uprated viscous cupplings

st185-sainz

New member
hi,

I found a company that can uprate our viscous centre differentials. I did one example for my car and it feels great. The car seems to have much more traction and does not have so much understeer anymore!
The company already made some visco units for a lot of rally cars, also the TTE gr. N cars.

I paid 590EUR to get mine uprated. It was a special price...

Is there any interest from your side?

cheers
mario
 

st185-sainz

New member
changing the fluid - but that's the only thing that can be worn in such a cuppling...

everybody who has ever thought of changing the fluid should have seen that our visco is welded and has no screw to change the fluid. the unit needs to be machined and welded! they will make a screw then to make another revision easier...
 
stupid question here, but i'm guessing our centre diff is in the transfer case so the motor has to be out and the transfer case accessible in order to have this done correct? If that's the case, my window of opportunity is about to end since my motor is about to go back in any day now.
 

st185-sainz

New member
no, it is possible to change the visco without taking out the engine. If I remember correctly, the only difficulty was to get out the long shaft which goes through the unit, but finally everything worked fine! I took us around 4hrs to change it (with proper tools...)
 
interesting. I will have to look into that, but at a later date. I just need to focus on getting the car back together and on the road then i can actually look at it and understand where the vc centre diff is etc etc.

let us know how the uprated diff works for you as you spend more time with it.
 

Simba

New member
Sounds interesting. I would suspect more people would be interested if they could do it on an exchange basis for a pre-modified VC.
 

sleeper

New member
I`m interested in this, but since i live in nnorway, it would be extremly expencive to shipp it to austalia..

So do you have the name on the company or a guide on how to do it yourself?
What type of fluid did they use?
 

MWP

New member
Im interested... what new fluid was used?

Does the original fluid degrade, so slip more, or is this new fluid just heavier = less slip?
 

st185-sainz

New member
They open the unit, change the fluid and test it! They set it to the specific torque you like. Depends if you would like to use the handbrake or not!
The old fluid gets worn out and allows more slip.
 

gtfour77

New member
I am looking into this right now...anyone in the US that could do this upgrade? If not i am going to tackle this over winter.... Front diff is also on the list. If either of these don't work out I am building an SSM MR2... Another note, talked to one of Quaife reps and seems like thay might be able to help us with the front at least, they even offered to send me a sample diff from an MR2 turbo to test fit and design a transfer shaft for it. I'll keep everyone updated. If nothing else we need ~20 people to do a group buy and they'll design a front diff for us.... any interest?
 

CMS-GT4

Active member
Keep us posted on the front diff. We tried to hold a group buy years ago for a front dif, but could not generate enough interest. I am interested to see what you come up with as far as fitment goes with the mr2 lsd.
 

gtfour77

New member
Like I said, I am going for it this winter, otherwise I am scrapping the project after next year. With an upgraded VC and front diff I think the car will be very competitive. My rear diff is also worn out so that didn't help but I was literally not going anywhere at the pro finale... :doh: I'll keep you guys posted, I'll just open up a new thread once I get started... around middle of October is when everything is coming apart.
 

st185-sainz

New member
what rear lsd are you using?! the stock torsen one?! the plate type aftermarket one can be rebuilt easily and you can also change the characteristics of it to fit your driving style!
at the moment I'm out of stock with the plate type ones but I will get some later this year...

the front diff is the last one should care about! I did the centre and the rear diff and the driveability improved a lot! at first I did the rear unit, that prevented from massive understeer. then I did the viscous unit and it gave much more traction and you really feel the car wants to move forward!
just a thought...
 

gtfour77

New member
st185-sainz":tyeh18yd said:
what rear lsd are you using?! the stock torsen one?! the plate type aftermarket one can be rebuilt easily and you can also change the characteristics of it to fit your driving style!
at the moment I'm out of stock with the plate type ones but I will get some later this year...

the front diff is the last one should care about! I did the centre and the rear diff and the driveability improved a lot! at first I did the rear unit, that prevented from massive understeer. then I did the viscous unit and it gave much more traction and you really feel the car wants to move forward!
just a thought...


I am on a Cusco 1 way (clutch type) right now, I have been tuning it with friction modifier but lately there is simply no LSD action seems like. It's going to be coming apart as well over winter with all new plates. Hopefully I can get the center one figured out. I have two of them so I'll do some testing on it to see where they are and maybe modify them... (lathe and torque wrench test) Do you know what type of viscous fluid they used? $580 euro is kind of high for us still but well worth it is there is nothing else available.
 

st185-sainz

New member
honestly I don't know what fluid they used! but the problem was to open the unit! ours is welded and needs to be machined to get it open and put a plug in it for refilling! that's the challenge...

testing with a torque wrench won't give you proper results as the visco needs a certain difference in the rpms from one end to the other...
they can test it on their rig with 50rpm difference and measure the torque value then! the standard unit has around 150Nm at 50rpm.
 

gtfour77

New member
st185-sainz":1cxqbwv3 said:
honestly I don't know what fluid they used! but the problem was to open the unit! ours is welded and needs to be machined to get it open and put a plug in it for refilling! that's the challenge...

testing with a torque wrench won't give you proper results as the visco needs a certain difference in the rpms from one end to the other...
they can test it on their rig with 50rpm difference and measure the torque value then! the standard unit has around 150Nm at 50rpm.


That's a good start to know the specs on the stock unit... I know Subaru people test theirs on a lathe at 100RPM...will need to look into it a bit more. Thanks for the info!
 

gtfour77

New member
Well i got the stock VC out of the spare tranfer case. It's in the lather right now and it is pretty tight. I'll measure the torque on it if I can, Didn't want to weld onto the shaft as I might need it later. I was able to turn the diff with a pipe wrench...if i had to guess it would be around 60 ft/lbs of torque to turn it. My lather will not turn the unit to measure it, that's simply too much force on the old machine. The unit also has a set screw that can be removed. Once I did there was a thick goo that started coming out so I plugged it back up....that means it's not dried out at least. I am not sure where to even begin to find fluid like that.... It was thicker than honey seemed like, quite similar though. It would be pretty easy to open and weld back together IMHO....I'll post some pictures tomorrow... This is just a start for now.

Mario, I might end up sending you or the company you mentioned my unit if this doesn't work out...how much would it cost in US currency? Thanks!

PS: I just got Quaife diff (MR2 turbo) specs and drawings emailed to me, I'll be measuring tonight...
 

gtfour77

New member
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