Tire lift rendering HLSD useless!!

[nlzmo400r]

Let me start off by listing my setup
d2 coilovers 7k/7k spring rates
all adj arms w/spherical bearings
225 falken azenis on 8.5in wheel x4
no front sway bar, stock rear
s15 hlsd

At the last open track event I went to, I had 9/7 spring rates on my car. The front was very bouncy, I counldnt keep the front tires on the pavement. I went home and ordered another pair of springs.
I just recently went to a smaller trackday event with a slightly different setup
255/40 azenis x4
7/7k springs
Now I have a problem with the inside tire lifting during cornering, rendering my HLSD useless. Now I understand the fundamentals of physics, and decided a front sway bar was definitely in order. After researching, progress sways seem to be what I'm looking for. Ive spoken with HALO about this (as he has a similar setup : 9/7k d2s, hlsd, tanabe sways) and he says he still has mad inside tire lift even with the sways. He also said he's gone as far as removing the rear bar in hopes of keeping the wheels down, to no avail. Anyone have any other ideas on how to keep the rear two planted during cornering? Ive got another open lap day on the 30th and hope to have this sorted and tuned out by then. Any help is greatly appreciated

[zads]

S13 or S14?
I run KTS Coilovers, 8/6 spring rates.
235s on 8in wheels
HLSD
Stock front sway bar, removed rear sway bar cuz of too much lifting and drifting :P

How much preload do you have on the front/rear springs of the car? I run virtually no pre-load to get as much droop travel as possible..

[nlzmo400r]

s13, and I dont have any preload on any of the springs. When I jack up the car in the rear, I get a little bit of 'droop' but not too much. Maybe a few inches.

[HaLo]

Oh, by the way... on track events, with A032R, I don't manage to lift rear wheels... Only on AutoX events, where cornering is very very hard.

[OptionZero]

i'm not an expert, but it seems to me the reason you lift is because the rear wheels are connected too much.

Remove the rear sway bar and you're good to go. If you need to deal with front and rear weight shifting balance, play with spring rates and damping. Sway bar is forcing your inside rear to lift as weight shifts outside during turning.

I've never had lift on my HLSD but then my chassis has a sunrooof, stock sways, no rear STB...its not that stiff in general so there's still plenty of chassis flop. i think i need new subframe bushings cuz the rear CREAKS sometimes.

[nlzmo400r]

http://www.noproblemraceway.com/track_facts.htm#roadcourse

this is a map of the racetrack im speaking of. The inside rear tire lifts on corners 4, 11 (although not much here), 13, and 14. Keep in mind this is on street tires (255/40 azenis). Im sure if I was on Rcomps it would much worse than it already is.

[Vatche]

maybe u need a wing?

[420sx]

yea.... APC alum....

[civicsi2]

do you think you would have been better off with getting the 5k for the back instead? Where are your dampening knobs?

I run 9/7, but i haven't lifted a tire on the track yet and i have vlsd. been wanting to get the helical. worth it?

[OptionZero]

Here's a random thought: would more rear negative camber help?

[nlzmo400r]

do you think you would have been better off with getting the 5k for the back instead? Where are your dampening knobs?

I run 9/7, but i haven't lifted a tire on the track yet and i have vlsd. been wanting to get the helical. worth it?

Well I used to have the 9/7 setup and found the front entirely too bouncy and couldnt keep the front tires on the road (tires on the road offer no grip obviously), which is why I went down to a 7k spring up front. Im sure getting a 5k rear spring would help, but I dont know how much lower I want to go back there because the car feels very neutral (when all the tires are on the ground that is) with even 7/7 setup.

Oh, and more negtive camber wouldnt help, its not a grip problem Im having, its a roll issue, but thanks for the input.

[OptionZero]

Alright, last one: wider track in rear with lower offset wheels...wouldn't that help fight some of the left/right weight transfer in the rear that's causing lift?

[nlzmo400r]

Alright, last one: wider track in rear with lower offset wheels...wouldn't that help fight some of the left/right weight transfer in the rear that's causing lift?

