# Haldex question To remove or not to remove.



## TT2RR (Dec 23, 2008)

ok so in front of the rear diff is the haldex clutch. the rear driveshaft spins all the time so there has to be a difference to make the clutch grab,
so my question is:
what happens if you just take the front cv shafts out and try to drive around im almost positive it will grab, but how quickly? and what kinda diff is in the back of these things? what gear n how big? must be tiny right? has anyon had one of these things apart?


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## 1.8Tabamoura (Jul 29, 2005)

I'm pretty sure it won't work , First you can only transfer up to 50% of the power to the rears no matter what , second, you will need the front wheels to slip ( sensors are on the hub) for the haldex to engage the rears unless you get a blue controller. 


_Modified by 1.8Tabamoura at 6:28 PM 12-23-2008_


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## l88m22vette (Mar 2, 2006)

*Re: Haldex question To remove or not to remove. (TT2RR)*

Don't know how quick, but it might grab since it thinks that there is front slippage (unless the ECU just freaks out). The diff is open (like 95% of OEM diffs), but I dunno the ratio. Also, if the Haldex stayed locked all the time the fluid would wear out even faster than with an Orange controller. That said, the whole point of the TT is a sports car with AWD...if you want RWD why not get a 350z or something else? The TT isn't built for it so chances are it would screw something up pretty quick...


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## TToxic (Nov 15, 2008)

*Re: Haldex question To remove or not to remove. (l88m22vette)*

kiss the clutch pack good bye, and it wont take long.


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## TT2RR (Dec 23, 2008)

*Re: Haldex question To remove or not to remove. (TToxic)*

well consider it kissed, ill keep you guys updated. Ps its not a stock engine either, ill keep you updated.


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## TT2RR (Dec 23, 2008)

i guess im just wondering more if its gonna even grab or not... lol


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## storx (Dec 6, 2006)

have you ever tried to engage the clutch while the car is suspended in the air.. the car literally bucks cause the front and rear tires dont know what to do.. you will see the front wheels start to spin then the car will buck a little and the rear starts to spin also... then after a few seconds it will just start bucking uncontrollably.. then the check engine light goes off..


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## TT2RR (Dec 23, 2008)

*Re: (storx)*

How did you engage the clutch? Check engine light is non existant on my car... as well as the engine and gauge cluster is different...

i used to have a subaru... the duty solenoid for the clutched rear axle went bad, theirs was inside the trans. but it went bad and it locked into 4wd SOLID... there was nothing u could do.. so i took the rear driveshaft out and problem solved..


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## 50trim S (Jun 3, 2008)

*Re: (TT2RR)*

i don't see why it wouldn't become RWD if you took everything from the front output shaft of the tranny, i think that's what its called, so wouldn't the ecu just think the front has 0 grip and send all the power to everything from the output shaft of the tranny to make it RWD. But doesn't anyone make a type of controller that you can set what % of power goes to each end or does the haldex version of AWD not work like that, i thought hpa made something that did something like this but it wasn't adjustable but if they could do that ....seems like they could make one that sends 100% the the rear end this would only need to even be thought about if your not on standalone and the prices hpa charges it would probably be as expensive for anything custom from hpa and software for the stock ecu to make ALOT of power and you could always make more power on standalone even if it was mega squirt.
if the gauge cluster is gone are you on standalone? 
if that's the case then are you trying to make it a drag car because it sounds like you are from your other threads? if so you could just have the spider gears in rear diff or whatever else in there that needs to be welded to make power go to both wheels at all times that or put a quaife in it. But if i was going for an all out drag car i would just have the stock one welded its been working on American muscle for 50+ years.
if your on standalone it would only be mechanical issue and I'm sure, even if it took having the output shaft removed and where it was, welded up but i honestly don't know what all is inside an AWD transmission. I don't know what all it would take. Tranny's aren't my thing but I'm sure it could be done somehow someway you could make that tranny RWD only.
this thread has the most info on your tranny than any other i have seen the best 02m transmission thread by far 
i would post in the transmission forum and maybe some of the old school vw guys could have some answers for you. If you didn't get any help in there i would go to transmission shop and ask them, but more than likely your going to be the "guinea pig" on this because the transmission is weird anyway because it has two final drive ratio's 
if you were doing the all out drag race thing now keep in mind this is an extreme option you could take the 2nd final drive gear along with 5th,6th, and unfortunately reverse as well and replace them with spacers because the some of 180 TT's are o2m's just like the 6 speed's but are 5 speed's and have a spacer in the place of the 6th gear.you then would have a 4 speed tranny and if you did that you might as well make it a custom one with the ratio's you want you have quite a few different gear ratios available if you include the euro diesel 02m that has extremely long gears because it can't rev that high. so as crazy as it sounds if you were making an all out drag car this is a viable option maybe some how a transmission guy could add the reverse gear to the first final drive gear set but i don't know this is way over my head but I've been up for about 36 hrs







