Learn Me FWD Handling

but won't making the rear stiffer affect the "way and when" that weight is transfered ... with my honda products the stiffer the rear ( springs/shocks/and sway bar) always affected the stability of the car as a whole....

soft sway bar coupled with soft shocks lessened the chances of the rear end coming around ... even when I did dumb things like lift in mid-corner, whereas stiff bar and stiff shocks .... and let the merry-go-round get started ... all this was with very stiff rear springs ( at least stiff for a street driven car )

nderwater wrote: The only Nubira I've ever had the chance to flog was a '98 like yours, but I found it to be prone to snap-oversteer at the limit. Unsettling, compared to the Lanos and Leganza I drove at the same time. What mods have you made to your suspension so far?

I have full poly bushings front and rear. I run 1.5 degrees negative in the front, 1 degree in the back. Front is zero toe and rear is 2mm toe out. Next time I go to the track, I'm probably going to double that rear toe out figure.

I run non adjustable Bilstein shocks along with 500 lb springs at all four corners. I don't run any swaybars front or rear. And no, the car doesn't have that much body roll. I have never achieved more than 2.7 degrees, and that was in a very high mu, cambered corner.

The front is lowered about 1 inch and the rear is lowered .5 inches. Next time I go to the track I'm going to lower the rear a little more as well. With the new, better tires, it is on the edge of jacking during sudden transitions.

I have modeled the suspension too, if that helps. The one thing I've noticed in particular is that my car seems to have abnormally high roll centers, particularly in the rear. The roll center axis is also pretty steep, which could explain the snappiness you experienced.

As it sits, the car is very stable and it's killer through transitions, but unless I do a Scandanavian flick or trail brake from high speeds, it's just not very adjustable. And it never plows unless I have people in the back seat.

As far as grip, I seem to have higher cornering speeds than the other guys on street tires that I run against.

kazoospec wrote: +1 on the rear bar suggestion. Just be aware that, since a front driver usually has most of its weight over the front wheels, freeing up the back end can also produce unwanted snap oversteer. (I.e. - One second happily motoring along, another "Hey, how did the trunk get in front of me?"). There's a reason front drivers typically understeer heavily from the factory. Also, maybe a limited slip diff if available? Its not going to change the "handling" of the car so much as allow you to potentially overcome the inherent limitations of corning a front driver with throttle inputs. If my SE-R starts to understeer, adding power (which seems totally counter-intuitive BTW and really adds some "pucker factor") will usually pull it through the turn.

If there's a rear wheel in the air already, I don't understand how a stiffer rear bar helps anything.

When my car does oversteer it's nothing I can't handle. It steps out slowly and is easy to real back in. The closest I've ever gotten to spinning it was on a long decreasing radius sweeper and, just like you said, I just put my foot down and the problem was solved.

I've never gotten inside wheel spin, so I don't think I need an LSD.

White_and_Nerdy wrote: On top of all the other wonderful suggestions (more rear bar FTW), learn and practice left foot braking. Technique alone can get the rear to swing around a bit if you get it right. Massive rally style drifting won't be the fastest way through the corners, but if you moderate it you could at least transfer weight to the front to help with the understeer problem.

Is this a good idea in a 107 hp car? I've never tried it in anything but high power cars.

pinchvalve wrote: Swap the front bar for a Civic Si front bar. Then swap the rear for a Civic Si bar. Then the struts, then the motor, then the chassis, then the interior... (you see where I am going here)

I've been on track with a Civic Si. He was a lot slower through the corners ...

That said, I'd love to swap this heavy, inefficient, fragile gutless piece of poo under the hood for a B series.

DaewooOfDeath wrote:

White_and_Nerdy wrote: On top of all the other wonderful suggestions (more rear bar FTW), learn and practice left foot braking. Technique alone can get the rear to swing around a bit if you get it right. Massive rally style drifting won't be the fastest way through the corners, but if you moderate it you could at least transfer weight to the front to help with the understeer problem.

Is this a good idea in a 107 hp car? I've never tried it in anything but high power cars.

I left foot brake in my ( mostly stock motored) CRX all the time

DaewooOfDeath wrote:

I run non adjustable Bilstein shocks along with 500 lb springs at all four corners. I don't run any swaybars front or rear. And no, the car doesn't have that much body roll. I have never achieved more than 2.7 degrees, and that was in a very high mu, cambered corner.

