How To Drivetrain :: Operation Vacuum Gain System (VGS)
6th Gear
Joined: Jul 2002
Posts: 3,446
Likes: 9
From: L.A ca
Originally Posted by MSFITOY
In the past I have mentioned my odd experience with the VGS...I have done some retesting and the results are similar...The VGS increases inlet temperture dramatically!
The testing environment was roughtly 78F ambient, dry weather, 80mph steady state cruise in 6th and WOT from 4th through 6th.
Subjective observations:
1-With the VGS installed, I noticed greatly improved intitial throttle response
2-Sudden let-off of the throttle results in abrubt engine braking...not sure that's good.
3-Feels like cable throttle...good!
Quantitative observations:
Without AGS installed:
1-80mph, vacume at -4inHg, inlet temperature 135F, outlet 94F.
2-Full boost at 15.7lbs, inlet temperature 185F, outlet 120F.
With AGS installed:
1-80mph, vacume -4inHg, inlet temperature 225F, outlet 120F.
2-15.7lbs boost, inlet temperature 275F, outlet 145F.
I have done this test twice at seperate times after installing/uninstalling the VGS and have gotten similar results. Can someone explain why there is such difference in temperatures?
Side note:
As you can see, there is a greater difference in temps from inlet vs. outlet while WOT as compared to 80mph cruise...I think this is because the DFIC is operating more efficiently as the speed rises...let's just say I was somewhere in the triple digits..."I was testing, not racing officer"
(actually got away with that excuse once
)
Even more strangely, the DFIC was also able to maintain reasonable outlet temperature inspite of the inlet increases...the readings were beyond 100F difference
That one I can't figure out...and yes, I have calibrated my instruments...
The testing environment was roughtly 78F ambient, dry weather, 80mph steady state cruise in 6th and WOT from 4th through 6th.
Subjective observations:
1-With the VGS installed, I noticed greatly improved intitial throttle response
2-Sudden let-off of the throttle results in abrubt engine braking...not sure that's good.
3-Feels like cable throttle...good!
Quantitative observations:
Without AGS installed:
1-80mph, vacume at -4inHg, inlet temperature 135F, outlet 94F.
2-Full boost at 15.7lbs, inlet temperature 185F, outlet 120F.
With AGS installed:
1-80mph, vacume -4inHg, inlet temperature 225F, outlet 120F.
2-15.7lbs boost, inlet temperature 275F, outlet 145F.
I have done this test twice at seperate times after installing/uninstalling the VGS and have gotten similar results. Can someone explain why there is such difference in temperatures?
Side note:
As you can see, there is a greater difference in temps from inlet vs. outlet while WOT as compared to 80mph cruise...I think this is because the DFIC is operating more efficiently as the speed rises...let's just say I was somewhere in the triple digits..."I was testing, not racing officer"
(actually got away with that excuse once ) Even more strangely, the DFIC was also able to maintain reasonable outlet temperature inspite of the inlet increases...the readings were beyond 100F difference
That one I can't figure out...and yes, I have calibrated my instruments...randy
M7 Tuning
Formerly PassatDoTd
Joined: Nov 2004
Posts: 1,817
Likes: 0
From: Phoenix, AZ
I tried to install the VGS mod this weekend but couldn't pull it off. I technically understood what I had to do and had all the tools required. But the space to get to the BPV line and the FPR line were so damn tight that I couldn't change out and re-route the lines.
Good news is that I was able to reinstall the IC without any real problems and no EMLs after some serious driving(to make sure everything was ok).
Interestingly enough taking off the IC moved a mod which was way down on my list up to the top. An oil catch can. I had thought that if you weren't doing track days that you shouldn't have much oil being sprayed through the intercooler. Well there was a decent amount, much more than I expected, of oil in the IC boots.
So looks like I'll have to deal with that annoying whistle until someone who has done the mod can oversee me while I attempt it and show me where I'm going wrong. So many people have done this I'm wondering why I can't get in there.
Then again maybe the temp difference MSFITOY has found will change my mind on doing this.
Good news is that I was able to reinstall the IC without any real problems and no EMLs after some serious driving(to make sure everything was ok).
Interestingly enough taking off the IC moved a mod which was way down on my list up to the top. An oil catch can. I had thought that if you weren't doing track days that you shouldn't have much oil being sprayed through the intercooler. Well there was a decent amount, much more than I expected, of oil in the IC boots.
So looks like I'll have to deal with that annoying whistle until someone who has done the mod can oversee me while I attempt it and show me where I'm going wrong. So many people have done this I'm wondering why I can't get in there.
Then again maybe the temp difference MSFITOY has found will change my mind on doing this.