and lack of sleep seems to make me think more out of the box than anything or anytime else.








if you wouldn't mind sharing your plans in one of these threads or pm me i wouldn't mind trying my best to help you out with what you are trying to accomplish http://****************.com/smile/emthup.gif








so in the end i want to make sure and answer your question if your going for an all out drag car REMOVE THE HALDEX, MAKE IT RWD AND PUT A BIG OLE SET OF SLICK ON IT AND I HOPE YOU MAKE 800+ WHP AND RUN 8'S MAKE IT 2.0 WITH THE NEW 2.0 CRANK PUT A SOLID LIFTER HEAD WITH THE MOST AGGRESSIVE CAT OR CUSTOM MADE CAM, AND REV TO 10,500-11000RPMS WITH EITHER AT LEAST A GT4202R OR BW S372 TURBO ON IT AND I HOPE YOU DO WELL IT'LL BE NOTHING BUT GOOD FOR THE VW AND AUDI COMMUNITY TO SHOW WHAT THESE ENGINES CAN DO WHEN SOMEONE IS SET TO ACCOMPLISH SOMETHING, PUT THERE MIND TO IT AND MONEY IS NOT AN ISSUE BUT IF IT IS AN ISSUE, I WOULD BE LOOKING FOR SPONSORS AND TELL THEM YOUR PLANS. IM SURE THERE ARE SOME COMPANY'S THAT WOULD LIKE TO HAVE THERE NAME ON AN 8 OR 9 SECOND AUDI AND I'LL END MY RANT THIS, I KNOW ITS NOT THE POLITICALLY CORRECT THING TO SAY BUT MERRY CHRISTMAS





























AND GOOD LUCK WITH WHAT YOU ARE TRYING TO ACCOMPLISH http://****************.com/smile/emthup.gif

















_Modified by 50trim S at 5:25 AM 12-24-2008_


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## l88m22vette (Mar 2, 2006)

*Re: (50trim S)*

If you'd search most of your questions would be answered, and the TT is transverse, not longitudinal (like an A4). The Haldex is a slave shaft from the 02M/DSG to an electronic clutch which varies engagement (it is right before the rear diff)

_Quote, originally posted by *50trim S* »_
if so you could just have the spider gears in rear diff or whatever else in there that needs to be welded to make power go to both wheels at all times that or put a quaife in it. But if i was going for an all out drag car i would just have the stock one welded its been working on American muscle for 50+ years.
if your on standalone it would only be mechanical issue and I'm sure, even if it took having the output shaft removed and where it was, welded up but i honestly don't know what all is inside an AWD transmission. I don't know what all it would take. Tranny's aren't my thing but I'm sure it could be done somehow someway you could make that tranny RWD only.
i would post in the transmission forum and maybe some of the old school vw guys could have some answers for you. If you didn't get any help in there i would go to transmission shop and ask them, but more than likely your going to be the "guinea pig" on this because the transmission is weird anyway because it has two final drive ratio's 
if you were doing the all out drag race thing now keep in mind this is an extreme option you could take the 2nd final drive gear along with 5th,6th, and unfortunately reverse as well and replace them with spacers because the some of 180 TT's are o2m's just like the 6 speed's but are 5 speed's and have a spacer in the place of the 6th gear.you then would have a 4 speed tranny and if you did that you might as well make it a custom one with the ratio's you want you have quite a few different gear ratios available if you include the euro diesel 02m that has extremely long gears because it can't rev that high. so as crazy as it sounds if you were making an all out drag car this is a viable option maybe some how a transmission guy could add the reverse gear to the first final drive gear set but i don't know this is way over my head but I've been up for about 36 hrs







