Drag Racing Gearbox

[BU5TER]

Leewah I guess once you've ran the car at a few meets with 593awkw and bettered your pb the gearset will have really proven itself, to be honest I thought with that power you would of torn it a new *****hole

SK I know of a standard box behind a 400rwkw 3L R33 GTST and he's blown 3rd in 3 box's drag racing what would the best choice for him be now? are you doing anything different to your box to make it stronger?

[Sydneykid]

I'm currently running an OS Cross Mission gearset with a billet sandwhich plate in my GTR and it's holding fine.  Last dyno run was at AutoSalon and my car made 617rwkw and 593awkw.  I'm happy with the box and it held together fine on the weekend when we went to Heathcote.

See, there is always an exception to every rule. I can give 10 examples of gearboxes in cars (like Buster can) that rip the teeth off 3rd gear with less than 500 rwkw and along comes Leewah to disprove it. I have seen 6 X OS gearboxes lined up in a workshop in Japan, all of them being rebuilt after killing 3rd (and sometimes 4th). I know of a Japanese team that takes a spare gearbox to every drag meet because 9 times out of 10 they have to change it over the weekend.

Sometimes they are OK and sometimes not, but I suspect anyone with over 400 rwkw in a GTR is living on borrowed time with a helical cut gearset.

Hi Buster,

are you doing anything different to your box to make it stronger

Well I was talking to Rohan from Guru at Philip Island 2 weeks ago, but he isn't really interested in Skylines, Mazdas are his thing. Pfitzner has done a couple of gearboxes for us (not Skylines) and I have talked to him about doing what Leewah did, using a billet sandwich plate. The theory being that the standard one allows the case to distort and lessens the contact area of the gear teeth. For less than $1K it may well be something we try in one of the gearboxes.

If it doesn't work I can always use the billet sandwich plate with Pfit's straight cut dog gearset, so it won't be wasted money. I have a little more research to do before I can decide which way to go.

[R31Nismoid]

I think the standard auto is Jatco? or could use one out of a VL?

Nah, they are a Jap electronic Box, were from the R31 Imports.

They cost a fortune to get them tough.

More wothwhile buying a trimatic or a powerglide... depending on the setup etc.

And putting one of them in if your looking the Auto path.

Less stress on the drivetrain with an auto too.

[Drifterdan]

Try www.keas.com.au or ask for "transman" at calaisturbo.com

[judd]

good read....

seems what ever gearbox i look at around 10k i hear bad things about....cant afford a Hollinger as much as i would LOVE one..scared to use the OS GIKEN gearset as heard of a couple of cases myself in japan of them stripping teeth..Leewah is your car making 600+kw when dragging? If soo you could/should be in the high 8s low 9s..

comes down to maybe Trust(Grex) 6-speed Dogbox or HKS 6Speed dogbox spec 2.

any thoughts on which is better one or the other...as have heard they both have there issues...

[Leewah]

scared to use the OS GIKEN gearset as heard of a couple of cases myself in japan of them stripping teeth..Leewah is your car making 600+kw when dragging? If soo you could/should be in the high 8s low 9s..

comes down to maybe Trust(Grex) 6-speed Dogbox or HKS 6Speed dogbox spec 2.

any thoughts on which is better one or the other...as have heard they both have there issues...

Judd,

When we went dragging on the weekend, we were running the car with a little less boost than at AutoSalon (it would have been closer to the 570rwkw mark). The reason as to why the car won't be running 8s or low 9s besides not using a dogbox is simply due to the fact that my car has no weight reductions. The windows are still glass, the door trimmings and dash are all still intact and the airbags are still there. The only things which have been removed are the spare tyre, amps and subwoofer from the boot and things under the bonnet to make room for the engine mods. I still run the car with the A/C system as I drive the car on the roads quite regularly. We believe that the gearbox is holding nicely as the custom built clutch is taking a lot of the stress from the box. Also, the fact that the car is still standard capacity means that we don't make the same torque numbers as Kier or Munro who run 3L bottom ends.

Don't know anything bout the HKS box but I know that the Trust box strips gears under large amounts of power. The RacePace GTR (1:16 around Sandown and 11.06 quarter mile) has stripped 2nd once, 3rd twice and 4th once and it runs around the 420rwkw mark around the track. This maybe due to the 3L bottom end in it too.

I'm happy with the OS box but due to it not being a dogbox I would recommend you ask Munro about the Pfiztner dogbox. He's using one in his street GTR at the mo and I hear he's quite happy with it.

[meshmesh]

We believe that the gearbox is holding nicely as the custom built clutch is taking a lot of the stress from the box.

I thought, by having a stonger clutch to handle the power, adds load to the next part being the gearbox, then if you have a gearbox that can handle the required load, this puts pressure on the next part... etc etc

I'm about to install my clutch/flywheel ORC Ogura Twin Plate on the GTR, and was warned that it could be detrimental to the life of the gearbox?? I planned getting a triple but again was told my gearbox would go...PS: I'm only making around 320kw @rw.

[judd]

We believe that the gearbox is holding nicely as the custom built clutch is taking a lot of the stress from the box.  Also, the fact that the car is still standard capacity means that we don't make the same torque numbers as Kier or Munro who run 3L bottom ends.

Thanks for info leewah,

mesh mesh as per above i think he is quoting that the custom clutch he is using is actually knowing what to do with the power and not putting too much strain on the gearbox...which would mean it is set with the right resistance..? therefor the clutch will slip a little under too much load, or will slip and slowly grab under a 9000rpm launch..is that right leewah?

and yes Tripple Plate will blow gearboxs will over 1100HP clamping load..which means it will hold almost 1100hp anything past that it will slip a tad..etc etc...

