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BMW DCT Gearbox

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Old 10-04-2015, 01:46 PM
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Default BMW DCT Gearbox

This just popped up here in the UK.

A couple of UK companies working together, initially installed on a Toyota Supra, but clearly the technology could be applied to any rwd vehicle with custom flywheel/bellhousing adaptors etc.

Overall if you can source a lot of the parts 2nd hand it would be a pretty cost effective transmission for anyone wanting that sort of thing. It would be superb for any sort of race track, road course, etc etc
Even for drag applications it would work very well as long as you're within the abilities of the clutches etc.
An added bonus is getting a superb engine control ecu at the same time via the Syvecs

http://us7.campaign-archive2.com/?u=...8&e=3230f6c490

https://www.youtube.com/watch?v=LdLi...ature=youtu.be

In brief

This is a world first bringing the Supra bang up to date using the latest transmission technology. After a lot of work we've fitted the amazing Getrag 7 speed DCT gearbox as used in the latest BMW M3 and M6, this is the first time a dual clutch transmission has been fitted to a Supra anywhere in the world.

The DCT (dual clutch transmission) gearboxes have been steadily taking over from the manual gearboxes over the years, most of the supercar manufacturers use them in their cars these days, Ferrari, Lamborghini, Porsche, McLaren, etc all use DCT gearboxes. And are now being used in main stream cars too like Audi, VW, Renault, etc.

The benefits of the DCT's are:

1. Super fast gearchanges, the 7 speed Getrag gearbox we are using changes gear in 80 milliseconds. This in turn massively reduces acceleration times improving the cars performance. The DCT version of the M3 is 0.2 seconds faster from 0-60 over the manual version, thats just one gearchange. Imagine if you're on a race track,how much faster it would be on a lap.

2. Manual and auto modes. So if you want to just poodle around in auto mode it drives as smooth as a normal automatic. Then flick the gearlever to the right and you have a sequential gearbox or you can use the flappy paddles on the steering wheel.

3. Throttle blipping on downshifts, this sounds amazing!

4. Better fuel economy and less power loss than any auto gearbox as its direct drive, no power sapping torque converter.

5. Launch control, this can't be done on auto cars.

6. Clutches are immersed in fluid so don't wear as fast as normal clutches.

We've managed this feat by using a Syvecs S6Plus ecu to control the engine and gearbox, with the gearbox control exclusive to Whifbitz, you can't buy this conversion anywhere else. A lot of time and money has been spent making the gearbox work with the Syvecs ecu, all credit must go to Ryan at Syvecs for this part, he's done a fantastic job with the gearbox driving and working like stock.

The gearbox is attached to the engine with a custom made billet flywheel and billet aluminium adaptor plate. The conversion comes with a new mount for the gearbox which allows it to bolt onto the stock location and uses a new propshaft flange to bolt directly to a stock Supra propshaft too.

We've also fitted a drive by wire throttle using a Bosch item that's normally found on a Porsche 996 turbo. This bolts directly to the stock manifold with a custom made billet aluminium adaptor. The throttle pedal has to be changed to a drive by wire type too, all available as part of the kit.

The BMW M3 gearlever has been fitted to control all the different modes, which looks and feels amazing installed in the Supra. This is used to select between auto and manual modes, reverse and manual gear changes. This also has a separate button called Drivelogic which allows 6 adjustments on the shift speed from slow to fast, from soft to hard shifting depending on your mood.

We've also fitted carbon paddle shifts to the steering wheel so you never have to take your hands off the wheel to change gear, flick the right paddle to change up and the left one to change down.
Maybe not for everyone of course, but impressed that someone thought of the idea, and actually carried it through !
Old 10-06-2015, 01:51 PM
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I wouldn't run one because I like my 3rd pedal too much, but I'd be really interested to watch someone get this working on an F-body, probably a little pricey for the average 4th gen owner though.
Old 10-06-2015, 04:42 PM
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There would be very small market, but then for all specialised stuff it's small.

But for anyone considering a proper sequential box, but who also wanted something nice for the road too, this sort of thing offers the best of both worlds.
Old 10-06-2015, 09:32 PM
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Yes, A LOT less maintenance/parts replacement than a street driven, true dog ringed, crashbox, sequential (also about 1/1000th the gear scream), but it still is not as 'cool', and the conversion would probably cost you about half way to a real sequential box anyway.
Old 10-07-2015, 03:47 AM
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Originally Posted by dailydriver
Yes, A LOT less maintenance/parts replacement than a street driven, true dog ringed, crashbox, sequential (also about 1/1000th the gear scream), but it still is not as 'cool', and the conversion would probably cost you about half way to a real sequential box anyway.
Price seems cheaper if many parts can be sourced used, faster smoother shifts plus as said, you get a proper engine control ecu at the same time. I'd say a DCT would be far cooler than any mechanical sequential

You could get a proper mechanical sequential for around US$12k plus some fitting costs.

Overall, probably not a huge difference in price, except the sequential price is for trans only, not a complete trans/clutch/engine control setup.
Old 10-08-2015, 08:49 PM
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Good general info, but light on tech...Will it live behind a 600 hp LS engine?

