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AWD and LSD or spools - discuss !

Posted by A1337STI 
Pete
Pete Remner
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Re: AWD and LSD or spools - discuss !
August 03, 2014 05:49PM
Can't be worse than my clutch diff, it binds and pops and bangs and scares old ladies and little children and you can NOT turn and accelerate at the same time without spinning tires (and you can't turn and coast without the thing binding and crabbing and poppopBANGpopBANG)



Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
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Reamer
Jeff Reamer
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Re: AWD and LSD or spools - discuss !
August 03, 2014 06:30PM
What you dont like titan! lol Still not sure how to spell tighten? That closer.
All of the Nascar teams run lockers. The rules are open torun what you want. Every single car has a locker. Now i didnt go to this past race and confirm but its been pretty well known to be the diff of choice for a moons age in top level stock cars.



First rally 2013
Rally car type AWD subaru
Total rallies as driver 6
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heymagic
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Re: AWD and LSD or spools - discuss !
August 03, 2014 08:08PM
Application info and general info here
http://www.eaton.com/Eaton/ProductsServices/Automotive/AutomotiveAftermarket/Differentials/PCT_221432#tabs-2

Pretty neat if you can find one that works for your application.
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Doivi Clarkinen
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Re: AWD and LSD or spools - discuss !
August 03, 2014 11:22PM
Quote
Morison
Quote
Doivi Clarkinen
Why would they check for that? Diffs were free in PGT class.

Diffs were free but final drives and/or drop gears weren't.

Which is exactly my point, really. No reason to run illegal drop gears when the diffs are free...
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Morison
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Re: AWD and LSD or spools - discuss !
August 04, 2014 12:34AM
Quote
Doivi Clarkinen
Which is exactly my point, really. No reason to run illegal drop gears when the diffs are free...

Except that the drop gear mod wasn't in place of doing diffs it was done in addition to the diffs. (IIRC)



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Driver (7), Co-Driver (44)
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A1337STI
Alex Rademacher
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Re: AWD and LSD or spools - discuss !
August 04, 2014 12:45PM
So really all i need is a drop gear and i can forget all my diffs. smiling smiley

how much Tork, sorry Jam do i use when i Titan up the transmission when i'm all done?

on a serious note, what does grinding down the ramps do for the Clutch pack LSD Diff? does that make it lock up faster? / more break away torque ?


I found a good lead on a cheap (not used in the US) 20 kg center. its phase 1 though. I do have a phase 1 transmision but i found a phase 2 (2002) one with better gears (outback)

we may look at moving the gears over to the phase 1 and using 20kg center .. cause i should be able to do it really cheap.

Then i'll have 20kg center, and a subaru mechanical LSD rear . i think its a 1-way
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Nubby
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Re: AWD and LSD or spools - discuss !
August 04, 2014 01:05PM
Quote
A1337STI
on a serious note, what does grinding down the ramps do for the Clutch pack LSD Diff? does that make it lock up faster? / more break away torque ?

Then i'll have 20kg center, and a subaru mechanical LSD rear . i think its a 1-way

To lock the diff under accel/decel, the pinion stub shaft tries to split the carrier via the ramps and the carrier pushes on the clutch packs. If you look at it from overhead so the clutch packs look like vertical lines and the carrier is split in the middle you can see in your head how it works.

Now take the extreme case, a ramp angle of 90*, if you look at it from overhead, that's essentially a "shelf" and pushing on it won't split the carrier. So as you lower the angle, it's going to push on the clutch packs harder.

And you can probably figure out that the angles on one side of the shaft are for accel and the on the other side are for decel. If you have a 90* angle on one side, it's a 1-way diff, there's no dynamic lockup in that force direction which usually is decel.

I even found a pic of a Ralliart diff where you can see the gear shaft peeking through and the ramp angles:



All this has nothing to do with breakaway torque. The clutch pack will have some sort of spring arrangement helical or belleville that will pre-load the clutch packs that in part determines breakaway torque. Obviously the friction of the clutch packs matter, you can put shims or more discs to up the breakaway torque, etc..

And as an aside, the salisbury diff is clever as shit.



Edited 3 time(s). Last edit at 08/04/2014 01:57PM by Nubby.
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A1337STI
Alex Rademacher
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Re: AWD and LSD or spools - discuss !
August 04, 2014 03:03PM
Ah, gotcha. now that is very cool.

so on a 1-way one side would have an angle and the other is gonna be a 90 degree "ramp" but you can grind that into some sorta angle and then its a 2-way? (or perhaps its a 1.5 way if you only added a little bit of ramp)

I believe 1 of the 3 clutch pack R160s i have is a 2-way . From the picture and awesome information sharing above i should be able to figure that out very easily if i just take them apart . or take the LSD part out of the carrier ... smiling smiley

I guess the Ideal thing to do would be for me to actually try out both and see if i Like the locking under Decel/braking or not.



