zedsaid Posted February 10, 2007 Share Posted February 10, 2007 I recently bought a 280zx, and am enjoying the hell out of it. Thing is, if the ground is wet (believe it or not, it does happen in LA) the rear end looses all traction in turns. I'm not running anything heavy duty, the car is stock, as far as i know. (though the suspension feels a little stiff, even for a sporty car) I don't really notice any roll. It's an auto, and in a straightaway i'm not laying any rubber, (actually had a tough time keeping up with my brother's '06 tacoma) but the rear end will spin free if i pull a u-ey from the curb (my 7 yr old neice thought that was the coolest thing she'd ever done in a car). I'll admit i'm pushing the car a little hard, and if i drive carefully there shouldn't be a real problem, but i want to be able to take it on the twisties north of San Simeon without the fear of going sideways over a cliff. I'd like to be able to take a turn at twice it's posted speed recomendation (when dry). I'm not looking to go widebody kit, and don't particularly like the fatties sticking out sideways look. What's the widest tire/wheel that'll fit in there and what kind of inset can you get without rubbing the wheel well, springs, etc.? Anything else that i can do to help keep me from ending up sideways in my lane? (so glad i've been able to stay in my lane all three times it's happened) I'm really not driving it that hard (knowing that it's just rained and all) and i'm affraid of what's to come once i get some real power to the wheels. Maybe i should learn how to drift? sorry for the ramble. help appreciated. Quote Link to comment Share on other sites More sharing options...
rudypoochris Posted February 10, 2007 Share Posted February 10, 2007 What is the tire size and what brand/make tire just to get an idea? An LSD would help... Quote Link to comment Share on other sites More sharing options...
260DET Posted February 10, 2007 Share Posted February 10, 2007 Rear subframe bushes are probably buggered, yeh LSD would be good, check why the rear suspension is stiff, check springs and dampers, that will do for a start. All relevant to rear end grip and stability. Quote Link to comment Share on other sites More sharing options...
Twoeightnine Posted February 10, 2007 Share Posted February 10, 2007 Maybe someone welded the diff or it has a problem. An open diff would spin one tire and you would be hard pressed to "kick it" sideways...... Quote Link to comment Share on other sites More sharing options...
Guest TeamNissan Posted February 10, 2007 Share Posted February 10, 2007 Maybe someone welded the diff or it has a problem. An open diff would spin one tire and you would be hard pressed to "kick it" sideways...... Thats a rediculous thing to say, a open diff would kick it sideways even easier. Quote Link to comment Share on other sites More sharing options...
Twoeightnine Posted February 10, 2007 Share Posted February 10, 2007 Thats a rediculous thing to say, a open diff would kick it sideways even easier. Rediculous you say? Not sure that rediculous is the right word but, check out the link and the statement below.... http://www.houseofthud.com/differentials.htm#wacky%20demo%201 So what's wrong with the open diff? The problem is an open diff always tries to balance the torque. That's a hard statement to get a grasp on, but it means that if the spider gears are pushing on both drive gears and one of them offers lots of resistance (tire sitting on pavement or a weight loaded tire on the outside of a turn) and the other side offers no resistance (up in the air, sitting on a patch of ice, or an un loaded tire such as on the inside of a turn), then it will find a happy balance where both sides are receiving almost no torque at all. All the rotational energy is guided to the side with the least resistance. In the end, that side spins very fast and the pressure on each drive gear is the same.. Almost no torque is needed to spin one wheel, and therefore almost no torque is going to the other side as well. Anyone who's driven on snow or ice knows this issue. You find yourself spinning one tire, and going nowhere.... Quote Link to comment Share on other sites More sharing options...
Collectindust240Z Posted February 10, 2007 Share Posted February 10, 2007 Have you never driven a car with an open diff in the snow? Quote Link to comment Share on other sites More sharing options...
Guest TeamNissan Posted February 10, 2007 Share Posted February 10, 2007 I dont even need to read that (although I did). Anyone who has taken a turn in the wet with a open dif and pushed it a little can atest to what I said. I'll wait for more people to chime in instead of arguing the obvious right now though, 10am is too early to argue lol. Quote Link to comment Share on other sites More sharing options...
