I habe a high stall torque converter and a shift kit in my 95 and I was wondering is it supposed to slam into gears when the car shifts and down shift.
Yeah mine has a Transgo and i think the tranny's gonna fall out everytime it shifts, but what can I say....... 5-speed owners around here hate it.............
The "firmness" of a shift is good to a degree, and actually a harder and faster shift in most cases prolongs the life of a transmission. The stock LONG pause adds heat and friction, consequently wearing the tranny out. Now, I said firm shifts, not slamming shifts. If you car is slamming unusually hard, there could be a problem. I don't have a shift kit, but have heard that they do make some fairly violent shifts, and I can imagine that combined with your stall makes things feel extra "firm" at times.
I love the way my car shifts. Firm and crisp all the time, and at Wot, a very firm 1-2 shift, and a less firm but still fast 2-3 shift. Down shifts back into 1st or 2nd are much improved over stock as well.
I was originally going to get a Transgo Shift Kit and a cold air intake, but I just decided to go with gears.
I'm going with TweeCer so that I can program in the hard shifts, but still select softer shifts for normal driving.
The tweecer won't firm up your shifts like a shift kit. In fact, I don't see how it will firm them up at all. You can maybe program when the car shifts, but only a shift kit can make the car shift harder/faster. This is because with a shiftkit you do a number of modifications to the actual tranny such as improving valve body flow and reducing the amount of time it takes for the valve body to activate the physical shift of the tranny from the computer.
TwEECer can also adjust other eec parameters tha affect shifting, such as timing retard. It can do alot more than just control the transmission. My fbody would switch shift firmness from soft to neck stapping, and I'm sure that was also done by the computer. The guys using TwEECer to shifts their autos say that it works great. Here is a write up on some of the TwEECer electronic transmission tuning parameters, not all apply to the aode: Automatic Transmission There is something in the trans function called TV pressure, this is a throw back to when there was a TV rod from the throttle to a valve in the trans, and TV stands for Throttle Valve. There is an electric solenoid that controls TV pressure. TV can also be called EPC, Electronic Pressure Control. TV pressure acts on the main regulator valve to change line pressure. Line pressure, in most Ford transmissions, equals 1.6 times TV pressure plus 40. All trans speak is done in TV pressure. There are two components to TV pressure, they are called torque input and user input. Torque input pressure is calculated based on some inputs (which I'll cover in a minute) and user input is user controlled (that's you). When you are not shifting, TV pressure is just the output of a Y=mX+b slope, where m is a calibrated slope and b is an intercept. X is the calculated torque that the EEC thinks the engine is making, multiplied by the torque ratio of the torque converter based on the speed ratio that you are at . So, for example, lets say the slope is .2 (typical numbers are in the .1-.4 range) and the intercept is -4 (typical numbers are in the -20 to 10 range) and you are making 200 ft-lbs of torque. You take 200*.2-4 or 36 psi TV pressure. Now, most transmission have a minimum clip for pressure when you are not shifting so you cannot run the trans below a certain pressure. From the above example you can see why making sure the EEC calculates the correct torque is important. The b value in the equation, or intercept is trans_pressure_offset_x_gear, where x is the gear you are in at that time. The slope value, of m term in the equation, is trans_nonshift_slope_x, where x is the gear that you are in at that time. Now when you are shifting, it's a little different. It has a separate set of slopes for each upshift and downshift. Other than unique slopes the torque input part of shifting pressure is the same, other than where it gets it's torque from... These slopes are trans_upshift_slope_x where x is the gear you are shifting into and trans_downshift_slope_x where x is the gear that you are shifting into. When and engine is slowed down, during that transient, torque rises. This is why a car can get rubber on an upshift. That inertia from the engine results in a temporary rise in torque coming out of the transmission. When and engine is accelerated, the engine uses it's torque to accelerate itself, so torque actually drops during this transient. The EEC takes these into account. During an upshift, the engine speed is going to drop, assuming no torque converter slip, by the ratio of the gear you are going to divided by the gear you are coming from. On a 1-2 shift in a 4R70W the ratio would be 1.55/2.84, or .55. So, if you are at 6000 rpm, the engine speed, again assuming no converter slip, would drop to 55*6000, or 3300 rpm. Now it never really drops this much since you are accelerating through the shift, the input shaft of the trans is coming up and there is converter slip, but you have to assume something. So, now it takes the amount the engine speed has to drop, 6000-3300 or 2700 RPM, and basically multiplies it by a value (this is not exactly what happens but for our discussion, let's say