Originally Posted by Loadre

I had a Pro-Built vacuum modded 4L60E hold up to about 10k miles at 550rwhp and about 650rwtq. Shifted perfectly until I pulled it out because I toasted a motor. Everyone is entitled to their opinion on the vacuum modulators but I'm starting to get sick of seeing a certain Northern shop step over the lines a little bit and question other shops owners and builders and take cheap shots (both on cz28 and here).

Without PROOF that vacuum modulators destroy trannies I think the claim that they are antiquated pieces of garbage should be let be.

Originally Posted by Shane@CPT

As someone who has in their learning experience (which never ends BTW) experimented with vacuum modulators. I have come to a few conclusions.
At the VERY LEAST
they are a
* Un Necessary Mod
and at the WORST
* A complete mistake


Every transmission that i seen using a vacuum modlator ends up a burned up pile of garbage. My real world testing and others i know has shown that a EPC can control and regulate line pressure rise instananeously. With No lag. I have heard the reasoning fron Ed wright.

Take a computer and type in a command .. does the computer respond to the command instantly or does it take a second for the screen to come up.


That dosent apply on our LT1 LS1 PCM's and what WE are doing expecting out of the force motor. The force motor is NOT a super complicated piece of equipment.They respond instantly.

Some builders say yeah well i want to rule out any possibility of a bad sensor causing problems. Sure ok it covers YOUR buts and sticks your customers with an inferior product with antiquated technology.

When i was taking classes when going through GM training in college, we had a hydramatic engineer stop by. One of the questions asked was Why dont 700s have a vacuum moculator?Why do they have this finickey trouble prone TV setup. His answer was that they determined that Vacuum modulators were pieces of crap and they Hydramatic felt that the TV setup was superior to the POS modulator and that the 700 wasent even designed with it in mind PERIOD.

Im not here to bash any builder. As i am a student of life. However i have seen with my own eyes too many good 4l60e's that ended up as burned up piles of trash and some of them were built by some well known well respected builders. Not to say they never burnup. But when a supposidely 600+ hp trans burns up in 3k miles after a year of weekend driving or when a guy i know has to go through 4 transmissions to get one that works half *** (built by a poster in this thread)i start looking at whats done diffrently than what i KNOW works.

And i KNOW the EPC works. As far as the modulator.... im still heavily leaning to the side of more harm than good.Just by seeing what ive seen. Big name transmissions burned up when everything looks good. GOod builds just burned up because of the modulator. Sucking atf into the motor,Hell ive seen one LT1 at the track BEND A ROD because of the vacuum mod on his firebird due to hydrolock , number 6 got full of atf and yippie bent rod.

You make the call.From what i know i wouldent be calling frank so stupid.
FWIW shane@ the other CPT
Carolina Performance Transmission

Originally Posted by 12SCNDZ

I've been building transmissions, professionally, for over 17 years. Our shop specializes in racing 700/4L60E's. I worked at a shop for 7 years that was an R&D shop for the racing industriry. I helped develop a few of the parts that are now availible for these transmissions. The shop owner I worked for is now part of Sonnax Industries. I've tried every part and technique availible for the 4L60E, so I think it's fair to say I have "experience" with this particular transmission.

Frank
CPT