Smoking up Inside rear?? - Perth-WRX.com

Wheels · #1 27-06-2006, 08:37 AM

I did a sprint the other week at AHG and i noticed on several corners my car seems to be smoking up the inside rear tyre when accelerating hard out of corners.

I've never seen a WRX do that and several people commented on the plumes of smoke coming from the inside rear. I have noticed it before but not to this extent. I still seemed to get good drive out of the corners however.

I have an Automatic MY02 but they are supposed to have LSD in the rear just like the manuals right? In this case there should be minimal spin on the inside i would have thought.

My suspension mods are minor, just ALK, 22mm Sway bar on rear set to hard with metal links, Whiteline Flatout springs and camber bolts.

Anyways, is it possible my rear diff is screwed and now working as an open diff? Is there any way to test that it's working as it should? would a stiffer swaybar on the front perhaps put some more weight on the inside rear?

Cheers

jEstEr? · #2 27-06-2006, 10:46 AM

Hey marcel, long time no see.
I used to have the same issue with my 323. does your car free rev when the wheel is in the air and then bog down when your back on all 4? or does it feel like consistant power the whole way though?

Wheels · #3 27-06-2006, 11:07 AM

Yeh lovin my Raptor at the moment so the WRX has been relegated to second most favorite toy

It does seem to rev out a little when the inside rear is unweighted. It still gets a fair amount of drive but you can definatly feel the lost power from the smoking inside rear and then a burst of drive when all 4's are back on the tarmac. Kinda seems like the LSD is only half doing its job

JMAX · #4 27-06-2006, 11:16 AM

The standard LSD is only a viscous model, it is nothing like a competition type plated/mechanical diff. With a lifted wheel, most power will still get transferred to the light wheel. If you have a plated rear diff, you should get minimal wheel spin.

Wheels · #5 27-06-2006, 12:55 PM

Ahhhh, ok... Well at least theres nothing wrong with my car

In that case i might see if a heavier front bar wont help keep that wheel on the ground... That competition type diff sounds expensive.

subarooboy · #6 02-05-2010, 09:52 AM

Hi guys...

Thought I'd tag onto Marcel's old post here after doing a search.

I currently have R160 2-way Plated rear set up with a 6 Speed DCCD box- Redline Heavyweight in the rear diff etc. Also running 24mm sway bar on mid setting atm.
Since the last track day I am noticing similar things to what Marcel has described here. Car is generally a lot quicker and grippier now, however last event just couldn't put power down through coners, especially tight ones.

Symptoms:
* No power going down to wheels mid corner (or as I start easing throttle on harder)
* Tacho often shows revs climb eratcially- suggesting that something is spinning/ slipping at this point.
* Both power and revs drop back to normal the quicker I can turn the car out of corner
* Occasionally smell tryes which led me to believe it's inner wheel spinning etc
* Auto DCCD settings (off- aggressive etc) make little difference to this experience

Should my rear diff be doing this or have I got a lemon?? The only other idea I've considered is dropping the sway bar setting down to softest in order to get more inner wheel contact but somehow I doubt it is suspension geometry here...

Mister Two · #7 02-05-2010, 10:51 AM

The Clutch packs in the LSD could be wearing out by now.

Get the car off the ground (preferably on a hoist so you can stand under it) and grab the two rear wheels with your hands and try to turn them in opposite directions. It should be fairly difficult if the LSD is still tight.

If it feels a bit loose you can either get a new clutch pack overhaul kit so that all the plates get replaced with new ones, or you could get a few 0.2mm shim laser cut and just insert one at the either end of the LSD case to see how it feels and add more if you need later. Overhaul kit is definitely the better option.

Japanparts has the R160 plate LSD overhaul kits.

tuna · #8 02-05-2010, 11:23 AM

front swaybar is too soft

subarooboy · #9 02-05-2010, 03:14 PM

Got a 22mm on their stace... plus TEIN HA coilovers, which are a lot firmer than most!

Ludwig- how much are these overhaul kits and how much labour is involved??

Mister Two · #10 02-05-2010, 03:32 PM

the part no on japanparts is 1005G-028-071 and its 17,800 yen. So it'll probably be around the AU$300 mark landed.

Labour is easy. Drop Oil. Diff out. back plate and side bearing carriers out. LSD out. Rattle the crownwheel bolts off. Crownwheel off. 4 Bolts off to separate the the 2 halves of the LSD center. Replace all the plates inside with the kit. Lubricate the plates as you layer them in the LSD casing with gear oil. Assembly is reverse of what I just said. Use locktite on the crownwheel bolts but not the 4 bolts that hold the 2 halves of the LSD together. Those 4 bolts dont need to be very tight as they just hold the LSD together until the crownwheel goes on and really clamps it all up.
There's no need to muck around with adjusting the backlash if you are not changing the bearings. Just make sure the shims that pull out with the side bearing carriers stay with the side they came off with.
You may want to use this chance while the diff is being re-assembled to put in fresh shaft seals and O-rings in the side plates. Clean out as much of the old oil while the diff is apart and then put fresh stuff in when you re-assemble it. Use the OEM metal shim gasket for the back cover plate and dont use any gasket goo or silicone to seal it. Just torque up the cover plate bolts properly 1 quart of oil needed for re-fill.

The LSD will need breaking in once fresh plates go in I think. I don't know what Subaru recommend, but I remember reading Cusco recommend doing slow low throttle figure 8s for their LSDs so Id imagine it would be ok to do the same with a STI plate LSD. Check with Doug. Im not sure if you need to drop the oil and then put fresh oil in that you will actually use.