[RugbyBro]

Originally Posted by Hit_Apex

No way. I believe it is an Xtrac sequential box.

It’s a ZF box but I’m unsure as to whether it is the ZF8 with 8 disabled (like in the Supra GT4) or if it is one of their DCTs. BMW’s literature only states ZF 7 speed. The xtrac is used on the GT3 car though

[Hit_Apex]

Originally Posted by RugbyBro

It’s a ZF box but I’m unsure as to whether it is the ZF8 with 8 disabled (like in the Supra GT4) or if it is one of their DCTs. BMW’s literature only states ZF 7 speed. The xtrac is used on the GT3 car though

Gotcha, the GT4 may be different than the GT3. The ZF tune in my CSL is impressive. Not sure how the GT3/4 rules apply but it would not surprise me if the G82 ZF box is just as good as the F82 DCT in a track setting.

[RugbyBro]

Originally Posted by Hit_Apex

Gotcha, the GT4 may be different than the GT3. The ZF tune in my CSL is impressive. Not sure how the GT3/4 rules apply but it would not surprise me if the G82 ZF box is just as good as the F82 DCT in a track setting.

That's really the question here - is this a ZF8 w/ 8th disabled, because it looks like the transmission is DCT/Sequential level of responsiveness. Most telling on the rev-matched downshifts (from what I've seen, even the CSL doesn't have those quite at DCT crispness). So it stands to reason that if this is a ZF8, there is programming that exists which could get you there. Whether you would need it is a different question altogether as ZF8 is good on track. But just interested since i've never seen a ZF8 this crisp; even the Supra GT4 slurs its downshifts a bit.

[vetteflier]

Originally Posted by 02M3ForMe

ASD; I hate the idea but love the implementation.

After living with a straight-piped NA mid-engine V8 that revs to 9000RPM and pumps out 130dB at full throttle, pretty much the pinnacle of street car exhaust sound inside and out, I must concede that I enjoy a well-done simulated sound experience without all the headaches (literally and figuratively) that come with aftermarket exhaust hardware. Fumes, neighbors, CEL, smog checks, police attention, warranty.

Doing it “for real” is obviously better, but I’m totally OK with ASD. For now, at least.

I like it. With the new AWE Track, it enhances it further--particularly burbles that you don't hear well in the car with the windows closed. . Performance notwithstanding, the M4 is a luxury car and has sound insulation to match. You really can't hear the actual exhaust like in a Mustang, for example. The sound is pleasing and befits 550 or so HP.

[Hit_Apex]

Originally Posted by RugbyBro

It’s a ZF box but I’m unsure as to whether it is the ZF8 with 8 disabled (like in the Supra GT4) or if it is one of their DCTs. BMW’s literature only states ZF 7 speed. The xtrac is used on the GT3 car though

You right. Engineer mentions around 23:45 that GT4 uses Steptronic, but doesn't clarify 7/8.

[RugbyBro]

Originally Posted by Hit_Apex

You right. Engineer mentions around 23:45 that GT4 uses Steptronic, but doesn't clarify 7/8.

Well he does say it's the same 8 speed steptronic so I assume that 8th is just disabled and it has much more aggressive shift logic. That would make sense considering the race cars don't have the same longevity requirements as the street cars.

[RTC3000]

Originally Posted by Hit_Apex

Gotcha, the GT4 may be different than the GT3. The ZF tune in my CSL is impressive. Not sure how the GT3/4 rules apply but it would not surprise me if the G82 ZF box is just as good as the F82 DCT in a track setting.

BMW states that the ZF auto in the M3 shifts faster than ANY DCT they ever used in ANY BMW car.

[Hit_Apex]

Originally Posted by RTC3000

BMW states that the ZF auto in the M3 shifts faster than ANY DCT they ever used in ANY BMW car.

I believe it. I haven’t driven a regular G8x recently but in CSL trim the ZF is unlike any auto I’ve experienced. Even vs the ZF in my F95 it is night and day. Shifts are very fast and crisp in S2. S3 is almost overdone the way it jerks into the next gear.

[HudsonHornett]

Originally Posted by RTC3000

BMW states that the ZF auto in the M3 shifts faster than ANY DCT they ever used in ANY BMW car.

Out of interest, where is this stated?

[RugbyBro]

Originally Posted by HudsonHornett

Out of interest, where is this stated?

In a CSL marketing video though very little context is given

[RTC3000]

Originally Posted by RugbyBro

In a CSL marketing video though very little context is given

What context do you need?

The truth is: There is a reason why many manufacturers use the ZF auto, it is an excellent product.

[HudsonHornett]

Originally Posted by RugbyBro

In a CSL marketing video though very little context is given

Interesting, the only reason I ask is I wonder how much the “DCT is much faster” brigade are actually talking nonsense or is basically an “emperors new clothes” effect.

I remember reading years ago that somebody had worked out that if a gearchange took less than 0.2s, then to all intents and purposes this would be perceived as instantaneous by any human. I think it was Ferrari who had said this in one of their press releases.

[lovesm3s]

Originally Posted by Hit_Apex

I believe it. I haven’t driven a regular G8x recently but in CSL trim the ZF is unlike any auto I’ve experienced. Even vs the ZF in my F95 it is night and day. Shifts are very fast and crisp in S2. S3 is almost overdone the way it jerks into the next gear.

I agree. I was wondering if we can somehow code the F95 ZF to shift the same way or at least quicker. I didn't think it was slow until I drove the CSL

[RugbyBro]

Originally Posted by HudsonHornett

Interesting, the only reason I ask is I wonder how much the “DCT is much faster” brigade are actually talking nonsense or is basically an “emperors new clothes” effect.

I remember reading years ago that somebody had worked out that if a gearchange took less than 0.2s, then to all intents and purposes this would be perceived as instantaneous by any human. I think it was Ferrari who had said this in one of their press releases.

The actual action of change is comparable on both ZF and DCT, any difference in objective shift speed is imperceptible. The primary issue is typically the responsiveness or lead up to the change. Upshifts are DCT fast but without the intense physical response, however, downshifts are with ZF is typically where you feel a “lack of response”. There are mechanical reasons for this (planetary clutches vs DCT clutches). The shift itself is quick but the response from pulling the paddle to getting a rev matched downshift is not as crisp/quick. Granted I haven’t driven the CSL but have driven all manner of ZF8 over many manufacturers including the current generation of M-Steptronic - none of them get the downshifts as crisp. G82 GT4 is the first time I’ve seen a ZF act so responsively - you can see and hear the shifting just thru the video.

But really does any of this matter? In terms of performance, no. ZF is a lightning quick transmission and it’s cheap to implement across the platform w/ xDrive (which is the real reason BMW uses it). It’s more of a feel & theater thing. If that GT4 video truly is the same ZF from the street car, mark me as a believer. Though I doubt anyone would be able to get their hands on that programming, no one has cracked the nut on the F82 GT4 software. Plus it probably wreaks havoc on a street driven transmission that needs to last 100-200k miles.