Yes, physically that would work, however I dont want to widen the track in the rear (keep in mind, im also trying to avoid understeer). Also, getting new wheels is quite a dramatic step to solving my problem. I will first try to remove the rear sway bar and see if that helps. Between this and damping adjustments, if neither solves this I will go down from 7k springs in the rear to 5k springs.

[OptionZero]

But going from 7k to 5k springs will increase understeer by shifting more weight rearward; won't the front's lose grip (less weight) faster?
Although improving the effectiveness of your diff may counter that...

I dont know what sort of clearance you have fender wise, but if you push both front and rears out with lower effective offsets, you might not get too much more understeer than before as both ends will be more "stable," as I understand it.

man tuning theory is complicated, hope you a solution that works!

[nlzmo400r]

well, tomorrow I will try to disconnect the rear bar, and throw my friends front strut bar on as well as trying to re-connect my front swaybar (oem). If this doesnt work, I'll have to get some 5k springs for the rear. Im pretty damn sure that'll solve the problem (although I went down in spring rates in the front solving a problem, and it only caused another to arise)

[KA24DESOneThree]

Cage. Track. Line. Throttle application. Car height.

All of these can help and will cost various amounts to apply.

[jmauld]

Anyone have any other ideas on how to keep the rear two planted during cornering? Ive got another open lap day on the 30th and hope to have this sorted and tuned out by then. Any help is greatly appreciated

I'm having the same issues with my car. I haven't sorted them out yet, because of the new baby and not having any time to do events. I plan on doing the things listed below in this order until the problem is solved. I'm running similar spring rates as you are. No bar on the rear.

- Increase front spring rates by another 100-200lbs
- Get a larger front bar. I already have a front ST bar, I think a Tanabe or Largus is in order
- Rear tender springs (Not to be confused with helper springs) These springs are around 150lbs and are real short. They compress with the weight of the car on them, but should work to keep the tire down when the car is lifting it's weight off of that corner. This basically turns the rear springs into a progressive rate spring.

[ryan hagen]

i run 8/6 and a stock front bar with poly bushings and rear whiteline on full stiff, and for the first time since i ve had the h-lsd i had it one wheeling at a drift day, i had no clue what it was doing because i had never had it do that before.

[nlzmo400r]

i run 8/6 and a stock front bar with poly bushings and rear whiteline on full stiff, and for the first time since i ve had the h-lsd i had it one wheeling at a drift day, i had no clue what it was doing because i had never had it do that before.

As stated above, g-load, track, line and throttle applcaton will all have effects on whether or not you get lift.

Today, I tried removing the rear bar (couldnt get the front one back on) and setting the front dampers to full stiff and it still lifted. So I ordered a pair of 5k spirngs for the rear. Im almost positive ths will solve the problem.

[yokotas13]

thats weird, im running 10/8 stock 180 rear adn front sways, no probs at all on teh track

[nlzmo400r]

excuse the post that WAS here, it was posted by a retarded friend with a DSM who is still rwd envious

[yokotas13]

my new quote

lolz, im sorry man, its more than a word explanation, google it not veing an ass seriously

[HaLo]

Well, i do know what an apex is... and you want to see wheel lift? here is some:

http://images17.fotki.com/v9/free/6914a/9/935694/3685148/064-vi.jpg

[backroadtouge]

this sounds liek a stroke problem? also, im sure getting strut towerbars to reduce body roll, and make the suspension do its job, would help.

[HaLo]

My car has all that... it's pretty modded already, I think the design of coilovers just don't work with the rear geometry..

[backroadtouge]

mmm yes. i looked at your cardomain and youve got all that covered, but the otherguy is running without swaybars even, so shouldnt his car roll wayy more? i know yours is due to stiffness and settings, but he apprently is just running coils. it could come down to the valving in the coilovers or just how you take the line of the course.

