RB5 Boyo

Hi everyone,
i have ben gradually upping the power recently on my RB5 and will be fitting my new turbo and injectors to the car next month, taking it to hopefully around 350bhp/350lbft torque.

My standard gearbox crunches sometimes in first and fourth so im thinking of upgrading come the summer time as im sure the uk box wont take much more power. I was wanting a 6 speed box but theyre crazy money so im now thinking of something else....ive been told the P1 box is the same as the V5 sti box with a longer fifth gear so this would suit me well, but im wondering how well a V5 sti box or a P1 box would cope with this sort of power?

Im not planning on any serious track days or hard launches so any opinions or suggestions on alternative gearboxes for me would be greatly appreciated here!!

Thanks

Kevin

banny sti

iTrader: (68)

The P1 and STi 5/6 gearbox are identical 1st-5th no difference at all, they share the same gearbox code TY754VBAAA.
It will be fine are your intended power level as long you are not launching it at every chance you get, would also get a decent clutch to go with the gearbox.

Banny

Tidgy

350ftlb is gonna be getting to the limit though, so bear this in mind of you do fit one.

as banny says hard launch's will rip it part in very short order if you do a few of them.

i'm runnign 340/315 at the min and am at the limit of the engine, but i want more so when mine blew last year i had a ppg striaght cut set fitted , not the cheapest but def very very strong

Fat Boy

Isn't the RB5 a Uk gearbox? i.e. it has 1.1:1 drop gears, not the JDM spec 1:1 drop gears of the P1/Sti?

If so, you'll need to make sure the the front and rear diffs are the right ones as the P1/StiV ones are 4.44 front and rear, whereas UK boxes have differing front and rear diff ratios

RB5 Boyo

Yep the RB5 is a uk gearbox, but i was under the impression if i got the p1 or sti box with matching rear diff i would be ok?

I know were there is a sti v5 box for sale with matching diff and dccd with ecu, the boys looking for £750 for the box alone, is this a reasonable price and would this be a good box for my job?

There u go now, i thot the p1 gearbox and the sti one had some differences between them!!

Fat Boy

If you mean a new matching rear diff then Ok, but you have to be careful

The P1 and STi boxes will have a 4.44 front diff, viscous centre diffs, 1:1 transfer gears and will work only with a 4.44 rear diff. Your UK car will almost certainly have a non 4.44 rear diff unless I'm mistaken.

As the Uk set up has 1.1:1 transfer gears not 1:1, your front and rear diff ratios will not be matching currently and the rear is not 4.44 as far as I know.

So, if you fit the p1 box you will have to fit a different rear diff which may or may not be an easy find. The P1 runs an R160 sized diff (like the UK) with a 4.44 ratio ( Not standard UK internals either)

You can't tun with a 1.1:1 transfer box and equal front and rear diff ratios, neither can you run with different front and rear diffs and a 1:1 transfer set up as the differing axle speeds hitting the centre diff will burn it out rapidly.

renno rannes

STI ver 5/6 / P1 is suppose to be the strongest of the 5 speed boxes. Plenty people running 400 / 400 longish term road use. Im sure if your doing trackdays and launching it wont last to long though.

Renno

RB5 Boyo

Not all as easy as a straight swap then with a box and matching diff!! If i got a P1 box and a rear diff out of a P1 surely this would fit my car, or are the rear shafts/hubs a different story again then in that case??

What would you guys recommend for my sort of power other than going ***** out and fitting a 6 speed at 2 grand or thereabouts!!

dazdavies

iTrader: (22)

Just get a six speed then you'll be certain. IMO you will wreck a p1/sti 5 box.

Mine was the First RB5 six speed conversion. It was also the first classic 6 speed conversion that RCMS had done.

If you go down the p1 box route by the time you'll realise that you should have gone six speed you'll have already spent the equivelant on repairing broken 5 speeds. I've been there done that.

Get the six speed and be done with it. It's an easy conversion all you need is a UK 6 speedbox, linkage and either a 6 speed or an auto prop. It bolts straight on without the need for changing diffs and hubs etc.

That's some advice from someone that's been there and done that on his RB5 (4 years ago now). There should be plenty of posts on the RB5OC (was number 263)

Cheers

Daz

RB5 Boyo

Cheers then matey, thats good advice then and i think i mite take heed to it

I always wanted the 6 speed its jst the £2k+ price tag putting me off, but as u say id be better putting in the 6 speed rather than mucking about with a few sti boxes and various diffs etc!!

I take it the 6 speeds are viritually unbreakable then??

And if anyone knows a good uk 6 speeder and prop shaf etc comming up for sale, please PM me.

Cheers again!!

Kevin

banny sti

iTrader: (68)

I bought a JDM 6speed box, linkage, propshaft, starter motor and rear diff for £450 from a member on here.

Banny

Tidgy

i've seen them last a few weeks, and i've seen them last couple of years, but you don't ealy expect to be replacing box's every 18-24 months surely?

since you have to change diffs and things like that as well then tbh i don't think its worth the risk

dazdavies

iTrader: (22)

Christ, you got yourself a bargain there.

RB5 Boyo

Jez what a bargain is right ....but do i not need a uk 6 speed to match the diff in my car or woulkd a jdm 6 speed be more hassle just to fit?

renno rannes

Well yeah I got a Ver 6 box and rear diff and running a 2.5 with over 400 of each, if your going to spend that kind of money go for a PPG rather then a 6 Speed I reckon. Or else just go with a 20g and run a nice 380 or so.

Renno

renno rannes

Few people doing it below,


https://www.scoobynet.com/drivetrain...i-gearbox.html

dazdavies

iTrader: (22)

You will need a UK six speed. If you get a Jap 6 speed you'll need the matching rear diff.

For a PPG you're looking at around another £1200 ontop of the six speed price.

RB5 Boyo

Right, cheers everyone, think im im gonna start the hunt to find a good UK 6 speed for the car think, looks like a better option in the long run cuz i mite go big power next year or year after so better have the box to cope now!!

Daveo

I'm running 350/380 at the moment on standard sti 6 gearbox and had not probs

burt2000

iTrader: (1)

what is it that makes the sti v5/6 stronger than a 99-00 uk box, are they not both a TY754? with a pre 98 one being a TY752

dazdavies

iTrader: (22)

Different gearset i believe.