Revshift 75D Polyurethane Coupler installed!
09-14-2014, 07:10 PM
#1
Revshift 75D Polyurethane Coupler installed! In case you're just tuning in...
Over the past several weeks, I've been trying to find time to install and beat on Revshift's latest invention: a 75D polyurethane giubo.
This is actually a really f***ing big deal. This functioning, fully-formed polyurethane giubo is a first for the car industry, and was only made possible by recent chemical process improvements from Bayer--the company that originally invented polyurethane back in 1937. For this application, the advantages of polyurethane are:
- Polyurethane can be tuned to produce polymers of different hardnesses to suit the application (unlike aluminum and rubber)
- Polyurethane is elastic and can absorb an enormous amount of trauma without permanently deforming (unlike aluminum)
- Polyurethane is resistant to ultraviolet light, water, oil, gasoline, salt, antifreeze, and most solvents (unlike rubber)
- Polyurethane is half the weight of aluminum and about 20% lighter than rubber
As many of you know, the bulk of the driving force behind this product was the fact that some cars--particularly the CTS-V--have miserable drivetrain misalignment angles. This puts their owners in a bind: either stick with the mushy rubber giubo included by the manufacturer, or replace the driveshaft with a new one featuring multiple constant-velocity (CV) joints. In this instance, aluminum giubos really aren't an option because they can't accept more than about 0.25° of misalignment at the transmission without creating a scary amount of vibration at above 15 miles per hour.
Prior to ordering, my big question that I had was, "am I just pouring money down a hole?" As some might recall, I previously purchased an aluminum Revshift driveshaft coupler, which effectively turned into a nice paperweight after my CTS-V attempted to rattle the teeth out of my head. That disappointment left me very wary about trying another giubo.
But I'm glad I changed my mind: after taking the plunge and running the 75D giubo at up to 7000 RPM in 2nd, 6000 RPM in 3rd, and 4000 RPM in 4th (85 mph)--with zero vibration--I have to say that this new giubo is freaking awesome. It feels just like the rubber one--except that the lag between pressing the pedal and feeling the car accelerate is reduced. My plan is to test much higher speeds later this week when I have more time.
Anyway, I hope this was useful information--I know my rubber coupler was basically shot and the thought of having to replace it with ANOTHER rubber coupler was a disgusting one. If you're interested in the other half of the videos and pictures I took for this installation, you know where I live.
Over the past several weeks, I've been trying to find time to install and beat on Revshift's latest invention: a 75D polyurethane giubo.
This is actually a really f***ing big deal. This functioning, fully-formed polyurethane giubo is a first for the car industry, and was only made possible by recent chemical process improvements from Bayer--the company that originally invented polyurethane back in 1937. For this application, the advantages of polyurethane are:
- Polyurethane can be tuned to produce polymers of different hardnesses to suit the application (unlike aluminum and rubber)
- Polyurethane is elastic and can absorb an enormous amount of trauma without permanently deforming (unlike aluminum)
- Polyurethane is resistant to ultraviolet light, water, oil, gasoline, salt, antifreeze, and most solvents (unlike rubber)
- Polyurethane is half the weight of aluminum and about 20% lighter than rubber
As many of you know, the bulk of the driving force behind this product was the fact that some cars--particularly the CTS-V--have miserable drivetrain misalignment angles. This puts their owners in a bind: either stick with the mushy rubber giubo included by the manufacturer, or replace the driveshaft with a new one featuring multiple constant-velocity (CV) joints. In this instance, aluminum giubos really aren't an option because they can't accept more than about 0.25° of misalignment at the transmission without creating a scary amount of vibration at above 15 miles per hour.
Prior to ordering, my big question that I had was, "am I just pouring money down a hole?" As some might recall, I previously purchased an aluminum Revshift driveshaft coupler, which effectively turned into a nice paperweight after my CTS-V attempted to rattle the teeth out of my head. That disappointment left me very wary about trying another giubo.
But I'm glad I changed my mind: after taking the plunge and running the 75D giubo at up to 7000 RPM in 2nd, 6000 RPM in 3rd, and 4000 RPM in 4th (85 mph)--with zero vibration--I have to say that this new giubo is freaking awesome. It feels just like the rubber one--except that the lag between pressing the pedal and feeling the car accelerate is reduced. My plan is to test much higher speeds later this week when I have more time.
