RS246.com Forum :: The World's #1 Audi R, S and RS Enthusiast Community

I have the opportunity to get a delivery KM only 8 speed trans from a dealer contact for extremely good money.

Does anyone know of anyone who has retrofitted one? im not to worried about the electrical side more so the physical fitment.

Not sure it's been done, go for it and report back

As above. It would be a first. The V10 mated to the zf8 would be the magic combination.

CHEQUERED wrote: ↑

Mon Jun 18, 2018 3:13 am

I have the opportunity to get a delivery KM only 8 speed trans from a dealer contact for extremely good money.

Does anyone know of anyone who has retrofitted one? im not to worried about the electrical side more so the physical fitment.

Go for it

The Q7 did get the 8 speed with the mid life face lift. The Q7 is a bigger car, but it was designed to use the ZF 6 speed, so the fitment must be similar.

This would be my dream upgrade. Talking to a few C7 owners who had upgraded from the C6 it's the best of both cars that they'd prefer to have.

I wonder how easy it is lining up the front axles to the engine/GB mounting as the shorter V8 sits further back than our V10 which, I'm guessing, would push all the alignments out. If, with the front axles lined up, the GB sits a little too far to the rear thats an easier fix than if the GB sits too close to the engine making it unfitable (same as the C5 can't fit a C6 GB).

*edit* - fixed the god awful spelling!

IanH755 wrote: ↑

Wed Jun 20, 2018 7:53 pm

I wonder how easy it is lining up the front axles to the engine/GB mounting as the shorter V8 sits further back than our V10 which, I''n guessing , would push all the alignments out. If, with the front axles lined up, the GB sits a little too far to th rear thats an easier fix than if the GB sits too close to the engine making it unfitable (same as the C5 can fit a C6 GB).

From a quick glance it looks like the box is in the same place, im getting a c7 to put on the hoist in coming days.

This quote is taken from a GM site; suggests package size is the same;

"Some of the details:
There are only five friction locking elements (three clutches, two brakes), and in any gear just two are open. Further, a low-viscosity lubricant is used (5.6 cSt vs. 7.5 cSt in the Chrysler 5-speed), which reduces spin losses. So total energy losses from drag through the transmission are under 2%.
Although there are four planetary gearsets, the total bill of material is less (467 parts vs. 471) than the ZF 6-speed with its three planetary sets. At about 91 kg (201 lb), weight of the 8HP is about 2-3 kg (4.4-6.6 lb) less than the ZF 6-speed, and the package size is the same. The 8-speed is just 3 kg (6.6 lb) heavier than Chrysler's 5-speed.
The oil pump is offset and chain-driven, so it is sized according to engineering requirements, rather than by dictates of a conventional location on a transmission main shaft. The pump itself is responsible for at least one percentage point of the fuel economy boost.
The torque converter includes an advanced damper adapted from the ZF 6-speed, which permits the converter clutch to lock up at lower speeds, even in top gear. The clutch can, however, partially unlock if necessary to reduce NVH in top gear.
The relatively tall first gear (4.71) reduces the amount of torque converter multiplication required. With the early lockup of its clutch, the converter is used almost exclusively for vehicle launch.
The transmission gearing (4.71, 3.14, 2.10, 1.67, 1.29, 1.00, 0.84, 0.67) means small ratio steps (1.50 or below) and a large overall ratio spread of 7.03 (4.71/0.67). The large spread contributes to fuel economy.

The rear axle ratios selected —2.65 for the 300 RWD, 3.06 for the AWD model—locate shift points according to brake specific fuel consumption (BSFC) maps. And further, Chrysler has 40 control maps that modify the shift patterns for different operating conditions."

Im guessing you need the mechatronics unit too to make this work for either the c7 8 speed or q7 8 speed. Also would these boxes be able to hold the torque produced by the RS6 v10t?

But the very nature of the V10 is different to the C7 V8, and hence the C6 slush box is the correct partner for the V10. Granted you can map the box to the engine but I don’t think it would be the same engine - the V10 likes to be wound up like a true old school bruiser, unlike the quicker changing and more agile V8.

Having played a bit with both (and countless other cars that we increase he gear count), i can say it would be a huge step forward.

rtd wrote: ↑

Thu Jul 12, 2018 7:34 pm

But the very nature of the V10 is different to the C7 V8, and hence the C6 slush box is the correct partner for the V10. Granted you can map the box to the engine but I don’t think it would be the same engine - the V10 likes to be wound up like a true old school bruiser, unlike the quicker changing and more agile V8.

I find this a really odd post. You're talking about these cars/engines like they are alive and have actual personalities! Are you saying that the C7 V8 is a 'more agile' engine than that of the C6 V10?! Agile how? Got more inertia, maybe it's able to kick off its heels and tip-toe around a tuner's workshop without knocking over tools? I'd have thought that 'an old-school bruiser' would be better with many shorter gears keeping it in the upper rev range... where it will be "breathing heavier" (sorry, I'm just trying to give this engine more of a personality).

Both engines make similar power out of the box and again once remapped, ne? Doesn't the C7 quarter quicker than the C6, is this down to the 'box, weight or a combination?
Anyways, regardless of the above, let me put this scenario to you and I'd be very interested in your retort; let's just say that Audi was building the C6 RS6 today and the ZF8 was available, would the engineers be like...
Fritz: "Hey Hans, check out this new Übertragung, it is faster, stronger, lighter and it has 8 gears. Let's use it in our C6 RS6"
Hans: "Nah, fcuk that ZF8 'box off, we'll be using this heavier, slower shifting, 6 speed Übertragung because it is the correct partner to the V10"
Fritz: "Hey Hans, you're not allowed to come to work drunk, please get out"

I think this ZF8 swap into the C6 is going to be awesome.

What I was trying to say was that the way the V10 has been set up in the C6 suits the box which was also fitted.

I’m not that technically minded so if the C7 box can make the engine behave differently then great .


Sent from my iPhone using Tapatalk

Can't believe this thread is nearly three years old, and there's little progress in replacing the 6 speed ZF gearbox with the 8 speed.

So to those who have been saying this forum has been quiet of late, I'll try to liven it up and have a go at fitting the 8 speed box.

I have a feeling that you're going to need some patience, though.

Nick

Good luck and looking forward to the progress updates.


Sent from my iPhone using Tapatalk