[CCARVER]

nvm, i think it may be my driving skill. i'm not exactly sure what an "apex" is. my friend with an awesome dsm said that when he rode with me he noticed that i tend to cut in late and fast. im goin to try this "apex" thing that he speaks of. can anyone give me information on what an "apex" is and where i can buy one... or two if i need them?
There are actualy three apexes in a turn. First is your turn in point. Second is your crossover(inside) Third is your outside finishing point. This is a flexable curve that gives you the optimum speed and control for a corner.
Like Corner 4 at NPR, there is that random cone on the left of the track as you aproch the turn. That is most peoples first apex of that turn. As you know that turn is around 197 degrees, and set up is everything.
I will have a passenger seat in my car for the next couple of events. Make it out and catch a ride. I hope I can share what I have been taught.
Carver

[DoriftoSlut]

Why don't you fools run mechanical clutch diffs instead? Eliminate all these problems. Or hell, even a spool! LOCK muffuckazzzz!


HLSD is for the birds, all race teams run clutch diffs, or even spools (JGTC cars are spool rear ends). F1 cars are clutch diffs. Do it.

[HaLo]

Why don't you fools run mechanical clutch diffs instead? Eliminate all these problems. Or hell, even a spool! LOCK muffuckazzzz!


HLSD is for the birds, all race teams run clutch diffs, or even spools (JGTC cars are spool rear ends). F1 cars are clutch diffs. Do it.


Since when a diff eliminates the Tire lift problem?

Not putting the power down on the exit of a corner is just 1 side-effect of tire lifting...

[OptionZero]

the HLSD requires both wheels on the ground; the resistance of the outside wheel initiates the helical-ness inside. With one wheel up in the air, the HLSD acts as an open diff, sending all the power to the useless outside wheel that spins in the air.

a clutch type, as i understand it, does not require the "preload" of the outside wheel's contact with the ground in order to lock, meaning it will make sure there is some power at least going to the wheel that IS on the ground (in the event you have one lifting).

having never ridden in a clutch-type equipped car i can't speak definitively on the matter, but in theory, it seems to me an HLSD might be just as good or better than a clutch type

as for why racing teams run clutch types exclusively, i have no idea, but i speculate it has to do with much better tires, far stiffer chassis/suspension, and certain track layouts (bumps?) which would create even more of the wheel lifting problem experienced by nismo400r above.

[jmauld]

My car has all that... it's pretty modded already, I think the design of coilovers just don't work with the rear geometry..


Have you tried using a rear progressive spring. Seriously, I think the solution is to use those tender springs along with your main springs.

[KA24DESOneThree]

D2s are crappy coilovers as well. Their stroke is, I would imagine, rather short.

I had a HLSD and sold it once I realized how often I lifted my rear wheels. I now have an ATS 1.5-way carbon. All the smoothness, none of the weakness.

[nlzmo400r]

There are actualy three apexes in a turn. First is your turn in point. Second is your crossover(inside) Third is your outside finishing point. This is a flexable curve that gives you the optimum speed and control for a corner.
Like Corner 4 at NPR, there is that random cone on the left of the track as you aproch the turn. That is most peoples first apex of that turn. As you know that turn is around 197 degrees, and set up is everything.
I will have a passenger seat in my car for the next couple of events. Make it out and catch a ride. I hope I can share what I have been taught.
Carver

I'll probably jump in for a ride. Thanks carver. Oh, and excuse that post please (drunk friend wth a dsm thought he was funny)

[Wiisass]

You mentioned earlier that your rear springs are not captive, right? So when you lift up the rear of the car, the spring is free. Fix this and it should help out. It may not solve all the problems, but it should help you. When your car rolls to the point where the spring is loose nothing is pushing that tire down other than gravity and gravity is fighting the rebound in the dampers.

Also, about the D2's, on full stiff, they're way to stiff. The valving on them kind of sucks, but you can deal with it, I would suggest somewhere in the middle. And maybe try the stiff springs back in the front again and mess with the damper adjustment until you can get it to work out for you. I don't know if you did this, or how much you tried to get them to work, but the problem you were describing seems to lie more with the damper than the spring. And with stiffer springs on the front the car will want to roll less.

And when is the car lifting the wheel, I know you mentioned turns on that one course, but under what conditions? Steady state cornering, corner entry on the brakes, corner exit on the gas, etc?

