GTR Forum banner
1 - 10 of 10 Posts

·
Registered
Joined
·
105 Posts
Discussion Starter · #1 ·
I was thinking about getting a complete OS Giken os88 transmission i know several people on here use them. I was wondering if they had fixed the issues that the early versions had? also would a sequential transmission hold up for say 100,000 kms in a moderate HP application or do they need to be rebuilt more often then a similarly strong H pattern. Thanks


BTW: It will be used in a OS Giken RB31 setup pushing round 800 awhp.
 

·
Registered
Joined
·
2,110 Posts
Since its a dog ring box, it would need to be serviced regularly (e.g. every 5,000 kms depending on how you drive it) to keep it in good running order. An equivalent H pattern would be similar on overhaul time.
 

·
Registered
Joined
·
3,171 Posts
Dog boxes are not suitable for high service interval usage, they are competition only, IMO, but some people seem to fit them because they have a certain cachet...
 

·
Registered
Joined
·
3,171 Posts
I'd recommend a light foot and wet roads, with cheap low grip tyres ;) Or a proper transmission and overhaul regime, there are no reliable half way houses I'm afraid. It's not BHP that kills drivetrains, it's torque, and you have a lot of torque there, and with 4WD you have the ability to hook it up solidly, and without sympathy, shockingly, to the road. Those conditions mete out a real torment to transmissions. My 2WD Skyline isn't nearly so hard on drivetrain parts as it's traction limited.
 

·
Registered
Joined
·
105 Posts
Discussion Starter · #8 ·
so what part of the dog box makes the increased overhaul schedual neccesary, the lack of syncros? if so what is the most uprated example of a box that uses syncros. I was looking at the os88 v2 so a half baked solution i was not looking for. all i want is to go 20,000kms between re and re of the box
 

·
Registered
Joined
·
3,171 Posts
The dogs are sacrificial, especially if you are not good with dog boxes and maul the changes, so they wear and contaminate the oil with metal fragments.

There may be a synchro box that will handle the torque, but I doubt there's one commercially available to go in the stock casing. My dealings are 99% with race dog boxes, so i am not fully qualified to advise here, sorry. Maybe the Holinger range list a suitable transmission, or they may all be dog gears, I don't know?
 

·
Registered
Joined
·
10 Posts
Hi there canadian, we have two seperate GT-Rs one that is used for both street/circuit dutys, the other for drag racing, both using OS-giken RB30 engines for motorvation and have used Holinger sequential, OS-88 v1,PPG dog 5-speed (local aus made),OS-giken Cross Gear synchro 5-speed with varying results! Firstly the Holinger has been overall the most reliable of all (drag-car), but has to be maintained (15-20 drag passes) and is not particulary streetable. The OS-88v1 was a complete disaster in our drag car (enough said) hopefully v2 is better! The PPG dog box is a 5-speed gear set used in std case,has had some reliabity probs but slowly working that out.The most 'streetable' of the lot is the OS cross-gear set mainly for its synchro operation, and has also proven the be the most reliable, albeit with the car de-tuned to suit lower rpm shifting of design. Unfortunately IMHO you wont see 20000ks between rebuilds of any of these gearboxes, knowing the sort of torque/power that OS motors can make:thumbsup:

Hope this helps
 
1 - 10 of 10 Posts
Top