as above whats the max bhp 4x4 sierra cosworth standard running gear can handle??
thanks for your help

 

forgot to say clutch will be 6 paddle

 

BHP is not the limiting factor, its torque that will cause you drivetrain issues.

my Old T34 car was running around 420lb/ft and smashing std 4x4 boxes and diffs for fun,. this was on the T34 55s package at around 380bhp.

 

hmm thats no great new then as i was planing to use a t34 .63 , siemens 55s , bd14/bd8 cams, and was planing to use one of your msd 380 off the shelf chips .
so i am rather stuck now as i dont like the idea of killing the gearbox a diffs

 

The T34.63 is better for drivetrain than the T34.48 i was using as the power is more linear, the .48 is a real low down punchy turbo.

You may be ok on the .63, but its a little like russian roulette, your next time on boost may just be the gearboxes last, you never know lol.

 

i will have to down spec

 

so its really down to how much you press the pedal lol
bet the uprated boxes are mad money too

 

It does depend how you drive, we do plenty of the T34.63 55s conversions, most are fine on the std boxes its just an unknown how long they will last, they are certainly at the limit up there.

My Bara box was around 5k i think.

 

well that makes me feel a bit better lol , i only drive it at the weekends and sometimes not even then and i am not a hard driver just want to have the power to sort out boy racers now and agein
and yep thats about the price i was thinking lol

 

I had a standard 4x4 gearbox go with 270bhp@wheels! But to be honest that had a hard life for 15-20K miles with a T34.48 and greens.

Think alot is to do with how you treat it, I dont have much mechanical sympathy.

 

lol love it
as i said i will be mainly driving normally giving it the odd boost
think i will go ahead with my plans the if it dies down spec

 

mine has been like that for yeas and never dona a gear box

im waiting now tho

 

ive done 25k at 390lbft, and only done one box, and even then, i only changed it cause the oil came out very silver. i don't do standing launches, but i drive it hard otherwise...

 

lol makes me feel better

 

that makes me feel even better lol and i wont be doing launches just normal road use and i wont drive it hard all the time so i will give it a go

thanks for everyones help

 

Anything more than 300 ft/lbs through a standard box you're on borrowed time, but saying that as said its a lot to do with driving style, I had 400ft/lbs on a standard box and organic plate have just removed it and I'm selling the gear kit on the bay as its still in working condition.

Have just had my gearbox built using the oppliger big tooth kit and have gone for the ap 6 paddle, best value for money box on the market imo


Luciano

 

3rd gear is how to kill your 4x4 box

I broke a gearbox and rear diff on my t34.48, got the car mapped by MSD on a t34.63 and fingers crossed haven't had any failures (I drive the car a lot harder now!). I do have a Bara box and front thickwall'd ATB though.

 

Just go 2wd and man the fuck up lol

 

why 4x4 mate if your not an aggresive driver 2wd is fine and when you do want to go sideways which you will want to do lol you can.

and you wont have to cut the halfmoons out of your front chasis for the driveshafts.

 

That is high torque for standard box, but it also depends how you drive it. Did you take some hard launches or donuts with it alot? I've heard some people running stock 4x4 drivetrain, bar clutch, with a bit over 400 hp and no probs.

With over 360-370 hp and associated torque, the box should be ticking time bomb waiting for the one hard launch to kill it.

By the way, how easy it's to break a diff without doing any hard launches? Only fast road use but no launches? And to add, yes I've broken my center VC by doing few donuts on a 100k mile car, it has about 300 lb-ft.

 

the reason is my brother has all the 4x4 parts sitting there so makes sense to me , and as for cutting the two half moons i recon it will be easier than putting the cossie rear on

 

as for lanches the car wont be doing that as thats how you break things on mostly any car , will just be normal road use with a bit of ass kicking now and agein , no launches and wont be on any track

 

hi mate if you dont mind me asking how much was your kit ?

 

oh thought it had cossie rear in it.

good luck with the build do a build thread for it and keep us updated mate.

 

hi mate yea the rear has the 4x4https://passionford.com/forum/picture.php?albumid=5743&pictureid=26410 cossie on it heres a pic

 

Kit was Ł1950 and was about another Ł600 to get it fitted into my casing it doesn't come with 1st or reverse gears though


Luciano

 

is there no way to swap the gearbox/diffs ect for stronger stuff off another car?
I no it wont be straight forward but surly it could save hassle in the long run?

 

skyline /cossie box bellhouseing welded together an a jag or some supra diffs ,not sure bout front diff

 

celica gt four ST205 stuff is hard as nails, would that not work?

 

hmm thats not that bad , thanks for the help

 

can you not get a 4x4 skyline ?

 

this seems like good money..

http://bbs.rsownersclub.co.uk/showthread.php?t=501400

but as said above opplinger seem to have it on lock at the moment as far as good gearbox setups go

 

yes its been known as Godzilla for many years...........

5 or 6speed switchable 2/4wd in the GTR Skylines

 

Anything much over 300lbft and they dont last long if you drive them hard

 

Lottery, there are some people that have had them last for ages and a lot of people, that have had them last for a short space of time.

I've smashed loads of them, never at launch, so thats a common misconception that people make, although launching it may contribute to wear it matters more higher up the rev range when your boosting it, in higher gears at max torque. Bottom line is even if you don't launch it, there's no guarantees it won't break.

Also just to add I have never broken a front diff, from reading feedback on the escos forum it appears they are substantially more reliable than is made out to be. Again, not saying it is bullet proof, but the box is way more likely to go bang first.

Since I have done a bit of research into the boxes I shall share what I have found as the fault cause. Basically the MT75 box/bearings are susceptible to wear, and what happens is that over time this creates movement of the shafts in the box, given that helical gears create a thrust force, i.e. naturally push apart from each other when engaged, then this is essentially what destroys the gearbox. With a straight cut gear you don't generate the same axial loads and therefore (theoretically) it is less likely to fail. Principle is the same for most boxes, the gears only break becasue the bearings fail or parts are worn, the broken gears are just a result of the play in the box.

Also compare this to a turbo, when you destroy this, it's not usually anything but the fact the bearing is shot and it has contacted the inside of the housing becuse of the excessive movement of the shaft

 

so how long whould they last on a focus cosworth with just under 500 bhp and say 450lbft only asking as am buying it and dont want to be changing them ever 2 minutes

 

Not long at all!

 

You ain't got to cut the half moons out I never have .

Never had no problems never hit the chassis rails
It's lowered 25mm too.

 

that's right

 

i was thinking about building it up then seeing it there is any need for the half moons and i run coil overs so not like it moves much