| speedyHAM | 10-14-2006 12:13 AM |
LSD for Autocross
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How much of a difference do LSD's make in Autocross?
I have a GC with a WRX engine (in SM obviously) with open front and rear diffs. How much of a benifit would a good lsd setup be for autocross? A lot? None? 1 second on a 30 second course? Lend me your opinions if you know something. Thanks.
-S
I have a GC with a WRX engine (in SM obviously) with open front and rear diffs. How much of a benifit would a good lsd setup be for autocross? A lot? None? 1 second on a 30 second course? Lend me your opinions if you know something. Thanks.
-S
| Kostamojen | 10-14-2006 01:29 AM |
1 second on a 30 second course, maybe... Yes it does help, especially if you have a bit of power like you do. I'm underpowered for my front and rear LSD :p
| bknblk | 10-14-2006 02:17 PM |
[QUOTE=speedyHAM;15608371]How much of a difference do LSD's make in Autocross?
-S[/QUOTE]
They make you see all kinds of pretty colors. I 'm guessing they would have a negitive effect on your times but you wouldn't care. :banana: :alien: :cool:
I have nothing useful to add...
-S[/QUOTE]
They make you see all kinds of pretty colors. I 'm guessing they would have a negitive effect on your times but you wouldn't care. :banana: :alien: :cool:
I have nothing useful to add...
| xdrian | 10-14-2006 06:00 PM |
from what i hear; when you dont have lsd and you are going out of a turn you understeer a little and the car tends to slide out. When you do have lsd the car will hook and start to pull around the turn.
| adhowe70 | 10-14-2006 08:24 PM |
I see answers but no one has asked the important question:
Which differential do you want to install the LSD unit into? Whether its a front or a rear will change my answer.
Which differential do you want to install the LSD unit into? Whether its a front or a rear will change my answer.
| Master2192 | 10-14-2006 08:37 PM |
I hear good things about doing a Front LSD (good thread on the OBX one as well) and leaving the rear open diff.
You may have to try different strength/type of LSDs in the front or rear, or center, to match your driving type. I am personally going to mess with my suspension first before playing with differentials.
You may have to try different strength/type of LSDs in the front or rear, or center, to match your driving type. I am personally going to mess with my suspension first before playing with differentials.
| Kostamojen | 10-14-2006 11:23 PM |
Ya start with suspension first, my last Impreza was all open diffs and was damn fast in terms of handling... (not as fast as my current impreza, but still fast)
| Homemade WRX | 10-14-2006 11:58 PM |
trust me he has suspension done...Sean, I think doing a front lsd will definately help with corner exits...and right now you can pick up rear clutch type (oem) rear ends with axles for $190 on ebay. I already picked mine up
| Kostamojen | 10-15-2006 12:05 AM |
What would help the most would be the Cusco center diff with the extra rear bias...
| SR20gawd | 10-15-2006 10:42 PM |
Agreed. The Cusco Tarmac diff is amazing. Only bad part is that to be able to use the Tarmac diff to it's full potential you really should have good LSD's in both front and rear diffs. The Tarmac diff is not a limited slip.
| speedyHAM | 10-16-2006 11:02 AM |
The suspension is already highly tuned. Neal Tovsen was really impressed yesterday with how well it handles. I drove his car and it was unbelievable. I want to get closer to that. I am thinking front and rear LSD's, as doing one end without the other would just make my current issues worse. The suspension will need a re-tune after LSD's are added to take advantage of the new power delivery capability.
This Cusco center diff you speak of- where can I find one?
Thanks for all those who added something.
This Cusco center diff you speak of- where can I find one?
Thanks for all those who added something.
| DumbUglyDragon | 10-16-2006 11:16 AM |
IIRC Rallispec used to carry them but I dont find pricing on their website anymore??
Nukabe can get you anything Cusco:
[url]http://www.napsusa.com/cgi-bin/napsusa/665-020-A.html[/url] ??
Nukabe can get you anything Cusco:
[url]http://www.napsusa.com/cgi-bin/napsusa/665-020-A.html[/url] ??
| c'dalerider | 10-16-2006 11:24 AM |
[QUOTE=Master2192;15614772]I hear good things about doing a Front LSD (good thread on the OBX one as well) and leaving the rear open diff.
You may have to try different strength/type of LSDs in the front or rear, or center, to match your driving type. I am personally going to mess with my suspension first before playing with differentials.[/QUOTE]
i thought you wanted a front open or TB diff and Limited Slip rear. This will help in many ways, brings the back around easier on engin braking and no oversteer (front diff will not lockup on turns)....
This is for Rear Wheel drive cars, adding a TB to a front AWD car will work.........
TB diff> [COLOR="Blue"]These differentials function almost totally as an open differential while off throttle, which makes them vastly inferior to a limited slip differential, as you will see. I have always considered this style differential to have very limited usefulness on a race course,
Limited-slip differentials provide lock-up on both acceleration and deceleration. The amount of lock-up on accel and decel can be adjusted by selection of the internal plate sequence. Lock-up on deceleration allows aggressive entry into a turn and late braking, reasons why all Pro race teams (that we are aware of) utilize LSDs, rather than TBDs.