[meshmesh]

mesh mesh as per above i think he is quoting that the custom clutch he is using is actually knowing what to do with the power and not putting too much strain on the gearbox...which would mean it is set with the right resistance..? therefor the clutch will slip a little under too much load, or will slip and slowly grab under a 9000rpm launch..is that right leewah?

Thanks Judd & Leewah, if that's correct...Where can I get me one of those?

At the moment the car is only making 320kw and I had an already slight fautly synchro go on me within the first 3days after my mods. So I've got a new box going in this week with the clutch, but was thinking about rebuilding my old box just incase... but not sure whether straight cut, OS sets.. etc etc

[judd]

im just a bit scared on how japan quotes there power figures as they always measure in PS or HP...and never Torque..

which is why i think these OS Boxes are going kaaboom...dont know if its the same with there clutchs....but never heard of anyone complaining yet about a tripple plate not holding its power..although i do know they make have 4plate clutchs available for 1500HP+

[judd]

Thanks Judd & Leewah, if that's correct...Where can I get me one of those?

At the moment the car is only making 320kw and I had an already slight fautly synchro go on me within the first 3days after my mods. So I've got a new box going in this week with the clutch, but was thinking about rebuilding my old box just incase... but not sure whether straight cut, OS sets.. etc etc

First 3days after the mods you had synchro probs..so your going to use a bandaid and put a new std gearbox back it? what makes you think it wont have the same prob another 3days later?

I heard Jim Berry (or something like that) does some good custom clutchs???

im also just a bit scared on how japan quotes there power figures as they always measure in PS or HP...and never Torque..

which is why i think these OS Boxes are going kaaboom...dont know if its the same with there clutchs....but never heard of anyone complaining yet about a tripple plate not holding its power..although i do know they make have 4plate clutchs available for 1500HP+

[meshmesh]

First 3days after the mods you had synchro probs..so your going to use a bandaid and put a new std gearbox back it? what makes you think it wont have the same prob another 3days later?

They're covering it under warranty as they were supposed to have fixed that problem. So no real skin off my nose. But I agree with you, that's why I'm planning to beef up the old box but not sure which way to go.

[Blitz]

Interesting thread guys.

I was actually contemplating building up a second gearbox with the OS gearset to eventually replace my existing box once I get my build underway. Im only looking for what seems like a conservative power output of around 320-350awkw (compared to the likes of leewah ) so my understanding is the OS gearset should happily handle the load.

[Leewah]

Ok, here's the thing.

I have gone through 1x OS Triple plate and 1x Ogura Triple plate and I had less than 450rwkw when we went dragging with these clutches. They simply couldn't hold the power and then slipped when they got too hot.

I then consulted with some drag racers and they recommended Jim Berry up in Qld.

I rang Jim and spoke to him at length about our problems and he agreed to rebuild by Ogura clutch using his special materials and rather than rebuilding the clutch as a triple plate, he was only going to building it as a twin. The clamping pressure was also raised from the 2500lbs of the Ogura to 4400lbs using Jim's pressure plate.

The car has now been out on the track now with over 100rwkw more than what the previous clutches have handled and the only thing that can describe it is magic!! After about 6 runs, the clutch felt no different to the 1st run. The way the clutch has been built also allows for more slipping off the line but grips hard when in gear at full throttle.

Judd is correct in saying that there is a bit of play in the clutch when power is applied allowing us to put the power down hard when required.

I am of the opinion that a gearbox in our realm of power levels is only as strong as the driver allows it to be. Noone expects the box to hold up if we flatshift or try to pull the gearshift from the box. It's simply too harsh. Smooth changes and treating the box with respect will preserve the life of the box.

Even expensive boxes break. Kier has busted his Hollinger on a number of occasions but that is most likely because he is pushing the box to the ultimate power levels.

Another thought about boxes. You many want to give Frank Modena of Modena Engineering a call here in Melb. He maybe able to build a custom box for you. He's responsible for a lot of the internals in today's V8 supercars.

[meshmesh]

Thanks Leewah, that was very helpful.

[markr34gtr]

love the r34 gtr getrag...ha ha 10.87 at 130mph.....full weight car done heaps of passes at the track...making close to 600 rwhp now....i do believe my box is lucky to be still alive ...

my view is they are way stronger than r32 gtr boxes....

also i use a nismo g max 2 with heaps more clamp...all good so far.....

using redline mt 90 oil in it... maybe lucky but it still drives perfect....

but the ppg box sounds the goods for faster shifts and bigger power levels....

cheers..

[low747]

Big difference i think here guys, you are all talking about manual boxes taking the punishment with dyno's etc, but isn't the topic about a gearbox for drag racing with around 500+rwkw. Even a car that can make 600rwkw on the rollers, prob won't last long flat shifting on the drag strip at those power levels, but an auto powerglide built correctly could and for a margin of the cost... So an auto may be the cheapest and best way to go if you just want times etc like try09's etc.

I personally would use an auto, along the lines of jatco 3 speed or powerglide. Powerglide if you want a reliable proven combination.

Cheers.

[Guest DIRTgarage]

Big difference i think here guys, you are all talking about manual boxes taking the punishment with dyno's etc, but isn't the topic about a gearbox for drag racing with around 500+rwkw.  Even a car that can make 600rwkw on the rollers, prob won't last long flat shifting on the drag strip at those power levels, but an auto powerglide built correctly could and for a margin of the cost...  So an auto may be the cheapest and best way to go if you just want times etc like try09's etc.

I personally would use an auto, along the lines of jatco 3 speed or powerglide.  Powerglide if you want a reliable proven combination.  

Cheers.

get me one with a GTR transfer case fitted to it and im there!

[blk180]

This post is over a yer old

[r33_racer]

lol...yeh someones found it and posted prob not realising that its been sitting here for over a year...wonder if he solved the gearbox problem???