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Ok, I'm here to answer a multitude of questions in regards to what this is, why it works and whatever else you'd like to throw my way. We'll start with the factory differential mounting strategy-for whatever reasons, bmw opted to utilize a 3 point mounting system on this car.Any understanding of torsional loading will quickly unveil the faults of the design, perhaps it isn't as apparent on factory or lightly modified cars,but when a supercharger or added displacement,etc falls into the mix, the weakness of this design becomes apparent-especially with the dsc off. I was approached by a local s/c M3 owner preceding the OP's install do devise an M variant after the success of the N54 version. Balancing between effectiveness and low nvh was not immediate, I ended up having to utilize the solid forward diff mounts (same as an N54 car) which are billet aluminum. Originally,the brace was solid mount to the subframe, but excessive nvh became apparent, so the design was altered. Two brands of polyurethane were used before deciding to have a softer formulation made via Energy suspension, which is now in use. The way it works is rather simple, it essentially mounts to the differential via 4 of the cover screws and then affixes to the subframe via a custom insert nut and sleeve system in the drain holes located just inside of the rear subframe to body mounts. It does it's job by restricting the differential from rotational movement under load. Wheel hop is created by a reactive effect of a multitude of areas. the first being the tires as the fight for grip-all this rotational loading is applied back to the differential-which is receiving steady power in via the propeller shaft. The resulted reaction is a push-pull effect which is where the 3-point system shows it's weakness. The passenger side will then bounce up and down creating a tramping effect, which transfers back to the wheels and the suspension will amplify this motion via the springs. that's how wheel hop works, and why it's prevalent to some with higher output and more aggresive driving styles. It's interesting to note that these effects can be tamed slightly via stiffer suspensions/ coil-overs on some cars, alignment plays a role-but none of those solutions solve the core of the issue, they're simply band-aid approaches. If you drive your car in a way that hop doesn't present itself then obviously this product isn't for you, I'm not here to argue why every M3 needs one, because they don't. Those of you who do experience these issues are whom the product was intended for,plain and simple. Results so far have been very positive, I understand we live in a suspicious and proof thirsty world(I'm probably worse in regards to skepticism than most of you, so I can understand)
As far as shift feel goes, the same benefits apply to DCT or MT6 cars. Restriction of unwanted movement results in tighter upshifts and stability regardless of transmission type. As far as track testing is concerned, It's winter here in PA so that's currently impossible although proper before/after documentation will come in the spring.If there's any specific data anyone would like to see, feel free to ask.
The brace shown in the OP's pic is one of 3 variants, it is the "plate" style. Next in line is the 4130 chromoly tubular version, which is lighter obviously. I'm currently working on a limited run of Titanium braces which will be a numbered production run. These are all currently made to order, I will post pictures of the other versions as they are made, which will be within the next week or so. Any other questions you may have, feel free to ask me via post/PM. I will inquire into vendor fees before discussing sales here.
Thanks Rick@Defiv Fabrication.
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