... and an other Question (maybe dumb)

would a 1-way or a 2-way last longer in-between rebuilds ? I would think the 1-Way would last longer due to paved Transits . every time i'm deceling or braking (maybe to go around a highway off ramp) the 2-way is trying to lock up , and if the paved friction is higher than the break away TQ its not going to be able to, but it will try (thus wearing down)

where as the 1-way won't be trying to do anything under Decel/ brake/ coast and should only be wearing out when i'm on the gas, turning, and too much grip forces the lsd to differentiate output speeds .
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john vanlandingham
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Re: AWD and LSD or spools - discuss !
August 04, 2014 03:14PM
Quote
Nubby
Quote
A1337STI
on a serious note, what does grinding down the ramps do for the Clutch pack LSD Diff? does that make it lock up faster? / more break away torque ?

Then i'll have 20kg center, and a subaru mechanical LSD rear . i think its a 1-way

To lock the diff under accel/decel, the pinion stub shaft tries to split the carrier via the ramps and the carrier pushes on the clutch packs. If you look at it from overhead so the clutch packs look like vertical lines and the carrier is split in the middle you can see in your head how it works.

Now take the extreme case, a ramp angle of 90*, if you look at it from overhead, that's essentially a "shelf" and pushing on it won't split the carrier. So as you lower the angle, it's going to push on the clutch packs harder.

And you can probably figure out that the angles on one side of the shaft are for accel and the on the other side are for decel. If you have a 90* angle on one side, it's a 1-way diff, there's no dynamic lockup in that force direction which usually is decel.

I even found a pic of a Ralliart diff where you can see the gear shaft peeking through and the ramp angles:



All this has nothing to do with breakaway torque. The clutch pack will have some sort of spring arrangement helical or belleville that will pre-load the clutch packs that in part determines breakaway torque. Obviously the friction of the clutch packs matter, you can put shims or more discs to up the breakaway torque, etc..

And as an aside, the salisbury diff is clever as shit.

Nice piccie.
here's looking inside:

The side gears, planet gears and cross shafts are all nestled in the 2 "Pressure rings".
Pressure rings have lugs splining them to the case which you can see in the square form grooves...---and in modern stuff---like last12-14 years you may have shorter "big fawkin teeth----like 4 groups of gigantor splines with a 45* PA which is way better-er-er cause they can be shorter (leaving more area for friction on the discs and plates and for drastically less stress from the 45* thing vs the 90* which makes stresses in the L of the plate..) Like this: SEE drive and coast ramp angles in 120'clock ish position



So the power flow comes in from ring gear--which is bolted (most of the time except sometime in my Saab) to the diff case and the ring gear goes ----> that moves the case ----> and the cross shaft pushing on the ramps pushes them this way V and that way ^ and that pushes on the clutch discs and plates---which are splined to the side gears into which we have half shafts plugged in..

Changing the angle of the notches---ramps in the pressure rings---changes the rate the cross shaft ride up them and hence rate and max lock up effect...

In the beginning there was the 45* pressure angle---makes a 90* angle seen from above...
Then in mid 70s Ford came up with 30* PA "pressure angle" for a harder lock and Escort dominated...
When the mid 90s came along and much of the rally world did mostly asphalt and people saw how nicely "active" diffs worked (bazzillion dollar clutch plate diffs with elector-hydraulic pressure varying according to what some genius tech nerd decided was needed), and they worked especially well on asphalt, the idea of alternate angles on COAST was introduced so the asphalt guys could get nicer turn in and then progressive lock up on exits..

Interestingly in the years Tommi Mäkinen was being Tomi, Team Manager and ex-Dubya Aresey drive Andrew Cowan of Ralli-Art fame was axed about if they were using active diffs all over 9gotta be some "trick" to 'splain Tomi"s results) and he said "No, clutch plate rear and front"
When questioned like "Huh? No active, Oh Noez!!!" he siad

"It may not be the most sophisticated set up, but with a clutch plate diff, you know what you have."

After all the infinite wisdom generously shared here by people far smarter than Cowan, and far faster than Mäkinen, I look back and can't help wonder how virtually all the world has been fooled into wasting time on Salisbury type diffs when it's been proven right here that lockers are the best set up?



