Haldex Performance Part


A number of aftermarket companies were selling an upgraded Haldex ECU to allow you to fix the drivetrain at 50/50 split.

I heard that the were stopped by Haldex who brought out there own unit which is still ecu controlled but being approved has all the safety features with hopefully no concerns of reliability from Haldex.

I believe from the EIP info below they helped with some development. I'm not going repeat what's already available online, check out the links below.


I got mine with some help from www.greedspeed.com for less than £500, but you need friends across the pond for that, I bought US because Awesome had this up for £699+vat which I though was a mad price compared to the US.

www.awesome-gti.com were doing it for £499 +vat when this was written, I guess someone noticed the unreasonable price differential.


You get a Haldex ecu, some new bolts, gasket and some fitting instructions.

More information on and via Steve Schwings Site http://public.fotki.com/ttschwing/haldex_mods/
(Many thanks Steve for all your background information and help)

Its a bit disappointing when you open the box and for your money you get a teeny weeny little box about the size of a CD, but that opinion changes when you install it! :o)


I'm not going to repeat what has already been documented quite well but will offer tips.

Install Instructions

It is possible to do with a pair of Jacks but a lot easier if you can borrow a ramp from someone.
Allow at least 1 hour to fiddle around to fit it, with a ramp! :o)
It is straight forward however its a fiddly job as the access is very tight and restricted.
You will lose approx 1 tablespoon of Haldex Oil, but not enough to worry about.

You will need:-

A rubber band (and something to cut it with),
Some Wire/String
(when you pull a connecter over the haldex, tie to string so you can pull the new one back over)
4mm hex drivers (one longer that average),
small socket set 1/4inch,
1/4 drivers and extensions,
plus a swivel end as you will have to undo/do-up a 4mm allen bolt at approx 45 degree angle,
Also a low rating Torque Wrench, 6nm needed. (Borrowing a garage ramp helps as they usually have a torque wrench.)


Haldex have already written about the "PREX" software here

HALDEX Information on the benefits

What it does is changes the characteristics of the Haldex, in simple terms, it normally waits for a difference in wheel rotation from front to rear before engaging the rear wheels. The Haldex with PREX listens to the rate of throttle depression and engages the Haldex sooner with more torque transfer to the rear that the standard Haldex software.



EIP Tuning is a North American distributor for Haldex Performance Parts. Haldex is an OEM supplier of AWD components for VW & Audi as well as other auto manufacturers. Haldex is offering unique upgrades for both VW R32 and Audi TT AWD systems.

The new Haldex Performance Controller is a total replacement of the mechanical and electronic controller that directly affects how the RWD portion of the AWD system works and how aggressively it reacts under acceleration, cornering and braking.

EIP is currently testing this entirely new Haldex Performance design which is used by the VW R32, Audi TT, and other Haldex controlled AWD applications. This new product is a complete self contained unit that encloses both the Haldex ECU and the Haldex Valve Control Assembly. This new performance upgrade is a full aluminum assembly with the latest Haldex performance ECU software, and features an upgraded Primary Valve controller.

The Primary Control Valve Assembly:
This upgrade increases torque transmission at acceleration providing consistent performance with increased over-steer. The torque-transmission is influenced by how fast you press the accelerator down. The Haldex system can transmit torque before the engine delivers torque. At greater speeds the torque will decrease enabling less over-steer and safer driving properties.

The advantages of this HPP upgrade are itís ability to predict the onset of torque much like the PreX which is for their newer hardware but even more aggressively. This upgrade takes into account the TPS signal more so than the oem software and therefore can proactively begin applying power to the rwd clutch packs before wheel spin begins. As power is increased, more power lock occurs in the rwd unit until full lock is achieved. To summarize, the new HPP is more aggressive with how it transfers power and does so much more proactively than the oem system. This is ideal for autocross, road racing, and street driving as well as enhancements to poor weather driving.

Haldex Integration:
All OEM security systems are retained and work as originally designed. The ABS braking system or engagement of the ESP is not disturbed with the upgraded Haldex system. Economy at highway cruise conditions is retained by still enabling the transfer of primary power to the front wheels when cruising.

The HPP kit comes complete with the plugs (two) that fit right into the OEM connectors, replacement bolts and a gasket for a simple clean installation. No additional fluid is required. Completely Plug -N- Play.


I have been running this for 3 weeks now and wanted to get all weather conditions before writing.
(Remember I am running Koni Coilovers, R32 ARBS, Forge Tie Bars.)

After fitting and driving off I initially thought "hmmmm, so whats different? not a lot!

However that changed quite quickly after a few more mile of driving. Remember this is meant to behave similarly to the oem when driving normally and it does, but is actually better in normal driving as well purely from the higher torque transfer over the standard software.

I advise you to pay attention to your cars handling before fitting as you will appreciate what its done a lot more. 

Standing starts don't raise the nose as much and you feel the car is neutral on take off, seems to stay flat like adding an anti roll bar between front and rear wheels.

One noticeable test is staying in say third gear at 3000 revs and stabbing the throttle every now and then, the car would lift and drop the nose. This is much less with the Haldex PP, as there is no wait in torque transfer its there and the whole car is shoved forward by 4 wheels instead of 2+2

Normal driving is so much more a pleasure and you kind of don't notice what used to happen but now the car feels flat and level when pulling off, Its just a pleasure to drive.

Coming out of bends flooring it is fantastic, this mod takes more under steer away although you have to have the bottle to keep planted.

I'm still too scared to simply push on through a bend on the roads as its better to play on track, but have had a play when and where its been safe to do so. When you are stamping on it, she doesn't break away or go into an understeer nose dive, She has a 4 wheel drift that feels like you are very much still in control with power application.

Grand Tourismo feelings come to mind! :o)

Bends in the wet exaggerate things but she feels very much more sure footed, its a mod that has is subtlety in certain conditions that still make the 4wd much more enjoyable, but whatever the condition a little enthusiasm in the bends feels much more rewarding. It really feels like someone is tugging on all 4 corners in how the car behaves.

I don't think anyone will be disappointed whatever your state of modification, it will reward the more enthusiastic driver as well as your normal driving pleasure.

Just remember 4 Wheel drive is about traction in a straight line, it doesn't mean you can defy the laws of physics.
Improving the 4WD delivery means you get an illusion of cornering better because the rear drive is doing more to help the front drive. If you go sideways, 4wd, 2wd, no wheel drive....its all the same, be careful.

This is a hard mod to explain but it has made a great improvement and I feel I have a proper 4 wheel drive car with the benefits that Haldex envisaged for this system.

Hope this helps.