Anyway, I hope this was useful information--I know my rubber coupler was basically shot and the thought of having to replace it with ANOTHER rubber coupler was a disgusting one. If you're interested in the other half of the videos and pictures I took for this installation, you know where I live.
Last edited by FuzzyLog1c; 09-14-2014 at 07:19 PM.
09-14-2014, 09:33 PM
#5
Update: I ran the car up to 110 mph. Like before, zero vibration! 
I haven't published that information yet. It was gathered as part of a private technical discussion between myself, Chris @ Gforce Engineering, John @ Revshift Engineering, and a small cadre of other forum members. I'll eventually post the results and pictures of the measurements, but not on this forum. We're making great progress on fixing many of GM's mistakes in private discussions, free of distractions.
I haven't published that information yet. It was gathered as part of a private technical discussion between myself, Chris @ Gforce Engineering, John @ Revshift Engineering, and a small cadre of other forum members. I'll eventually post the results and pictures of the measurements, but not on this forum. We're making great progress on fixing many of GM's mistakes in private discussions, free of distractions.
09-15-2014, 12:08 AM
#6
TECH Fanatic
Good stuff. Glad it worked out better than the aluminum one. I had high hopes for the aluminum unit but elected not to get one. I might have to check into this one later though.
09-15-2014, 09:39 AM
#7
In case you're just tuning in...
https://www.youtube.com/watch?v=HmGJOTJFJo0
Over the past several weeks, I've been trying to find time to install and beat on Revshift's latest invention: a 75D polyurethane giubo.
This is actually a really f***ing big deal. This functioning, fully-formed polyurethane giubo is a first for the car industry, and was only made possible by recent chemical process improvements from Bayer--the company that originally invented polyurethane back in 1937. For this application, the advantages of polyurethane are:
- Polyurethane can be tuned to produce polymers of different hardnesses to suit the application (unlike aluminum and rubber)
- Polyurethane is elastic and can absorb an enormous amount of trauma without permanently deforming (unlike aluminum)
- Polyurethane is resistant to ultraviolet light, water, oil, gasoline, salt, antifreeze, and most solvents (unlike rubber)
- Polyurethane is half the weight of aluminum and about 20% lighter than rubber
As many of you know, the bulk of the driving force behind this product was the fact that some cars--particularly the CTS-V--have miserable drivetrain misalignment angles. This puts their owners in a bind: either stick with the mushy rubber giubo included by the manufacturer, or replace the driveshaft with a new one featuring multiple constant-velocity (CV) joints. In this instance, aluminum giubos really aren't an option because they can't accept more than about 0.25° of misalignment at the transmission without creating a scary amount of vibration at above 15 miles per hour.
Prior to ordering, my big question that I had was, "am I just pouring money down a hole?" As some might recall, I previously purchased an aluminum Revshift driveshaft coupler, which effectively turned into a nice paperweight after my CTS-V attempted to rattle the teeth out of my head. That disappointment left me very wary about trying another giubo.
But I'm glad I changed my mind: after taking the plunge and running the 75D giubo at up to 7000 RPM in 2nd, 6000 RPM in 3rd, and 4000 RPM in 4th (85 mph)--with zero vibration--I have to say that this new giubo is freaking awesome. It feels just like the rubber one--except that the lag between pressing the pedal and feeling the car accelerate is reduced. My plan is to test much higher speeds later this week when I have more time.
https://www.youtube.com/watch?v=v8q8AlgT19Q
Anyway, I hope this was useful information--I know my rubber coupler was basically shot and the thought of having to replace it with ANOTHER rubber coupler was a disgusting one. If you're interested in the other half of the videos and pictures I took for this installation, you know where I live.
https://www.youtube.com/watch?v=HmGJOTJFJo0
Over the past several weeks, I've been trying to find time to install and beat on Revshift's latest invention: a 75D polyurethane giubo.
This is actually a really f***ing big deal. This functioning, fully-formed polyurethane giubo is a first for the car industry, and was only made possible by recent chemical process improvements from Bayer--the company that originally invented polyurethane back in 1937. For this application, the advantages of polyurethane are:
- Polyurethane can be tuned to produce polymers of different hardnesses to suit the application (unlike aluminum and rubber)
- Polyurethane is elastic and can absorb an enormous amount of trauma without permanently deforming (unlike aluminum)
- Polyurethane is resistant to ultraviolet light, water, oil, gasoline, salt, antifreeze, and most solvents (unlike rubber)
- Polyurethane is half the weight of aluminum and about 20% lighter than rubber
As many of you know, the bulk of the driving force behind this product was the fact that some cars--particularly the CTS-V--have miserable drivetrain misalignment angles. This puts their owners in a bind: either stick with the mushy rubber giubo included by the manufacturer, or replace the driveshaft with a new one featuring multiple constant-velocity (CV) joints. In this instance, aluminum giubos really aren't an option because they can't accept more than about 0.25° of misalignment at the transmission without creating a scary amount of vibration at above 15 miles per hour.
Prior to ordering, my big question that I had was, "am I just pouring money down a hole?" As some might recall, I previously purchased an aluminum Revshift driveshaft coupler, which effectively turned into a nice paperweight after my CTS-V attempted to rattle the teeth out of my head. That disappointment left me very wary about trying another giubo.
But I'm glad I changed my mind: after taking the plunge and running the 75D giubo at up to 7000 RPM in 2nd, 6000 RPM in 3rd, and 4000 RPM in 4th (85 mph)--with zero vibration--I have to say that this new giubo is freaking awesome. It feels just like the rubber one--except that the lag between pressing the pedal and feeling the car accelerate is reduced. My plan is to test much higher speeds later this week when I have more time.
https://www.youtube.com/watch?v=v8q8AlgT19Q
Anyway, I hope this was useful information--I know my rubber coupler was basically shot and the thought of having to replace it with ANOTHER rubber coupler was a disgusting one. If you're interested in the other half of the videos and pictures I took for this installation, you know where I live.
But, it doesn't take a team such as that to come to the conclusion that for a driveshaft in an IRS car with a fixed differential to be smooth, the output shaft of the transmission needs to be parallel to the input shaft of the differential....this I learned in a 5 minute internet search and has been a proven constant sense the 50's....you aren't changing this.
Additionally, While it's shared opinion that the shafts can't be perfectly in line with each other in order for u-joints to function properly, the closer you can come to a 1 degree angular difference between the two, the smoother the driveline will be....you aren't changing this either.
The challenge becomes what we do about driveline misalignment and this is where I hope you guys have come up with something. The problem with correcting drivleine vibrations in this car is that you are severely limited in your ability to adjust any of these angles. I have UMIs in my car currently (which totally lock the location of the motor in place...it ain't movin) and the only adjustablity I really have is shimming the trans crossmember, shimming the bearing carrier or shimming the cradle. These will give me adjustment in what I will call a vertical direction but from a side to side perspective, all I can do is loosen the front and rear cradles, breakout the pry bar and hope for the best because the UMIs don't give and neither do the upper or lower motor mount brackets.
The other challenge we have is inconsistencies between the 1000 different combinations of parts we have to work with. We have 3 different aftermarket motor mounts, 2 transmission mounts, 5 driveshaft variations, 3 differential choices and 2 different suppliers of cradle bushings. All of these parts or any combination of them will yield any number of different driveline alignments possibilities.
Beyond this, we need to check the runout on the transmission output shaft and the runout on the differentials input shaft. These will also be inconsistent from car to car.
In other words....there won't be a 100% "one size fits all" solution from the aftermarket for a V1 with driveline vibration issues....there are just too many variables at play here.
I was going to order a set of headers but decided that a carbon one piece with 2 CVs was a wiser way to spend my performance dollars....all the horsepower in the world is useless if you can't put it to the ground. While I was thinking I should check all these angles before installing the shaft, I've decided to install the shaft and go from there....I talked with DSS and I should have my drivehaft this week.
