These are not expensive cars... Just how it is I think.
That's the problem. It's not an expensive car, and yet it's packed with technology rivaling cars that cost ten times as much; in some ways beyond them.
Why? How? Where was the value?
These are not expensive cars... Just how it is I think.
Great write up. Have to say it seems quite an elegant solution. Complex (only in the way it has to be activated), yes, but so much more flexible than a mechanical lsd.
The engineers now have the ability to linearly control the amount of diff slip at any time by adding a few lines of code. You could even have a button on the dash to lock it at any time. Does it react fast enough? As fast as the anti lock system. Probably can detect slip within less than half a turn of the slipping wheel, but I don't know how fast it can pressurise the plates to react and lock.
I think we may have to change the first letter in the acronym ECU, given it no longer just controls the Engine...
I suspect the MK8 GTI and R will cost a bit more than the current generation, the base model mk8 GOLF is listed as €25,730 in Germany with the mk8 GOLF style starting at €28,735, not far off the current prices but up a little!That's the problem. It's not an expensive car, and yet it's packed with technology rivaling cars that cost ten times as much; in some ways beyond them.
Why? How? Where was the value?
That's the problem. It's not an expensive car, and yet it's packed with technology rivaling cars that cost ten times as much; in some ways beyond them.
Why? How? Where was the value?
I have to say I suspect a computer controlled diff lock is actually cheaper than a mechanical one,
Second hand VAQ units from scrap car are circa £800
Brand new Wavetrak diff circa £1,000
I don't know about the reaction times either; a fluid based diff lock requires a certain amount of slip to invoke the fluid's response,
Its called Preload, & a proper LSD can be altered using shims, or thicker/thinner oil, but LSD like the Wavetrak use bumps/cogs to overcome the majority of this "problem"
but conversely the computer controlled diff can be locked at the first sign of slippage and KEPT LOCKED until the algorithm determines it's safe to let go, which may well avoid repeated lock-release-slip cycles in a mechanical LSD.
The VAQ unit has NO preload as it called & cannot physically detect preload & has to told to active by the cars ABS sensors…& what preload it has is controlled by the cars existing XDS systems...
But more than this I suspect the key difference is the system is able to NOT lock the diff even when there IS some slippage, because the computer knows things about the car's inputs and overall trajectory that a simplistic mechanical diff cannot know. So for example you'll get no diff lock when using extreme steering angle, whereas you would in a standard limited slip diff - along with all the accompanying steering kickback that we know from other cars.
IMHO it's a smart solution, and if done right could produce all the benefits of a traditional limited slip diff and none of the downsides.
The mechanical diff will always act in a predictable & controlled manner...the VAQ unit will react differently every time around the same corner at the same speed as there will be minuet variations in the conditions that it gets its signals from the sensor on all 4 wheels via the ABS systems...
Without the existing ABS & XDS systems this VAQ unit is an 11kg dead weight...even the TCR race cars which have this unit, don't have the ABS brakes so the electronics have to rigged to allow ABS sensors to be fitted so the VAQ unit can work!
Answers in BOLD..please go & re-read & understand my thesis...
So .. why do people dislike it so much? Is it just the perceived complexity of yet another system that used to have a mechanical governor handed over to a computer algorithm instead? Is it the risk of future service costs and failure costs outside warranty? Is it the perceived unpredictability?
So .. why do people dislike it so much?
Its an 11kg dead weight.....swap out the existing open diff & fit a proper LSD......less to go wrong..& cheaper to maintain...& lighter...
I don't mind tech so long as it doesn't over complicate things..the VAQ does just that & then some...
I'd never buy a GTI PP or TCR or CS or CSS....all have the VAQ unit & rubbish brakes....
Better to buy a plain jane GTI & modify....& have a better drivers car...
Whether that's entirely justified on a car as modestly quick as a golf GTi is another matter... but it adds to the safety margins, and you know they like safety margins.
So, would I buy one?
Hell no my Corrado VR6 has no limited slip diff, traction control nor even an electric throttle body and I never missed either even when I'm spinning up both front wheels. I think that even without this particular computerised intervention most modern cars barely pass as "driver's cars".
But if I got it for free I don't think I'd complain.
11kg .. yeah it's heavier than a standard LSD probably when you add this on as an external unit. But I think it's a clever solution, and you've said yourself it has the potential to perform in an infinitely more advanced way than a tradtional LSD, and is likely to be measurably better at doing the job it's supposed to do - i.e. of controlling the distribution of torque between the front wheels to improve traction when it's required.
Whether that's entirely justified on a car as modestly quick as a golf GTi is another matter... but it adds to the safety margins, and you know they like safety margins. I suspect the ability to operate the diff with no pre-load during normal running will also reduce wear and improve miles per gallon, so for a lot of reasons I think it's actually a really neat bit of tech. Plus, from a manufacturing POV, the engine, gearbox and diff are one standard assembly and don't have to be changed regardless of whether the final vehicle has VAQ fitted or not, they just change the casing and the drive shaft to support adding it further down the production line.
So, would I buy one?
Hell no my Corrado VR6 has no limited slip diff, traction control nor even an electric throttle body and I never missed either even when I'm spinning up both front wheels. I think that even without this particular computerised intervention most modern cars barely pass as "driver's cars".
But if I got it for free I don't think I'd complain.
I'd say a traction aid is justified, here. This is certainly a car that can benefit greatly from being able to managed induced oversteer smoothly.
VW's solution has to step in afterword, but before that even happens, it takes everything away from you. There is no "feel". It can't respond instantly, either, so it has to step in early.