OVERDRIVE
Joined: May 2003
Posts: 7,926
Likes: 40
From: Greensboro, NC
Originally Posted by maxmini
Sid were you referring to VGS with and with out ? You typed AGS and about gave me a heart attack ..
randy
M7 Tuning
randy
M7 Tuning
My BAD:impatient Corrected!
6th Gear
Joined: Dec 2003
Posts: 1,805
Likes: 30
From: Quebec City, Qc
WOW!! MSFITOY, those are scary results against the VGS...
I'm going to remove mine tomorrow. Anyway, the DetroiTuned BPV does a great job and I think that having both VGS & DT BPV is a bit too much...
You're the 3rd guy that states high temps issues with VGS.
I'm going to remove mine tomorrow. Anyway, the DetroiTuned BPV does a great job and I think that having both VGS & DT BPV is a bit too much...
You're the 3rd guy that states high temps issues with VGS.
OVERDRIVE
Joined: May 2003
Posts: 7,926
Likes: 40
From: Greensboro, NC
Originally Posted by DarkMiniCooperS
WOW!! MSFITOY, those are scary results against the VGS...
I'm going to remove mine tomorrow. Anyway, the DetroiTuned BPV does a great job and I think that having both VGS & DT BPV is a bit too much...
You're the 3rd guy that states high temps issues with VGS.
I'm going to remove mine tomorrow. Anyway, the DetroiTuned BPV does a great job and I think that having both VGS & DT BPV is a bit too much...
You're the 3rd guy that states high temps issues with VGS.
6th Gear
Joined: Sep 2002
Posts: 2,196
Likes: 0
From: Hampton, VA
Don't have a vacuum/boost gauge but as you know I've done a lot of temp logging recently.
I'll try to test this soon as well.
I won't be yanking things off in a panic based on 1 post though
even though I trust the source a lot.
The full boost part puzzles me since at this time the bypass valve isn't doing anything.
Did you also adjust the BPV butterfly to close better like most of us did?
I'll try to test this soon as well.
I won't be yanking things off in a panic based on 1 post though
even though I trust the source a lot. The full boost part puzzles me since at this time the bypass valve isn't doing anything.
Did you also adjust the BPV butterfly to close better like most of us did?
Originally Posted by PassatDoTd
I tried to install the VGS mod this weekend but couldn't pull it off. I technically understood what I had to do and had all the tools required. But the space to get to the BPV line and the FPR line were so damn tight that I couldn't change out and re-route the lines.
Good news is that I was able to reinstall the IC without any real problems and no EMLs after some serious driving(to make sure everything was ok).
Interestingly enough taking off the IC moved a mod which was way down on my list up to the top. An oil catch can. I had thought that if you weren't doing track days that you shouldn't have much oil being sprayed through the intercooler. Well there was a decent amount, much more than I expected, of oil in the IC boots.
So looks like I'll have to deal with that annoying whistle until someone who has done the mod can oversee me while I attempt it and show me where I'm going wrong. So many people have done this I'm wondering why I can't get in there.
Then again maybe the temp difference MSFITOY has found will change my mind on doing this.
Good news is that I was able to reinstall the IC without any real problems and no EMLs after some serious driving(to make sure everything was ok).
Interestingly enough taking off the IC moved a mod which was way down on my list up to the top. An oil catch can. I had thought that if you weren't doing track days that you shouldn't have much oil being sprayed through the intercooler. Well there was a decent amount, much more than I expected, of oil in the IC boots.
So looks like I'll have to deal with that annoying whistle until someone who has done the mod can oversee me while I attempt it and show me where I'm going wrong. So many people have done this I'm wondering why I can't get in there.
Then again maybe the temp difference MSFITOY has found will change my mind on doing this.
1) To hook the new hose up to the bottom of the FPR, its easier to slide the hose in from way over by the BPV and come up from under the FPR. Easy to do, and using needle nose plyers, i was able to get a much better angle ont the hose to hook it up.
2) after removing the small hose from the BPV DONT PULL TOO HARD. The hose will come off the lower nipple. For me this was a good and bad thing. Bad cause we paniced and couldnt get our hands in to hook itup. good news is #3.
3) remove the driver side bracket which holds the back mount for the intercooler. 3 quick bolts gives you ample room around the BPV to a) fix the line you pulled off
, b) hook the new line into the BPV and c) make it easier to plumb the hoses where you want themI find the car MUCH smoother without the VGS done. Feels like it has more torque mid band. Im sure there isnt any more, but it feels smoother, making it feel stronger. That said, if any more temp issues come in, I think i will remove it anyways.
Those of you smart kids who have the tools and instruments to test, please keep us posted on your findings. Also, would really like to hear Andy's take on this
OVERDRIVE
Joined: May 2003
Posts: 7,926
Likes: 40
From: Greensboro, NC
Originally Posted by obehave
Don't have a vacuum/boost gauge but as you know I've done a lot of temp logging recently.
I'll try to test this soon as well.
I won't be yanking things off in a panic based on 1 post though even though I trust the source a lot.
The full boost part puzzles me since at this time the bypass valve isn't doing anything.
Did you also adjust the BPV butterfly to close better like most of us did?
I'll try to test this soon as well.
I won't be yanking things off in a panic based on 1 post though
even though I trust the source a lot. The full boost part puzzles me since at this time the bypass valve isn't doing anything.
Did you also adjust the BPV butterfly to close better like most of us did?
You are right, this is only data from one Mini...but from multiple tests. I have examined my BPV and it has retained it's prior "closed" adjustment and is in working order.
One theory I have for the high temp during 80mph cruise is this:
Since the VGS operates by tapping into post-SC pressure as opposed to the standard vacuum only pre-SC fitting, it can receive positive pressure as well, which will assist the spring in shutting off the BPV. During the relatively high load conditions which the motor sees while cruising in 6th gear at 80mph, the vacuum is nearing 0 and close to transition into positive boost. At this juncture, the VGS is somehow enabling the BPV to close prematurely prior to the motor entering positive boost...which then leads to needless compression of air...which the motor doesn't yet need...which results in the raised inlet temperature...does that make sense?
6th Gear
Joined: Sep 2002
Posts: 2,196
Likes: 0
From: Hampton, VA
Originally Posted by MSFITOY
I hope that someone else with instruments will either substantiate or debunk my findings...
You are right, this is only data from one Mini...but from multiple tests. I have examined my BPV and it has retained it's prior "closed" adjustment and is in working order.
One theory I have for the high temp during 80mph cruise is this:
Since the VGS operates by tapping into post-SC pressure as opposed to the standard vacuum only pre-SC fitting, it can receive positive pressure as well, which will assist the spring in shutting off the BPV. During the relatively high load conditions which the motor sees while cruising in 6th gear at 80mph, the vacuum is nearing 0 and close to transition into positive boost. At this juncture, the VGS is somehow enabling the BPV to close prematurely prior to the motor entering positive boost...which then leads to needless compression of air...which the motor doesn't yet need...which results in the raised inlet temperature...does that make sense?(Bolding added by obehave)
You are right, this is only data from one Mini...but from multiple tests. I have examined my BPV and it has retained it's prior "closed" adjustment and is in working order.
One theory I have for the high temp during 80mph cruise is this:
Since the VGS operates by tapping into post-SC pressure as opposed to the standard vacuum only pre-SC fitting, it can receive positive pressure as well, which will assist the spring in shutting off the BPV. During the relatively high load conditions which the motor sees while cruising in 6th gear at 80mph, the vacuum is nearing 0 and close to transition into positive boost. At this juncture, the VGS is somehow enabling the BPV to close prematurely prior to the motor entering positive boost...which then leads to needless compression of air...which the motor doesn't yet need...which results in the raised inlet temperature...does that make sense?(Bolding added by obehave)
I will specifically duplicate that cruise scenario in my car.
Real feel temp today is 110º so messing with a hot IC on a very hot, humid day is low on my priorities
I might have to look into an easy way to switch back and forth if the temp thing really is an issue. The VGS helps in auto-x for sure. I've run with and without, I'll take with.
Originally Posted by MSFITOY
At this juncture, the VGS is somehow enabling the BPV to close prematurely prior to the motor entering positive boost...which then leads to needless compression of air...which the motor doesn't yet need...which results in the raised inlet temperature...does that make sense?
OVERDRIVE
Joined: May 2003
Posts: 7,926
Likes: 40
From: Greensboro, NC
Originally Posted by inimmini
Not questioning your observations, but if the above were true, why wouldn't you see a higher boost pressure when cruising at 80 mph with VGS than without it?
OVERDRIVE
Joined: May 2003
Posts: 7,926
Likes: 40
From: Greensboro, NC
Originally Posted by inimmini
If the BPV closes, how can the motor not see boost?
To paraphrase Meb's sig..."Dammit Jim! I'm a Designer! Not a Scientist!"
6th Gear
Joined: Jan 2006
Posts: 1,808
Likes: 3
Originally Posted by obehave
The full boost part puzzles me since at this time the bypass valve isn't doing anything.
