I have an 04 Auto Coupe with the performance package. Does this hae the brake LSD or the V-LSD?

04 Coupe Auto/DG/Prem/Nav/Perf

 

If you have the perf. wheel and tire package then I strongly believe you have the V-LSD.

04' G35S 6MT Ivory Pearl, Willow, Premium
Z-Tube / NFC Y-Pipe / Custom Mid-Pipe / 350 EVO Rear Sway/ '03 350Z Shocks and Springs

 

Try locking the driveshaft in place on the 6MT py putting it in gear then spin one wheel. You will find the opposite wheel will spin the oppostie direction. Only, it will be much harder to do so as the viscious coupling will add resistance to the shafts turning in opposite directions.

Laying 2 strips of rubber using an open diff is possible. Traction in both wheels have to be near equal so that the difference in traction between the 2 tires will not be enough to overcome the natural resistance in the differential gears. Put one wheel in dirt or water and the other on dry pavement and do the test again and you'll find quite a different outcome. Assuming of course there is not electronic braking on the wheel that is slipping. Cars with IRS suspensions and open diffs can do this much better than cars with solid rear axles as the torque at the driveshaft will not be trying twist the drivetrain relative to the centerline of the car.

 

"The electronic traction or stability control wouldn't work with an open differential. With power going to one wheel only, braking the non-driven wheel would have little effect."

Actually braking the wheel with less traction will force torque to transfer to the opposite wheel. Pick up the drive wheels on any 2WD car. Put the car in gear and let it idle. Stop the wheel on one side(don't hurt yourself) and you'll notice the free wheel will spin twice as fast. The nature of an open diff is to transfer the torque to the wheel with the least resistance. Adding brake to a slipping wheel will force torque to transfer to the wheel with less resistance.

LSD's are designed to help put torque to the wheel with the most traction. Or at the least, more of it.

 

Why in the world does infiniti put open diff on a G35. Is there any advantages at all, there doesnt seem to be any.

 

The advantage is that its cheap.

04 Coupe Auto/DG/Prem/Nav/Perf

 

QUESTION:

I have an 03.5 Auto...I have documented recently that the left rear inside tire is the one that goes up in smoke with VDC off..at leat when I am take a left turn out of my street...lol...anyway, what do I have. I have every option the car offered minus the Aero Package.

John
03.5 G35 5AT 14.00 @ 100.56 10-06-04
13.74 @ 104.86 GTECH Comp Pro
Grounding * Stillen Air Box * K&N CAI * UR UD CP
Mid Pipe * CrawfordV5.0 * TS * 350Z 170F Stat

 

You definitely have an open diff. No '03 sedan wether auto or stick came with a VLSD.

04' G35S 6MT Ivory Pearl, Willow, Premium
Z-Tube / NFC Y-Pipe / Custom Mid-Pipe / 350 EVO Rear Sway/ '03 350Z Shocks and Springs

 

ok, that's what I thought. So again to recap, what should I expect out of an open differential in a nut shell?

John
03.5 G35 5AT 14.00 @ 100.56 10-06-04
13.74 @ 104.86 GTECH Comp Pro
Grounding * Stillen Air Box * K&N CAI * UR UD CP
Mid Pipe * CrawfordV5.0 * TS * 350Z 170F Stat

 

Well a open diff always applies the same amount of torque to each wheel. So in a turn, the outside wheel is going to be spinning faster than the inner wheel. Thus the limiting factor is going to be obviously the tire and how much traction your good wheel is getting on the ground. So since the torque is being applied 50/50 to each wheel, the slipping wheel is just wasting torque whereas in a LSD that wasted torque is transferred and will be applied to the non-slipping wheel and thus getting better traction. Bascially, with all that said, don't expect much out of an open differential performance wise wether dragging the 1320 or racing on a road course. The limiting factor will be the tires and the conditions of the environment.

04' G35S 6MT Ivory Pearl, Willow, Premium
Z-Tube / NFC Y-Pipe / Custom Mid-Pipe / 350 EVO Rear Sway/ '03 350Z Shocks and Springs

 

Nice explanation, thanks.

What are your thoughts on why then, if I am taking a left hand turn, that my left inside driver's side tire is the one spinning and laying rubber down?

John
03.5 G35 5AT 14.00 @ 100.56 10-06-04
13.74 @ 104.86 GTECH Comp Pro
Grounding * Stillen Air Box * K&N CAI * UR UD CP
Mid Pipe * CrawfordV5.0 * TS * 350Z 170F Stat

 

Not exactly sure what your question is. If your making a left hand turn then your left side wheel is the inner and your right side wheel is the outter. Your outside wheel is spinning faster than the inside wheel is because it has more ground to cover than the inside. In a hard left turn you'll notice that body roll will lean to the right (outside) thus compressing your right side of the supension more toward the ground and rising up on your left (inside) side of your supension. Since the left side is actually being lifted up that left side tire is losing traction since it's not making as much traction as before. In the extreme case the inside tire can lift all the way off the ground and if far enough can roll the car. That's where stiffer springs, better dampened shocks/struts, and sway bars come into play to get rid of that body roll. I think that answers your question. Perhaps a more qualified suspension guru can answer it in a better way. Oh yeah, nice 1320 time with your 5AT!

04' G35S 6MT Ivory Pearl, Willow, Premium
Z-Tube / NFC Y-Pipe / Custom Mid-Pipe / 350 EVO Rear Sway/ '03 350Z Shocks and Springs

 

Thanks Re: the times! :-)

I think that answers me...b/c if the weight is shifted to the outside wheel...even if just for a second...and I punch it...then it makes sense that only the inside driver's side wheel (on a left turn of course) would be the one laying rubber down.

Thanks again!

John
03.5 G35 5AT 14.00 @ 100.56 10-06-04
13.74 @ 104.86 GTECH Comp Pro
Grounding * Stillen Air Box * K&N CAI * UR UD CP
Mid Pipe * CrawfordV5.0 * TS * 350Z 170F Stat

 

Well, not exactly true. It is true if both wheels are on a the same surface (hopefully clean and dry). If however, one wheel is on a slippery surface (ice) and the other on a dry one, all the power will go to the wheel without the traction, and you wont go anywhere. In the begining, this was the reason LSDs were so attractive. It allowed people that lived in snow, to have one wheel on ice and the other on a dry surface to move. It was discovered later, that it was also great for performance.

Lou

 

Actually to correct, body roll is caused by weight transfer. The body roll isn't what causes the wiehgt transfer. Weight transfer is caused by the change in direction/speed.

As far as lifting a wheel, while extreme levels of weight transfer can cause the inside tires of a car to leave the ground, typically the traction in a tire will give before this actually happens. If you are referring to what you see out of some FWD race cars(lifting a rear wheel) it's not a result of weight transfer. It's a result of the bodyroll coupled with a stiff rear anti-roll bar. FWD car owners in their search for a more balanced neutral handling, have to use large, stiff rear sway bars. The overall body roll will be dependent on the overall roll-stiffness. In extreme cases then the front sway bars are relatively soft compared the rear, the body will lean more than if a front bar that is more porportionate to the stiff rear bar is used. As the weight transfers away from the inside rear wheel there is nothing left but the spring to push down on it. When the bar is stiff enough that the spring can not push down hard enough to keep the left rear wheel down while the right side is being compressed, it lifts the wheel.

Generally, a tire will lose it's lateral grip on the road and slide before a car will tip over. Even SUV's will generally slide first. If you watch them perform rollover tests on SUV's you'll notice they have to make some intense transient manuevers to get it to tip over.