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Quaife ATB and TVC: Mystery solved

PCA-1

Senior Member
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Le Sueur
#1
I had the opportunity to ask an authority about the interaction of the Quaife and TVC. This is coming from an ST owner installing a Quaife ATB differential in a few months, who is an automotive engineer since 2000 and is currently the Technical Project Manager at Robert Bosch LLC for Chassis Control Active Safety - North America :

What is it that has you wanting the Quaife ATB diff and do you have concerns about the interaction of the TVC and the Quaife?

No, I?ve no concerns. The Quaife (or other ATB) and the TVC (e-diff) are complimentary. The Quaife active wheel (driveshaft) torque biasing is ?faster? and offers better granularity, in that it is not dependent on active brake pressure increases/decreases at the wheelends. Unfortunately, brake applications generate heat, so with (particularly) track use (frequent TVC activations), heat is being put into the brakes, both on vehicle deceleration (under braking) AND acceleration. Not ideal. And, as the brake temperature changes and the rotor/brake pad clearance (retraction/knockback) changes, TVB performance varies. Actually, the combination of an ATB and TVC is beneficial, as the ATB cannot bias torque in the case where one wheel has low/zero normal force (axle torque), as is the case with weight transfer causing a lifted or near-lifted wheel (or riding curbs / dropping a wheel). In this case, TVB brakes the unloaded wheel, permitting again torque transfer via the ATB. The Wavetrac ATB also functions in this way, by generating internal friction to ?brake? the unloaded driveshaft. For that reason, the Wavetrac is a great choice, but (so far) no FST application and the potential added maintenance/complication of changing bias ratio friction material. Ford SVT chose the Quaife for the ST-R. It was a well-thought choice and reason enough to trust the application.


Is the Quaife worth it for a street car?

Is it worth it? That is, of course, for each individual to determine. It is certainly my primary interest in tracking the car, that makes it quite easy to rationalize.

Is it beneficial for a street car? In my opinion, yes. The vehicle is more driveable/ more ?predictable?, due to better torque biasing response and lack of brake temperature, caliper piston retraction/knockback influence.

Is it a ?must have? for solely street-driven vehicle? Honestly, my answer would be no. If I only drove on public roads, it would be hard to justify. It?s just too difficult (and typically illegal) to use the vehicle hard enough on the street to substantially benefit.
________________________________________________________________________________________
Straight from the horses mouth. I found the discussion on TVB, Torque Vectoring by Braking, to be the most in depth information on this topic I have read.

It has been clear from the start this upgrade is not for everyone and a very select few actually do this upgrade, which historically has always been the case. Now, at least we know what the benefits of the Quaife are and the performance issue of TVB.

PCA is a Quaife dealer as well as a Wavetrac dealer. There is a Wavetrac Focus ST unit expected out in a few months. No exact ETA as there has not been reported vehicle testing. Zero activity for the FiST.
 


rodmoe

5000 Post Club
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#2
Nice Thanks for the Input and time it took to aquire this feedback.. Its about what I figured and about where I am at with my thoughts on lsd and TVC from what I gleemed from the FoST install I followed on another board...
Now if Ford US would only price the bearings I could move forward in my planning and getting all the parts for the install lol ...
 


Colin1337

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#3
Awesome read. I think in a few years when this tiny turbo doesn't do it for me any more, and I'm craving something more, I'll def be getting one of these.
 


Perry

Active member
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Leawood
#4
Very interesting. Makes me want to need the Quaife ATB, or similar. I'd certainly love to drive one (hard) and feel the difference (esp. with long runs).
 


RAAMaudio

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Carson City
#5
Quaife review, track, street, cold, wet, dusty, sandy, etc.....conditions.

I had to post this as just did my first "hooning" around on a back road nobody ever goes on.

I love this ATB, it is nearly seamless, I can hardly tell it is there.

I have far more traction than expected wet, dirty, sandy back roads, so much so it makes me think about making my car a rally car at times:)

Track, road race, jumping the curbs, lap after lap, never once felt the unit unlock while a wheel, sometimes two, sometimes felt like more, were off the ground.

Torque steer, barely any and only when in full boost and spinning a bit but it still pulls really hard even on a wet road in second gear, what little there is I kind of like, makes things more interesting.

Launch, I do not do that much, too hard on parts I need to last a long time, it hooks and goes even if spinning the tires a bit though.

I have owned and used on the street and track and back roads quite a few LSD units.
Phantom Grip, Matrix and Scion tC(not an LSD but when nothing else is made, pretty darn good and feels like the Quaife)
Gear Vendors, ATB, Tacoma, lots of off road use, as long as the wheels on the ground, it would climb until I ran out of power.
Getrag, I assume, Vettes, BMWs, whatever the factory diffs used, stock, not so great, full race or highly modded street use, great, had many
Dana, or whatever they used in the diesel trucks I have owned
OS Giken, $$$$$, the best of the best clutch type, 20 disk, neary as smooth as the Quaife, does not unlock with a wheel in the air.
And more.

I like the Quaife the best of them all in this particular application I would not get a different type of LSD.

If you are really serious about your car this is one must have mod in my book, power is great, being able to fully use it even better:)

Thanks to PCA for making them available here and Rodmoe for being the FiST pioneer:)
 


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