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Gtr Gearset Options

Gav
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Gav Mentor

Gav

Posted
Posted

It has been discussed somewhat in old posts, but I would like to get some recent feedback on syncro gearbox options for street driven GT-Rs. I'm NOT interested in going to dog engagement gears, so I figure that leaves:

1. Replace/rebuild standard gearbox as required. I guess that this is the most common practice as it works out cheapest. Reliability will obviously depend on factors such as abuse, main duty of car (drag racing etc) and torque.

2. OSG helical gearset with syncros. These would appear (to me anyway) to be basically the same size and design as OEM Nissan gears, with the benefit being that they (theoretically) are manufactured with higher strength due to their metallurgy and finishing.

3. PAR straight cut gearset with syncros. If you believe PAR's caim on their website, the large tooth profile means that there is added strength and reliability in going to this straight cut profile. The downside is the noise, however in theory this should only be in 1st, 2nd and 3rd gears (4th is 1:1 ratio and 5th will retain standard helical gears).

I would appreciate feedback on the OSG and PAR options from people who have tried the products. Any premature or unexpected failures?

Cheers

Gav

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Beer Baron Grand Master

Beer Baron

Posted
Posted

ppg also make a synchro GTR box i think. most people i know who have used both, favour there product over the PAR ones.

from what i know the other difference the OS box has over stock is the tooth pitch is different. slightly 'straighter' profile so there is a little more gear noise than stock. i have one in my car, but only running around 250rwkw so as expected no failures or problems. i can say it's not as easy to shift when shifting slowly at low engine speed as a stock box, but at high RPM with faster shifts it is beatiful to use. i'm also running a OS solid centre twin plate, which may be half of the driveability problem, but it is not that bad (the box i mean).

CruiseLiner Mentor

CruiseLiner

Posted
Posted (edited)

i reckon someone in w.a should start selling some cheap gearsets and they would be millionaires :P or even second hand gtr boxes as they will be breaking like twigs between u, simon, bobbo, mine and a couple of other high power 26's haha :P

Edited by CruiseLiner
Mik Experienced

Mik

Posted
Posted
Auto Gallery Yokohama make a double syncro coned gearset...

http://www.ag-y.com/english.htm

I think Auto Gallery yokohama just do a double syncro conversion. They also upgrade gearsets...but I'm pretty sure they use OS Giken gear sets.

One think with the Giken gearset is that 1st is so damn tall. It would be a pain for hill starts and driving up driveways, especially in a heavy R33/R34/Stag with biggish cams.

Swiper the Fox Grand Master

Swiper the Fox

Posted
Posted
OSG helical gearset with syncros. These would appear (to me anyway) to be basically the same size and design as OEM Nissan gears, with the benefit being that they (theoretically) are manufactured with higher strength due to their metallurgy and finishing.

The size and tooth profile of the OS gerset is vastly different from the Nissan design.....big thick chunky teeth.

Amaru Veteran

Amaru

Posted
Posted

Im leaning towards the PAR, simply for value for money reasons. It looks like a very strong box, and they guarantee it up to 750bhp. It costs less than $5000 for them to rebuild the box with new gearset and a freshen up of the box (new bearings etc).

Have seen one installed in a GTR, the owner said driving it was very similar to the stock box. The only real downfall is they are -very- noisy 1st through 3rd.

Mik Experienced

Mik

Posted
Posted
Amaru: OS Giken 5 Speed Gear Set all the way for me, I know of PAR and Sam the owner and im not a fan of his designs or buisness sense.

NissanFreak

Haha...I was going to post something along those lines, but you beat me to it.

Strange how he doesn't put his name to his gear anymore...

Gav Mentor

Gav

Posted
  • Author
Posted
The size and tooth profile of the OS gerset is vastly different from the Nissan design.....big thick chunky teeth.

Oops - my bad, shows that it's dangerous to assume! I would be keen to see a set of OEM gears next to the OSG set.

With regards to the OSG set, I remember Mario basically writing them off as a waste of time (actually sh!te was the term he used I think), but I guess it depends on what the ultimate use is and how they're "abused"

T04GTR Grand Master

T04GTR

Posted
Posted
One think with the Giken gearset is that 1st is so damn tall. It would be a pain for hill starts and driving up driveways, especially in a heavy R33/R34/Stag with biggish cams.

il second that. my little ts2bd clutch is feeling the strain. just like taking of in second :)

T04GTR Grand Master

T04GTR

Posted
Posted
Im leaning towards the PAR, simply for value for money reasons. It looks like a very strong box, and they guarantee it up to 750bhp. It costs less than $5000 for them to rebuild the box with new gearset and a freshen up of the box (new bearings etc).

Have seen one installed in a GTR, the owner said driving it was very similar to the stock box. The only real downfall is they are -very- noisy 1st through 3rd.

nice con rods too. all the meat in the right place. did he tell you no one here buys his stuff. and that it all goes to the states? :lol:

m&m Rising Star

m&m

Posted
Posted

I have a PAR gearset in my S15.The standard set didnt like 250rwkw much.So far no problems,feels strong,a bit noisier,drives like standard.Cost me $4800 all up with delivery to NSW and back,with them rebuilding the box.

I think I'll be using the OS set for my GTR though.

Sam doesnt return calls but he does reply to emails.

Anyone used his rods on a GTR???

NissanFreak Collaborator

NissanFreak

Posted
Posted (edited)

Here's a picture of the OS Giken Gear Set. As far PAR rods one comment "they are way too heavy, anyone can build a strong rod if they dont take weight into account" and because of this PAR rods in a high rpm RB26 it would put extra load on the bearings etc.

And my engine builder also said that he once ordered a set and one rod was 1mm shorter than the other three, had him dumb founded on dummy assembly why his squish was out on one cylinder LOL.

Anyway as people may have guessed I am not a big PAR fan.

NissanFreak

post-25763-1140273791.jpg

Edited by NissanFreak

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