vacuum mod or not?
#41
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Originally Posted by billc5
I vote with your builder, vacuum modulator is a BAD IDEA. You'll know why the first time you start sucking transmission oil through the engine.
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#42
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I use the vacuum modulator on the vast majority of my 4L60E's performance rebuilds, and with little or no problems. The majority of performance transmission builders, do not know how to build the 4L60E correctly, as you can see from the responses of customers who have had them rebuilt over the years with 4L60E problems. The case of "local builders" has been a major problem when it comes to these units. When someone says that it does not work, ask why, and how using it, destroys or ruins the transmission. I for one would like to know?
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Hmmmm, interesting ..... over on cz28.com, vacuum modulation has always been a real no-no!![The Judge](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_judge.gif)
..... I'm no tranny builder, I don't know the "facts" or "theories" one way or another. All I know is that vac. mod has been credited for burning up lots of "built" 4L60E's?
But this feedback has come from one of the most reputable builders on that board (while I'm a new member on here, I've been a "lifer" over there, but I'd say the builder I'm referring to on cz28.com has just as solid a reputation as Rock-on does
).
..... I'm now confused again as to which is the best configuration to setup a 4L60E ... the explanations both ways seem equally convincing!!
![The Judge](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_judge.gif)
..... I'm no tranny builder, I don't know the "facts" or "theories" one way or another. All I know is that vac. mod has been credited for burning up lots of "built" 4L60E's?
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..... I'm now confused again as to which is the best configuration to setup a 4L60E ... the explanations both ways seem equally convincing!!
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#44
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I would not own a built 4L60E without it. IMO, get the computer out of the line pressure business. plain & simple.
Many builders have alot of experience, but how much of it's specifically related to the 4L60E family of transmission?
BTW, been around numerous amounts of cars with this mod and I've never heard of one sucking tranny fluid into the motor. Thinking about how my vacuum modulator is setup, it would take a pretty major failure or someone installing it wrong to cause that.
Many builders have alot of experience, but how much of it's specifically related to the 4L60E family of transmission?
BTW, been around numerous amounts of cars with this mod and I've never heard of one sucking tranny fluid into the motor. Thinking about how my vacuum modulator is setup, it would take a pretty major failure or someone installing it wrong to cause that.
#45
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vacuum modulators belong in the same category as dual point distributors, poly glas tires, double hump heads, etc. they're antiquated and will never be capable of controlling the pressure in a 4L60E the way an EPC will.
Remember the fact that TH350's and TH400's came from the factory with vacuum modulators. When most enthusiasts added a big cam, or forced induction, what did they do next??? They went to a manual valve body! Why? Simple...Because vacuum modulators couldn't control the transmissions accurately any longer. Now you guys are thinking about replacing a state of the art piece with something that didn't even work 20 years ago?
Yes, I've used vacuum modulators in 4L60E's. We did until we found out they just don't work. To this day, we still remove many vacuum modulators from transmissions built by our competitors...So we can build the customer a transmission that will last.
If anyone has a problem burning up 3-4 clutches in their 4L60E's, don't blame the EPC solenoid. Maybe they should analyze the rest of their building techniques and parts. I know enough now to never install another vacuum modulator in a '60E...and...no, we don't have any clutch failure problems.
Frank
CPT
Remember the fact that TH350's and TH400's came from the factory with vacuum modulators. When most enthusiasts added a big cam, or forced induction, what did they do next??? They went to a manual valve body! Why? Simple...Because vacuum modulators couldn't control the transmissions accurately any longer. Now you guys are thinking about replacing a state of the art piece with something that didn't even work 20 years ago?
Yes, I've used vacuum modulators in 4L60E's. We did until we found out they just don't work. To this day, we still remove many vacuum modulators from transmissions built by our competitors...So we can build the customer a transmission that will last.
If anyone has a problem burning up 3-4 clutches in their 4L60E's, don't blame the EPC solenoid. Maybe they should analyze the rest of their building techniques and parts. I know enough now to never install another vacuum modulator in a '60E...and...no, we don't have any clutch failure problems.
Frank
CPT
#46
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Originally Posted by WILWAXU
Many builders have alot of experience, but how much of it's specifically related to the 4L60E family of transmission?
Frank
CPT
#47
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#48
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I have over 29 years at this..... Guess how many TH400's & TH350's I have built using Trans-Go Performance Shift kits, all using vacuum modulators, except one. They number in the hundreds over the years, from low 9 second vehicles, on up. The vacuum modulation works very well even with a large duration cams (you have to know which vacuum modulator to use with the large duration camshafts). If you do a research on this, (as far as quality performance transmission builders) you will find that there are quite a few who have used vacuum modulation with much success. "Like the guy in the post above said, why would you want to go 20 years backwards in technology when it wasn't even good enough back then" Are you kidding, these units (TH400) were the most successful in terms of reliability in GM's history. Just look at this for an example, "you change the camshaft" to a larger duration..., more lift...., closer or further lobe separation..., the vacuum modulator "sees the vacuum changes" right now, and will compensate immediately, as far as load (torque input), and line pressure changes, where is the downside??? there isn't any "think about this"....