I would also keep the rear sway bar on the car. A sway bar will lift a wheel but this usually happens with an overly stiff bar and softer springs.

You have to figure out what is causing the lift. I'm still leaning towards the spring coming unseated and the damper extension being too slow to keep the wheel on the ground. But there could be other possibilities, look for binding, I doubt the shock is bottoming out, etc. If you know what the real cause of it is, you'll have a much easier time eliminating that from happening.

[jmauld]

You mentioned earlier that your rear springs are not captive, right? So when you lift up the rear of the car, the spring is free. Fix this and it should help out. It may not solve all the problems, but it should help you. When your car rolls to the point where the spring is loose nothing is pushing that tire down other than gravity and gravity is fighting the rebound in the dampers.


My car does this in just about all corners. Even slaloms, where I "try" to hold a somewhat steady throttle position.

I'm 99% sure that my spring is extending to full length, and the shock is getting into the scenario where it has gravity trying to pull it down. It's kind of a catch 22. If you run stiff springs, you have to have enough rebound to control those springs. Unfortunately, I think that's enough rebound to cause the shocks to lift the wheel off the ground. That's why I feel that a 150lb 3" long tender spring would get the job done. This spring would fully compress with the weight of the car on it and would only work when you're unloading the inside wheel. Obviously, I don't have the proof to back this up, yet, but I do plan on testing it.

I have ran with no rear bar, stock rear bar, and the ST rear bar. It's worse with the ST bar. About the same with the stock bar vs no bar.


I was under the impression that a clutch diff is just going to slip under a rear lift condition as well. If this isn't the case, I may just consider switching to one of those.

[timtiminy]

i think that the cheapest way to solve this problem would be to just use different driving tactics on the corners you have the problem of wheel lift. on these corners don't trail brake, brake earlier and longer in the straight in order to be able to put the power on earlier in the corner and have weight shift rearward keeping your rear tires on the ground(thinking of lifting the front inside tire instead or rear inside). you may have to take a different line using an earlier apex, but if you can adapt to the track and your setup i would think it would be better because you can have your car setup the way you are used to it and its best responsiveness. This way only sacrificing on the corners you are having problems with instead of sacrificing on every pert of the track except for those few corners. to me it makes more sense to deal with this problem by learning a new way of taking those corners than changing the setup to your car, and you should acutually end up being faster that way, rather than sacrificing the setup of your car and not learning new techniques to build upon your experience and learn to become quicker. just my advice. hopefully either way you get things solved. best of luck to you.

[nlzmo400r]

i think that the cheapest way to solve this problem would be to just use different driving tactics on the corners you have the problem of wheel lift. on these corners don't trail brake, brake earlier and longer in the straight in order to be able to put the power on earlier in the corner and have weight shift rearward keeping your rear tires on the ground(thinking of lifting the front inside tire instead or rear inside). you may have to take a different line using an earlier apex, but if you can adapt to the track and your setup i would think it would be better because you can have your car setup the way you are used to it and its best responsiveness. This way only sacrificing on the corners you are having problems with instead of sacrificing on every pert of the track except for those few corners. to me it makes more sense to deal with this problem by learning a new way of taking those corners than changing the setup to your car, and you should acutually end up being faster that way, rather than sacrificing the setup of your car and not learning new techniques to build upon your experience and learn to become quicker. just my advice. hopefully either way you get things solved. best of luck to you.

Ive tried many different techniques on attacking the corners and unfortunately its all the same result. Ive tried braking very early (although my usual technique is to dive very deep) and straight, and then getting back on the throttle early to transfer weght, but the tire still lifts a little bit.

[Wiisass]

Jmauld, you may be right about the weight of the tire and wheel being enough to not cause the damper to lift the wheel. If you are, then there's not really anything generating any force on the tire. So it almost wouldn't matter if it were in the air or lightly touching the ground. One way to check if the damper is the reason would be to jack up the car. You would need a quick jack, like one of those fancy 3-pump ones so you could lift it up quicker, but even a normal jack will help you see if it is. You just have to watch when the spring becomes free and how quickly the tire falls.

