[canadian]

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.

 

[hipogtr]

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.

 

[canadian]

service as in oil change? is this becuse you need to remove the metal debris from the inside on a regular basis

 

[Bean]

service as in oil change? is this becuse you need to remove the metal debris from the inside on a regular basis

Service as in; checking to make sure the dogs have not worn out and replacing the ones that have.

 

[Chris Wilson]

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...

 

[canadian]

so what would you reccomend for a RB31 OSG Kit that i will use for between 700-850 hp in a club car type of situation. i dont want to have to tare down my box every 10K.

 

[Chris Wilson]

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.

 

[canadian]

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

 

[Chris Wilson]

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?

 

[Willall Racing]

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