If the megan rear lower tie bar works, why doesnt the dc sports?

[JFern]

Suspension Tech 101: "The stiffest part of a car will slide first (front stiffer = understeer, Rear stiffer = oversteer"
That being said, most FWD cars are made to understeer from the factory for safety and driveability (grandma doesnt usually take turns going 80mph) so of course putting on stock swaybars would make it understeer, that is why the vigor sway bar mod or aftermarket ones work well. Stiffening the rear (either by welding or adding pieces) will help achieve overrsteer as well, but it has to be in the right place. Honestly, I can't see how this mod helps much considering how the suspension geometry is setup, But this mod does have the potential to stiffen it a little bit. is it worth it? IMO no, not at all and another mod would be better suited, especially since you take away from the integrity of the unibody in order to add a small bit of chassis stiffening, you would be better off stiffening the body itself.

[frantik]

i have vigor rear sway bar and justin's rear upper strut bars and my back tires will break loose. i recommend doing the rear sway bar (either vigor or ST) before doing this mod

[lostforawhile]

the reason i said to reweld the rear subframe,is to give the rear arms a more precise location to work from, if it doesn't move, those rear arms can function to control the handling that much better. the rear suspension movement is controlled by both the upper and lower arms and the more precise those work such as welding that subframe and urethane rear arm mounts, the better it will work.

[2drSE-i]

it's not a perfect science, but if you wanted to tinker with getting more of an oversteering car than an understeer (as is most common with damn near all FWD cars), take your stock front springs from your pile of parts in the corner and cut the needed amount of coils off them to get them at the same ride height of your rear. Then swap them out in place of your lowering springs up front, and viola, oversteer.

I did the same thing you did. I had already put the rear 88-89 LX-i bar in my DX (which came with no bar in back from factory) and loved the way it felt. Then a few years later I got off my ass and put the front LX-i bar on in place of the stock DX, and I was PISSED OFF. I hated it. Understeer like mad. Slam the car into a corner, start turning, then it just pushed through and the steering wheel didn't help much. I was just in it for the ride. ...and I yanked that bar, put the stocker back in, and now I stuck the turn without the 'push' (aka. understeer).

I'll put the LX-i bar back in front once I get the SusTech of Addco for the rear. ...in time, in time.

Well said. Its pretty cool to watch some of those VW's go around the track with solid rear suspension. Absolutely sick, talk about oversteer! But for daily driving or even more agressive autocross, i think our setup is pretty badass. I would love a nice 28mm rear swaybar paired with a 22mm front on our cars, but que sera.

[JFern]

the reason i said to reweld the rear subframe,is to give the rear arms a more precise location to work from, if it doesn't move, those rear arms can function to control the handling that much better. the rear suspension movement is controlled by both the upper and lower arms and the more precise those work such as welding that subframe and urethane rear arm mounts, the better it will work.

agreed

[Strugglebucket]

I have the old tubular lower braces that Justin made, both front and rear on my car. I'll post some pics of them later since I haven't seen any pics of them installed on the site, except for some really tiny ones. I happen to think getting rid of any amount of chassis flex is a good thing, provided you're not adding a ton of weight.

it's not a perfect science, but if you wanted to tinker with getting more of an oversteering car than an understeer (as is most common with damn near all FWD cars), take your stock front springs from your pile of parts in the corner and cut the needed amount of coils off them to get them at the same ride height of your rear. Then swap them out in place of your lowering springs up front, and viola, oversteer.

I did the same thing you did. I had already put the rear 88-89 LX-i bar in my DX (which came with no bar in back from factory) and loved the way it felt. Then a few years later I got off my ass and put the front LX-i bar on in place of the stock DX, and I was PISSED OFF. I hated it. Understeer like mad. Slam the car into a corner, start turning, then it just pushed through and the steering wheel didn't help much. I was just in it for the ride. ...and I yanked that bar, put the stocker back in, and now I stuck the turn without the 'push' (aka. understeer).

I'll put the LX-i bar back in front once I get the SusTech of Addco for the rear. ...in time, in time.

I sort of disagree. I have ST bars front and rear along with Sprint/Konis, and I would not want any more oversteer than I have now. I get PLENTY of oversteer on corner entry, mild oversteer mid-corner, and of course understeer on corner exit if I put my foot into it too much. Having the thick front bar is good because the extra roll stiffness helps keep me from bottoming out the front suspension in corners, which I still manage to do sometimes with the 350lb springs. If I could get a thicker front bar I would, because I'd rather have that than stiffer springs, which is what I'm probably going to wind up with (along with re-valved konis -ugh$$).