Now here's another thing to think about. If your spring is coming completely unloaded then that means that all the weight is transferred off of that tire and onto the other three. That seems like a little much. I just did a quick calculation and assuming a 16" CG, stock track, 1270 rear axle weight and a 1g turn, you're looking at about 350 lb of weight transfer. So that's obviously not enough to completely unload the inside tire. You'd need about a 1.8g turn to completely unload that tire.

So I don't know, I doubt it's the sway bar in this case. I still think you should move the spring perch and keep the spring captive. I wonder how much hysteresis is in the back suspension, it could be more than a lot of people think. It could also be entirely too much rebound for the damper, plus the hysteresis would be enough to lift the tire. So you could try softening the dampers.

If I were you, I would put the car up on stands. Take a jack and mess aroudn with one of the rear corners. Jack it up and put a little of the cars weight on it (be careful not to knock it off the stands) and then quickly let the jack down and see how the wheel/tire reacts. See if it comes down slowly, or if it comes down quickly until the spring becomes free and then comes down slowly. Try making the spring captive and do the same thing. You could even try without the spring and damper in place to get an idea of the hysteresis in the bushings themselves. Or just do it without the spring and you'll have an idea of the hysteresis in the bushings and damper combined. I think you really need to take a deeper look back there and find the route of the problem, this isn't something that should be happening and there's a reason why it is.

[timtiminy]

With the advice that Wiisass gives going back to the source, that coupled with adjustment with driving technique should be your best bet on keeping your car in good balance and getting even quicker.

[jmauld]

Jmauld, you may be right about the weight of the tire and wheel being enough to not cause the damper to lift the wheel. If you are, then there's not really anything generating any force on the tire. So it almost wouldn't matter if it were in the air or lightly touching the ground. One way to check if the damper is the reason would be to jack up the car. You would need a quick jack, like one of those fancy 3-pump ones so you could lift it up quicker, but even a normal jack will help you see if it is. You just have to watch when the spring becomes free and how quickly the tire falls.


When I jack the car up, the springs extend immediately. Once it gets to the end of the spring, it takes about 20-30 seconds for the tire to fully extend the shock.

I don't have enough adjustment in my coilovers to make the spring captive, without changing springs.


Now here's another thing to think about. If your spring is coming completely unloaded then that means that all the weight is transferred off of that tire and onto the other three. That seems like a little much. I just did a quick calculation and assuming a 16" CG, stock track, 1270 rear axle weight and a 1g turn, you're looking at about 350 lb of weight transfer. So that's obviously not enough to completely unload the inside tire. You'd need about a 1.8g turn to completely unload that tire.

I've visually seen the tire come off of the ground with my wife driving the car through a slalom. I've also seen this happen on a 3series bimmer, so this issue isn't isolated to our cars.

I do run r-compound race tires, but I know I'm not getting 1.8g of force at any point.


So I don't know, I doubt it's the sway bar in this case.

I agree, remove the swaybar and I get the same results.

So you could try softening the dampers. I've put the dampers on full soft, but the back of the car bounced around so much I couldn't get any real info on if the tire was lifting or not.


If I were you, I would put the car up on stands. Take a jack and mess aroudn with one of the rear corners. Jack it up and put a little of the cars weight on it (be careful not to knock it off the stands) and then quickly let the jack down and see how the wheel/tire reacts. See if it comes down slowly, or if it comes down quickly until the spring becomes free and then comes down slowly.

Done that. The tire drops immediately to the end of the spring, and slowly falls after that. I don't believe this is a bushing binding issue. I'm running completely stock bushings in the rear, and I would hope that Nissan wouldn't design a bind into the factory suspension. Although, it's not impossible that they would do this.

Or just do it without the spring and you'll have an idea of the hysteresis in the bushings and damper combined. I think you really need to take a deeper look back there and find the route of the problem, this isn't something that should be happening and there's a reason why it is.
Haven't gone this far with it yet. Mainly because I'm pretty confident the problem is in the lack of spring travel. Not positive though. I did not have this problem when I was running RS-R race springs, which have a progressive portion of the spring that closes with the weight of the car on it.

