Does an 05 STI have a rear LSD?

seattle sti · 05-19-2007, 08:59 PM

I have finally got my suspension figured out for serious track driving by running -2.5 F and -1.6R Camber. Now my car absolutely dives towards the apex, and actually lifts the inside rear wheel. The thing that I did experience however was that when I was powering out of the corner that wheel would momentarily spin untill the tire came in contact with the ground again. My question is How can this happen? I thought that our cars came with a rear LSD. Any advice on this???????

**twiSTies** · 05-19-2007, 09:50 PM

yes..

***MacSTi*** · 05-19-2007, 09:54 PM

Yes it does...

hinshawwrx · 05-19-2007, 10:24 PM

Survey Says....................

Yes!

Greg · 05-20-2007, 08:31 AM

Quote:

Originally Posted by seattle sti

My question is How can this happen? I thought that our cars came with a rear LSD. Any advice on this???????

Some LSDs require that there is some resistance on both tires. Even if one tire is spinning, the slight resistance is enough for the LSD to kick in. A wheel off the ground offers no resistance, a conditon the LSD can't cope with. I'm not LSD expert and if you want more details, it might be good to ask this in the drive train forum.

***wdb*** · 05-20-2007, 01:45 PM

Quote:

Originally Posted by Greg

[,,,] it might be good to ask this in the drive train forum.

Indeed.

***wdb*** · 05-20-2007, 01:47 PM

My own experience is that OMFG YES IT DOES have a rear LSD. However I can't really say that very much of my experience has been with one wheel completely without traction.

supermarkus · 05-20-2007, 01:51 PM

Quote:

Originally Posted by Greg

Some LSDs require that there is some resistance on both tires. Even if one tire is spinning, the slight resistance is enough for the LSD to kick in. A wheel off the ground offers no resistance, a conditon the LSD can't cope with. ...

I believe this is true for torsen type diffs, IIRC the R180 diffs on the STI are mechanical, clutch type LSDs and should lock up with a wheel in the air. I think newer STIs (06 and 07) have a torsen rear lsd though. Please correct me if I'm wrong.

lackskill · 05-20-2007, 06:37 PM

I think these are the diffs by year... some1 correct me if Im wrong.

04: Suretrac F, Helical R
05: Helical F, Helical R
06: Helical F, Torsen R
07: Torsen F, Torsen R

supermarkus · 05-20-2007, 06:42 PM

helical=torsen

**nhsilversti** · 05-20-2007, 07:22 PM

"limited" slip

a clutch/mechanical diff cant hold all the power if a wheel is off the ground and will "slip"

a helical diff will need wheel contact to make it work correctly. helical diffs are just like an open diff if a wheel is in the air.

what you need to do is fix the problem that making you lift a wheel.

**SWortham** · 05-21-2007, 11:14 AM

"Limited" slip is right. I'd expect some power will still be going to the rear tire on the ground. At least that's better than an open diff where practically all the power would be going to the tire that's in the air. This may be something you'll just need to deal with as a driver. In other words, if the suspension is working for you other than this one issue, it may not be worth the trouble of changing the setup.

LilJohn · 05-21-2007, 01:05 PM

my limited experience with LSD's is that there are 3 kinds.
1-way LSD's only work under acceleration
2-way LSD's work under acceleration and engine braking
3-way LSD's work all the time, even when your not accelerating or decelerating

3-way's are what you want for auto-X

j87w · 05-21-2007, 10:40 PM

I believe its actually a 1 way, 1.5 way, and a 2 way. The descriptions of the LSDs are correct but just different "number ways"(I think thats the correct wording).

unclemat · 02-08-2008, 11:29 AM

Quote:

Originally Posted by lackskill

I think these are the diffs by year... some1 correct me if Im wrong.

04: Suretrac F, Helical R
05: Helical F, Helical R
06: Helical F, Torsen R
07: Torsen F, Torsen R

Wrong. Torsen = Helical. It's just brand name for the same concept.

And 04-06 have clutch type rear. Here is corrected table:

04: Suretrac F, Clutch R
05: Helical F, Clutch R
06: Helical F, Clutch R
07: Helical F, Torsen Helical R[/quote]

05-19-2007, 08:59 PM	#1
seattle sti Junior STI Driver Car: 2005 Subaru Aspen Wh Fav Mod: Cobb Springs Location: Seattle, Wa Posts: 151 Join Date: Dec 2005 Trader Rating: (0)	Does an 05 STI have a rear LSD? I have finally got my suspension figured out for serious track driving by running -2.5 F and -1.6R Camber. Now my car absolutely dives towards the apex, and actually lifts the inside rear wheel. The thing that I did experience however was that when I was powering out of the corner that wheel would momentarily spin untill the tire came in contact with the ground again. My question is How can this happen? I thought that our cars came with a rear LSD. Any advice on this??????? This ad is not endorsed by this member. Please register or login to hide this ad.

