The Percentage Increase In Shift Firmness Is Not Out Of What Is Avaible But Out Of What Would Be Concidered Safe For A Stock Transmission... So When You Say You Have It At 25% Firmness You Are Not Getting The Figure Your Are Stating But 25% Of The Difference Between The Stock Settings And The Setting That Hypertech Deemed Acceptable For A Stock Tranny, Personally Ive Found That Even Most Tech Support Guys Ive Tried To Ask Really Are Not Too Helpful In Hypertech's Products Mainly Beacouse They Dont Use Them. When I Caled The Guys At Hypertech Ang Got Their Medioker Tech Support The Guys There Were Somewhat Helpful And The Best They Could Really Do For Me Is To Reccomend What They All Use On Their Cars (the T\a Drivers) They Told Me 75% Which I Tried And Liked Somewhat , After Some Personal Expirmenting I Went To 100% Setting Which Is What They Deem To Me Max Safe Pressure And I Love It Now Foe The Last 7k Miles. My Personal Non Perfessional Opnion Is Your Setting Should Be Based On Your Driving Habits, From My Understanding Having High Line Pressure Really Only Transfers The Stress(heat) Off The Clutches And Applies It To A Weath Of Other Internals. The Way I Look At It Is 90% Of The Driving I Do Is Crusing At 50-80 And Raceing So Lost Of Pressure Would Be Benficial To Me And Since Im Not Going Thru The 1-2 Dance Every 100 Ft Like City Cars Do Im Not Really Getting That Much Heat Build Up From Constant Hard Shifting... If I Was Living A City I Would Think Id Want A Bit More Slippage In Ymtranny As So To Not Be Constantly Slaming **** Arround.... This Is Just My General Logic So I Could Very Well Be Wrong But So Far So Good And What I Ment About Most People Not Knowing About Hypertech Is That Alot Of People Have The Same Thought As 4genretard Did About Hypertech Settings So They Say 100% Has To Be Too High While According To Them Their Settings Are Made Up Of Testing Whats Good And Bad And Just Letting The End-user Custmise The Settins A Bit Biased On Prerence And Evnioment

 

It is definately car specific in my experience. You need to know the calculated torque value the motor is referencing to calculate prtessure on shifts. Also, different year cars have different tranny pressure tables and different internal calibrations for pressure. I have tuned enough cars that I have base tables for each model year and segment ID so I have baselines. After that I do plenty of in-car testing to get the info I need to tweak the tables and then check that the correct pressures are being referenced and executed by the car. Sounds easy enough doesn't it?

Chris

 

THAT sounds like torque management to me-or hitting the rev limiter. I know that when I first put the ST3500 TC in my car, it took a lot of time adjusting shift points/rev limit with the only tool I had - HPP3- to get acceptable shifting w/o bogging down.
I defer to those who know about line pressures, though.
(EDIT) I found that ATAP was not always accurately recording max rpm and I had to monitor just rpm and current gear over and over to determine I was hitting the rev limiter.

 

Well let me start by saying I have a 4L60E
It was built by John Goebal in Waco. It has lots of billet peices and a billet pump of coarse. I am runnning about 275-300psi on shifts. I have had this tranny in the car for about 1 yr now. It has broken once. It broke the output shaft in half. My fault that it happened also. I cut the overrun clutch seal so that I would not have overrun in order to pull down gears and the engine didn't try and slow me down. In essence the car would jump out on any 6-speed on the highway at any RPM (flash the $hit out of the converter). Over time it broke the output shaft. It has been in the car for the second time for about 5 months now. It works fantastic. My last pass at the track went 6.37 in the 1/8 with a mph of 101.( Nitrous went off at the 330 mark) 1.41 60ft. I like this tranny and the fact that I still have an overdrive. My tranny builder said that if you don't have this kind of pressure in the tranny that the 4L60E will not make a 3-4 clutch pack hold for very long. There is not enough surface area on the clutch pack piston and therefore not applying enough claping force on the clutch pack. This over time will burn them up. I have yet to have a 3-4 clutch pack go and I feel that is becuase of the pressure in the tranny. If you do this kind of pressure with a stock pump of coarse you will break it. This is JMO, but so far my tranny has held up really nicely for me.

 

I lost the 2-4 band and 3-4 clutch pack in my A4. My car only has 13000mi. on it and is not running big power, so what caused it? We discovered that when the Transgo kit was installed the valve body screen mod was not done. I'm told that at over 5500 RPM's the screen can collapse and reduce line pressure. There are a few other line pressure and release mods that can be done. Along with those, a heavy duty band and a 9 disk clutch pack were installed. I'd never seen the screen mod mentioned. We will see if it all works. It snowed today so WOT was out, but the trans feels really solid. Of course I probably was driving with some slippage and didn't know it because of the PT4000 I'd installed. I thought it was normal.

 

Im running 275-300psi in my 200r4 without a problem. You have to get good parts for the pump to live, hard chromoly pump rings are a must, along with making sure both pump halfs are flat and true. i dont think a stock trans will live long with alot of upgrades thru-out if your going to run high psi.

 

Look at the Transgo instruction sheet titled Pulse Lockup Upgrade. In the bottom left corner is EPC Screen fix. My fix was left out the first time. I've been told it's not rare that it's skipped and that it will cause low line pressure at high RPM's. There is no way for me to know how effective this fix is. If you are having it done ask them to save the removed and leftover parts. You can tell what was done that way.
If you have'nt already considered it, you should replace the plastic accumulator piston with a 700R4 metal one.It is GM#24204496
Piston kit DK61985A. You can find it in GMparts direct under 1996 Corvette.

