14.2 in an auto AU??

[Moya]

Originally Posted by XDSLIDER

Lets say you have a car with 180rwkw.

Open Wheel Centre
All 180rwkw are put to the ground by 1 wheel. 180kw wont have much trouble spinning 1 wheel in a straight line.

LSD CENTRE
All 180rwkw are put to the ground by 2 wheels. Therefore you have twice as much effective traction.

When using a high stall convertor, you launch the car in its power band. When you hit the rear wheels with a high amount of power they will spin. It can only compared to dropping a clutch at a given rpm.

If you drop a clutch at 3000rpm, will the back wheels spin????
Thats the same as using a 3000rpm stall.

Hope that makes sense.

LUKE

My point is, a LSD only does work when the car is turning due to the difference in circling diameter made by both wheels. In a straight line, the circle diameter is identical, and even with a solid diff, both wheels will spin at the same time. Correct dumping the clutch at 3000+ will light up the back wheels, but it lights up both back wheels. Not one of them.

The only way that 1 wheel in a straight line can light up is if a) that wheel is in oil b) diff is ed.

[xr8ute]

Moya, you need to recheck your information.

[XDSLIDER]

Originally Posted by Moya

My point is, a LSD only does work when the car is turning due to the difference in circling diameter made by both wheels. In a straight line, the circle diameter is identical, and even with a solid diff, both wheels will spin at the same time. Correct dumping the clutch at 3000+ will light up the back wheels, but it lights up both back wheels. Not one of them.

The only way that 1 wheel in a straight line can light up is if a) that wheel is in oil b) diff is ed.

NO, an open wheel diff only spins 1 wheel. given enough torque or loss of traction both may spin.

EXAMPLE
Jack up the back of a car.take 1 wheel off and put the car down on an axle stand. (1 tyre on the ground and the other in the air) Now you can start the car, put it in drive and hit the gas and the car won't move. why??? Beause 1 wheel is spinning, the diff centre pushes the power to that wheel.(Note: 1 wheel has traction, the other dosent) This is an open wheel diff. The diff will favour the wheel with less traction.

Do the same to a car fitted with an LSD and your garage door will look pretty bad.

The only way to make an LSD single wheel is to provide enough traction to one wheel. SO, your LSD centre is set up to 80ft/lbs. That means it requires 80ft/lbs of torque to slip the centre. So if you put a skinny 185/60/15 retread on 1 back wheel and a 15" wide slick on the other, and drop the clutch only 1 wheel will spin as you have provided enough traction on 1 wheel to exceed the slip rating of your diff centre. However, the car will still move forward as it is only limited slip, not complete slip like an open wheel.

When you are turning, the only reason the centre slips is because the tyres provide enough traction to slip the centre. If you give your diff a higher load rating, it may "hop" when you turn.(I know mine does _2: )

An LSD is not the same as a SOLID or LOCK diff.
As the name says an LSD provides limited slip, so when you are cornering the inside wheel dosen't "hop". With a Solid Or LOCK diff the inside wheel must "HOP" as the 2 axles are locked together and both wheels have to spin the same amount.

LUKE

[Choca]

Hey its been ages since i replied as you can see on my previous post i wanted to know how quick my car would go down the quater ruffly. Unfortunatly i live in the ACT and we have to many greenies so we lost our drag way :( where are the closet drag strips to the ACT??

[jonbays]

Originally Posted by Choca

Hey its been ages since i replied as you can see on my previous post i wanted to know how quick my car would go down the quater ruffly. Unfortunatly i live in the ACT and we have to many greenies so we lost our drag way :( where are the closet drag strips to the ACT??

2 and a half hours to WSID.

[Choca]

WSID?? whats that.....ps dont tease me

[Walkinshaw]

Western Scum(Sydney) International Dragway

[loxxr6]

www.wsid.com.au for more info.

[AUFairmont]

Jonbays.....

Originally Posted by Brenden

The car is an AU Forte, 3.9 diff, dev 5 kit and unichip tuned at JMM...Is running the JMM 3000 series stall which helped drop .2 os 60 foot times now runs 2.0 60 foots as far as I know may be a little less. The car typically runs street tyres but the boys are playing with different tyres now.

Now this is what i was talking about, add to the a manual gearbox something like a nice 5 speed, and shave upto 0.2 seconds off that 14.2 and u would be on about 14 flat lighten the car a little a should be able to pull 13.9's....

my final goal to reach 13.9 or better

Originally Posted by AUFairmont

Jonbays.....




Now this is what i was talking about, add to the a manual gearbox something like a nice 5 speed, and shave upto 0.2 seconds off that 14.2 and u would be on about 14 flat lighten the car a little a should be able to pull 13.9's....

my final goal to reach 13.9 or better

thats my goal to ,but i seem to be going backwards at the moment.
would be great to see an au i6 in the 13's
i reckon hamo's would do it with a 2.0 60 footer.

[slamd ef wagon]

Originally Posted by Moya

Why would an LSD change how a car acts in a straight line?

Link.

with 180rwkw a 5speed and an open wheeler would have heaps of trouble getting traction ova the 1/4 mine hense would greatly affect his time thats why a LSD would be a must

[Stav]

I dont see why 13.9's cant be the new standard ? Just need to take advantage of what youve got.

[INJECTED_250]

Originally Posted by XDSLIDER

Lets say you have a car with 180rwkw.

Open Wheel Centre
All 180rwkw are put to the ground by 1 wheel. 180kw wont have much trouble spinning 1 wheel in a straight line.

LSD CENTRE
All 180rwkw are put to the ground by 2 wheels. Therefore you have twice as much effective traction.

When using a high stall convertor, you launch the car in its power band. When you hit the rear wheels with a high amount of power they will spin. It can only compared to dropping a clutch at a given rpm.

If you drop a clutch at 3000rpm, will the back wheels spin????
Thats the same as using a 3000rpm stall.

Hope that makes sense.

LUKE

An open center diff does not put all its power through one wheel dont know how u came up with that one pull it apart and look at the mechanicals and it should be pretty straight foward . Get a locker and snap an axel, it will fry the tire that has the good axel and u will hardly be able to take of . THat is driving one wheel an open wheel diff defently has bags more traction than that.
An open wheeler diff if the suspension is set up corectly can be made to spin 2. I ran my car with an open center 2 pin dif and it hooked 2 up every time on the strip.
BUT I 100 percent agrea a decent lsd is defently going to be alot beter than an open center as the 4 pin open center diffs loves one leggers

[snortingboost]

Open wheel diffs are a mechanical torque splitter, they will work ok providing the tractive effort is equal to both wheels/axles. Drive/torque is lost to the wheel with the least traction, an lsd/locker removes this from the equation. Injected 250 i agree with you on this one.