Last edited by PBA; 08-20-2006 at 06:42 AM.
#49
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#51
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^ ^ Vince ... I liked your post
. It seems you're not pushing one method over another, just stating real experience with both setups.
All I can make out of this is that it's critical to go to a shop who REALLY KNOWS what's going on with these 4L60E's. And regardless of whether running vacuum modulation or not, it seems that whatever the shop specializes in, that's probably the best route to go with for THEM? If the guys at Rock-On, FLT or PBA build WITH vac. mod., then stick with that. Frank @ CPT doesn't run it, then go with that!![Mr. Cool](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_cool.gif)
What we need are HONEST reports of failures from all the big builders, and see what the failures are attributed to?
Is there REALLY a "better" way of building the 4L60E, or is it just hit & miss regardless?
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All I can make out of this is that it's critical to go to a shop who REALLY KNOWS what's going on with these 4L60E's. And regardless of whether running vacuum modulation or not, it seems that whatever the shop specializes in, that's probably the best route to go with for THEM? If the guys at Rock-On, FLT or PBA build WITH vac. mod., then stick with that. Frank @ CPT doesn't run it, then go with that!
![Mr. Cool](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_cool.gif)
What we need are HONEST reports of failures from all the big builders, and see what the failures are attributed to?
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#53
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I support the vac mod.
I have 2 4l60 trans with them in. Shifts on the 150 shot. With no modulator installed hits the rev every shift. I know this because last fall we had a problem with vaccum line in the case colapsing before the vaccum modulator, so right before I took it to the 1/4 we swapped it out for the computer controlled modulator and it bounced of the rev every shift on the bottle. This year it shifts once we found and fixed the colapsed line. Have vids of me on the track hitting the rev in every gear last year and I can go out right now take a vid and spray 150 and it will shift in each gear holding 550 hp to the wheels. Cam specs are in sig.
Now that is real world results
![](http://i27.photobucket.com/albums/c165/paulq1319361/IMG_1068.jpg)
![](http://i27.photobucket.com/albums/c165/paulq1319361/IMG_1071.jpg)
But what do I know I'm just the driver.........
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I have 2 4l60 trans with them in. Shifts on the 150 shot. With no modulator installed hits the rev every shift. I know this because last fall we had a problem with vaccum line in the case colapsing before the vaccum modulator, so right before I took it to the 1/4 we swapped it out for the computer controlled modulator and it bounced of the rev every shift on the bottle. This year it shifts once we found and fixed the colapsed line. Have vids of me on the track hitting the rev in every gear last year and I can go out right now take a vid and spray 150 and it will shift in each gear holding 550 hp to the wheels. Cam specs are in sig.
Now that is real world results
![](http://i27.photobucket.com/albums/c165/paulq1319361/IMG_1068.jpg)
![](http://i27.photobucket.com/albums/c165/paulq1319361/IMG_1071.jpg)
But what do I know I'm just the driver.........
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Last edited by speedo; 08-22-2006 at 01:42 AM.
#54
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I have the vacuum mod on my H/C LT1. I just installed my 3000 fuddle stall, adjusted the pin, and now when the car is pretty hot it has a very soft 2-3 shift. Yes I have a trans cooler. I think my car has some valve float issues. Can valve float have an affect on the vacuum mod?
#55
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If the pin is to short, you will lose maximum line pressure. Now this will soften the 2-3 WOT shift. Run the longest pin length when using small diameter torque converter. If the throttle body is too small, and you are using a larger duration camshaft, it will create more vacuum at WOT openings. This will lower the line pressure at WOT, which will soften the shifts. To check this, disconnect the vacuum line and do a drive test to see if the shifts firm up. If they do then the throttle body is too small, and is creating vacuum at WOT, this will lower the main line pressure. I have seen this several times, and going to a larger (cfm) throttle body will solve this. As for valve float... if this happens the power drops off at an incredible rate, which would give the appearance of a soft shift.
#56
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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
Edit non-sponsor company
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
Edit non-sponsor company
Last edited by JNorris; 09-01-2006 at 10:48 PM.
#58
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This thread is starting to worry me...good information yes, but I have a vacuum modded 4L60E that I paid a good chunk of money for to last me a long time as my car evolves and the power increases. I was assured that there is nothing to worry about.
#59
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Originally Posted by BlackHawk T/A
This thread is starting to worry me...good information yes, but I have a vacuum modded 4L60E that I paid a good chunk of money for to last me a long time as my car evolves and the power increases. I was assured that there is nothing to worry about.
#60
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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.
Without PROOF that vacuum modulators destroy trannies I think the claim that they are antiquated pieces of garbage should be let be.