RB DCT gearbox conversion

[Gareth87]

Been looking into future gearbox options for a while now and while my brand new R34 GTS box is great.. it won't last forever.

I've got mates with dog boxes and while they're a logical next step, they aren't super friendly in some settings.

I've been looking into DCT boxes. There is a company in Norway that do the conversions parts for plenty of JDM engines and I'm keen to hear thoughts on it. It would be a pretty cool thing behind my FJ20 bluebird and price for all the parts including 7 speed BMW box is comparable to a 5 speed dog box.

Has anyone done it and if so.. is it worth it?

[GTSBoy]

There's already at least 1 thread on here on the topic. Have a search for it. They might have been talking about it in the ZF 8HP thread too.

[robbo_rb180]

@klutched is converting to zf8 hp75

Plenty of info out there in europe, simon michealmore has the dct in his drift car and it seems that it took a lot of work to tune the TCU from HTG. He may be someone to contact and have a chat to about it. Have a look at the zf 8hp** conversion too a youtube channel on sunny coast has done it on his bmw with decent power and talks about the pro & con of it.

[robbo_rb180]

Also check this thread out

 

 

[Gareth87]

Great info, thanks for the feedback everyone. I would love to drive a DCT converted car just to see if it's worth the trouble or is it just better to outlay on a dogbox/sequential.

Time to do some research! 

[robbo_rb180]

1 hour ago, Gareth87 said:

Great info, thanks for the feedback everyone. I would love to drive a DCT converted car just to see if it's worth the trouble or is it just better to outlay on a dogbox/sequential.

Time to do some research! 

Definitely do some research, will be very hard finding a converted car in Australia.
Biggest issue is the tuning of the gearbox as from my research all the TCU are still really in testing. If wanting a bolt in solution a PPG sequential gearset is the easiest option for r33/34 boxes.
 

[TurboTapin]

Have you looked into running a CD009? 

[Butters]

I've been looking at the DCT box conversions with much interest, i love the one in my Audi.  So far not seen an example that really works better than an auto due to the programming required, as noted above. The idea has a lot of potential though. 

 

I have am r34 getrag gtr in one car and a os gearset rb25 in other, both are amazing to drive and both cars are over 600rwhp.  The only down side to the OS is the ratios, specially first is really long for a street car. 

 

People LOVE the CD009 but stuffing around with adapter plates and clutches is a pita.  Worth if it limited options are around like sr20 but not sure why people don't go gearsets for RB, you don't have to go dog people !

[GTSBoy]

32 minutes ago, Butters said:

not sure why people don't go gearsets for RB

I'd like a 6th gear for driving at 100+ on highway.

[Gareth87]

@GTSBoy @TurboTapin @Butters

If I was to change from my 34 GTS box, I wouldn't go anything with synchros.

love the idea of something new or different, especially in my 40yr old Nissan Bluebird, but if its largely untested with not much info on it.. that's definitely a consideration.

Sequential boxes are just crazy money and while I'm on the outer limit of my setup at 600hp, a dct box would make it faster and more of a match to some bigger hp 6 cyls.. Same goes with a Sequential i guess.

[BK]

1 hour ago, Gareth87 said:

@GTSBoy @TurboTapin @Butters

If I was to change from my 34 GTS box, I wouldn't go anything with synchros.

But a DCT box does have synchros

[Butters]

1 hour ago, GTSBoy said:

I'd like a 6th gear for driving at 100+ on highway.

Unless you have a t56 with double overdrive this doesn't make a lot of sense.  The CD009 is .79 and and rb25 is 0.81 on overdrive, so near the same. 

 

The 6 gears are really nice to have a better spread of ratios from 1 to 5(1:1),   Then still have an overdrive. 

I have found for drag racing the 6 speed is slower due to the more gear changes, not yet tried launching in 2nd. 

1 hour ago, Gareth87 said:

Sequential boxes are just crazy money

Amm how much are you expecting a DCT will cost ?

When I looked at it, in aus a used DCT box  $4-7k. Conversion kit is $4k landed.  Controller and etc was $3k. 

So by the time its in the car , lets call it 15k+ DIY with a used box.  Add $5k for someone to do it. 

If you want better clutches, which yes you do ($3-5K) and a box refresh add another $3k. 

Then you need tuning, which won't be quick or cheap. 