it is). The result of this calculation results in a torque value that gets added to the calculated engine torque, which is then multiplied by torque converter torque ratio for the total torque going into that shift. On a downshift the inertia term results in a negative torque, thus reducing pressure during a downshift. So now you have an engine torque that gets an inertia torque added to it and then you determine an amount of static shifting TV pressure for the shift. The next part of shifting pressure is user input pressure. There are several things that get added together to make the user input TV pressure number. I'll cover a few the more important ones. There is a user input TV pressure table for each shift, trans trans_TV_pressure_xy where xy is the shift you want to change, like a 1-2 shift of a 2-3 shift. These tables are throttle position across the X-axis and vehicle speed across the Y-axis. The output of this table is the dynamic pressure for that shift. In some of the older software these are just functions of throttle position on the X-axis and added pressure on the Y-axis. There are things like blip pressures, stroke pressure, TV ramps, pressure profiling, and some other adders that all get added together to make the total dynamic TV contribution. Now, user input TV is added to torque input shifting capacity TV to end up with total TV for the shift. In the tables, the far left column is used for all closed throttle shifts, both upshifts and downshifts. If you want to make a shift firmer, just add pressure to the tables. The throttle position across the X-axis is A/D counts. Typically 750 is WOT for TP_REL, throttle position relative to closed throttle. The vehicle speed is ratio'd from the stock axle ratio divided by the axle ratio you have in there now. During shifts, the EEC can reduce engine torque. This is done either via spark retard or shutting of fuel injectors. In most cases shutting this off makes the shifts firmer and the vehicle performance improves. On some of the E4OD and 4R100 transmission, if you disable the torque reduction the shifts get softer since the transmission does not have enough capacity to stop the oncoming clutch with the power its making. In these cases, you should reduce the amount of torque that is reduced during the shift. In the some software there are two ways to disable this torque reduction, setting trans_min_tp_for_torque_mod to 900 or setting trans_min_ECT_for_torque_mod to 250 will disable this reduction. In some versions of software there will be these two values plus two others that need to be set to 900, trans_min_tp_for_torque_mod_upshift and trans_min_tp_for_torque_mod_downshift. If you do not want to shut off the torque reduction and just want to reduce it, then you can change the amount in the torque reduction tables. These tables are a percent of total torque you want the engine to have. A value of .8 means you want the engine to have 80% of its normal torque, or a 20% reduction. These tables are specific for each shift and are as follows, trans_tqmod_xy where xy is the shift you want to change. A 1-2 shift would be trans_tqmod_12. The shift schedule is pretty straightforward. There are functions for each upshift and downshift, trans_shift_schedule_xy where xy is the shift. These are throttle position relative to closed throttle vs. what speed to shift at. You must make sure that the pair of shift curves do NOT cross. For example, you cannot have the 1-2 and 2-1 shift curves cross. If they do, the trans will most likely just shift back and forth at a fairly high frequency in the range that they cross. It is also recommended that you keep the existing shift schedule for that vehicle and just modify it. Making a whole new schedule is very difficult and probably won't work right. The same applies to the torque converter lock schedule, make sure they don't cross. At WOT, a locked up torque converter WILL transmit more torque to the wheels than an open converter, period. So, it is recommended to have the converter locked at WOT in all gears. Some of the older 5.0L Mustangs with AODE's had the torque converter locking at light throttle in 2nd gear to increase fuel economy. It is recommended to eliminate this to improve the driveability of the car. To eliminate this, just raise the MPH points so that they are very high and it will no longer lock. You can then step the curve down at heavy throttle positions so that it is allowed to lock up at WOT. To also improve driveability of the vehicle, it is recommended to take the 3-4-shift schedule and paste it into the 3rd gear lock function, trans_converter_lock_3rd. This prevents the torque converter from locking in 3rd gear before the 3-4 shift and will generally improve the feel of the car when driving it. At WOT, the trans shifts off of one of two things. Either the vehicle speed that is in the shift schedule functions or the WOT engine speed scalars, trans_wot_shift_xy, where xy is the shift, like 12. What this means, in most cases, is that this is where the shift is COMMANDED and not where it will occur. In some transmissions it can take up to one second to fill the on coming clutch. If the engine is accelerating at 1000 RPM per second (not unusual for low gear with a 3.73 ratio) that means that from the commanded of the shift to the actual shift point, the RPM will increase by 1000 rpm. So, if you