Torque-biasing differentials provide lock-up on acceleration only. The amount of lock-up (5-80%) increases as the amount of torque increases. [B]On deceleration, lock-up is negligible,[/B] making the TBD the ideal diff for the slower speed turns of autocross. (In the same slower-speed turns, an 80% LSD would most certainly cause understeer.)
A torque-biasing differential performs like an open diff whenever one of the two drive wheels lifts off the ground. Lock-up and traction are lost until both drive wheels are again planted firmly on the ground.[/COLOR]
You may have to try different strength/type of LSDs in the front or rear, or center, to match your driving type. I am personally going to mess with my suspension first before playing with differentials.[/QUOTE]
i thought you wanted a front open or TB diff and Limited Slip rear. This will help in many ways, brings the back around easier on engin braking and no oversteer (front diff will not lockup on turns)....
This is for Rear Wheel drive cars, adding a TB to a front AWD car will work.........
TB diff> [COLOR="Blue"]These differentials function almost totally as an open differential while off throttle, which makes them vastly inferior to a limited slip differential, as you will see. I have always considered this style differential to have very limited usefulness on a race course,
Limited-slip differentials provide lock-up on both acceleration and deceleration. The amount of lock-up on accel and decel can be adjusted by selection of the internal plate sequence. Lock-up on deceleration allows aggressive entry into a turn and late braking, reasons why all Pro race teams (that we are aware of) utilize LSDs, rather than TBDs.
Torque-biasing differentials provide lock-up on acceleration only. The amount of lock-up (5-80%) increases as the amount of torque increases. [B]On deceleration, lock-up is negligible,[/B] making the TBD the ideal diff for the slower speed turns of autocross. (In the same slower-speed turns, an 80% LSD would most certainly cause understeer.)
A torque-biasing differential performs like an open diff whenever one of the two drive wheels lifts off the ground. Lock-up and traction are lost until both drive wheels are again planted firmly on the ground.[/COLOR]
| zzyzx | 10-16-2006 12:13 PM |
Replace in this order: front, rear, center
Front: Torsen or clutch type 1-way. I have a Quaife.
Rear: Clutch type (1, 1.5 or 2 way). I have a CUSCO 1.5 way.
Center: CUSCO tarmac 35/65. I have the tarmac gear.
Front only: Will reduce understeer on corner exit under power. By itself, an excellent upgrade, particularly if you make a lot of power.
With all three diffs in my Impreza, it drives like a RWD car. Power overtseer on demand. It really doesn't resemble how a stock Impreza handles on the power at all.
Most people overlook the fact that the stock center diff has limited slip function. This becomes readily apparent when you don't have this - such as using the tarmac gear. You CANNOT upgrade to the tarmac w/o first doing front and rear. Well, you can, of course, just not if you want your car to handle worth a damn.
Front: Torsen or clutch type 1-way. I have a Quaife.
Rear: Clutch type (1, 1.5 or 2 way). I have a CUSCO 1.5 way.
Center: CUSCO tarmac 35/65. I have the tarmac gear.
Front only: Will reduce understeer on corner exit under power. By itself, an excellent upgrade, particularly if you make a lot of power.
With all three diffs in my Impreza, it drives like a RWD car. Power overtseer on demand. It really doesn't resemble how a stock Impreza handles on the power at all.
Most people overlook the fact that the stock center diff has limited slip function. This becomes readily apparent when you don't have this - such as using the tarmac gear. You CANNOT upgrade to the tarmac w/o first doing front and rear. Well, you can, of course, just not if you want your car to handle worth a damn.
| Scooby921 | 10-16-2006 12:15 PM |
I autocrossed a WRX with a 1.5-way rear diff a couple weekends ago. I didn't like it at all in the corners. A lot of it was due to suspension setup. The suspension isn't all that great and the way the car was setup it 3-wheeled in the corners. When that happened the car just died. The diff sent most of the power to the spinning wheel, and when it finally touched down the car only bogged more. And reading the above post its sounding like it operated as a TB diff...
| Crazykev | 10-16-2006 12:19 PM |
Same here with my Tarmac center diff. The car really does handle and act like a RWD.
I run an OBX helical front diff, V6 sti RA rear suretrac and the Tarmac center.
I run an OBX helical front diff, V6 sti RA rear suretrac and the Tarmac center.
| IT Swift | 10-16-2006 12:23 PM |
[quote=Homemade WRX;15616066]and right now you can pick up rear clutch type (oem) rear ends with axles for $190 on ebay[/quote]
OEM lsd's on wrx's are not clutch type, they're viscous.
OEM lsd's on wrx's are not clutch type, they're viscous.
| dwx | 10-16-2006 12:59 PM |
I liked the Kaaz 1.5 way I had in the rear of my SM WRX although it's really damn noisy and good luck getting the axle out of the diff once it's in there... When I with a new front I put in a Cusco 1-way but I haven't really driven that car much to test it out.
| makofoto | 10-16-2006 02:27 PM |
My added front Spec C helical Torsen2 LSD didn't help my SM WRX very much. I didn't have enough droop in my coilovers to keep the inside wheels on the ground. So, suspension first.
