Dual Clutch Transmission (DCT)

[TrendSetter]

what is the expected rough cost of doing this conversion on a ls swapped older gm ?

[loudandproud]

what is the expected rough cost of doing this conversion on a ls swapped older gm ?

Depends on the route you take and what computer your car already has. Ideally you want to be able to command a throttle blip and a shift cut signal. If you are DBW on a factory computer, the throttle blip is tricky. The shift cut is simply an ingnition cut.

If you can get that handled, this is what I'll have in it.

Transmission (GS36D7SG): $750-1350
DKGEcu Controller: $1100
DKGEcu Harness: $550
Domiworks Transmission adapter and hub: $1050
Transmission Parking Lockout: $50
Transmission Cooler adapter: $70
Transmission Cooler and lines: $300
BMW Yoke to 1350 adapter: $250
Transmission fluid and Filters: $350


Totaled up: $5000 ish with the factory clutches (Good to like 750 fw ftlbs).

Spec R clutches are good to like 950 ftlbs, but theyre $2600 a set.

It basically costs the same as a T56 Magnum swap with similiar power holding ability stock.
Spec R it costs about the same as a built, faceplates T56 magnum swap, and will hold about the same power.

The difference is, when you blow up you built T56 magnum, you need another $2500 rebuild. When you blow up one of these, you rip it out and put another $750 trans and fluid in it.

[loudandproud]

This is the goal of it all...

[TrendSetter]

i went the ar5 route on my tt5.3 wagon and shattered third within a week of driving it, so i figured i was stuck needing a t56mag, this gives me something to think about. thanks for sharing so many details.

[andrewb70]

I see people use the AR5 as if it was the holy grail of transmissions. Then I promptly see the same people breaking and replacing the AR5 with another AR5...insert facepalm...

Why do people insist that a transmission that is rated at 260 lb/ft is adequate for a turbo LS boggles the mind. I guess if Sloppymechanics says it's good, it must be good...

Andrew

[TrendSetter]

Budget build, I really wanted a third pedal. I have about a grand (including the second ar5) in it compared to 3500ish for a t56m. I thought it was an interesting option and gave it a shot, but it’s not a good fit for my use. I’d guess it would last better in a Dyno car that throws numbers down and doesn’t shift at wot. I really want to keep a clutch pedal for the funsies but this dct is very intriguing for me and I may jump in.

[TrendSetter]

Ok I read through again, couple more questions.
How big is this trans? Will I need to cut out my trans tunnel? Th350/400 is original
Is the throttle blip/ignition cut required? Is that like the clutchless upshift I had on my zx10? I have a terminator x ecm so I doubt that’s natively possible.
I wish Facebook wasn’t where the adapter plate guys post. I’d like to start looking for a trans but these things don’t seem to have a consistent name to search for. I’m interested in a .67 final.
Thanks again everyone for sharing

[DblTrbl]

So I pulled the starter out of the Vette to do a test fit in the DCT. It doesn't fit. Needs some metal removal from the transmission. The adapter ring is ok. The starter needs about 11-12mm clearance.







Got the marker out again.



Used a cutoff wheel to make the clearance.





Now the starter fits fine.








I took about 13-14 mm out, could probably get by with 11-12. I don't think the coutout will have any issues with case strength.

Keep in mind this is the V8 DCT. Don't know how the inline 6 version will fit. Also don't know how the inline 6 will do for oiling. The inline 6 engine is installed at quite an angle.

Gotta say, getting the GM starer in and out is a piece of cake. Especially since I have a battery cutout switch.

[DblTrbl]

Ok I read through again, couple more questions.
How big is this trans? Will I need to cut out my trans tunnel? Th350/400 is original
Is the throttle blip/ignition cut required? Is that like the clutchless upshift I had on my zx10? I have a terminator x ecm so I doubt that’s natively possible.
I wish Facebook wasn’t where the adapter plate guys post. I’d like to start looking for a trans but these things don’t seem to have a consistent name to search for. I’m interested in a .67 final.
Thanks again everyone for sharing

Don't know if it will or won't fit my 77 Vette tunnel, which is fairly small. I was surprised the 4L80E fit fine however.

I don't think the throttle blip action is required for mild shifting, but it may serve to reduce clutch wear while shifting (just an opinion). For aggressive shifting, I don't know. I can implement the throttle blip with my AEM ecm and DIY transmission controller combo, but it's very custom.

[John McIntire]

I wonder if an aftermarket starter would just clear the DCT since there is no nose or cone on the front of it, just the pinion itself?

[John McIntire]

Any updates?

[whitepark]

TTT - any updates ?

[loudandproud]

Im not sure if OP has any updates, but i did install mine DCT and adapter and everything went well. The new adapter i got has the bolt pattern for the LTx engines as well. I went with a mini style starter and didn't have any clearance issues with the starter.

[Kenova]

Interesting engine mount. I'll have to keep that in mind for future builds.

Ken

[DblTrbl]

I test fit the DCT into my turbo LS powered C3 vette. I does fit with no change required to the tunnel or firewall. It's a little closer to the firewall than the 4L80e because the adapter plate comes straight back a bit, but nothing is interfering. If I keep raising the DCT until it's forced against the tunnel, the middle, center of the DCT touches first right around where the shifter cable comes through the body.

I should have measured the height of the 4L80E output shaft before I removed it. The DCT output shaft appears to be around the same height, maybe a tad lower, but not enough to create a bad pinion angle.

Now I'm going to fabricate an adapter to the existing rear trans support. I plan to leave the support in it's current location and build the adapter so it can support either 4L80e or the DCT.

[DblTrbl]

Did some measurements.

Both the 4L80e and the DCT hang lower than the engine.

Turns out both the 4L80e and the DCT oil pans are tapered rather than being at right angles to the engine block. The side near the engine hangs lower on both and tapers up towards the back. The taper on the 4L80e is slightly more aggressive.. The DCT hangs about 3/8" lower at the engine side. That's tolerable.

However, the DCT hangs about 3/4 to 1 inch lower in the back than the 4L80e did. I can't raise the back any more without modifying the tunnel.

I've got decent ground clearance now with the 4L80e so an extra 3/4 to 1" wouldn't kill me, but I'm not happy about it, especially with a plastic oil pan.

Curious how much ground clearance there is in a BMW. Tomorrow I'll drop the Vette back on the ground, with the DCT still up there, and measure the ground clearance.

[DblTrbl]

I dropped the car on the ground and jiggled the suspension. The front of the oil pan can fit a 2x4 under it. The back is about 3/8 too low to fit it. Overall, I'd need to raise the back a minimum of an inch. 1.5" might be better. If I raise the back (will need some major tunnel work) the clearance should be good front and back.

loudandproud. I like that you're building your tunnel to fit. Looks like you are keeping the water to oil cooler. Stock location for that is even taller. I already have a temperature controlled trans oil cooler that has AN fittings, so I'm going direct to that instead of the water/oil. I've heard that the DCTs like to have a certain temperature fluid, so your way may get it up to temperature faster.

[AU Doc]

I just stumbled onto this thread, and my checkbook is probably going to wish I hadn't. I have a project now that I'm in the process of deciding on a transmission, and this is very tempting.

Sub'd.

[FlyDoc]

Just Like AU Doc, I Stumbled across this thread. My Son has a "65 C80 Chevy that is/was a Fire Truck. the plan has always been to do a low SCCA cone smasher, C6-C7 suspension, AWD, GTR transfer Case. Big dreams, but you have to have a goal! there seems to be good aftermarket support for the GTR Transfer case but they are supper pricey!! the BMW DTC as price I can only find about Double the as stated above, but I'm looking on e-Bay. We have started calling the "fire Truck" the *******, because its going to have a German trans, a Japaneses Transfer case, now maybe find something other than LS power?

Keep the Info coming!

[vette427-sbc]

So I got bit by the bug... DblTrbl is my neighbor and has so generously loaned me his v8 DCT with the adapter for fitment measurements. My car already has a t56, and I happen to have a magnum at my shop so I snapped a few comparison photos. The DCT is certainly more beefy, but I think it’s shorter length keeps the extra girth in the section of the tunnel that’s usually bigger anyway.
My car isn’t even done, and the drivetrain has zero miles on it. But these are just too cool to NOT have