Andrew
Old 10-09-2015, 03:36 AM
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It's their first conversion, so no doubt there will be a lot of stuff kept under wraps as I guess certainly in the UK at least they'l be trying to keep it all exclusive to themselves. No sense doing loads of R&D for something like that, just to give it all away.

BMW offer their normal V10 M5 wit around 500hp, so presumably that gearbox would handle 600hp all day long and well into the night....for several years.
I dont know and they arent totally specific about which trans they're using though. But I'm sure the control strategies for one DCT box wouldnt be too far removed from another.

As said, it wouldnt be for everyone, but I think the fact someone has done the conversion and got it all working is superb. It can only open up more options for everyone, I'm just very surprised at how cheap they seem to say the used parts are.
Old 10-12-2015, 01:12 PM
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I would be very interested but my trans tunnel is kinda small. T-56 and dual 3" exh leaves very little room to spare.
Old 10-12-2015, 01:33 PM
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The hardware integration would seem to be straightforward. I see the controls being the most difficult to implement.

Doing a quick search those transmissions seem to be readily available and are fairly reasonable priced. Looks like the pump is a critical component and needs to be sourced with the transmission.

Andrew
Old 10-12-2015, 07:32 PM
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Point by point comparison to an 8L90, anyone?
Old 10-12-2015, 07:41 PM
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I'm sure BMW has improved their sequential box since I drove a 2008 M5. Could not stand that gearbox, it lurched/bucked, etc so bad in traffic that I thought a 15 year old girl on her first lesson driving stick was working the clutch. Also in that application behind the V10 they are extremely failure-prone.

The 6 speed box in the Supra is a total beast of a transmission, you can double or triple the horsepower on those cars and not break it.
Old 10-14-2015, 04:36 PM
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Originally Posted by AronZ28
The 6 speed box in the Supra is a total beast of a transmission, you can double or triple the horsepower on those cars and not break it.
That was a Getrag box, correct??
Old 10-15-2015, 04:31 AM
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Originally Posted by dailydriver
That was a Getrag box, correct??
6 speed V160 was a Getrag based unit.
Old 10-15-2015, 11:12 AM
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The ratios I've found are a bit odd. The M3 seems to have a 1:1 7th gear and the M5 v10 is something like a .67:1 7th.

BMW M3 DCT
Gear / Ratio / Max Speed / RPM drop on upshift
1st 4.780 44
2nd 2.933 71 5200
3rd 2.153 97 6200
4th 1.678 124 6500
5th 1.390 150 6900
6th 1.203 173 7300
7th 1.000 208 7000
Final Ratio 3.154
Redline 8400

BMW M5/M6 DCT
Gear / Ratio / Max Speed / RPM drop on upshift
1st 4.81 38
2nd 2.59 72 3900
3rd 1.7 108 4750
4th 1.28 144 5400
5th 1.0 184 5700
6th .84 219 6000
7th .67 275 5800
Final Ratio 3.150
Redline 7200

Look at that 1st - 2nd and 2nd to 3rd RPM drop in the M5.... Our V8's would need a 3.08 or taller..... Supposedly a clutch pack swap away from supporting 1000hp.
Old 10-15-2015, 11:21 AM
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A lot of BMW's are odd, they use a 1:1 top with a very tall diff ratio.

They've done that for years. No idea why when most other inline boxes dont do it.
Old 10-15-2015, 11:32 AM
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Originally Posted by stevieturbo
A lot of BMW's are odd, they use a 1:1 top with a very tall diff ratio.

They've done that for years. No idea why when most other inline boxes dont do it.
I suspect this is done to slow down the driveshaft speed at high vehicle speeds.

Andrew
Old 10-15-2015, 12:23 PM
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Absolutely. Our speed limits are 75mph at most IIRC. Autobahn is a different ballgame.
Old 10-16-2015, 12:02 PM
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The DCT trans even behind a mildly modified e90 V8 M3 gets heat soaked as progressively the shifts get slower when road racing. The first few laps its amazing... then starts going to sh*t. My buddy has one and that is his main complaint... aside from the car weighing over 3600lbs.

Anything associated with Syvecs (Skyline GTR) is big $ stuff. The DCT trans is still the achilles heel in a BMW when they get higher mileage.

Last edited by gnx7; 10-16-2015 at 12:10 PM.
Old 10-16-2015, 12:21 PM
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The new S6Plus brings the price of the GTR's kits down a bit, previously they needed the S8.
The base S6 that I'm using is very good value, although isnt as nice as it could be for a V8. S6Plus would cover that though and I'll be upgrading eventually anyway or moving to the S8
But almost 2 years with the S6 so far and no complaints at all.

It still isnt cheap, but then you get what you pay for. They really are superb ecus although not really for an average DIY'er
Old 10-16-2015, 06:01 PM
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Originally Posted by gnx7
The DCT trans even behind a mildly modified e90 V8 M3 gets heat soaked as progressively the shifts get slower when road racing. The first few laps its amazing... then starts going to sh*t. My buddy has one and that is his main complaint... aside from the car weighing over 3600lbs.
Have any of their owners tried a pump/cooler/fan set up on these, or do they come stock with something like this already??


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