Twoeightnine Posted February 10, 2007 Share Posted February 10, 2007 Agreed. I need more coffee! While sipping said coffee, I ran into a couple of interesting links. They are very nicely written. Enjoy... http://auto.howstuffworks.com/differential2.htm OPEN DIFFS http://auto.howstuffworks.com/differential3.htm DIFFS and TRACTION http://auto.howstuffworks.com/differential4.htm LIMITED SLIP Quote Link to comment Share on other sites More sharing options...
alexideways Posted February 10, 2007 Share Posted February 10, 2007 The thing is that the open diff will make it way harder to control once you start going sideways... Quote Link to comment Share on other sites More sharing options...
Twoeightnine Posted February 10, 2007 Share Posted February 10, 2007 Thats for sure!!! Ever seen a young'in that borrowed Daddy's F150 or Buick Lesaber try and impress the crowd with some smokey doughnuts. Only to go around in a perfect circle with the insde tire just a burning away? The outside tire just coasting along for the ride? That would be an open diff. Was that a good example? Quote Link to comment Share on other sites More sharing options...
alexideways Posted February 10, 2007 Share Posted February 10, 2007 Sure was, I call those... Peg Leg burnouts:lmao: BTW, thanks for the nice links. Quote Link to comment Share on other sites More sharing options...
Twoeightnine Posted February 10, 2007 Share Posted February 10, 2007 Peg Leg!! That is too funny! Yeah, everyone in the parking lot, just standing there, shaking their heads! I like the links too. Especially the visuals. Zedsaid...if you do have an open diff, you might take a look at the rear swaybar. Sounds from what you are saying that someone might have modified the suspension. The Z, having independent rear suspension, does not benifit from too large a sway bar. Especially if slightly underpowered and wet pavement. It can swing around if that is the case. Now if you have a LSD, and an oversize aftermarket sway bar, it would be even worse. Quote Link to comment Share on other sites More sharing options...
buZy Posted February 11, 2007 Share Posted February 11, 2007 I have lived in a winter state my whole life. Mastering oversteer (and yes I have hehe) on ice is a way of life and driving survival. Getting the right slide can actually increase cornering traction. An open diff will oversteer the car but more initial force and throttle opening is needed to whip the car sideways. On the other extreme end of things, a welded diff would aid in more traction but will oversteer way to easy. Front wheel drive cars really go great in snow...but very boring to drive, unless you have a console mounted parking brake. I know every car, enviroment and situation is different.. Quote Link to comment Share on other sites More sharing options...
johnc Posted February 12, 2007 Share Posted February 12, 2007 Whether and open diff or a limited slip diff will break the rear end loose in a corner and slide sooner is one of those "it depends" questions. With an open diff the inside rear wheel will break loose first and the amount of lateral grip provided by the wheel drops significantly. If the outside rear wheel is not at its lateral traction limit, it will most likely be able to handle the additional lateral grip that the inside rear wheel was providing. If it does slide it will start in a more gradual manner but is more difficult to control. In that case, no rear slide. But, there's an added rear grip loss caused by weight transfer forward because acceleration is reduced. This might be enough to induce a slide. With a LSD you don't have the inside wheel traction loss problem so ultimate lateral grip under acceleration is higher. But, depending on the LSD (and more so with a spool or welded diff) once the accelerative traction limit is reached, breakaway is quicker then with an open diff, but more controllable. So, to summarize, the LSD will have higher lateral traction limit under acceleration then an open diff but will breakaway in a more abrupt manner (depending on the style of the diff). Once sliding it is very controllable with the throttle. The open diff will have a lower lateral traction limit under acceleration then a LSD and will break away in a more gradual manner, but be less controllable once things start sliding. Throttle changes will not affect the slide very much. Quote Link to comment Share on other sites More sharing options...
Twoeightnine Posted February 12, 2007 Share Posted February 12, 2007 That was a very interesting analogy. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 12, 2007 Share Posted February 12, 2007 I'd bet the issue here is as Richard says, subframe mount bushings or semi-trailing arm bushings gone soft. There aren't any adjustments to make in the rear from the factory, but you might have the car aligned just to see where it is at, if the thrust angle is off and what the camber and toe are like in the rear. Then you can replace bushings or go to a slotted crossmember to adjust it from there. Search on 510 sites for slotted crossmember. Basically the same rear suspension as far as that is concerned and they have been doing it for years. There have been some threads about slotting the crossmember on a 280ZX here as well, but not for several years as I recall so you'll have to do some digging through the archives to find the info... Quote Link to comment Share on other sites More sharing options...
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