[frantik]

pico has the justin lower tie bar installed iirc

[LX-incredible]

If you want to make that rear center member stronger,the best way is to remove it and weld it solid instead of spot welds. that will make it fully boxed, and as strong as crap.a also on the front if you have the lude control arms, you can box the control arm with plate steel and make it a lot stronger too.

Sounds like the best idea in here to me.

[stat1K]

^^ do it and post pics budddddy.

[markmdz89hatch]

I sort of disagree. I have ST bars front and rear along with Sprint/Konis, and I would not want any more oversteer than I have now. I get PLENTY of oversteer on corner entry, mild oversteer mid-corner, and of course understeer on corner exit if I put my foot into it too much. Having the thick front bar is good because the extra roll stiffness helps keep me from bottoming out the front suspension in corners, which I still manage to do sometimes with the 350lb springs. If I could get a thicker front bar I would, because I'd rather have that than stiffer springs, which is what I'm probably going to wind up with (along with re-valved konis -ugh$$).

The oversteer going into and mid/apex of the turn is due to the loading of the corner with the weight of the car. Once the weight/load settles (once you're already in the turn) it's the rotation/looseness of the back that will keep the traction on the front tires and keep them from sliding (ie. the rear 'pushing' causes the understeer). I'm not suggesting stiffening up your rear if you're already at the 'it's-too-stiff-for-my-liking' point, but instead, just soften up the front. As a test, why not pull that SusTech bar from the front and put in the stock 88-89 LX-i bar. Then if you have an upper strut bar, pull that too. Keep everything in the back as it is.

At this point, you'll have to re-learn how your car dives and exits turns because the ass may want to rotate on you or at least break traction a bit, but once you get a handle on that I'm willing to guarantee you'll drop time faster than quick.

JFern hit the nail on the head with his post, and I completely agree with his opinion on this Megan mod (if it requires cutting of the uni).

[stat1K]

I love these suspension questions because they always turn into a good solid debate lol, great points from everyone keep it going!

[Strugglebucket]

The oversteer going into and mid/apex of the turn is due to the loading of the corner with the weight of the car. Once the weight/load settles (once you're already in the turn) it's the rotation/looseness of the back that will keep the traction on the front tires and keep them from sliding (ie. the rear 'pushing' causes the understeer). I'm not suggesting stiffening up your rear if you're already at the 'it's-too-stiff-for-my-liking' point, but instead, just soften up the front. As a test, why not pull that SusTech bar from the front and put in the stock 88-89 LX-i bar. Then if you have an upper strut bar, pull that too. Keep everything in the back as it is.

At this point, you'll have to re-learn how your car dives and exits turns because the ass may want to rotate on you or at least break traction a bit, but once you get a handle on that I'm willing to guarantee you'll drop time faster than quick.

JFern hit the nail on the head with his post, and I completely agree with his opinion on this Megan mod (if it requires cutting of the uni).

I'm at the point where reducing any roll stiffness is going to hurt me more than it will help me. If you look in the engine bay of my car, there is a dimple either side of the frame above where the upper control arm is from it smacking the top of the fender when the suspension is loaded up. I'm also running -2.5 static camber in the front to keep the tire temperatures even. Any less stiffness in front and I'll be bottoming out more as well as losing contact patch (unless I add even more camber, but -2.5 is pushing it a bit as it is).

And like I said, I get mild oversteer mid corner (already settled in the turn), so the car is pretty much balanced how I need it. FWD is going to understeer on corner exit with throttle no matter what; if I added enough oversteer that it felt like it wasn't, the car would be on the verge of spinning like a top everywhere else. And probably scrubbing off more speed with the back end sliding to keep up with the front end breaking traction from throttle that it wouldn't be worth all that sliding just to keep the car rotating with your foot in it, when you could be keeping more traction on the rear while managing the understeer by gradually getting on the throttle and not having to deal with a car that is so tail-happy.

It probably has something to do with my lack of driving skill, but I'd much rather have a car that pushes a little than something that is ready to swap ends every time I lift.

[Strugglebucket]

Here are the Justin bars on my car. There are two for the rear subframe, one that ties in the long lower control arm mounting bolts, and another that ties together the subframe mounting bolts nearer the short arms. The bar clears everything (barely) without cutting anything and the other one bends around the gas tank. I also put a picture of the front bar. Probably can't see in the picture, but I had to flatten the bar a little to make clearance for my Pacesetter downpipe.

[2ndGenGuy]

A lot of FWD racers will actually put a huge rear bar on the car, and run with no front bar at all. Big issue with that, from what I've read / heard is traction. You get too much swaybar up front, and when the car leans, your inside tire will lift. Then trying to accelerate out of the corner, you're just totally screwed as all the power goes to the wheels that spins the easiest.