[jmauld]

With the advice that Wiisass gives going back to the source, that coupled with adjustment with driving technique should be your best bet on keeping your car in good balance and getting even quicker.

Humor me, and let's assume that this isn't a driving technique issue....

Perhaps there are actually issues with the rear suspension design that could be improved on, instead of driven around.

[Wiisass]

I don't really think this is a driving technique issue.

Jason, I forgot you have an S14. I guess D2 never really fixed their issue with them? What do you mean you don't have the adjustment? Is the shock already bottomed out in the lower perch? If not, just move that down and move the spring perch up.

I know this isn't an issue that only S-chassis cars see. I was just using those numbers to illustrate how much lateral acceleration you would need to have a weight transfer equal to the weight of that corner. It's going to be different if the CG height is different or track is widened due to different wheels, etc.

What setting do you run the dampers on? If full soft is too bouncy, what about one turn from full soft? Or two? Just somewhere were the rebound is softer than what you usually run to see if that's too much. Have you ever driven over a very bumpy section and had the car jack down? I'm just trying to figure out if it could be because the rebound is too stiff.

Do you know if the spring ever becomes free during driving? I really doubt that it could though. What do you mean when you say you think it's a problem with lack of spring travel? When you load the spring with the cars weight it will be compressed a certain distance. The only way to increase or decrease that distance is weight transfer. So unless the weight transfer from that corner is greater than the static weight of the corner the spring should always be loaded. We need to figure out why it's coming unloaded. I mean, I just ran some more numbers and under 1g braking and 1g cornering there's still about 200 lbs on that inside wheel.

Someone needs to get a video camera down there and take some footage the next time they go to the track to see if they can see anything going wrong. I don't think it's a suspension design issue, I still think hysteresis and rebound damping could be the main reasons for this.

[jmauld]

I don't really think this is a driving technique issue.

Jason, I forgot you have an S14. I guess D2 never really fixed their issue with them? What do you mean you don't have the adjustment? Is the shock already bottomed out in the lower perch? If not, just move that down and move the spring perch up.

I'm running Konis and GCs. The GCs are already adjusted to their heighest setting. Rear springs are 6" springs. The koni extends 2-3" past where the springs fully extends.


What setting do you run the dampers on? If full soft is too bouncy, what about one turn from full soft? Or two? Just somewhere were the rebound is softer than what you usually run to see if that's too much.


I've tried full soft, full stiff, 1/2 way, and 3/4. I settled on the 3/4 adjustment to have enough rebound to control the springs.

Have you ever driven over a very bumpy section and had the car jack down? I'm just trying to figure out if it could be because the rebound is too stiff. Not so much, but most of our sites are fairly smooth.


Do you know if the spring ever becomes free during driving? I really doubt that it could though. What do you mean when you say you think it's a problem with lack of spring travel? When you load the spring with the cars weight it will be compressed a certain distance. The only way to increase or decrease that distance is weight transfer. So unless the weight transfer from that corner is greater than the static weight of the corner the spring should always be loaded. We need to figure out why it's coming unloaded. I mean, I just ran some more numbers and under 1g braking and 1g cornering there's still about 200 lbs on that inside wheel.
I don't know if it's coming unseated. I've always heard that you would hear when a spring comes unseated. I've never heard it.


Someone needs to get a video camera down there and take some footage the next time they go to the track to see if they can see anything going wrong. I don't think it's a suspension design issue, I still think hysteresis and rebound damping could be the main reasons for this.
I could actually have a camera mounted there. Do you want to see the spring or the tire? It will be at least February (maybe November) before this happens. I wasn't planning on doing any more events this year.

I think it's a rebound damping issue. But how do you correct that when running stiff springs?

[nlzmo400r]

^^ pretty much exact same problem. Im was beginning to think it could be the dampers. When I first put my coilovers on, I thought the springs were a little short. I think a 'tender' spring would be an EXCELLENT idea and probably would solve the issue.

