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Torque Curve

6 Speed gearset for R32 & R33 gearbox

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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. 

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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

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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

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8 hours ago, Old man 32 GTR said:

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. 

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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?? 

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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.

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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.

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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.

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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.

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