Drivetrain with over 300kw

[terbulent]

Just wondering what gearbox / t/case / diff people are using when making over 300kw at the wheels

im making 450hp and recently a workshop (who rally an evo 3 and evo 6) mentioned my t/case is on its way out due to the amount of power i've pushed through it

 

[CLuTZ]

Replace it with another dude, these drivelines can handle it.

 

[JAP63]

Replace it with another dude, these drivelines can handle it.

Now thats confidence! I know they can get around with absolutely no isues around the 200-20 kw mark, remember, feeling notchy isnt an issue, its standard....with these cars anyway.



How much it will take will ultimately depend on the considertation you have in the manner you drive it. You will find if your driveline is healthy youll be fine..just no hamfisted gearchanges, clutch sidesteps, or jerky clutch moments.If your Xfer is on the way out then replace it, it may just be tired, theyre usually the weakest link.

The problem lies in the way in which cars with 300 wheel Kw are driven, never lightly are they!, always respect it like it "could" break.
Keep the oils fresh....

BTW, everything i said then is in reference to Evo III stuff, i dunno how a GSR would fair against it.

 

[Liberoz]

depending on condition they can be over hauled as per the "Pdf workshop manual" re-setting preloads & back lash, input shaft splines is one of the main areas they will wear in mostly which makes them chatter.

Unless your around the 500 mark like the APC boys I doubt you'll need anything custom, just maintaining the factory one will keep her on the road and you smiling.

 

[runuts]

To add to what John said, remember most of these components are quite old. A freshen up with new bearings and preloads set correctly, will aid in their ability to hold hp greatly.

Also, its not the hp that breaks them. Its the torque. Most of the big hp cars, only have issues because they are old components, or from the way they are driven and the rate at which torque is applied. Generally, if its driven nicely, they'll happily hold well beyond 400kw@wheels. But put slicks on it, and start sidestepping the clutch and see how long they last. Once you are at that power, when racing, if you can preload it before you launch, you'll save alot of driveline components, mind you at the risk of more clutch servicing, but i think I'd rather replace clutches than everything else.

 

[runuts]

Oh yeah, definitely do something about the centre diff though, they are weak

 

[terbulent]

I have only ever given it a hard launch once, and never since coz i got bad whiplash lol most of the time ill give it a squirt every now and then in 2nd or 3rd and continue on my merry way.. guess ill get a replacement t/case and see what happens from there. any recommendations for overhauling the 1 i have ?

 

[runuts]

They can sustain very hard launches, its how you diesngage the clutch that usually hurts them.

The one you have, its difficult to say without stripping it down. But providing you got it before any gear damage was done. Some new bearings and adjust the preload correctly and it'll be good to go.

 

[OFFON-4]

Rob Barac ran 9z with a standard drivetrain... It can be done

 

[CLuTZ]

Its been done/proven lots in N.Z too. ENVYIT (chris) on these forums ran a 9 with stock driveline (rebuilt gearbox) too.

 

[evopwr]

centre diff will definitely be the first thing to fail due to hard launches.

 

[JAP63]

The point ppl make about the bearings is a good one.
A worn bearing accentuates everything when torque is put through it and just leads to earlier failure. Start making more torque and more power, it fails earlier again

 

[terbulent]

so back to the question lol any recommendations to overhaul them ?ill buy another one and get it serviced and fitted, and get the 1 in my car serviced also once the replacement is in.. cant afford down time at the moment

 

[JAP63]

so back to the question lol any recommendations to overhaul them ?ill buy another one and get it serviced and fitted, and get the 1 in my car serviced also once the replacement is in.. cant afford down time at the moment

Yerah i started doing mine a while ago
Do you have any mechnaical knowledge? u can buy all the parts from mitsi, and the bearings from a bearing shop, then its just up to you to knock the bearigns in and shim them to the correct spot to ensure the teeth mesh correctly.

Theres a PDF on how to do it somewhere, one of the guys here will know where it is, its not too dificult to do mate.

 

[thirteen]

Checking your transfer case:
http://www.youtube.com/watch?v=7DyxXJ42Vpc

And to give you an idea of what a transfer case rebuild kit is:
http://cgi.ebay.com/ebaymotors/Mits...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

 

[GSRWRC]

As mentioned, the centre diff is the big weakpoint. Look into a 4 spider conversion and it'll hold up to 300kW+ fine though. Otherwise you'll probably have to lock it or find an aftermarket centre ($$!)

Transfercases are fine in general. From memory the Evo III item has an alloy casing which can crack. The earlier steel cased ones are better.

Rear diff hats are another weak point, as they're alloy and are mounted on the moustache bar that can bounce around makes them prone to flying apart on launches, solid mounting the rear diff to the subframe and body will prevent this (Not sure how legal this will be in Aust!) Start stocking up on rear diff hats (GSR/Evo I-III use the same hat, just do what I do - anytime you see someone selling a cheap diff, snap it up for the rear hat)

The gearboxes themselves are pretty good, although big power cars can and do pop teeth off 4th gear. Nick Chesters SuperGT Evo did this several times, pretty sure Chris' ENVYIT has at least once aswell, plus I know of a few others. A refresh of bearings and synchros will work wonders, also consider mixing the ratios to get them closer to each other.

My 'box runs an Evo II/III 1st and 2nd, Evo I 3rd and 4th and a GSR 5th with a 3.545:1 rear diff. I highly reccomend the GSR 5th gear for guys running Evo 3.909:1 gearing, its a lot closer to 4th than the Evo 5th and at the drags doesn't drop your revs as much if you have to change from 4th to 5th just before the line. Anyone running 3.545s should be able to hold 4th across the line unless they're running 9s!

 

[envyit]

i have a open unwelded centre in my box and it hasnt broken before.
plate front, viscous rear and a vce.
never broken a t case on a launch only had failures from the rear seal leaking out.
and ive only broken one rear axel from running on slicks.

yip 4th isnt so much a gear any more its pieces of gear now, the gsr 5th gear does help over the evo 5th.

Rear diff hats are another weak point, as they're alloy and are mounted on the moustache bar that can bounce around makes them prone to flying apart on launches, solid mounting the rear diff to the subframe and body will prevent this

mine isnt as trick as Jarred's set up, mine has solid ploy type munts with machined metal hats to hold it tight in place.

the factory driveline can hold large amounts of power, its how you treat it which determins how long it lasts.

you can alro run 9's whilst holding 4th on a 3.9 box just under 9000rpm

 

[EVO-00X]

Speaking of a welded centre diff, does anyone have a pic of one already done that they can post up?

 

[to4garret]

Speaking of a welded centre diff, does anyone have a pic of one already done that they can post up?

i have some pic's at home, will try and remember to post them up.

 

[to4garret]

its a miracle i tell you... i remembered.

anyway, here is the only picture i got



what can not been seen in this photo, is where the VCU usually is, the two parts have been welded around.

so the left hand side of the picture controls the rear wheels, which has the most welding.

the right hand side of the above picture controls the front wheel, unfortunatly because of the design of the diff, there is not alot of meat to weld too. but if it breaks you'll just wind up RWD :thumbsup: