again, very powerful

Jeramie
 
The $750 version is the one I used, and was describing above. The simple version looks neat, but you get so much more technology in the $750 version.. It all depends on what you want out of it.

The advanced version allows you to change between two different calibrations as well. Have a soft shifting, fuel economy mode, then a track or performance mode at the flip of a switch. Did you ever see my videos of it in operation?

See here: http://www.sccoa.com/forums/showthread.php?t=104216&highlight=4r70w+video

Jeramie
 
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