 

Sorry about the 7. You only need one, nothing else. Ignore the remaining #'s. I gave you everything that was on the parts bag. Glad you figured it out.
I just saw a post regarding the plastic one with cracks.

 

Just as a follow-up for anyone, the one part # gives you both accumulator pistons, but you only need the one, since the 4th gear one is already metal in the 4l60e.

 

Dean, just in case you still are unsure of EPC it is a Electronic Pressure Control solenoid

 

The 4L60E in the "D" position has about 170 - 185 pounds max. line pressure from the factory. The Trans-Go Performance Shift kit raises this slightly. You cannot raise max. line pressure electronically. The Trans-Go vacuum modulator (which eliminates the force motor) raises this to about 210 - 220 in the "D" position. The modulator increases accumulator pressure which can cause a very firm 1-2 shift. To get the "maximum longevity" from this, (with those using 9.5" torque converters) you need to modify the 2nd gear accumulator (Trans-Go has this option in their kit, use 1 spacer at the most) & do not drill the 2nd gear feed hole to more than .096" on the street with the Corvette style servo & .110" for "Pro Street" to strip only use. If you do this, you can have "smooth" part throttle 1-2 shifts, and still have the firm WOT shift. In the manual "1" or "2" position will have higher than 210 psi (200 - 240 max.). You do not need more line pressure than this, if you do, then something else is not being addressed correctly. The only accumulator that should "ever" be blocked, is 4th gear. Understanding accumulation will allow you to get the "shift firmness" or "smoothness" needed/desired for your particular application, along with longevity.

 

(when is too much).....ummmm lets see, anything more than is needed to hold a clutch at a given horse power.......just my two cents. Thanks for listening Dave

 

In the manual "1" or "2" position will have higher than 210 psi (200 - 240 max.). You do not need more line than this, if you do then something else is not being addressed correctly. The only accumulator that should ever be blocked, is 4th gear. Understanding accumulation will allow you to get the "shift firmness" or "smoothness" needed/desired for your particular application, along with longevity.[/QUOTE]

Dana,
What pressure do you get in the 3rd position? The changes in my trans, you helped with, are working well.
Joe( North Carolina)

 

The pressure (using the EPC solenoid) should be about 180psi in the "D" position, when you use the Trans-Go boost valve setup. With addition of the modulator, it should be about 210-220psi in the "D" position.

 

Did that mod to my trans, no issues with it. I did snap a band, but I also have the billet servo, a shift kit, and a converter. Also, I've heard of a few Raybestos bands snapping, so it probably had nothing to do with adjusting the solenoid. I turned the EPC PWM solenoid back down 1/8 a turn after the band snapped, but I didn't like it and wound up going back up with it again, no issues since, and the 1-2 shift is a monster at 3/4-WOT, but very drivable and comfortable at normal throttle under 50%.

 

The billet servo is known to break bands, that is why I use the Corvette servo in all my builds, no broken bands in the last 10 years.

 

Well what I got out of this thread.
Most are running trans-go and vacuum modulation,
With about 220 lbs line pressure with stock pump.
If the pump has been upgraded some use up to 300 lbs line pressure.
With the electric setup the force motor is turned up to 240 lbs line pressure. Still using the Trans -go and monitored with a gage.
Then the program is turned down some percentage ? amount?for every day driving but with which base pressure vs torque or brake pressure vs torque or positive pressure vs temp.
The only one I have used is the latter pos.pressure vs temp.
Thanks
John

 

Couple of questions.

1) The "Corvette Servo" P/N 24204496 - is this
a good-to-go "kit" with the O-ring or whatever,
or do I need anything else to swap?

2) Do any two people agree on how/where line
pressure should be checked, if I were to have
my mechanic check & tweak the EPC a bit to
up base pressure? I would just have him keep
nudging it until it's close to the max stock
line pressure spec, to stay within warranty.

 

I increased my line pressure that wait4me gave me and it works great.

Here is what I used for my TCISSF3500:

the base shift pressure vs torque put in this
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320
Normal 2nd 0 0 0 0 2 5 8 12 16 19 24 28 32 37 41 45 49 53 56 60 62 64 68 71 74 77 81 84 87 89 91 94 98
Normal 3rd 0 0 0 0 3 7 11 15 20 25 30 34 37 40 42 44 46 47 49 51 53 56 59 62 65 68 71 73 75 77 78 80 82
Normal 4th 0 0 0 2 4 8 12 16 20 22 26 30 34 38 41 45 49 53 58 63 67 71 75 78 82 86 90 94 98 102 104 104 104
Perf. 2nd 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104
Perf. 3rd 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104
Perf. 4th 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104 104

Bill

 

on the 4l60e the line psi is controlled by a pulse width modulated solenoidin the pan that is pcm controlled.
main line psi is controlled by the pump spring.
adding washers and/or stiffer spring will raise main line psi all the time - i think obd2 cars will compensate for the change or p1860 will set - adjusting line psi percent will change shift feel at different throttle openings.

the 4l60e in my 1993 sonoma makes @ 325 max line psi!!!
- according to trans go this will blow the 2-4 servo out of the case, but it hasnt happened in 3-1/2 years and it sees alot of strip use and is daily driven @ 20,000 miles per year.