John Vanlandingham
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Edited 2 time(s). Last edit at 08/04/2014 03:16PM by john vanlandingham.
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A1337STI
Alex Rademacher
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Re: AWD and LSD or spools - discuss !
August 04, 2014 05:52PM
That actually does make a heck of a lot of sense now smiling smiley



too bad my R160 trade for a 20KG center fell through.. that would have been perfect and 0$ out of pocket (the best type of upgrade LOL)
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Doivi Clarkinen
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Re: AWD and LSD or spools - discuss !
August 04, 2014 06:10PM
Quote
Morison
Quote
Doivi Clarkinen
Which is exactly my point, really. No reason to run illegal drop gears when the diffs are free...

Except that the drop gear mod wasn't in place of doing diffs it was done in addition to the diffs. (IIRC)

Well then that is even more idiotic and unnecessary. But it was on the internet so it must be the hot ticket...
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Doivi Clarkinen
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Re: AWD and LSD or spools - discuss !
August 04, 2014 06:17PM
Quote
A1337STI
So really all i need is a drop gear and i can forget all my diffs. smiling smiley

how much Tork, sorry Jam do i use when i Titan up the transmission when i'm all done?

on a serious note, what does grinding down the ramps do for the Clutch pack LSD Diff? does that make it lock up faster? / more break away torque ?


I found a good lead on a cheap (not used in the US) 20 kg center. its phase 1 though. I do have a phase 1 transmision but i found a phase 2 (2002) one with better gears (outback)

we may look at moving the gears over to the phase 1 and using 20kg center .. cause i should be able to do it really cheap.

Then i'll have 20kg center, and a subaru mechanical LSD rear . i think its a 1-way

You can swap center diff sections back and forth between phase 1 and 2 transmissions, it's a direct bolt up either way. The only thing you have to watch out for is the transfer gear situation. The early center diff section uses 1:1 transfer gears so it's not going to work for an early WRX unless you're using the same R&P ratios fron and rear.

A phase 2 gearset will not work in a phase 1 transmission case because they moved the position of the reverse idler gear by 1mm and shit won't mesh.
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A1337STI
Alex Rademacher
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Re: AWD and LSD or spools - discuss !
August 05, 2014 03:34PM
wow you just saved me (well mostly my crew chief) a lot of wrenching time .

our phase 2 transmission is a 2002 Outback

far as i can tell it does the normal 1:1 transfer gears as both its front and rear FD ratios are 4.11

thanks mr Clarkinen smiling smiley

I'll be getting a slightly longer 1st and 2nd gear , and a much shorter 5th by moving over to the outback transmission. i **think** the gears are slightly wider and there for maybe stronger as well.

but it was a free upgrade for me (also gives me a spare transmission) so i jumped @ the chance.
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Cosworth
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Re: AWD and LSD or spools - discuss !
August 06, 2014 08:57PM
Quote
john vanlandingham
When the mid 90s came along and much of the rally world did mostly asphalt and people saw how nicely "active" diffs worked (bazzillion dollar clutch plate diffs with elector-hydraulic pressure varying according to what some genius tech nerd decided was needed), and they worked especially well on asphalt, the idea of alternate angles on COAST was introduced so the asphalt guys could get nicer turn in and then progressive lock up on exits..
Test and trial there amigo. Back in the 90's teams were running over 100k kilometers in testing alone. And in group A, some cars were so sad that if it werent for active diffs they werent drivable in anything twisty and slow.... *cough**cough* escort cosworth*cough* by 94/95 Ford HAD to go active cause the escort was shite... understeering just as bad as the Saphire 5 years before.
Quote
john vanlandingham
Interestingly in the years Tommi Mäkinen was being Tomi, Team Manager and ex-Dubya Aresey drive Andrew Cowan of Ralli-Art fame was axed about if they were using active diffs all over 9gotta be some "trick" to 'splain Tomi"s results) and he said "No, clutch plate rear and front"
When questioned like "Huh? No active, Oh Noez!!!" he siad
Not true, they had active center and fronts, he only started winning rallies with the Evo in 96 and by then everybody was on it.
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john vanlandingham
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Re: AWD and LSD or spools - discuss !
August 06, 2014 11:07PM
Maybe Cowan's memory was mistaken

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Mitsubishi Lancer Evolution I, II, III

Engine


No. cylinder


4 in line

CC (x1.7 if turbocharged)


1997 (3395)

Bore / Stroke (mm)


85 / 88

Comp. Ratio


8.5:1

Max.Power (bhp)


300

Revs.


7000

Max.Torque (kg/m)


45

Revs.