Also, my spring doesnt come unseated unless I go up a steep driveway or something like that (that requires a lot of travel on the unloaded wheel).
And, no my tires dont lift on slalom, it takes a fairly sharp corner with lots of load. But this load is easily exceeded on any autoX or roadcourse

[AceInHole]

The rear tire lift problem is EASILY fixed with the D2's, or any short stroke coilover, for that matter.

The problem stems from the lack of rear suspension travel beyond static ride height (rear "lift"). While cornering, your rears are hitting maximum travel before your fronts are, which is causing rear wheel lift. This is why removing the rear bar on Halo's car didn't help, and why Kaje (Mark Brook) had the same problem on his car. After having Kaje precompress his fronts slightly, he reported his car behaving much better.

Solution:
Precompress your front springs slightly. This basically forces the front end to come up first, shifting the center of balance from your inside rear and outside front to the inside front and outside rear. It's a fairly dumb way of doing it, but it's effective untill you can run a proper front swaybar (which is the "best" way of fixing the problem).

My car:
http://video.tinypic.com/player.php?v=21b0wg4

[jmauld]

Solution:
Precompress your front springs slightly. This basically forces the front end to come up first, shifting the center of balance from your inside rear and outside front to the inside front and outside rear. It's a fairly dumb way of doing it, but it's effective untill you can run a proper front swaybar (which is the "best" way of fixing the problem).



What size bar did you run to get the front wheel to lift first?

[timtiminy]

have you thought of using helper springs in the rear to keep the suspension preloaded?

[nlzmo400r]

THANK all of you guys for the help and advice. I left the fronts alone (not much preload at all, just enough to not be able to move the spring with your hands) and put a pair of 5k springs on the rear. Problem solved it seems. Car absolutely shoots out of corners now.

Also, as far as the helper springs, a friend of mine has them on his new Stance coilovers, and their soft enough to compress with your hands, I dont see what good that will do

[nlzmo400r]

The rear tire lift problem is EASILY fixed with the D2's, or any short stroke coilover, for that matter.

The problem stems from the lack of rear suspension travel beyond static ride height (rear "lift"). While cornering, your rears are hitting maximum travel before your fronts are, which is causing rear wheel lift. This is why removing the rear bar on Halo's car didn't help, and why Kaje (Mark Brook) had the same problem on his car. After having Kaje precompress his fronts slightly, he reported his car behaving much better.

Solution:
Precompress your front springs slightly. This basically forces the front end to come up first, shifting the center of balance from your inside rear and outside front to the inside front and outside rear. It's a fairly dumb way of doing it, but it's effective untill you can run a proper front swaybar (which is the "best" way of fixing the problem).

My car:
http://video.tinypic.com/player.php?v=21b0wg4

nice video, but if thats what you were thinking about when I said I was getting lift, then you're mistaken, i was getting maybe 6-10 inches off the ground. Nice video none the less

[timtiminy]

supposedly the helper springs are suppose to help in the event your suspension unloads completely and the damper still has a few inches of travel to extend. that and it suppose to put the dampers in a nice preloaded state. thats why they are also called traction springs. wasnt sure if maybe they would help in this event, i am glad you got it solved with the 5k springs, how does it feel overall? i plan on using stance Gr+ pro 9k front 7k rear or 8k f 6k r. depending what feels better for grip on the track...what do you all think?

[jmauld]

Also, as far as the helper springs, a friend of mine has them on his new Stance coilovers, and their soft enough to compress with your hands, I dont see what good that will do


I don't think the helper springs will help in this situation. I was previously referring to tender springs.

Helper springs = ~30-60lb/ft, 2-3" long springs

Tender springs = ~150-250lb/ft, 2-3" long springs

[timtiminy]

using tender springs would be equal to using progressive rate springs, no?

[jmauld]

yep.

Take a look at my post on the first page of this thread.

[nlzmo400r]

^^^oh, ok, then the stances must have 'helper springs', not tender springs. Either way, with the 5k springs, the car feels great. Another reason I love these springs so much is because they soak up the bumps better. And obviously soaking up the bumps also helps keep the tires on the road. There is a little more body roll now than with my old 9/7 set up so Im definitely ready for some sway bars (either Progress Group, or Tanabe). Thanks again for all the help guys

[HaLo]

nlzmo400r, are you running a 7/5 setup or 9/5 setup?

i am having better results at correcting my driving style to reduce the rear tire lift...