set the trans_wot_shift_12 to 5000 rpm, the shift could occur 6000 rpm. This is important to know when setting up WOT shift points. There is an excel spreadsheet to allow the graphing and calculation of shift points. Now the tricky part. The vehicle speed in the shift functions is not always the actual vehicle speed that the speedometer shows. Here is why. First there is a parameter called N/V, say N over V (this actually shows up on the dynojet software right before you click OK, to a graph with all the values on it). This is the engine speed (N) over the vehicle speed (V) of the vehicle in direct drive ratio of the trans (typically 3rd gear in a 4 speed trans). A typical 3.27 axle ratio Mustang has an N/V of 44.5, meaning that in 3rd gear (with an auto) for every 44.5 increase in engine RPM, you get a 1 MPH increase in speed. Now, the transmission shift schedule is setup for a certain N/V, this is called trans_Base_N/V_of_Vehicle. There is another value on some older cars called trans_4_times_NVBASE. This value will either be 4 times or 10 times the trans_Base_N/V_of_Vehicle. You'll have to look at the production file to see if it's 4 times of 10 times. If you want to change trans_Base_N/V_of_Vehicle then you'll also need to change this values, if it's there, by either 4 or 10 times trans_Base_N/V_of_Vehicle. Now, all the MPH's in the shift and lock schedules are based on this trans_Base_N/V_of_Vehicle. So, if you change the axle ratio what happens? Assuming there is range in learning, and this will be covered later, it adjusts if you give it the right information. On, the cars where the EEC sends the vehicle speed info out to the cluster this means changing the axle ratio value in the software. On cars with vehicle speed sensors, this means changing the speedo gear so that the speedo reads correctly. This is important since the EEC always assumes that the vehicle speed is correct. So, let's say you put a 3.73 axle in a Mustang that was setup for a 3.27. The MPH's in the shift and lock functions are ratio'd by the trans_Base_N/V_of_Vehicle divided by the current calculated N/V of the vehicle. The EEC is smart enough to calculate a new N/V based on the driveshaft speed (which it knows since it has a sensor to measure this) and then divides this by what it thinks the vehicle speed is. The EEC now treats this at the real N/V of the vehicle. In this example, the N/V of a 3.73 axle Mustang with production tire diameter, is about 50.5. So, it would take a ratio of 44.5 divided by 50.5 to get a ratio of .88. So, it now takes all the MPH's in the shift and lock functions and multiplies them by .88. So, if you had a shift setup to be at 50 MPH, with this axle change, it would be at 50 * .88 or 44 MPH. There is an Excel spreadsheet to calculate N/V and Tire Rev per Mile in the software package and a spreadsheet to plot the shift curves. The min and max correction allowed can be changed. Trans_Min_learned_N/V is the min correction, set this to .75 and trans_Max_learned_N/V is the max correction, set this to 1.25. There are a few other shift point values that are available to change. Trans_2-1_pullin_max_speed This is the speed to allow the trans to shift into low gear when the shifter is placed in manual 1. Trans_3-2_pullin_max_speed This is the speed to allow the trans to shift into 2nd gear when the shifter is placed in manual 2. Trans_vs_o/d_cancel_override Above this vehicle speed, if the OD cancel button is pressed so the driver has the vehicle in 3rd gear, the OD Off light will go out and the transmission will shift into 4th gear. Make this value 127.5 Trans_man_shift_12_limit Above this RPM, the transmission will shift out of manual 1 and into second gear even though the shift was not moved. To prevent this from happening, set this RPM above the engine rev limiter. Trans_Tm_Sequence_thru_3rd_P4 This is the time the EEC must be commanding 3rd gear before letting the trans shift into 4th gear. This value should be at least 1-1.5 seconds. Trans_Tm_Sequence_thru_2nd_P4 This is the time the EEC must be commanding 2nd before it will command 3rd. This value can be lowered to zero but should be around .5 - 1.0 seconds. Trans_Tm_Sequence_in_man1 On some older applications, when you put the shifter into manual low, it delays the engagement into low by a long time, even though you are below the trans_2-1_pullin_max_speed. Make sure this timer is at or near zero. Trans_Tm_Sequence_in_man2 See above explanation of manual shifts into 1, this is the same thing but into position two. There is also a way to unlock the torque converter based on how fast the throttle is moved in or out. This can cause the converter to unlock when the drive may not be expecting it too. It is recommended to make this none functional. Make trans_thrtl_rate_lowTP_in and trans_thrtl_rate_hiTP_in to values of 500 and make trans_thrtl_rate_lowTP_out and trans_thrtl_rate_hiTP_out to -500. Shifting pressure was briefly mentioned before. There is either a function of TP vs. added pressure for each shift, or a table of TP on the X-axis and vehicle speed on the Y-axis for added pressure during the shift. These functions/tables are trans_TV_pressure_xy, where xy is the shift you want to add pressure too. For example, trans_TV_pressure_12 is added pressure for a 1-2 shift. Normally adding 10 psi to the 1-2 shifts makes them noticeably firmer. To get