That just doesn't sound right. My truck for example is what we call a "one wheel wonder". U just simply can't get both to spin. Not if it's wet. Not in mud. Not in the air. Not even while turning. (differential effect) I'm definitely not an expert on this, but I've always thought that if it wasn't LSD, only 1 will spin. (with the exception of a "true posi-traction" unit)



I also heard that all FC's were LSD's. The only differences were the ratios. (4.1 vs. 4.3) I have a base model SE that I would think is LSD. Both wheels spin together very easily. I am 3rd owner & I know pevious owners didn't change the diff. I have never had it to spin only 1 wheel @ a launch, whether soft or hard.



Aight, just so I didn't feel stupid by posting this, I found something to back me up. If U have a Haynes, turn to page 27. (this book covers all FC's...i.e. S4's, S5's, turbos, etc.) Under diff. lubricant, it says LSD(all). Correct me if I'm wrong, but doesn't "all" include S4 & S5 SE's, TII's, verts, GXL's, GTU's, GTUs's, and whatever the hell else I may have left out?

1: not all FC's have LSD

2: I've been in cars with open diffs that would light em both up, I've also been in cars that would not, this depends on a great number of variables... tire differences, IRS or not, weight distribution... these are all variables a LSD has more immunity to regarding getting torque to both wheels, where a standard differential will generally end up putting all the torque to the side easiest to turn.



My coworkers truck, a piece of **** ford splash, can get them both spinning if there is a passenger in the car of similar weight to him, and no offset load in the back (or if it is offset, preferably on the passenger side).



when you have no LSD or other torque sensing/directing device, it is more difficult, but certainly not impossible to get both spinning.



I've done burnouts and donuts in my FC with the open diff, it just takes a bit more effort to do. I had LSD initially but broke it doing 2nd gear donuts, then picked up a open diff from a S5 GXL in the junk yard (LSD is an option on this model) and ran that for the rest of the summer. Now another 4.1 LSD is going back into the car, it certainly is annoying to only spin one wheel in most WOT turns.



LSD is certainly better though https://www.nopistons.com/forums/pub...#>/biggrin.png



BTW I've also ordered diffs from mazda dismantling and every time requested an LSD, most of the time they shipped a open diff and had to send another out, sometimes multiple attempts required before they managed to get an LSD to me. It seems like the open diffs are far more common.

ok, where can I bet a GTUs rear end? or just the 4.30gear and diff?

Racingbeat.com

Mazdatrix.com

Rx7.com

They all sell the 4.30 final drive ratios. They are around $400 - $500 for the ring and pinion gear ONLY. I'm sure you can expact at least another $300 to have it installed. Not worth the money, IMO.

Yea, well when I get more power and need a Diff I might consider it well untill then I am cool, well right now at wot in corners i dont burn up the inside wheel, even on hair pins like turn 11 at sears point raceway.

That happens to be the same truck I have. Well, not a Splash, but the same thing. (all 2WD's had 7.5 rears) I can nail the throttle on my truck and the passenger wheel will sit there and spin. I don't even have to power brake it. (needless to say, it is modded out the watusi) No matter how the weight is distrubuted, the driver's side WILL NOT SPIN. It sounds to me like your coworker INDEED HAS a 7.5 LSD. Ask him and see. If he doesn't, that 2nd wheel isn't lightin' up. This is my 3rd Ranger and my brother has 1 as well. 1 of mine was LSD, the other 2 were not. The LSD (8.8 4X4 BTW) was the only 1 that would spin both. It's not IRS. The tires are the same. There are no other factors. It just won't spin.



Back when I considered a V-8 swap in this car, I visited Grannys Speed Shop, who are notoriously involved with the RX-7 swap. They told me all 2nd Gens. were LSD. Aight, if my SE isn't LSD then why do both spin together so easily? If it don't have to be LSD to spin, then what would be the difference in an open differential and an LSD?

I believe there is a difference in how it affects handling, in the corning power etc. Not just power distribution from a dead stop.

its because your truck has a solid axle. the engine torque tries to lift the passenger side of the diff, since on your truck the wheel is connected to the diff it can lift the right wheel and push the left one on the ground. thats why a solid rear will always spin one tire if it doesnt have an lsd.

the fc on the other hand, does not have the diff conected to the wheel. so it cannot pick up on wheel. thats is why they both spin on an fc, no matter what.



mike

my 89 GTU did left two strips but i was dropping the clutch at 8k rpm https://www.nopistons.com/forums/pub...#>/biggrin.png

And i thought i abused my vert. Hardest ive went is 6k. If i went any harder than that i'd break something.