OVERDRIVE
Joined: May 2003
Posts: 7,926
Likes: 40
From: Greensboro, NC
Originally Posted by etalj
This is the part that worries me, and is making me think that the other evidence is sort of invalidated....(no offense intended)
many of you have had this mod for almost or over a year now.
has anyone noticed any ill effects from this potentially additional heat?
Im leaving mine in for now. I figure if no one else has blown up this year, i can leave mine for a couple weeks till more info is found. Especially since i dont track the car, or beat it as much as some of you have
has anyone noticed any ill effects from this potentially additional heat?
Im leaving mine in for now. I figure if no one else has blown up this year, i can leave mine for a couple weeks till more info is found. Especially since i dont track the car, or beat it as much as some of you have
6th Gear
Joined: Sep 2002
Posts: 2,196
Likes: 0
From: Hampton, VA
Originally Posted by Bugs
many of you have had this mod for almost or over a year now.
has anyone noticed any ill effects from this potentially additional heat?
Im leaving mine in for now. I figure if no one else has blown up this year, i can leave mine for a couple weeks till more info is found. Especially since i dont track the car, or beat it as much as some of you have
has anyone noticed any ill effects from this potentially additional heat?
Im leaving mine in for now. I figure if no one else has blown up this year, i can leave mine for a couple weeks till more info is found. Especially since i dont track the car, or beat it as much as some of you have
Based on memory(I'm at work), normal temps run 125-150º range depending on small uphill grades, minor accelerator inputs, etc. Ambient temps in the 85-93º range along with our normal 60-85% humidity.
The highest temp I ever recorded was 245º and that was at the end of a 25-75 mph hard pull shifting at ~6K. Within a minute temps had returned to ~ normal for a 70 mph cruise on that day.
OVERDRIVE
Joined: May 2003
Posts: 7,926
Likes: 40
From: Greensboro, NC
Originally Posted by obehave
While I haven't done any logged 80 mph cruises I have done a large number of 70 mph runs.
Based on memory(I'm at work), normal temps run 125-150º range depending on small uphill grades, minor accelerator inputs, etc. Ambient temps in the 85-93º range along with our normal 60-85% humidity.
The highest temp I ever recorded was 245º and that was at the end of a 25-75 mph hard pull shifting at ~6K. Within a minute temps had returned to ~ normal for a 70 mph cruise on that day.
Based on memory(I'm at work), normal temps run 125-150º range depending on small uphill grades, minor accelerator inputs, etc. Ambient temps in the 85-93º range along with our normal 60-85% humidity.
The highest temp I ever recorded was 245º and that was at the end of a 25-75 mph hard pull shifting at ~6K. Within a minute temps had returned to ~ normal for a 70 mph cruise on that day.
6th Gear
Joined: Sep 2002
Posts: 2,196
Likes: 0
From: Hampton, VA
Originally Posted by MSFITOY
Are these numbers from the OBD showing post IC temps?
Honestly didn't know the OBD did post IC temps.... D'oh!
Now I do.
those numbers are a lot less scary..
What ODBII scanners/loggers do you guys use? Im interested in doing some of this myself. Also , would like to know more about the car in general
What ODBII scanners/loggers do you guys use? Im interested in doing some of this myself. Also , would like to know more about the car in general
Originally Posted by obehave
No. Those are from temps probes in the IC boots ala Andy.
Honestly didn't know the OBD did post IC temps.... D'oh!
Now I do.
Honestly didn't know the OBD did post IC temps.... D'oh!
Now I do.
6th Gear
Joined: Sep 2002
Posts: 2,196
Likes: 0
From: Hampton, VA
Originally Posted by inimmini
Do you have to put holes in the boots and caulk the TC wires in with something like silicone RTV, or can you get the wires between the boot and the "horns" without a leak or destroying the wires?
These
http://scientificsonline.com/product.asp?pn=3105400
MSFITOY's solution is cleaner.
6th Gear
Joined: Mar 2006
Posts: 1,710
Likes: 1
From: Northampton MA
Quite frankley I'm not too concerned about the inlet temps on this car. The spring in the BPV is a little on the weak side ( early 03 ) so you not only feel but hear the SC start working hard. When the SC is stuffing it will produce heat, how much, depends on how much air the engine can use.
Msfitoys theory is correct. The SC is going to make heat & more heat when the engine can't use the additional air. All compressors make heat.
Modulateing the BPV to close on demand ( like a NOS button ) might be 1 solution.... Some have wired tied the BPV closed. For now there is no positive answer
Msfitoys theory is correct. The SC is going to make heat & more heat when the engine can't use the additional air. All compressors make heat.
Modulateing the BPV to close on demand ( like a NOS button ) might be 1 solution.... Some have wired tied the BPV closed. For now there is no positive answer