If I still have vibrations, I'll need to check the alignment of the drivetrain and the runouts on the shafts. Hopefully, I can get it aligned with what little flexibility I have but if not, I'll need to introduce some adjustability into the drivetrain somewhere. The easiest place to do this is in the motor mounts. I'll buy another set of UMIs and modify them to accept shims and then slot the through bolt holes so I can move the motor in several directions. This should be all the flexibility I need to achieve whatever driveline angle I'll need to make the car happy but hopefully I won't need to go this far. The UMIs positioned the motor not only 1/4 lower in the frame than my shot stockers, it also shifted the motor almost a 1/2 inch to the right side of the car...these aren't machined pieces and while they are nice, they aren't built to an extreme level of accuracy....in other words the motor isn't setting where it used to be and neither is the transmission.
So....I'm hoping that Fuzzy has devised some sort of an adjustable motor mount because that's the only road I see to give us the flexibility we need to fix this problem with all the different driveline combinations we have at our disposal and runout possibilities we face.
Last edited by ls1247; 09-15-2014 at 09:52 AM.
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09-25-2014, 07:09 PM
#9
Wasnt something like this mentioned for us similar to what the BMW guys run, maybe even from the same company? just wondering what would make this first or is it just first of a certain material?
09-25-2014, 07:17 PM
#10
Typically, when you see an aluminum driveshaft coupler on a Camaro, Charger, M3, or M5, it's being used in conjunction with a universal joint or a plunging CV joint (technically a VL-type CV joint), which takes most (or all) of the misalignment stress out of the equation.
Last edited by FuzzyLog1c; 09-26-2014 at 11:21 AM.
09-26-2014, 01:56 AM
#11
I too have been dealing with a vibration since installing a CS 8.8 and 1 piece CF driveshaft. Only bushing that I haven't replaced with poly is the motor mounts. They are new but are still OEM. Curious about the UMI mounts and possibly PUO mounts as far as alignment. 1/4 inch drop would definitely help with the trans to diff alignment but the shift to the right I would think would only make the problem worse. Any one else dealt with something like this? Vibration only comes on about 100mph and goes away at about 120.... running rev shift trans mount and have tried shimming the trans mount and while it lessened the vibration it also created one at slower speeds as well.
09-26-2014, 02:28 AM
#12
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So this one is the green 75D one correct? Does this mean that the blue one is no longer sold or good? I have one. I just haven't installed yet. I'd like to when I swap out the dual mass turd for my LS7 package.
09-26-2014, 08:24 AM
#14
I too have been dealing with a vibration since installing a CS 8.8 and 1 piece CF driveshaft. Only bushing that I haven't replaced with poly is the motor mounts. They are new but are still OEM. Curious about the UMI mounts and possibly PUO mounts as far as alignment. 1/4 inch drop would definitely help with the trans to diff alignment but the shift to the right I would think would only make the problem worse. Any one else dealt with something like this? Vibration only comes on about 100mph and goes away at about 120.... running rev shift trans mount and have tried shimming the trans mount and while it lessened the vibration it also created one at slower speeds as well.
You might be able to get a little "wiggle room" out of the CS or Revshift mounts but if you were to force them in any direction other than where they naturally want to sit, would they eventually tear because you put them in a bind? I have no idea...
I put a CS trans mount in the car and I forgot to mention in this thread that it raised the transmission about 1/2 inch over the sagged out stock mount. What we don't know is what the installed height of the factory mount is supposed to be. It appears that both the Revshift insert and the CS replacement mount both raise the transmission up to a level that would be equal to the stock mount in a perfectly erect, non-collapsed state but what we don't know is did the engineers know that the stock mount would sag and account for that when they built the car?
My guess, even when new, the stock transmission mount sagged right off the showroom floor.
So are the aftermarket mounts too high? We'll never know because the only way to establish a reliable baseline for this measurement is to pull a car off the showroom and measure it...don't see that happening.
So with the UMIs relocating the engine 1/2 to the right and a 1/4 down and the CS trans mount raising the transmission 1/2 inch, there is no telling how screwed up my driveshaft alignment is. Of course, I'm still limping on my shot stock driveshaft as I roll into week 9 waiting for my DSS shaft which they just told me they're going to have to rebuild because the shaft they built for me had too much runout to be balanced...all I could do was laugh.