Seems to me that it's really quite "preferred" by a lot of people to have the car's ass end be a bit happy. I imagine that it gives a more balanced feeling to the car, because usually you can control the rear end slide by steering and / or throttle. When you get into a nasty understeer situation, you're pretty much screwed. All you can do is let off throttle, or straighten out the wheel. No counter-steering and trying to carry that understeer perfectly through the corner. Could just be that it's more fun too...

[Strugglebucket]

Yeah but if you spin out on corner entry or a transition you're a lot more screwed than if you understeer a little on corner exit. And I've yet to see a FWD car lift it's inside front wheel. Spin it because of an open diff, yes, but not lift it. I've heard of it happening when the shocks have been shortened too much so the suspension doesn't have enough droop to keep the wheel on the ground.

And another thing, I think the super-stiff rear springs on civics and integras has a lot to do with them wanting to limit the suspension movement as much as possible because the geometry sucks and they get crazy toe changes if the suspension is allowed to move too much. I'd like to think our rear suspension is a lot better design, but I've yet too actually plot out the bumpsteer. Maybe next time I take the springs out.

Don't get me wrong, my car oversteers in a steady state corner, I'm just saying I wouldn't want it to oversteer any more than it does now.

[lostforawhile]

Yeah but if you spin out on corner entry or a transition you're a lot more screwed than if you understeer a little on corner exit. And I've yet to see a FWD car lift it's inside front wheel. Spin it because of an open diff, yes, but not lift it. I've heard of it happening when the shocks have been shortened too much so the suspension doesn't have enough droop to keep the wheel on the ground.

And another thing, I think the super-stiff rear springs on civics and integras has a lot to do with them wanting to limit the suspension movement as much as possible because the geometry sucks and they get crazy toe changes if the suspension is allowed to move too much. I'd like to think our rear suspension is a lot better design, but I've yet too actually plot out the bumpsteer. Maybe next time I take the springs out.

Don't get me wrong, my car oversteers in a steady state corner, I'm just saying I wouldn't want it to oversteer any more than it does now.

you are forgetting these cars have a double wishbone on all four corners, and handle a lot better then even some new cars. there's a reason Honda adapted this design and used it on most of the other models even to this day they still use a modified version of it. most people who have front wheel drive cars and want to get rid of understeer have to do a lot more work then we do. you want nuetral and a little bit of oversteer. the reason almost all cars are understeer is the average clueless person, would spin them right out. The hatchbacks like to wag the tail with an overhauled suspension as it is, I've taken the hatch out on the taxiway and i can get the back to come around without too much trouble.

[stat1K]

my fit doesn't have rear independent trailing arms and it doesn't handle near as good as a 3g, i wish they wouldn't mess with good things.

[JFern]

The oversteer going into and mid/apex of
JFern hit the nail on the head with his post, and I completely agree with his opinion on this Megan mod (if it requires cutting of the uni).

Thanks

A lot of FWD racers will actually put a huge rear bar on the car, and run with no front bar at all. Big issue with that, from what I've read / heard is traction. You get too much swaybar up front, and when the car leans, your inside tire will lift. Then trying to accelerate out of the corner, you're just totally screwed as all the power goes to the wheels that spins the easiest.

A lot of RWD racers do the opposite, it has to do with the drive wheels through a turn and how the power is transferred, since LSD's are not TRUE 50/50 power side to side (like say a 4X4 locking diff) the wheel with the least resistance does have a tendency to spin more than the other (not as much as an open diff, but same idea) The reason you take out the bar out is because a sway bar WANTS to stay flat, even through a turn. So when you turn hard and the wheel has power going to it, the sway bar wants to lift the inside tire to stay flat (it can't push down the ground duh!), and the wheel breaks traction, so you take out the bar to reduce this.
oh and strugglebucket, the tire doesn't physically lift enough for you to see it (its not like a dr dre video with is 64 impala), but its enough to break traction and cause a shimmy or worse

[Strugglebucket]

I would not remove the front sway bar unless you've got some seriously stiff springs that can provide enough roll resistance of their own. Otherwise you'll have so much body roll that all the suspension movement will be used up and you'll be riding the bumpstop and getting positive camber on the outside tire.

[2ndGenGuy]

Positive camber on the outside tire? I think you're thinking of the way a MacPherson setup works. The whole point of that upper arm, is to prevent positive camber from happening when the strut is compressed past a certain point. It essentially is shorter than the lower arm, always pulling in the top of the steering knuckle as it compresses.

