jl123

On your RA do you have a sure-trac front LSD? If so do you find it useful?

Thanks, JL

David_Wallis

no he doesnt..

STi7's on do.

David

jl123

I didn't think so. John never seemed to complain about his car needing more traction or grip- in fact the major gripe I hear him make is the need for the new automatic version of DCCD. My point is that does anyone think it is really that useful? Does it really make a objective improvment in the Impreza's handling?
Thanks

johnfelstead

I have never said i need the Auto DCCD on my car.

My RA has a mechanical front LSD, this is not a suretrack unit, suretrack LSD's dont work when you get one wheel off the ground so is useless for rallying or kerb hoping on track, which is what the RA is designed to cope with.

johnfelstead

p.s what i do say is the UK STi should be fitted with the same transmition system that the USDM and Japanese spec STi gets, which is the DCCD-A. In comparison, the UK STi is a poor relation and doesnt have the same balance.

jl123

John,

Sorry I had misunderstood your prior comments on DCCD.

However about your comment reguarding sure-trac: would it not hold that since this unit does not work when a wheel comes off the ground that it really (as the evo team have said) kind of misses the point of the use of the Impreza. That is, the Impreza's is supposed to be a go anywhere public road warrior- meant to handle often bumpy/irregular road surfaces? Might not the mechanical diff you have on your car be more effective for more broad public road applications?

I'm surprised some sti owners have not switched lsd's.

Thanks

jl123

Any sti people who agree. Or is it too cost prohibitive to take the LSD off?

dead_neurons

im about to complete a deal on a Type RA Sti, on a 98S, what rear diff will this have? it was described to me as a "plated diff" is this just another word for mechanical diff? is this an upgrade over the standard diff to handle more power? since the car also has an STI paddle clutch?

cheers!

/2ob

johnfelstead

The STi5 TypeRA has the R180 rear diff fitted as standard with a plated LSD. The front LSD is a gear type arangement. Centre LSD is a DCCD clutch type adjustable diff.

johnfelstead

"However about your comment reguarding sure-trac: would it not hold that since this unit does not work when a wheel comes off the ground that it really (as the evo team have said) kind of misses the point of the use of the Impreza. That is, the Impreza's is supposed to be a go anywhere public road warrior- meant to handle often bumpy/irregular road surfaces? Might not the mechanical diff you have on your car be more effective for more broad public road applications?

I'm surprised some sti owners have not switched lsd's."

I dont think most drivers would notice the diference between an open diff and a suretrack to be honest, it makes no sense finacially to change it.

For a road diff the suretrack is ideal i would say, most people dont go kerb hopping and in standard trim the STi7/8 isnt that stifly damped to cause a major issue with front end patter unless the road was very bumpy. I have only driven one STi8 TypeUK PPP on a bumpy B road and it was torque steering all over the place, but i wouldnt like to judge the car based on a short run on such a bumpy road. My front LSD will work better on bumpy roads, but most people dont really drive them hard on these, for most roads i would think the suretrack is a good diff.

dead_neurons

Many many thanks for that john, i wasn't sure if the salesman was feeding me a line. One last question then, when we reversed into a layby, the rear diff did make quite a lot of noise whilst manoevering, sort of rumbling/vibration, fairly loud as i remember, now the salesman said it was perfectly normal at low speed & i'd notice it most when parking up etc, however i've never heard what a diff is supposed to sound like, if they are indeed supposed to make any noise at all ...im coming from a 'normal' car...
The guy seemed pretty honest and given he wasn't feeding me a line about the 'plated' diff, was he also telling the truth about the noises?

-hopefully i'll be getting a call about the car tomorrow, im so excited im almost wetting myself LOL

thanks!

/2ob

jl123

Thanks for the heads up John. Most people I know with US Sti's (which by the way is the spec C with an extra 500 or so Lbs added on (2.5 engine, plus luxury stuff- would be nice to be able to lighten it up) here in the states do also complain that torque steer is a problem on bumpy roads. Agreed though that a swap might be expensive.

