shrader

Hi

Please can someone explain to me how the STI's Diffs work .. I know that the centre diff is electronic and distributes the front to rear traction ( don’t know by how much )

The rear Diff is this Suretrac thing .. is this a LSD torque sensing one and then what about the front Diff ?

Sorry for this but my local dealer was unable to explain how it all works!!! I understand the EVO’s 4WD system but want to understand the STI8’s

:O)

AK47

I'm no expert, but you'll find some very good and useful information on the DCCD from a gentleman by the name of John Felstead in the following link "Centre Diff Control Use, the real translation!":

http://http://www.scoobynet.co.uk/bb...hreadID=143750


also suggest you do some searches on the topic and you'll come up with all sorts of goodies



ps. hope my first clicky works

AK47

clicky works but not the thread damn it... [img]images/smilies/mad.gif[/img]

search under "Centre Diff Control Use, the real translation!"

Harry_Boy

Thought the UK STI8 had a mechanical centre diff, and that the front diff is the Suretrac one.

AK47

I dunno, I've got a jap spec Sti8 and don't use the DCCD...

Jza

UK version doesnt have the (JDM only) DCCD - you just get a cheap pants suretrac version on the UK model.....

One day we'll all be equal....

Jza

shrader

Ha ha this is crazy !! Ive spoken to 4 dealers now , they all conflict each other ...

Its looking like the STI has normal diff on the fron ( No LSD) Electronic Torque Centre diff and the "Sure Track" on the Back that is LSD

I think ?

johnfelstead

If its a UK STI then you have a Viscous coupling centre diff, suretrack front diff and Plated rear diff with a 50/50 torque split.

If it's a japanese spec STi then you can have a few variations, some have no front LSD, some have a suretrack front LSD. You can specify the DCCD-A as an option (standard on the Spec C). With VC centre diff its 50/50 torque split, with DCCD-A its 64R/36F torque split and the locking ratio is variable either automatically or manually.

If its a USDM version then you have the same transmition as the Spec C, which is a Rear plated LSD, Centre DCCD-A and front suretrack LSD with a 64/36 torque split.

[Edited by johnfelstead - 9/9/2003 11:28:14 AM]

shrader

Cool Thanks , so what is the suretrack diff ? is it just a Branded LSD or Open diff ... I only ask as the dealers patter is that the STI8 has "suretrack" but couldnt tell me what that meant.

:O)

johnfelstead

suretrack is a torque biasing diff made by AP Racing

johnfelstead

your dealer sounds clued up. LOL

shrader

Cheers Mate, Tell me about it !! Im looking at spending £26k and only wanted to know how the 4wd worked !!!! I hope they service the car better than they sell them

:O)

T5NYW

iTrader: (4)

I'm not 100% certain, But 'Generally they are both classed as LSD's'

As John F said (and he aint wrong often ) The Front is a Suretac diff using mechancal gearing/planet wheel arrangement to supply Torque to which ever side wheel can take the most Torque. If the wheel on one side loses traction(spin) more torque is transfered to the other wheel, therefore a limited Spin Diff
The rear is I believe more a traditional limited Slip Diff, which will give 50% Drive through a friction Plate to each wheel. AS the differencial torque between the two wheels exceeds a given amount, the wheel with the highest load will Slip (ie if slipped by 10% wheel split torque 60-40)
This is assentcial to aid cornering, for as anyone who driven a car with locked rear diff would understand understeer will only want to go straight on

So they work on totally different logics one works on the principle as you lose traction at one wheel it gives more to the other. The other if too much Torque difference between one wheel and the other it slips and the side with most Strain/Torque. IMHO IIRC AFAIR etc.

Like you have been given loads of conflicting info from different sorces but this is how I understand it, FLAME suit at the ready LOL

Tony

Your best to ask Mike Wood or Daimon Harty from Prodrive They would be best to discribe

edteid for Spoolink mistacks

[Edited by T5NYW - 9/9/2003 4:55:39 PM]

shrader

he he Cheers Mate ...now that does make sence

T5NYW

iTrader: (4)

This is only as I understand it and hopefully it's close to how it is but not guaranty'd.
Tony