MacPherson struts will do what you describe though, as the control arm passes it's horizontal axis, it begins to pull back in towards the car. Even on the 2g with it's Mac strut, it won't ever see positive camber on compression due to the angle that the strut is mounted on the car. It will gain positive camber, as in once the control arm hits 90 degress with the strut it will start to lose negative camber. But it would have to compress way more than possible to ever run in a positive state under compression. A double wishbone should never, ever gain camber under compression. At least I can't see how it would...

If you mean the inside tire running under positive camber, then I could possibly see that depending on the initial geometry. But if your weight is transferred that much, I doubt the angle of the inside tire is making as much difference. As, like you said, it's probably spinning away due to an open diff.

I've never seen one lift a tire off the ground either, but too stiff a swaybar up front definitely doesn't help that inside tire with traction any, especially accelerating out of a corner. I was using that more as an example, than a case of it actually lifting. A little easier to visualize. If you're lifting any tires, IMO, your swaybar is too big.

[Strugglebucket]

No, I mean the outside tire. If you load up the suspension beyond where it is fully compressed then you stop getting any camber gain.

I'm just saying that if you have grippy tires and not enough roll resistance, you can easily run out of suspension travel and start messing things up. So if you want to get more weight transfer on the rear of the car by way of decreasing the front roll resistance, you had better already have enough roll resistance on the front end that you can afford to reduce it.

[2ndGenGuy]

Right, well it's just the tradeoffs of going too far one way and too far another. I guess the key is finding the right balance that makes you fast. I'd probably never remove my front bar either, but that's just what I've heard of people doing, and the logic sort of makes sense. Most of them probably do have some insane springs up front.

[Strugglebucket]

That's the thing. And then if you've got the really stiff front springs, you have to have them for the rear too, to balance the handling. And then driving on the street the back end is bouncing all over the place because there's no weight back there.

If I ever get around to getting some coilovers, it's going to be really tough to decide what spring rates to get. I need to ride in someones 3g with really stiff springs and see just how bad it is on the street.

[markmdz89hatch]

see all the fun I miss when I'm away from the computer for the weekend....

Oddly enough, I just spent about 1.5 hrs on the phone with a friend of mine that's a crazy racer. He's been racing things like EVO's and his current 350Z, but is working with a good friend of his to tweak a CRX. We spent all that time working on this very same issue.

He's currently running a 450/350 lb rating (front/back) and is getting (an I paraphrase his claim) "great bite on turn-in, and pretty much flat at apex, but on exit when I'm heavy on the right foot, it just plows and gets crazy understeer."

Anyway, he wants to spend as little as possible and keep using as much as he can that's currently on there. He's also got a decent sized rear anti-sway bar and upper strut bar. Up front pretty much the same thing. After so much time, we got out of him that it's not so much a matter of bouncing or even riding his bumpstops through the turn, but more-so that he's getting too much 'push' from his ass end and not enough traction to his front wheels.

This "push" is not happening so much because of his front end being too stiff, but more-so because his ass is still too soft (compared to the front) and it's getting too much traction.

Just as a test, we're going to have him disconnect the endlinks on the front bar and run it like that. Just to see if he's got any chance of keeping the 350 lb springs out back. Honestly, we're both at the point that we're telling him he needs to bump up the rear springs to more like 650-750 lbs and he'll be able to keep everything else as is (for now).

What it comes down to is that if you're starting to rotate the ass end around (not just break the ass end loose) on turn entry, you're going into it too fast. ...and possibly the same speed as you would enter the turn with an 'understeer' setup. The real difference is once you reach the apex, instead of playing the waltz on your throttle because you're trying to get your front end to bite enough to get the front tires to do what they're supposed to do, if the front is soft enough to keep good bite on both drive wheels, once you stomp the throttle on exit, you can just keep slamming it as hard as you want to and you'll stick the turn. If the ass starts to come around once you've started your turn-out, that means you hit an early apex.

When I took my first skip barber course, my instructor said the single most common problem of all racers starting out (I'm in that boat, and was definitely guilty of this) is too early of an apex. This took the top spot above "too fast on turn entry". (Cool Runnings: "Slow in, fast out.") He did say that too fast of an entry usually has a root cause of too early of an apex because the driver is planning on getting to (and thinking: also getting through) the turn. The problem is that too soon of a turn-in/apex and too fast of an entry usually means feathering the throttle and/or a quick tap of the brake or clutch-touch, and hence a significantly slower exit speed.

Anyway, I'm kinda thinking we've strayed pretty bad from the original topic of this thread, so I *might* brake this thread apart and leave the "Suspension Theory" to another thread. Anyone else have a take on this?

Struggle --> Props to you for posting up those pics. That's the first time I've seen pics of all three bars from what I can remember.

[stat1K]

i say take all the useful posts and losts initial thought of welding the shit and make a new thread lol... or just rename it and put a disclaimer that says good info starts a few posts down haha.