 

Blink and you have spent $30k hahaha

Edited September 23, 2022 by Butters

[BK]

8 minutes ago, Butters said:

have found for drag racing the 6 speed is slower due to the more gear changes,

Yeah funny that. I used to drag a Trust / Quaife 6 speed H pattern dog box with single overdrive 6th. At 10.5 and 130mph I was crossing the line in 5th.

[Butters]

4 minutes ago, BK said:

I used to drag a Trust / Quaife 6 speed H pattern dog box with single overdrive 6th. At 10.5 and 130mph I was crossing the line in 5th.

That's impressive !   

I should have been clear too, 6 speed H pattern syncro box is slower vs a syncro H pattern 5 speed at drags. 

A sequential or dog or both is not the same impact when added that extra shift.  

 

[BK]

3 minutes ago, Butters said:

That's impressive !   

I should have been clear too, 6 speed H pattern syncro box is slower vs a syncro H pattern 5 speed at drags. 

A sequential or dog or both is not the same impact when added that extra shift.  

 

For sure - being able to clutchless upshift on an H pattern dog definitely saves a couple of tenths !

[GTSBoy]

25 minutes ago, Butters said:

Unless you have a t56 with double overdrive this doesn't make a lot of sense.  The CD009 is .79 and and rb25 is 0.81 on overdrive, so near the same.

It's funny you should say that. I find the CD009 to be even more nasty than all previous nasty Nissan gearboxes. I would definitely go a T56 or Tremec of some other flavour if I was going to put the effort into a conversion.

Notwithstanding that, if stuck with a CD009, then the 6 gears are better applied to a slightly taller diff ratio, to a similar effect. Put a 3.69 or something in there after the 0.79 6th and win.

[BK]

2 minutes ago, GTSBoy said:

It's funny you should say that. I find the CD009 to be even more nasty than all previous nasty Nissan gearboxes. I would definitely go a T56 or Tremec of some other flavour if I was going to put the effort into a conversion.

Notwithstanding that, if stuck with a CD009, then the 6 gears are better applied to a slightly taller diff ratio, to a similar effect. Put a 3.69 or something in there after the 0.79 6th and win.

Tremec TR6060 with Transmax Z shifts like butter. Never driven one, but the CD009 is harsh ? 

[GTSBoy]

4 minutes ago, BK said:

the CD009 is harsh ? 

All Nissan manuals are notchy and nasty compared to the various nice manuals that are out there. Everything from 180Bs, through Stanzas, Bluebirds, all the various RB gearboxes.... all notchy. I don't like them. The various Celica boxes and the bigger Toyota boxes from the same era are all much better shifting.

[BK]

6 minutes ago, GTSBoy said:

All Nissan manuals are notchy and nasty compared to the various nice manuals that are out there. Everything from 180Bs, through Stanzas, Bluebirds, all the various RB gearboxes.... all notchy. I don't like them. The various Celica boxes and the bigger Toyota boxes from the same era are all much better shifting.

Yeah Supra R154 was good.

I miss my MA70

 

[Gareth87]

1 hour ago, Butters said:

Unless you have a t56 with double overdrive this doesn't make a lot of sense.  The CD009 is .79 and and rb25 is 0.81 on overdrive, so near the same. 

 

The 6 gears are really nice to have a better spread of ratios from 1 to 5(1:1),   Then still have an overdrive. 

I have found for drag racing the 6 speed is slower due to the more gear changes, not yet tried launching in 2nd. 

Amm how much are you expecting a DCT will cost ?

When I looked at it, in aus a used DCT box  $4-7k. Conversion kit is $4k landed.  Controller and etc was $3k. 

So by the time its in the car , lets call it 15k+ DIY with a used box.  Add $5k for someone to do it. 

If you want better clutches, which yes you do ($3-5K) and a box refresh add another $3k. 

Then you need tuning, which won't be quick or cheap. 

 

Blink and you have spent $30k hahaha

Well... shit hey. Thanks for doing the budget for me.. looks about right to me! Add another 2k for incidentals and a tailshaft then we've got ourselves a realistic budget.

Looking like a sequential 6 speed is the way forward!

1 hour ago, BK said:

But a DCT box does have synchros

You know what I mean... 🤣

 

This whole thing comes about because I'm surrounded by a bunch of mates with fast cars and I'm making the least power at 540hp 🤣.. it's a vicious circle!

I figure shedding weight and shifting faster is going to help my cause. I've spent stupid cash on it in the last 15 years.. this is probably the next venture.