gearbox options

[gary200]

right been thinking ... lots
going to need a box for the car in the next 2 months and to be honest am totaly stuck as to what to go for.

options out there i know of are:
1. rb25det box with polo spec adaptor plate around £800 all in..
2. OS Gyken 3 gear set rated to 500bhp and £1500 ish..
3.PPG rb25det with adaptor plate, dog box with streight cut teeth rated to 600+bhp but is going to cost almost £3500

engine will be runing between 480 and 530bhp sr20det
obviously u get what you pay for so the ppg will obviously be best and handle the power best but its a hell of a lot of money i dont have...

so my question is how much power will a polo spec rb25det box handle reliably as id rather spent £3k on a box that will last a long time than £800 on a box that will last a season and then need replaceing..
car is NOT going on the road so wont get much mialage but any it dose get will be hard track abuse..

advice please people

[gary200]

night time bump

[superclarkey]

Gearboxs have a figure they will handle, but 99% of the time its down to how much shit the driver gives it.

Polo smashed an R33 box on his first outing, so its not a 100% fix to the problem, with the power your running, a PPG is the ONLY option,

I would love to see a OS Giken gearset for £1500 fitted with new bearings, that cheap! But they are also shit, and break about the same as a stock gearbox, gears are the same size at the end of the day, and nothing can protect a box once its bearings have started to wear out.

If you go for the PPG go for the syncro mesh dog box, not the strait cut version as thats shit and will just get massive oil starve and destroy gears..

R33 gearbox is a good option but it will still break the same if it wears the bearings out.

Bottom line is, get used to rebuilding gearboxs or just keep throwing stock units at it and hoping for the best, most people do this because its the only option.

no gearbox is unbreakable.

EDIT: you need to think very carfully which clutch your planning to run also, as each gearbox needs a different type and load rating, not one clutch fits all.

Clarkey.

[SRRay]

clarkey speaks the truth,I was considering the same but rb boxes have rocketed in price here now so Im sticking with the sr box and will sick another in if it goes bang

[superclarkey]

My gearbox never broke, but its now worn out, it did 3 hard rounds of bdc with 375ft lb of torque and this is the figure that breaks gearboxs not BHP.

The bearings are just worn out on it, if i was to run it another round it would most likey fail, but clearly it can't be rebuilt as the gears will be also worn out now.

Bottom line is, its £150 for 3 rounds, i can live with that, its lasted that long because a/ i know how to change gear without killing geras, b/ i selected the clutch that would be the easyest on the box c/ i change the oil after every event with MT90 high impact oil.

clarkey.

[Mr Bizzle]

Realisticly Gary,
With a competition drift car it's not the strengh of the gearbox that's important. It's the transmission shock transfered through the clutch. That's where most people slip up. Your goal should be to minimise that shock as much as humanly possible. You can do this easily by re-bushing the rear subframe. Using solid bushing on the differential and subframe mounts and making sure the condition of your input shaft bearings on the diff are nice and tight.

Clutch wise, it's a very simple choice for maximusing gearbox live. A twin plate Carbonetic clutch is what i would use. Carbon fibre clutches are fantastic in drift cars because they don't bite in the same way traditional friction materials do. When you release the clutch on a carbon plate, it intially slips (although you don't notice it) then the hotter it get's (the more it slips) the MORE it bites. This goes a very long way to reducing transmission shock which is ultimatly what kills boxes.

In my opinion, if your going to go to the extent of doing a gearbox swap don't bother dicking around with an RB25 box that (in the real world) won't take that much more abuse than the SR (in drift land, on the road or track it's a different story) People blow up RB25 boxes on R32/R33's etc running 400+hp and this conversion isn't the golden ticket everybody makes it out to be. (as people are starting to find out to their own expense )

If your going to do a conversion, bang a Tremec T56 or Toyota R156 (supra) box in there and never worry about breaking one ever again.

[superclarkey]

Nice words spoken Bizzle

[gary200]

Originally Posted by Mr Bizzle

Realisticly Gary,
With a competition drift car it's not the strengh of the gearbox that's important. It's the transmission shock transfered through the clutch. That's where most people slip up. Your goal should be to minimise that shock as much as humanly possible. You can do this easily by re-bushing the rear subframe. Using solid bushing on the differential and subframe mounts and making sure the condition of your input shaft bearings on the diff are nice and tight.

Clutch wise, it's a very simple choice for maximusing gearbox live. A twin plate Carbonetic clutch is what i would use. Carbon fibre clutches are fantastic in drift cars because they don't bite in the same way traditional friction materials do. When you release the clutch on a carbon plate, it intially slips (although you don't notice it) then the hotter it get's (the more it slips) the MORE it bites. This goes a very long way to reducing transmission shock which is ultimatly what kills boxes.

In my opinion, if your going to go to the extent of doing a gearbox swap don't bother dicking around with an RB25 box that (in the real world) won't take that much more abuse than the SR (in drift land, on the road or track it's a different story) People blow up RB25 boxes on R32/R33's etc running 400+hp and this conversion isn't the golden ticket everybody makes it out to be. (as people are starting to find out to their own expense )

If your going to do a conversion, bang a Tremec T56 or Toyota R156 (supra) box in there and never worry about breaking one ever again.

lol cheers for the info peeps
and yea i had been told the os gyken boxes wearnt all that riliable..
chris: yea has solid subframe/diff bushes ect and was going to go for the exedy twin plate as it seems the best choice at the moment..
think i will go with my origional plan then by the sounds of it.
decent clutch, origional box and see how it goes if it breaks then sell myself and go all out on a ppg box, as i really really cant be arsed filling my garden and tow car up with spare sr boxes..
any opinions on clutches whilst we are at it??
unless the exedy twinplate is good enough

[superclarkey]

Speak to driftworks about the Exedy Twin plate clutch

[gary200]

already have a very good price for mate very much doubt dw could match but may be worth a try anyhow cheers

[Mr Bizzle]

CARBON CLUTCH - CARBONETIC - ACROSS Official Website

I have seen people break PPG boxes. They are good, but not cost efficent when you compare a standard T56/R156 and an adaptor plate.

Read the above again as to WHY you should use a carbonetic clutch.

[superclarkey]

Yeah give them a shout, they can only say no

[superclarkey]

Originally Posted by Mr Bizzle

CARBON CLUTCH - CARBONETIC - ACROSS Official Website

I have seen people break PPG boxes. They are good, but not cost efficent when you compare a standard T56/R156 and an adaptor plate.

Read the above again as to WHY you should use a carbonetic clutch.

how much is a twin from them ?

[Mr Bizzle]

Originally Posted by superclarkey

how much is a twin from them ?

About the same price as a genuine exedy.

[gary200]

Originally Posted by Mr Bizzle

CARBON CLUTCH - CARBONETIC - ACROSS Official Website

I have seen people break PPG boxes. They are good, but not cost efficent when you compare a standard T56/R156 and an adaptor plate.

Read the above again as to WHY you should use a carbonetic clutch.

will take a look now

[gary200]

1 more thing do we know anyone who sells a sr20det conversion plate for a supra box??

[Mr Bizzle]

Originally Posted by gary200

1 more thing do we know anyone who sells a sr20det conversion plate for a supra box??

Nobody to my knowledge, you'll need to have one made mate. Try RS Fabrications, give them the gearbox and an SR20 block and they'll fab one up for you. The biggest issue is going to be the input shaft connecting with the flywheel/clutch plates as the splines will be different.

It's do-able and it won't be massivly expensive. But i'll take some thought.

[gary200]

cool cheers dude and will have the info u need in a few moments

[gary200]

Originally Posted by Mr Bizzle

The biggest issue is going to be the input shaft connecting with the flywheel/clutch plates as the splines will be different.

It's do-able and it won't be massivly expensive. But i'll take some thought.

where would i go about haveing 1 made/costomised chris any ideas??
seriously considering this option now, and im guessing it would still run sr20det clutch and flywheel??
cheers for all the info dude

[Polo]

Originally Posted by superclarkey

Polo smashed an R33 box on his first outing, so its not a 100% fix to the problem, with the power your running, a PPG is the ONLY option,
.

Not true dude!!!! I used the car for 5 outings befor i blew the rb25 box and thats running more grip than i ever dared run on an SR box, also with a MUCH harsher twin clutch!!! I can 100% confidently say the RB box is lots stronger than a SR box, no doubt about it!! The conversion plate its self has been proven to be strong enough by holding the box firm enough to blow the box in the 1st place. If i ran the traction im running this year on a SR box i bet i would have blown a box every time i used the car The fact that im snapping drive shafts now rather than breaking box's also proves there stronger as i never broke a shaft with the stock box.
The hole conversion can be done for as little as £600 if you do some shopping around. And TBH, its worth doing the conversion just for the feel of the gears and the gear change.

Eliminating transmission lash is defo a MUST if you want to save boxs, low milage shaft, tight mesh of the crown and pinion helps LOADS!!! Also what helps is a lower ratio diff