[IMG]http://images15.fotki.com/v233/photos/4/43793/2786343/2WheelingMako-vi.jpg[/IMG]
[IMG]http://images15.fotki.com/v228/photos/4/43793/2687469/MakobyAlbert39_95-vi.jpg[/IMG]
[IMG]http://images15.fotki.com/v233/photos/4/43793/2786343/2WheelingMako-vi.jpg[/IMG]
[IMG]http://images15.fotki.com/v228/photos/4/43793/2687469/MakobyAlbert39_95-vi.jpg[/IMG]
| Kostamojen | 10-16-2006 04:36 PM |
Lifting your rear wheels is going to hurt the operation of a rear LSD.
I'd go with Crazykev's setup if I could afford to, I already have the OBX front and enjoy it a ton.
I'd go with Crazykev's setup if I could afford to, I already have the OBX front and enjoy it a ton.
| Homemade WRX | 10-16-2006 11:18 PM |
[QUOTE=zzyzx;15629364]Replace in this order: front, rear, center
Front: Torsen or clutch type 1-way. I have a Quaife.
Rear: Clutch type (1, 1.5 or 2 way). I have a CUSCO 1.5 way.
Center: CUSCO tarmac 35/65. I have the tarmac gear.
Front only: Will reduce understeer on corner exit under power. By itself, an excellent upgrade, particularly if you make a lot of power.
With all three diffs in my Impreza, it drives like a RWD car. Power overtseer on demand. It really doesn't resemble how a stock Impreza handles on the power at all.
[/QUOTE]
I can attest to this having driven a friends car with the tarmac center (also a cusco 1.5 rear :D)...also as he mentioned, a cucso (essentially open) is horrible with open front and/or rear as you then only peg leg the diff (end of the car) that is getting the power...
Front: Torsen or clutch type 1-way. I have a Quaife.
Rear: Clutch type (1, 1.5 or 2 way). I have a CUSCO 1.5 way.
Center: CUSCO tarmac 35/65. I have the tarmac gear.
Front only: Will reduce understeer on corner exit under power. By itself, an excellent upgrade, particularly if you make a lot of power.
With all three diffs in my Impreza, it drives like a RWD car. Power overtseer on demand. It really doesn't resemble how a stock Impreza handles on the power at all.
[/QUOTE]
I can attest to this having driven a friends car with the tarmac center (also a cusco 1.5 rear :D)...also as he mentioned, a cucso (essentially open) is horrible with open front and/or rear as you then only peg leg the diff (end of the car) that is getting the power...
| Homemade WRX | 10-16-2006 11:20 PM |
[QUOTE=IT Swift;15629502]OEM lsd's on wrx's are not clutch type, they're viscous.[/QUOTE]
never said it was a usdm wrx rear end...it's an imported old school clutch type rear end...
never said it was a usdm wrx rear end...it's an imported old school clutch type rear end...
| IT Swift | 10-17-2006 07:38 AM |
[quote=Homemade WRX;15638567]never said it was a usdm wrx rear end...it's an imported old school clutch type rear end...[/quote]
:rolleyes:
:rolleyes:
| Homemade WRX | 10-17-2006 10:44 AM |
[QUOTE=IT Swift;15641009]:rolleyes:[/QUOTE]
:confused:
feelings hurt or don't believe it is a clutch type?...
:confused:
feelings hurt or don't believe it is a clutch type?...
| MattNJ2.8 | 10-17-2006 11:29 AM |
[QUOTE=makofoto;15631499][IMG]http://images15.fotki.com/v233/photos/4/43793/2786343/2WheelingMako-vi.jpg[/IMG]
[/QUOTE]
That looks like a cool venue. Where was that pic taken?
[/QUOTE]
That looks like a cool venue. Where was that pic taken?
| Scoobyslack1 | 10-17-2006 04:16 PM |
I had an STi mechanical front diff, STi 20kg center and old Legacy turbo viscous LSD in my car last year....the front diff made the car pull like mad out of corners. I would just hammer the gas 1/2 way through the corner and point where I wanted to go. The rear has been upgraded to an STi 2-way, but I haven't driven the car yet.
I did the front and center at the same time to save labor of pulling/opening the tranny twice.
I did the front and center at the same time to save labor of pulling/opening the tranny twice.
| Storm | 10-18-2006 10:56 AM |
The OEM type he's referring to is not from a WRX...but from older scoobs that had real LSDs.... Get them while you can though, the 510 guys are also snapping them up and the boneyards are getting thinner and thinner.
[quote=IT Swift;15629502]OEM lsd's on wrx's are not clutch type, they're viscous.[/quote]
ZZYZX has the right combo. That is the ultimate autocross setup for the Impreza....hands DOWN.
Jay Storm
[quote=IT Swift;15629502]OEM lsd's on wrx's are not clutch type, they're viscous.[/quote]
ZZYZX has the right combo. That is the ultimate autocross setup for the Impreza....hands DOWN.
Jay Storm
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