6 Speed gearset for R32 & R33 gearbox

[Torque Curve]

I’m curious that no one has developed a drop-in 6 Speed synchro gearset for the standard R32 & R33 gearbox. 

I would imagine that there is a market for strong street gearbox with the Getrag ratios and maybe the Carbon Fibre syncros that are now available. 

PAR used to do a straight cut dog 6-speed gearset but no longer offer this product. 

Im interested if there are reasons it hasn’t been done before wether it’s space related or something I’m ignorant of. 

Seeing so many Getrag conversions are in 32’s and 33’s these days I would see a drop in gearset as being and attractive option to keep the modifications to minimum. 

Happy to hear all thoughts in this one. 

Cheers. 

[Old man 32 GTR]

Following as I’m very interested in this, currently doing a getrag conversion in my 32 as it was the cheapest option to upgrade, with the only other options being PPG dogbox at 10k used or sequential for 22k new. The other option is OS gearset but there is mixed reviews on those.
Parts for the getrag are scarce so not sure what going to happen when we can’t repair/rebuild them

[Torque Curve]

I’m actually starting to make enquiries to see what can be done. ??‍♂️

[sneakey pete]

There was a guy on one of the GTR groups looking into it start of last year, however progress had been slow and last I heard its now a sequential with a price tag to match.

Not particurally interested in a sequential, but i'd love a 6 speed manual in the standard housing with OS-88 option 2 ratios;

2.890, 1.981, 1.468, 1.174, 1.000, 0.757

[Old man 32 GTR]

I believe Action Dan did a thread on it,
https://www.sau.com.au/forums/topic/468151-getrag-parts-discontinued/

[Torque Curve]

8 hours ago, Old man 32 GTR said:

I believe Action Dan did a thread on it,
https://www.sau.com.au/forums/topic/468151-getrag-parts-discontinued/

I’ve seen that thread but it was to do with refreshing a Getrag 6-speed box and not finding a direct fit 6-speed gearset to suit the 5- speed R32 / R33 box. 

Thanks though. Appreciate it. 

[Torque Curve]

10 hours ago, sneakey pete said:

There was a guy on one of the GTR groups looking into it start of last year, however progress had been slow and last I heard its now a sequential with a price tag to match.

Not particurally interested in a sequential, but i'd love a 6 speed manual in the standard housing with OS-88 option 2 ratios;

2.890, 1.981, 1.468, 1.174, 1.000, 0.757

I would love to see if a 6-speed helical/ syncro box could be done. I’ve enquiries with 2 businesses already to get some information. 

using similar gear ratios to the stock R34 getrag, incorporating carbon fibre syncros and billet shift forks and a modern tooth profiles would be what I’m trying to achieve. 

Lest see where this can go?? 

[sneakey pete]

I don't see why it couldn't be done; the ppg sequential does it so physical space shouldn't be an issue (unless there's something with synchros vs dog engagement for space?)

 

Regarding ratios, bear in mind the 34 is made for 3.9 diffs, so you'd want to keep the overdrive .757 and not .79 of the 34. (personally i'd prefer even a little lower, as I have a 2.9 and running E85, however obviously if it was to get done there'd probably have to be only one set standardized on)

However, in reality i suppose something like the OS-88 ratios wouldn't really be ideal for a manually shifted box and something like the 34 ones would be, just use 2nd to launch.

 

I'd be very interested in one if the price/performance ratios match up, so let me know how you go.

[Torque Curve]

4 hours ago, sneakey pete said:

I don't see why it couldn't be done; the ppg sequential does it so physical space shouldn't be an issue (unless there's something with synchros vs dog engagement for space?)

 

Regarding ratios, bear in mind the 34 is made for 3.9 diffs, so you'd want to keep the overdrive .757 and not .79 of the 34. (personally i'd prefer even a little lower, as I have a 2.9 and running E85, however obviously if it was to get done there'd probably have to be only one set standardized on)

However, in reality i suppose something like the OS-88 ratios wouldn't really be ideal for a manually shifted box and something like the 34 ones would be, just use 2nd to launch.

 

I'd be very interested in one if the price/performance ratios match up, so let me know how you go.

I'm not 100% sure on how to calculate the best gear ratios to suit the number of teeth but i was thinking 

1st 3.07

2nd 2.19

3rd 1.625

4th 1.25

5th 1.00

6th 0.8 (or taller over-drive option)

Would like it to be good street gearbox that can take 800hp or over.

[Torque Curve]

Both replies so far are NO,

"We have considered it in the past but there is minimal available space for a syncro 6-Speed set within the 5-speed box that would allow a gear size to hold 800hp and over."

Ill keep up the search.

[GTSBoy]

I was going to post my opinion earlier, but was waiting to see the response from gearset manufacturers first.  But I concur with them.  The reason you can fit 6 speed dox sets in where 5 speed synchro sets came from is that you need more room between gears for synchros.  It's also not trivial to just jam a 6 speed set in because you also have to provide the shift mechanism, and there might not be a good way to do that.  That's why proper 6 speed swaps for 5 speed originals usually include a new case.

And just a point ref R34 GTR 6 speed diff ratios.  Not 3.9.  Something like 3.454.  Very tall compared to 4.11s.

[Komdotkom]

If you don't want 4WD just use a 370Z box and an adaptor from Collins.

[Torque Curve]

On 10/11/2018 at 12:25 PM, GTSBoy said:

I was going to post my opinion earlier, but was waiting to see the response from gearset manufacturers first.  But I concur with them.  The reason you can fit 6 speed dox sets in where 5 speed synchro sets came from is that you need more room between gears for synchros.  It's also not trivial to just jam a 6 speed set in because you also have to provide the shift mechanism, and there might not be a good way to do that.  That's why proper 6 speed swaps for 5 speed originals usually include a new case.

And just a point ref R34 GTR 6 speed diff ratios.  Not 3.9.  Something like 3.454.  Very tall compared to 4.11s.

Thanks for your comments.  I was thinking it would have to do with the available space but as I’ve never pulled one apart I just simply didn’t know. 

It seems I will need to stick with the well trodden path of an OSG gearset when the time comes.  

Cheers 

[Torque Curve]

On 10/12/2018 at 9:45 AM, Komdotkom said:

If you don't want 4WD just use a 370Z box and an adaptor from Collins.

Definitely keeping the Gtr a 4wd so no chance of this swap. Thanks for the thoughts though. 

[Stixbnr32]

I have been weighing up what to do with my gearbox in my 32 as well.  Its either spend $7000AUD+install on a PPG Helical 5speed dog set and be done with it.

Or OS Gearset (as you say mixed reviews) for about $3100 plus shipping and wait time+install

Or Rebuild it again for another $2000 and just see how long it lasts this time.

As for 6spd only real options that i know of are Sequential or R34 Getrag but they are way to costly for me.

[Wonderboi]

F

[khezz]

The problem I would think is the market is too small. By the time you spend money on development and testing, the units would be too close in price to 5 speed gearsets that are already available. They could even end up costing even more. Take out the people who will opt for a 5 speed upgrade, 6 speed getrag, sequential, auto plus cars are getting more rare in general. There is not enough market left. I am weighing up wether to go for new 5 speed ppg or second hand os88. I would love a new 6 speed H pattern option but I don't think it will ever happen.