Thanks

johnfelstead

the USDM STi isnt a spec C, it has some shared components, as do all STi's.

A healthy plated rear diff shouldnt be clanking in reverse, mine didnt until i buggered it.

What he may have done is have the centre diff in partially locked setting, that does give transmition windup in slow manouvers. Try it with the centre diff set to fully open, that is the bottom green light iluminated on the centre diff display.

jl123

According to Paul Hansen of Apex japan, the US version does posses the same basic chassis of the C spec-sans engine and diet parts. Yes even the roof is supposed to be thinner on our version. Notice how it too has the longer wheelbase of the C spec (100in). Also the US version requires the rear suspension lincs of the Spec C which owners over here order from Japan.

jl123

Here's the exact quotes,

"The difference in weight between the JDM Spec C and the USDM STi is due to engine weight, bumper beam, and the fact that the USDM is measured wet (all fluids) vs. dry (JDM measurement, no fluids). All evidence points towards the USDM being the RA Spec C JDM. If it was the regular STi, it would be heavier. The frame has been stiffened - you get the front Spec C additional bracing.

It *is* the real Spec C. There isn't as huge of a difference between a Spec C and the "regular" STi as people imagine. And you get two bonuses over the JDM Spec C - the aero kit is standard, and the BBS rims are standard.

STi spec C vs. STi around tsukuba track, there was only a half second difference. Different drivers experienced the same thing. Most of the time difference is likely due to the lighter weight and the front suspension geometry - which is two things the USDM STi recieved. Subaru really, really, really had to reduce weight on the USDM STi for very specific reasons, and for that reason, the USDM STi looks to be the Spec C with the limited edition package and BBS rims and aero thrown in.



Cheers,

Paul Hansen
www.apexjapan.com"

[Edited by jl123 - 9/9/2003 1:45:46 AM]

mutant_matt

Speaking as an onwer of a suretrac diff on an STi 7 and having driven many road and a few track miles in an STi 5 RA V-Ltd with the front mech LSD (phew, what a mouthful ), I would say that the Suretrac is a large improvement over the open diff fitted to the old Scoob and the new WRX. It is not, IMHO, as aggressive as the RA's LSD but there is not *that* much in it.This is probably/possibly true but as I said, I can tell the difference and the difference between the suretrac and the mech diff is not nearly enough to a)make the suretrac feel lacking and b)the cost would be silly for the small(ish) gain you'd feel on the road.Agreed My car has virtually no torque steer but then I have different wheels and tyres than standard (the standard tyres IMHO were not that great), different springs, ALK and decent geometry setup. The springs didn't make any difference so I put the improvement down to the tyres and the ALK/Geom.

Just my thoughts

Matt

mutant_matt

P.S. Forgot to add, I LUUUUUUUUURVE the RA and came within a knats whisker of buying one for myself but as insurance on my postcode on a JDM is stupid, I went for the STi 7.

Matt

Adam M

and such a shame it was superceeded so soon.

gutting

MorayMackenzie

Going from open front diff to Quaife ATB made a big improvement to my car, and that's ~four years ago.

jl123

Thanks for the thoughtful reply's.

Is the quaife just about the same diff as the sure-trac? Or does it have some plus/negatives?

Thanks, JL

MorayMackenzie

Quaife ATB is a helical gear diff, similar to TorSen, but different enough to avoid copyright prosecution.

I've yet to drive a front suretrac equiped car long enough and hard enough to compare them. The rover tomcat (220 turbo coupe) had a quaife gearset and ATB as standard... driving one is interesting, at the point you expect it to understeer if you put more power down, it doesn't... the nose tucks in and pulls it around. I thing ford use the ATB in the focus RS... which has had mixed reviews... but the "torquesteer" could be as much a function of the suspension setup as the diff.

MorayMackenzie

Theres some info here:

http://new.minimania.com/nmm/GEARBOX...lable__839.htm

Bear in mind that these guys are talking about LSDs on front wheel drive cars.