gearbox damage/28 psi,sticky tyres and left foot braking

[vrfour_nz]

Thought I would share some pictures of the gearbox I damaged on a tarmac hillclimb..I was lucky enough to have no damage to the brand new cusco lsd I had fitted pre-event /ubbthreads/images/graemlins/tongue.gif

 

[bazeng]

Damn,

Very lucky!!

Want to sell that Cusco now?
if not, where did you get it from?

 

[solidviper89]

that looks pretty bad...

 

[Bimmubishi]

4th gear? I have broken two boxes this year. This time I was in 4th and the car just stopped going forward. Same deal.. 28lbs, R Compound tires..

video of blowing up- not very exciting.

click

 

[Bimmubishi]

This was the first time earlier this year.

 

[mean_green]

sh*t son talk about hooking up. Absolutely LOVE the car BTW /ubbthreads/images/graemlins/worthy.gif

 

[Flip4G63]

you where pulling that car HARD in the straits!!!

 

[Bimmubishi]

That car isn't slow either. Fully prepped race car with a built high compression motor.

 

[blacksheep]

Is that blue crap tranny fluid, Al? Looks like liquified laguna seca blue E46 M3 paint /ubbthreads/images/graemlins/rofl.gif

 

[Bimmubishi]

I grind down M3s and feed it to my evo.

At least that's how my wallet feels.

 

[vrfour_nz]

Yeh 4th gear..big sideways around a big sweeping corner lost drive and spun out,should of left the restrictor on the turbo!Had the same thing watching brand new oil going down the drain.. Quoting Bimmubishi:
4th gear? I have broken two boxes this year. This time I was in 4th and the car just stopped going forward. Same deal.. 28lbs, R Compound tyres..

 

[vrfour_nz]

Nah not selling..got brand new front and rear cusco out of japan..the other option are kaaz units..should be readily available in aus /ubbthreads/images/graemlins/smile.gifQuoting bazeng:
Damn,

Very lucky!!

Want to sell that Cusco now?
if not, where did you get it from?

 

[bazeng]

Bimm,
What gearbox was that? a stock evo box?
What sort of power is it making to break the box in 4th??

vrfournz,
How much were to cusco items?
I've got a kaaz front, and evo3 rear.. I do need a centre diff because I currently have a spool and its not fun to drive in the parking lots...

Any advice on where to get it from?

 

[3rdstrikedsm]

An evo 3 box has a burst strength of like 360 ft lbs, Believe it or not that type of failure is due to heat. Not that it overheated the gear set but heat induced fatigue, This is why drag cars can run 600ftlbs through that evo box and run 8's with out it breaking because it cools down between runs but get some temp in it and put some power down and forget about it lasting.

 

[vrfour_nz]

I have seen this failure quite a few times with local dyno tuners when they do a run in 4th gear,the last one I saw was another rally car..when stripped down,a run-in rebuilt gearbox with crack tested shafts had let go pretty much straight away.On my car though definitely having a sump guard and higher temperatures under bonnet would of contributed to the failure.

 

[bazeng]

I've made about 40 dyno runs in 4th gear with 450hp - 550hp pulls without any signs of the box giving up (touch wood!!!!).

vrfour_nz, so are you running that viscous lsd and the centre lsd together?

I'm wondering why we dont lock the viscous when running a clutch type lsd?...
Or what if we ran a locked centre with a viscous?

 

[3rdstrikedsm]

You could get an oil cooler and have the return spray on the 3-4 gear set.
I know jacks trans will do this for you, Prolly worth looking in to for rally or road race.
I am also thinking of doing this.

 

[Dialcaliper]

The viscous coupling would interfere with the operation of a clutch type LSD. The correct way to run a clutch LSD in the center is to completely remove the VCU. Most of the center diff replacements don't have provisions to even install it.

Locking it with a VCE would essentially disable the LSD, turning it into a fully locked center.

Running a locked center with a viscous would also not change anything - the correct thing to do again is remove the VCU.

If you decide to run an oil cooler for the transmission, you need to be running thinner gear oil or ATF, and the cooler also needs a pump.


Quoting bazeng:
I've made about 40 dyno runs in 4th gear with 450hp - 550hp pulls without any signs of the box giving up (touch wood!!!!).

vrfour_nz, so are you running that viscous lsd and the centre lsd together?

I'm wondering why we dont lock the viscous when running a clutch type lsd?...
Or what if we ran a locked centre with a viscous?

 

[bazeng]

so vrfour_nz, are you running the ralliart VCU and the Cusco centre LSD together?
or is that the front LSD?


Where would I go about getting one of the centre LSD's by Cusco?

 

[mrnvit]

im interested to know whats left of my 4th gear in the drag car, there were lots of bits in the end of the case when i took it off, but i couldnt be bothered taking it down further to look.