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Old 07-26-2012   #1
afb312
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Question Race tranmission / gearbox

Hi,

I am trying to get the "weak" gearbox sorted out in my R32 build.
These are the options as I see it.

R32 5 speed
R33 5 speed (with improved syncros)

Both of the above have failures with third gear breaking and the syncros giving up. This tends to happen any where north of 500 bhp.


R34 Getrag 6 speed
Not sure where the limit is but it is not much more for sure.

All of the above can be refitted with new shafts and gears fro OS Giken, PPG and PAR. The adverts claim allsorts of hp ratings but these seem to be unmatched in service. There are options on shafts, dogs, straight or helical cut teeth and mid plates etc.

Moving to further expense there are two Quaife boxes, both with 6 speeds. One is the H selector and the other is a sequential box. The first is out of production and the spares are very difficult to get. The second is complete with the 4wd transfer box (a Quaife item). These are very expensive too.

There is also the OS 88 a sequential dog box that is rated up to 1500 bhp (I believe). Some people swear by them, others at them... This also uses the standard transfer box, which seems to cope with the power. These are very expensive too.

There is the Liberty Gears sequential drag box, which does not shift down the gears so as to be no use for road or road race applications. I am sure its great for the drag race though!

There is the old group A spec manufacturer, Holinger, who made back in the 1990's (when the Skyline became Godzilla). They make an updated sequential box, which is highly thought of, but very expensive.

I have even seen the Stagea 4wd auto box used to great effect in a drag application. Nissan RE403A automatic transmission.
http://www.2009gtr.com/2010/03/8-sec...gt-r-from.html

As you all can see there is a great choice out there, but are there others out there ?

As I see it there needs to be a substantial power (read torque really) rating on the product to make it reliable.

There are a number of sequential 6 speed gearboxes out there which have the power capacity and could be adapted.

Any one got any ideas?
I have wondered about these as a starting point, with maybe with PAR / PPG type internals...
Viper gearbox,
GM Camaro with the ZL1 engine,

Or a race option such as:

http://www.emcogears.com/dv46-photos/

http://www.quaife.co.uk/shop/products/qbe33g-0

http://www.quaife.co.uk/shop/products/qbe87g

http://www.quaife.co.uk/shop/products/qbe33g

http://www.quaife.co.uk/shop/products/qbe28g6h

http://www.quaife.co.uk/shop/products/qbe27g6s

http://www.quaife.co.uk/shop/products/qbe27g6h

http://www.maktrak.com/specs/4wd-inline.pdf

http://www.holinger.com.au/gtr.php

http://www.holinger.com.au/pdfs/gtr.pdf

http://www.ppgearbox.com.au/page.asp?categoryid=8
(I like the T56 option as there must be a load of parts and knowledge out there.)

They are either all too low in capacity or fiendishly expensive !

Anyway I posted this to stir up a hornets nest of opinions and wishes or both ! But please keep it practical and not pie in the sky stuff.

Last edited by afb312; 07-26-2012 at 03:32 PM.
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Old 09-19-2012   #2
mcfly
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Default Re: Race tranmission / gearbox

If I had my way I would go with a TH400, but I am a drag guy.
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Old 09-26-2012   #3
mrrbtwentysix
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Default Re: Race tranmission / gearbox

My BCNR32 has a Getrag six speed fitted. It was in it when I recently purchased it. I had to strip it because it wouldn't select third gear. The gearbox internally is very nice and is typically German. It has quite wide gears which will handle large amounts of power but the weak point is still the syncros, this is much the same as we have all experienced on the earlier boxes. The gear ratios are close which makes the car feel very quick but you are for ever changing gears and are constanly wanting to change up from sixth when cruising. Personally I will be looking for something with out syncros when the funds allow perhaps a PPG gearset with dog engagement. My biggest issue is from the tripple plate clutch dammaging the splines on the input shaft which is an issue I'm working through at the moment, this effects gearchanges due to the splines catching on the clutch.
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Old 09-26-2012   #4
afb312
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Default Re: Race tranmission / gearbox

I am not sure but I have a feeling that dog boxes do not last too many miles on the street. Having said that I have no evidence ! I would think that there is a huge variation due to the gear change technique. Dog corners will be subject to wear by definition.

Everyone will have their own usage driven criteria:

option A 100% drag 0% street 0% road race / track day
option B 90% drag 10% street 0% road race / track day
option C 33% drag 33% street 33% road race / track day
option D 10% drag 30% street 60% road race / track day
option E 10% drag 10% street 80% road race / track day

The next question is whether this is in terms of miles driven or gear changes ? I would assume the latter. In addition, there are high rpm changes which will be more damaging by far than low rpm ones. How much so I am not sure, may be 100, 500 or 1000 times.
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Old 09-26-2012   #5
mrrbtwentysix
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Default Re: Race tranmission / gearbox

I most likely fit option E, therefore I do want something nice on the street most of the time. After the frustration of having to do the syncros I was trying to find a better alternative. After watching this video I thought that this may be an option for me I was most cocerned with street driving a dogbox but it looks OK.
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Old 10-06-2012   #6
afb312
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Default Re: Race tranmission / gearbox

That does look easy enough although I am not sure it is so easy at 9250 rpm... I could be wrong and it would not be the first time ! I'll try and dig some more. Those t56 gears do look wide. I would like to see the R32/R33 5 speed or the R34 6 speed dog box used in anger.
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Old 10-19-2012   #7
afb312
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Default Re: Race tranmission / gearbox

Does anyone have any film links for high rpm up or down changes of a dog box ?
Street use is one thing...
May be I have answered my own question as they were designed for race use.
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