4500

Induction


ECI Multi Injection

Turbo


Mitsubishi

No. Valves


16

No. + Position Cams


2 Overhead Camshaft

Location


Front-Transverse

Transmission


Location


4WD

Differential (Front-Central-Rear)


All Mechanical


Clutch (Manufacturer)


Carbon 1 plate

Gearbox (Manufacturer)


6 speed

Brakes


Front / gravel


DV315

Front / asphalt


DV355

Rear / gravel


DV280

Rear / asphalt


DV280

Suspension (shock absorbers)


Front


McPherson

Rear


Multilink Independent

Dimensions


Length (mm)


4310

Widht (mm)


1695

Height (mm)


1395

Wheelbase (mm)


2500

Front track (mm)


1450

Rear track (mm)


1460

Weight (kg)


1205

Date 1st Homologation (number)


1.1.1993 (A5469)

1st Major Rally


Monte Carlo 1993

Debut: Lancer Evolution II


Greece 1994

Debut: Lancer Evolution III


Corsica 1995

WRC Wins (7)


Sweden 1995 (Eriksson)


Australia 1995 (Eriksson)


Sweden 1996 (Mäkinen)


Kenya 1996 (Mäkinen)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Mitsubishi Lancer Evolution IV, V, VI & 6.5 / Carisma GT

Engine


No. cylinder


4 in line

CC (x1.7 if turbocharged)


1997 (3395)

Bore / Stroke (mm)


85 / 88

Comp. Ratio


8.5:1

Max.Power (bhp)


300

Revs.


6000

Max.Torque (kg/m)


55

Revs.


3500

Induction


ECI Multi Injection

Turbo


Mitsubishi

No. Valves


16

No. + Position Cams


2 Overhead Camshaft

Location


Front-Transverse

Transmission


Location


4WD

Differential (Front-Central-Rear)


Active-Active-Active


Clutch (Manufacturer)


Carbon (AP) 3 plate

Gearbox (Manufacturer)


6 speed sequential (Xtrac)

Brakes


Front / gravel


DV310

Front / asphalt


DV368

Rear / gravel


DV280

Rear / asphalt


DV280

Suspension (shock absorbers)


Front


McPherson (Öhlins)

Rear


Multi-link+Coil (Öhlins)

Dimensions


Length (mm)


4350

Widht (mm)


1770

Height (mm)


1395

Wheelbase (mm)


2510

Front track (mm)


1530

Rear track (mm)


1525

Weight (kg)


1230

Date 1st Homologation (number)


1.1.1997

1st Major Rally


Monte Carlo 1997

Debut: Lancer Evolution V


Catalunya 1998

Debut: Lancer Evolution VI


Monte Carlo 1999

Debut: Lancer Evolution 6.5


Monte Carlo 2001

WRC Wins (19)


Portugal 1997 (Mäkinen)


Spain 1997 (Mäkinen)


Argentina 1997 (Mäkinen)


Finland 1997 (Mäkinen)


Sweden 1998 (Mäkinen)


Kenya 1998 (Burns)


Argentina 1998 (Mäkinen)


Finland 1998 (Mäkinen)


Italy 1998 (Mäkinen)


Australia 1998 (Mäkinen)


Great Britain 1998 (Burns)


Monte Carlo 1999 (Mäkinen)


Sweden 1999 (Mäkinen)


New Zealand 1999 (Mäkinen)


Italy 1999 (Mäkinen)


Monte Carlo 2000 (Mäkinen)


Monte Carlo 2001 (Mäkinen)


Portugal 2001 (Mäkinen)


Kenya 2001 (Mäkinen)
Mistubishi Lancer Evolution VI

Mitsubishi Carisma GT

Mitsubishi Lancer Evolution V



Mäkinen, Tomi:First win



1994


WRC FIN
Driver

Mäkinen Tommi


Ford Escort RS Cosw. oh noez


Oddly my memory of my own 4x4 Sierra---and the Sapphire is just a UK marketing name---
Isn't at all an understeering pig, it seems like "the perfect" RWD car---just RWD enough plus a bit of grip in the front...

And the guy I got my personal rear shocks from off his works spec 94-95 Escort Cosworth said of the car "just about perfect" and more or less "all the problems of the Sierra on asphalt were solved (referring to the large overhang in the rear--I asked)
And if it was such shite, it sure did good first time out 1 and 2 at a dry no-snow Monte Carlo 1993 untill the last stage
And relative newcomer De la Cour:




1993










21


MC


Ford Escort RS Cosworth


DG


2




22


P


Ford Escort RS Cosworth


DG


1




23


F


Ford Escort RS Cosworth


DG


1




24


GR


Ford Escort RS Cosworth


DG


engine




25


NZ


Ford Escort RS Cosworth


DG


2




26


AUS


Ford Escort RS Cosworth


DG


3




27


I


Ford Escort RS Cosworth


DG


accident




28


E


Ford Escort RS Cosworth


DG


1




29


GB


Ford Escort RS Cosworth


DG


4

Pretty good for a piece of shit



John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.
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