this same result on the 2-3 shift you need to add about 15 psi and for the 3-4 shift adding 10 has similar results. For maximum firmness at WOT, make the high TP columns near WOT, about 650+ TP, all 99's. This will ensure max pressure for WOT shifts. In some of the newer transmissions, the EEC measures the time it takes the clutch to apply and then the shifting pressure adjusted so the time it takes the clutch to apply is within a target range. These target values are in tables like trans_Tagret_slip_time_xy, where xy is the shift that that table controls. The value in these tables are in milliseconds. To make a shift firmer, make these values smaller. I'd move them in 100-150 millisecond increments. On some older software versions and applications, ramps were used to ramp pressure in or out during a shift. These ramps are trans_TV_Ramp_xyshift, where xy is the shift that pressure is being ramped into or out of. Just check these values to make sure there is not a large negative number in there. If there is, then as you try to add pressure, this will take the pressure back out. I'd make all these values zero or positive numbers. When manually shifting from 1 to 2, to make the shift firmer on some cars, make trans_manual_12 zero. This changes the way pressure gets calculated during 1-2 shifts. To make engagements faster there are two functions that control the pressure in the trans when the vehicle speed is zero. If you change the zero to low TP area of these functions, it will change the pressure the engagement is made on. These functions are trans_stall_curve_F for pressure into Drive and trans_stall_curve_R for pressure into Reverse. For pressure into drive, I'd make the value about 20 for a quick engagement and for reverse the value should be around 25. Torque converter lockup feel/function. The EEC controls the rate at which the torque converter can be ramped on. There are quite a few parameters to change. trans_Lockup_rate_w/high_TP controls the rate the converter locks when at high throttle positions. trans_Lockup_rate_after_upshift is the rate at which the converter locks after an upshift and trans_Lockup_rate_after_tip_in is the rate at which the converter locks up after a tip in from closed throttle or any other time not covered by the other two. Larger numbers are faster lockups. A stock converter can have these numbers increased by 50-100%. Different model years used different types of values in these scalars so don't be surprised from one vehicle to another that the numbers may be very different. Aside from the above values that control lockup rate, the following also control the rate, trans_slip_rate, trans_slip_rate_low_TP and trans_slip_rate_shifts. To make the lockup under these conditions faster, make these values smaller. Good values for these to start with are around .2 Some vehicles allow steady state slip across the torque converter. This is bad, it just generates heat and no good can come from it. The following 3 tables determine how much steady state slip the converter will try to control to, trans_tqconv_slip_2nd, _3rd and _4th. Make the values in these tables zero's. Some vehicles will also slip the converter for the A/C clutch apply, again no good can come of it. Setting the following two values to zero makes this go away, trans_ac_slip and trans_ac_slip_watchdog. During shifts, the torque converter can also slip. The amount of slip during a shift is trans_Slip_during_shift. This value can be made either zero of 8 rpm. trans_Min_Speed_Ratio_to_lock This is a ratio of transmission input shaft speed divided by engine speed, to allow the converter to lock. If you are below this value the converter will not lock up. A good value for this is around .85. trans_Tm_dealy_lockup_at_tipin When coming in from closed throttle, this is a time delay to lock the converter. A good value for this is around 2 seconds. trans_Tm_remained_locked_CT This is a time to keep the converter locked at closed throttle. There are several values for minimum transmission shifting pressure. They are specific for each gear and are for either power on (P/on), power off (P/off) or non-shifting. The none shifting values should all be around 30 to ensure enough line pressure to hold all the clutches on. The power off values should be around 10-20 psi and the power on values should be around 20 psi. These are trans_min_TV_P/off_into_1st, trans_min_TV_P/on_into_1st, and trans_min_TV_nonshift_1st. Are the values for 1st gear.
Sorry about how long that was. I'm so sure that the flexible programming of the TwEECer, plus all its other functions is great for performance, that I am organizing a Group Purchase on the Corral. Anyone here is free to join in.
I guess you dont own a TwEECer, b/c if you did, you would NOT have said that. You can change the pressures in the lines to firm up the shifts. Going back to the original question...you have a high stall converter? I had my shift kit first, the my PI Stallion. The shifts were much "harder" BEFORE the converter. I forgot what the reason was for this, but when I had read it, it made sense. You will NOT feel the same firmness with the converter as someone does that does NOT have one. RC
Well in that case, I guess it could firm up shifts. I will have to do some more researching on the Tweecer, I had no idea it could do those types of changes, it may be worth investing in.