In other words, I ain't screwin with it until the new shaft comes in but I'm not very hopeful that this new shaft will cure all my problems. And I'm not holding my breath for anyone to come up with a one size fits all cure for it either.
Last edited by ls1247; 09-26-2014 at 08:30 AM.
09-26-2014, 09:00 AM
#15
TECH Fanatic
09-26-2014, 09:35 AM
#16
Nothing to be curious about with the UMIs. There is no adjustment, period. The good news with this design of mount is that it could be easily made to accommodate adjustments for both side to side and engine clocking and if you really needed to, you could raise the motor as well by putting washers under it.
You might be able to get a little "wiggle room" out of the CS or Revshift mounts but if you were to force them in any direction other than where they naturally want to sit, would they eventually tear because you put them in a bind? I have no idea...
I put a CS trans mount in the car and I forgot to mention in this thread that it raised the transmission about 1/2 inch over the sagged out stock mount. What we don't know is what the installed height of the factory mount is supposed to be. It appears that both the Revshift insert and the CS replacement mount both raise the transmission up to a level that would be equal to the stock mount in a perfectly erect, non-collapsed state but what we don't know is did the engineers know that the stock mount would sag and account for that when they built the car?
My guess, even when new, the stock transmission mount sagged right off the showroom floor.
So are the aftermarket mounts too high? We'll never know because the only way to establish a reliable baseline for this measurement is to pull a car off the showroom and measure it...don't see that happening.
So with the UMIs relocating the engine 1/2 to the right and a 1/4 down and the CS trans mount raising the transmission 1/2 inch, there is no telling how screwed up my driveshaft alignment is. Of course, I'm still limping on my shot stock driveshaft as I roll into week 9 waiting for my DSS shaft which they just told me they're going to have to rebuild because the shaft they built for me had too much runout to be balanced...all I could do was laugh.
In other words, I ain't screwin with it until the new shaft comes in but I'm not very hopeful that this new shaft will cure all my problems. And I'm not holding my breath for anyone to come up with a one size fits all cure for it either.
You might be able to get a little "wiggle room" out of the CS or Revshift mounts but if you were to force them in any direction other than where they naturally want to sit, would they eventually tear because you put them in a bind? I have no idea...
I put a CS trans mount in the car and I forgot to mention in this thread that it raised the transmission about 1/2 inch over the sagged out stock mount. What we don't know is what the installed height of the factory mount is supposed to be. It appears that both the Revshift insert and the CS replacement mount both raise the transmission up to a level that would be equal to the stock mount in a perfectly erect, non-collapsed state but what we don't know is did the engineers know that the stock mount would sag and account for that when they built the car?
My guess, even when new, the stock transmission mount sagged right off the showroom floor.
So are the aftermarket mounts too high? We'll never know because the only way to establish a reliable baseline for this measurement is to pull a car off the showroom and measure it...don't see that happening.
So with the UMIs relocating the engine 1/2 to the right and a 1/4 down and the CS trans mount raising the transmission 1/2 inch, there is no telling how screwed up my driveshaft alignment is. Of course, I'm still limping on my shot stock driveshaft as I roll into week 9 waiting for my DSS shaft which they just told me they're going to have to rebuild because the shaft they built for me had too much runout to be balanced...all I could do was laugh.
In other words, I ain't screwin with it until the new shaft comes in but I'm not very hopeful that this new shaft will cure all my problems. And I'm not holding my breath for anyone to come up with a one size fits all cure for it either.
09-26-2014, 11:38 AM
#19
It'll be a stretch--I need to complete my KRC flow orfice testing so that I can make a recommendation and complete my writeup on my adjustable KRC Power Steering build. I also want to complete my review and installation guide for the MC adapter kit that Philistine and I worked on. There's a bunch of clutch/slave combination measurements that need to be posted and I need to address the issue with the kit where the longer Tilton rod (which Jaysen ground down to fit inside the CPPS) starts to buckle and scrape against the sides of the MC adapter after repeated use. Shouldn't be an issue that people with softly-actuating clutches (e.g. LS7 and LS9X) need to worry about.
Last edited by FuzzyLog1c; 09-26-2014 at 11:53 AM.