and lack of sleep seems to make me think more out of the box than anything or anytime else.










Are you serious? Weld the gears? Thats a retarded idea, this isn't a 1967 Camaro, its independant suspension controlled by a computer, something tells me the crap that works for muscle cars wouldn't work for our TT, and a welded diff is way dangerous. Old school matters if the cars are _old_, hence the clever name. Also, you want him to build a custom 4spd tranny? Uh, what?








Everything you're spouting is ridiculous, and thats why you tell him to ask people for help/info...isn't that what he is doing? Isn't he hoping for actual info, not a huge post which is all over the place without ACTUALLY HAVING INFO? It would literally take 5min and Google...


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## TT2RR (Dec 23, 2008)

this post experiment is just for fun, my motor points the other way now, but since the rear end isnt done, and the stock stuff is still sitting in there, i decided to put the haldex to the test, so we made the stock driveshaft fit the the trans im using. Think shes gonna go? is it gonna coast like an auto even tho its in gear? lol who knows?!


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## TT2RR (Dec 23, 2008)

oh and yes, its stand alone, but i think the computer will still try to contol that stuff, altho it wont see a mph... so i have no idea what is gonna happen...


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## storx (Dec 6, 2006)

ok first of all its takes the wheels 20 degrees of slip before it would lock 50% of the power to the rear wheels.. and that is the maximum the car can physically allocate to the rear without you modding the transmission. Also the rear is hydraulicly actuated by 6 clutchs. they are not very strong on stock platform can withstand a maximum of 600tq before needing to be upgraded. The reason they work so well in our cars now is because only 50% of the power is felt on the rear at any given time at max.. which on an stock 225 is about 100tq.. so it is barely used.. 
Second of all the whole idea of running the biggest cam.. is retarded.. the point of an turbo engine is flow and preassure not flow and overlap... as you get to big in cam.. you start subtracting in power...


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## TT2RR (Dec 23, 2008)

talking percentages doesnt really work, to be correct you would have to say its always 100% front wheel drive, our cars have 3 outputs that always spin, 2 sides for each front wheel and a rear output . These ALWAYS have 100% of the engines power, well aside from left to right open diff... just like any other front wheel drive, then the rear output goes to a driveshaft to the haldex clutch. then to the rear diff. 
Its my believe that it mainly sees a difference between the rear driveshaft speed ( as that should match the front tire speed ) to the back diff and tires, so basically if you do a fwd burnout the driveshaft spins and the rear diff stays still creating the difference and making pressure inside the haldex unit, i dont think there is ANY way to truely turn it off or on but only change how agressive it will be when it has pressure to work with via some valves that either restrict or open the flow to the piston that clamps the clutches...


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## storx (Dec 6, 2006)

you can run an controller that keeps the rear locked but the ratio from the engine to the trans to the transfer case is still 2:1 to the rear... so when the rear is locked up 100% its 100% of the 50% still going to the rear no matter what. 
jack the car up and put it in gear and watch the tires the rear can not physically spin faster then the front but the rear wheels while suspended can spin half as fast as the front. this is how the rear never overpowers in the corners cause the engine is still technically pulling the car around in the corners but because the rear has some power it trys to push the rear out some but cant. cause the gear ratio and drivetrain lost..... 
there is 6 clutchs in the rear and they are only actuated by one actuator so there is no true 90/10 or 70/30 like peeps say that is just the pulsing of the actuator rapidly to look like 90/10 and so and so. if you take the safety check valve out of the rear end and cross drill the vanes then tou will have a open diff when not needed or fully engaged diff... no more pulsing
if you really want rear wheel drive you can do like they did on the rwd v8 audi tt rally car...run oil cooler and plain rwd diff to the rear with the pump constantly applied but i dont see an real advantage of this over a normal rear end


_Modified by storx at 12:39 AM 12-25-2008_


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## 1.8Tabamoura (Jul 29, 2005)




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## Village_Idiot (Oct 16, 2004)

*Re: (1.8Tabamoura)*

You guys should remember the orientation of our motors, your talking about subaru motors and the such, these are longitutal motors with a different style transmission. Our RWD system is more of a joke than anything else, I know it gives our cars a huge edge with turns and launches compared to a FWD VW but our cars are unbalanced and that RWD system is really there as a supplement to FWD, not to drive the entire car. This is my understanding at least. I know it can supply power to the rear wheels and enough to kick them out around turns, but it's not meant to drive the whole car, just supplemental grip identical to the 911-C4 - primarily RWD but FWD supplement for slip, were the opposite. 
If you wanted to make the TT a RWD vehicle you would need our motor to be mounted longitudaly like a passsat or Audi quattro vehicle. Also you would need a RWD drivetrain setup where your transmission would feed a driveshaft to a rear differential to distribute power amongst the rear wheels.
If you disconnect the front axles from our cars the hubs you took them off of are still going to spin.
I have had all four wheels moving in the air on a lift and my car has never buckled in the slightest or threw any codes or a flashing CEL. I have always had all four wheels spinning in the air smoothly just as any other car would. The car thinks the front wheels are slipping and transfers power so fast to the rear you don't even notice the lag in the air.... my cars stock haldex controller and a very early 2001 though... 
These are just my thoughts & 1.8Tabamoura that is an awesome photo of our rear diff. deffinetly saving that NOW.
OP: Are you saying that you have swapped an longitudal motor in your car with a RWD style trans and your trying to use the stock rear diff? If so bad idea I doubt it will last long if out of your driveway.... but I want photos : )


_Modified by Village_Idiot at 1:17 PM 12-25-2008_


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## TT2RR (Dec 23, 2008)

thats not excatly our rear diff, altho the internals are the same, that pics from a v6 exposed site or something like that... i know ive seen it somewhere before... 
lol i cant wait to post some videos n pics of what happens


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## Bazzy (Jun 14, 2007)

*Re: (TT2RR)*

What are you planning to do with this car?


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## cincyTT (May 11, 2006)

*Re: (Bazzy)*

Just keep the car the way it is and call it a day.


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## TToxic (Nov 15, 2008)

*Re: (Bazzy)*

Hasn't it become obvious yet lol lol lol?


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## l88m22vette (Mar 2, 2006)

*Re: (TToxic)*

Everything you could need to know: http://public.fotki.com/ttschwing/haldex_mods/mods/ You're literally talking about re-engineering the drivetrain. Just settle or sell the TT if its _that_ important...


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## M this 1! (May 17, 2000)

*Re: (l88m22vette)*

or call up VW and ask what they did for the Tokyo Drift VWs that were rwd


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## yellowslc (Aug 29, 2000)

*Re: (M this 1!)*

Wow. I have never read so much false information about the haldex system in a single thread. 
W/o power to the haldex electric pump and the valve fully open within the haldex control module, not much is going to happen. The sole function of the mechanical pump in the haldex coupling is to circulate fluid. Without the CAN signal to the oem control module, the valve is fully closed at rest. Simply wiring up the electric pump does you no good either. 
Go ahead, tear it up.


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## l88m22vette (Mar 2, 2006)

*Re: (yellowslc)*

Thanks for back-up yellow...haven't seen you in the TT forum (ever?)


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## yellowslc (Aug 29, 2000)

*Re: (l88m22vette)*


_Quote, originally posted by *l88m22vette* »_Thanks for back-up yellow...haven't seen you in the TT forum (ever?)

I was in here for a bit when I had my Red/vanilla 03 225Q


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