[mmdb]

Didn't bother reading the previous posts, but have you tried increasing your rear dampening settings and decreasing your front? Not sure if you have adjustable dampening, but if you don't that's something I'd look into. Definitely helped me.

Btw I'm running apexi n1 pro's (8 front, 6 rear... or was it 9/7?), st sways, stock alignment, 235 tires all around, and an open diff.

[AceInHole]

nice video, but if thats what you were thinking about when I said I was getting lift, then you're mistaken, i was getting maybe 6-10 inches off the ground. Nice video none the less

the video is of my car, running D2 coilovers. limit your front suspension travel and you won't be able to lift the rear wheel.

on a side note: i'm running whiteline sways front and rear, set to "full stiff" all around. just drove my car at an SJR-SCCA event and had no troubles on the turnarounds. in theory you should be able to do the same.

[nlzmo400r]

nlzmo400r, are you running a 7/5 setup or 9/5 setup?

i am having better results at correcting my driving style to reduce the rear tire lift...

im running the 7/5 spring rates now. I originally ran 9/7 and didnt have lift, however I coudlnt keep the front tires down on midcorner bumps. So I lowered to 7/7 and lifted inside rears. Now im at 7/5 and couldnt be happier. Car soaks up bumps well and doesnt lift the inside rear tire, just shoots out of corners now.

[a_ahmed]

hey this was an interesting thread, sorry for a year later bump, but how's your car.

Awesome video from acehole. I wonder if you could post external videos like this one except now with u running koni 28s (that is a nice fast car with only D2s and whitelines).

So yeah, nizmo400r and acehole updates after a year :) ? :D

[AceInHole]

The Koni's I have are 8611's. Rhoades has the only 28's on a 240 AFAIK. No external vids yet. Just some in-car ones, as the car was hit (and totalled) by a drunk driver on the way to the DC ProSolo earlier this year.

Anyways, the car was on 600# front, 450# rear springs. Whiteline bar up front with heim jointed ends set to full stiff, and no rear bar. Koni 8611-1257 shocks up front (4 clicks comp and 1 turn rebound from full soft), standard Yellows on full stiff in back. Tires are 285/30/R18 front, 315/35/R18 rear, Kumho V710's.

http://i114.photobucket.com/albums/n247/AceInHole/autox/th_nnjr_dave_run08.jpg (http://s114.photobucket.com/albums/n247/AceInHole/autox/?action=view&current=nnjr_dave_run08.flv)

Puts power down pretty well with an OBX helical. I'd also like to note that with decent shocks, spring preload shouldn't be necessary at all.

[a_ahmed]

no way :eek: some drunk hit ur ride :(

[nlzmo400r]

hey this was an interesting thread, sorry for a year later bump, but how's your car.

Awesome video from acehole. I wonder if you could post external videos like this one except now with u running koni 28s (that is a nice fast car with only D2s and whitelines).

So yeah, nizmo400r and acehole updates after a year :) ? :D

I stil never had any problems until about 6 months ago my driver front damper started leaking oil. I eventually sold them (about a week ago actually) and just got some stances. Im waiting to put them on because I also upgraded to z32 uprights/5lug and bigger wheels. I'll post up a little thread once I get it done and on the ground again.

[a_ahmed]

I stil never had any problems until about 6 months ago my driver front damper started leaking oil. I eventually sold them (about a week ago actually) and just got some stances. Im waiting to put them on because I also upgraded to z32 uprights/5lug and bigger wheels. I'll post up a little thread once I get it done and on the ground again.


hey sounds really awesome :) Post the link to that thread if you're not going to post about it in here, so i can view it (i subscribed to this thread).

[240Stilo]

I found somewhere that people with hummers (they have hlsd) just apply some brakes to help out when both tires have no traction. It's not that the wheel is in the air that causes the hlsd but the lack of resistance. I figure running through a course pulling on the e brake might not be the salvation you needed but for curiousity sake you could try it out.