05-19-2007, 09:50 PM	#2
twiSTies Gold Member Car: 05 Subaru WRX STi Fav Mod: T2s and Recaros Location: Allentown, PA Posts: 3,089 Join Date: Oct 2005 Trader Rating: (6)	Re: Does an 05 STI have a rear LSD? yes..

05-19-2007, 09:54 PM	#3
*MacSTi* I has BOOST! Car: 2005 Aspen White STi Fav Mod: LightWerkz Projector Retrofit Location: Somerset, NJ Posts: 1,850 Join Date: Feb 2006 Trader Rating: (12)	Re: Does an 05 STI have a rear LSD? Yes it does...

05-19-2007, 10:24 PM	#4
hinshawwrx Lurker Car: 04 Subaru WRX Location: Peoria, IL Posts: 6 Join Date: May 2007 Trader Rating: (0)	Re: Does an 05 STI have a rear LSD? Survey Says.................... Yes!

05-20-2007, 01:47 PM	#7
*wdb* dances with roads Posts: 5,021 Join Date: Apr 2005 Trader Rating: (8)	Re: Does an 05 STI have a rear LSD? My own experience is that OMFG YES IT DOES have a rear LSD. However I can't really say that very much of my experience has been with one wheel completely without traction.

05-20-2007, 06:37 PM	#9
lackskill Moderator Car: 05 Ram 3500 CTD Fav Mod: Majin Posts: 14,608 Join Date: Apr 2006 Trader Rating: (9)	Re: Does an 05 STI have a rear LSD? I think these are the diffs by year... some1 correct me if Im wrong. 04: Suretrac F, Helical R 05: Helical F, Helical R 06: Helical F, Torsen R 07: Torsen F, Torsen R

05-20-2007, 06:42 PM	#10
supermarkus Spec C Club Car: 08 STi, SSM Location: Edmonds Washington Posts: 1,441 Join Date: Dec 2005 Trader Rating: (0)	Re: Does an 05 STI have a rear LSD? helical=torsen

05-20-2007, 07:22 PM	#11
nhsilversti Gold Member Car: 06 cgm sti w/ppg dog Fav Mod: RIP 04 psm sti Location: southern nh Posts: 449 Join Date: Sep 2003 Trader Rating: (0)	Re: Does an 05 STI have a rear LSD? "limited" slip a clutch/mechanical diff cant hold all the power if a wheel is off the ground and will "slip" a helical diff will need wheel contact to make it work correctly. helical diffs are just like an open diff if a wheel is in the air. what you need to do is fix the problem that making you lift a wheel.

05-21-2007, 11:14 AM	#12
SWortham Gold Member Car: 06 Subaru WRX STI Fav Mod: Ohlins struts Location: Mckinney, TX Posts: 757 Join Date: Oct 2006 Trader Rating: (0)	Re: Does an 05 STI have a rear LSD? "Limited" slip is right. I'd expect some power will still be going to the rear tire on the ground. At least that's better than an open diff where practically all the power would be going to the tire that's in the air. This may be something you'll just need to deal with as a driver. In other words, if the suspension is working for you other than this one issue, it may not be worth the trouble of changing the setup.

05-21-2007, 01:05 PM	#13
LilJohn Amateur STI Driver Car: 2004 WRX STi Fav Mod: Enginuity, custom ECU reflash Location: OC, California Posts: 35 Join Date: May 2007 Trader Rating: (0)	Re: Does an 05 STI have a rear LSD? my limited experience with LSD's is that there are 3 kinds. 1-way LSD's only work under acceleration 2-way LSD's work under acceleration and engine braking 3-way LSD's work all the time, even when your not accelerating or decelerating 3-way's are what you want for auto-X

05-21-2007, 10:40 PM	#14
j87w Senior STI Driver Car: 06 STi Location: New Mexico Posts: 393 Join Date: Oct 2006 Trader Rating: (1)	Re: Does an 05 STI have a rear LSD? I believe its actually a 1 way, 1.5 way, and a 2 way. The descriptions of the LSDs are correct but just different "number ways"(I think thats the correct wording).