Haldex 4wd vs syncro/rallye

[biggerbigben 0]

As many of you know I have the rallye set up in my corrado and I was chatting to a mate @ Edition 38 show this weekend who owns the ex-Dubsport orange mk2 4x4 20vt about which 4wd is stronger..

 

Now before all of you say the Haldex, have a think about it first... The ex-dubsport car is mapped for about 450bhp and it uses a dead standard rallye setup and until recently he has had no problems and he drags it every weekend.. With the dog box he is seeing 0-60 appearing in 3.2 secs and 1/4 miles in around 12 secs running @ about 400bhp... He recently has blown a few bearings in the rear diff, but it took nearly 1 1/2 years to do it.

 

Dubsport have built a 550bhp VR6 Turbo 4x4 corrado using the smae setup and that was ok for a few months then the rear diff went also.

 

Now the HGP R32 bi-turbo, which was @ Inters this year runs @ about 600bhp and apparently it blew its R32/RS6 hybrid gearbox shortly after Inters (meaning it was only on the road for a few weeks) and therefore brought the power down to 400bhp where it has since blown x2 rear haldex diffs....

 

So my question is really, which of the two systems can actually handle more power??

 

People say the Haldex should handle 600bhp, but does it??

[Red=Fast 0]

i wish i knew. i have seen more poeple do the rallye set up more than the haldex one... i am assuming there is a big difference in price between the two. i am quite curious to see what you guys think.

[Timo. 0]

Is the rallye setup permanent 4wd, unlike the Haldex, which only provides drive to the rear wheels when the front starts to lose grip or do they both work in a similar way?

[NormanCoal 0]

Before I write what I know, in my opinion its torque that kills diffs, not outright power

 

There is a particular 20VT syncro golf that I know that is running a huge amount of power - jabba built engine with a huge IHI roller bearing turbo. This car has twice blown rallye rear diffs to smitherins, and has since had a haldex rear diff installed. The trick bit of this installation is that it is switchable from 2WD to 4WD. This means that when it goes onto the strip it runs in permanent 4WD mode, not using the rallye type of system of throwing the drive to the back end once the front starts to lose its grip. That may be the difference in the examples you have described above.

Only from the knowledge that I know can I say that Haldex is better that the Rallye system (from the one car that I know with it fitted)

[PhatVR6 0]

I've got both, just haven't got 400bhp to put through it yet!

[MelG60 0]

I really *think* that the Haldex (in combo with the 02M MQ350 box) is stronger than the Rallye setup. The Saab 600hp Rallycross cars are running Haldex and the Xsara WRC also.

[Kevin Bacon 5]

Are there any alterantive rear diffs that can be used, from other manufacturers?

 

My mate's old impreza blew a rear diff when the power was increased, so it's not just the Rallye/Haldex systems that are affected!

[G60Jet 1]

its not a case of which is better, its a case of upgrading the bearings to match the power, otherwise its like more power with out more brakes

[Timo. 0]

 

The trick bit of this installation is that it is switchable from 2WD to 4WD. This means that when it goes onto the strip it runs in permanent 4WD mode, not using the rallye type of system of throwing the drive to the back end once the front starts to lose its grip. That may be the difference in the examples you have described above.

Only from the knowledge that I know can I say that Haldex is better that the Rallye system (from the one car that I know with it fitted)

 

I thought it was the Haldex system that puts the drive into the rear wheels as well, when the front starts to lose grip??

 

Timo.

[PhatVR6 0]

they both do.

 

the syncro system does it mechanically, by means of a viscous coupling onthe input to the rear diff.

 

the haldex does it elctronically, using the cars ecu and ABS sensors and stuff to tell it how much to transfer by means of a hydraulic pump. you can get it to run in full time 4wd though, just not with the stock setup.

 

several people are developting haldex controllers at the moment.

[Timo. 0]

oh right!! Thanks for that PhatVR6,

 

Makes everything clear!

 

Timo.

[MelG60 0]

The weak point of the Rallye Syncro system is the transfer box and the low speed the propshaft makes, not bearings

[biggerbigben 0]

I don't think I'm going to upgrade to Haldex quite yet, I'm going to wait for a few more nutters to chuck silly power through it first before I change over. In the mean time its a 6spd dog box for me and plenty of spare parts for the rallye 4wd... When I get the bigger turbo I will have a re-think. 8)

 

Keep the stories coming though, I want/need to hear peoples experiences.... everyone doing 4wd will benefit...

[Gman 0]

you should be able to uprate ( or get and uprated ) haldex diff to cope with the Torque. I will dig out a book I have on diffs and have a look.

 

G

[CoxyLaad 0]

Ben as far as I know a 6speed box that will work for the rallye viscous coupling will not work for the haldex due to the difference in ratios of the transfer boxes.

 

I may be wrong but I dont think I am. :roll:

[biggerbigben 0]

Ben as far as I know a 6speed box that will work for the rallye viscous coupling will not work for the haldex due to the difference in ratios of the transfer boxes.

 

I may be wrong but I dont think I am. :roll:

 

You are right, I'm getting a rallye 6spd dog box, or at least wish i was... I'll start saving..

[rmn 0]

The Halex is supposed to be much stronger, there is a lad here in Ireland with a 350 bhp MTM tuned S3 and its given him no problems, its electronic nature means it can react quicker than the rallye one.

He had a haldex controller in it and the problem was too much grip, it was eating tyres!

Am i right in thinking that you cant mix a rallye gearbox with a haldex diff?

I think i read that somewhere, so you might want to bear that in mind when getting the 6sp box, but i could be wrong

[CoxyLaad 0]

yes you are right - thats what I just said 2 posts ago!!!!

 

hence the reason I brought it up cos biggerbigben is getting a rallye 6speed box, which would mean he wont be able to run a haldex at all.

[biggerbigben 0]

sorry i didn't read it properly. I thought that the rallye gearbox+transfer box rotates differently to the haldex... i.e to every 1 rotation of the rallye gearbox + transfer box would equal 1.1 or 1.2 rotations of the haldex diff and therefore are not compatible......???? I may be wrong, but thats my understanding....???? please tell me different...

[MelG60 0]

Thats correct, the transfer box/ rear diff have different gearings. I dont know if there is a trick around that but AME runs a sort of 02M 6 speed with Seat WRC Syncro rear diff... Does Nutter4x4 use a 02M with his Haldex setup?

[PhatVR6 0]

Just as well all my gear is VR6 syncro stuff then eh!

[PhatVR6 0]

Nutter4x4 uses a haldex. and a rallye box with quaife 6 speed. I think the transfer box is off a skoda octavis 4x4 or something mad like that.

[biggerbigben 0]

like to know how he uses rallye and haldex parts in combination...?

[PhatVR6 0]

designa dubs know, but he won't tell you, you'd have to pay him to do it for you

[MelG60 0]

I have discussed the ratios on the 02M MQ350 transfer box and the Rallye 02C transfer box with a friend of mine, trying to find out if you could swap the MQ350 transfer box on the Rallye 02C.