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Re: 7 Speed DCT Vs 8 Speed TC Gearbox

Posted: Thu Apr 21, 2022 12:47 pm
by JFDIT
@Oldie, your argument is senseless. DCT's are more efficient than Slush Boxes. So imagine what a super efficient driver such as yourself would have achieved with one.

Re: 7 Speed DCT Vs 8 Speed TC Gearbox

Posted: Thu Apr 21, 2022 1:12 pm
by Deleted User 3629
@JFDIT - driven a Q3 2.0-TFSI DSG for years prior and it was far less efficient than a B4 TC XC40 :o - in Lab conditions the DCT maybe more efficient, but that efficiency is far too narrow to be of any significance driven in real world conditions, as there are too many variables - and feel should anyone apply any real sense to that argument would surely agree ;)

Re: 7 Speed DCT Vs 8 Speed TC Gearbox

Posted: Thu Apr 21, 2022 1:21 pm
by JFDIT
@Oldie, as we previously established, you have no experience of the XC40 DCT vs TC.
Thanks to everyone that has replying with interesting insights as to what I may expect when I get one.

Re: 7 Speed DCT Vs 8 Speed TC Gearbox

Posted: Thu Apr 21, 2022 1:33 pm
by Deleted User 3629
@JFDIT - oh, sorry for the differing points of view - its because you are having a DCT you want to read positive views - understand and I would be the same - I am sure it will be fine and you will reap the benefit of the extra available MPG - might take a many years to buy a drink with it, but a saving is a saving, oh and watch out for speed traps with that lower 0.60 performance :lol:

Re: 7 Speed DCT Vs 8 Speed TC Gearbox

Posted: Thu Apr 21, 2022 1:37 pm
by Richard_Hants2
Personally I couldnt say whether gearbox type A is better than gearbox type B in a certain model of car unless I had driven both of them.

Car manufacturers have been set EU fleet-wide CO2 emission performance standards for new passenger cars and vans and these include financial penalties for excess emissions.

The makes the relatively small efficiency inprovements made by introducing such things as mild hybrid powerplants and DCT gearboxes to existing models really important when measured per car sold.

From my perspective the fact that Volvo waited until they had introduced hybrid powerplants on the XC40 before changing to a DCT gearbox is a good thing as the battery assistance removes the hesitation which was apparent in my previous 3 VW cars all of which were fitted with DCT gearboxes.

Re: 7 Speed DCT Vs 8 Speed TC Gearbox

Posted: Thu Apr 21, 2022 1:52 pm
by Deleted User 3629
Volvo's DCT is an oil-filled double clutch system - the 7-speed DSG of VW is a dry-clutch, and dry-clutch systems have had their history of problems, mainly due to overheating, and being a dry-clutch may have also contributed to the sizable hesitation?

Re: 7 Speed DCT Vs 8 Speed TC Gearbox

Posted: Thu Apr 21, 2022 5:17 pm
by Felindre
Oldie wrote: Thu Apr 21, 2022 1:52 pm Volvo's DCT is an oil-filled double clutch system - the 7-speed DSG of VW is a dry-clutch, and dry-clutch systems have had their history of problems, mainly due to overheating, and being a dry-clutch may have also contributed to the sizable hesitation?
Don't generalise, only some if the smaller boxes are dry, DQ200 and DQ250. My tiguan had the DQ500 high torque box and this was wet clutch.

Re: 7 Speed DCT Vs 8 Speed TC Gearbox

Posted: Thu Apr 21, 2022 5:52 pm
by Deleted User 3629
Wow, its a forum not a tech site Felindre :o - generalising is what we "generally" do - thought the 7-speed DSG was a dry-clutch and the 6-speed DSG was a wet clutch - how very dare I generalise :roll:

Re: 7 Speed DCT Vs 8 Speed TC Gearbox

Posted: Thu Apr 21, 2022 6:55 pm
by Deleted User 3629
And for those who require we must not generalise :roll: . The 7-speed version of the DSG gearbox referred to under the post as a dry clutch system has a few different names including, 0AM, 0CW, 7DSG and DQ200, it was brought in to supercede the 6-speed “DQ250” DSG unit. The DQ500 transmission is also a 7-speed but not to be confused with the dry-clutch as it is a wet-clutch that is mounted transverse for larger and high torque output vehicles rated up to 600 Nm :P

Re: 7 Speed DCT Vs 8 Speed TC Gearbox

Posted: Thu Apr 21, 2022 8:39 pm
by Felindre
That's better! It's just you said ALL the VW's were dry clutch, and it ain't necessarily so. P.S. They're all transverse. As the one in out T-Cross.