I would be thinking about softer springs in the front. You've got the rear to where you may have snap oversteer? Softening the front will allow the front end to bite better.

I'm using 440# front and 750# rear in a FWD FX16 with a 19mm rear bar. Sounds like you need to look at a spring rate differential front to rear. Some differential of softer front and stiffer rear seems to work for fast FWD machines.

I would definately soften the fronts a hair, or stiffen the rear. Either or. The rear needs to be fairly stiff, and the front soft enough to handle the turns and bumps without causing wheelspin on corner exit. DEFINATELY put a rear bar on the car, and maybe a small front bar if you soften the front.

@ Bobzilla

Maybe I'm being dense but I don't see how a rear bar helps anything.

Correct me if I'm wrong but here are my assumptions.

The function of running a bar, or stiffer springs or whatever is to shift weight around the chassis. The side loading remains constant regardless of where the suspension goes, but a stiff rear and soft front transfers weight from the inside rear to the outside rear and inside front. Since the side loading is constant, this improves the grip of the front relative to the grip of the rear.

Once the inside rear lifts off the ground, there is no more weight to transfer. Increasing the rear stiffness or decreasing the front stiffness just means more body roll.

I don't want to use bars unless I absolutely have to, but that's a different topic for a different thread. ;)

trucke wrote: I would be thinking about softer springs in the front. You've got the rear to where you may have snap oversteer? Softening the front will allow the front end to bite better. I'm using 440# front and 750# rear in a FWD FX16 with a 19mm rear bar. Sounds like you need to look at a spring rate differential front to rear. Some differential of softer front and stiffer rear seems to work for fast FWD machines.

I actually don't have snap oversteer. The car is really friendly once it lets go and I have a lot of grip. It's just not very adjustable.

The car is by no means a handling wreck. It turns better than any street car I've driven before, it's really good in transition and I've outcornered stuff like Pilot Sport shod S2000s on track with my little 205/50 Hankook 280 treadwear street tires. I'm mostly looking for help with fine tuning.

I was thinking about bumping up to 12kg front springs and 15kg rear springs, but I decided not to for fear of the long, bumpy corners at my home track. Right now with 9kg/mm springs I really handle those corners well. Actually, considering my power disadvantage vs everyone, long sweeping corners are pretty much the only places I can pass.

The problem is that sometimes I'd like the rear to slide while I'm trail throttling and right now the car won't step out unless I provoke it. I would also like better low speed turn-in and a little less push on the throttle.

I could be wrong, probably am, but I don't understand how more rear spring/bar or less front spring helps if I'm already lifting a tire.

the bar transfers the weight SOONER. Sure, I could get inside rear wheel up with a stock 13mm bar on the Elantra. But it was at the very far limits of grip. THe bar controlled the roll faster, transferring the weight quicker taking less time for the car to "settle". Macstrut cars really benefit from big bars.

wbjones wrote:

DaewooOfDeath wrote:

White_and_Nerdy wrote: On top of all the other wonderful suggestions (more rear bar FTW), learn and practice left foot braking. Technique alone can get the rear to swing around a bit if you get it right. Massive rally style drifting won't be the fastest way through the corners, but if you moderate it you could at least transfer weight to the front to help with the understeer problem.

Is this a good idea in a 107 hp car? I've never tried it in anything but high power cars.

I left foot brake in my ( mostly stock motored) CRX all the time

What situations? I'm fascinated.

Bobzilla wrote: the bar transfers the weight SOONER. Sure, I could get inside rear wheel up with a stock 13mm bar on the Elantra. But it was at the very far limits of grip. THe bar controlled the roll faster, transferring the weight quicker taking less time for the car to "settle". Macstrut cars really benefit from big bars.

Ah, I see. How much spring were you running with the Elantra, if you don't mind my asking?

DaewooOfDeath wrote:

Bobzilla wrote: the bar transfers the weight SOONER. Sure, I could get inside rear wheel up with a stock 13mm bar on the Elantra. But it was at the very far limits of grip. THe bar controlled the roll faster, transferring the weight quicker taking less time for the car to "settle". Macstrut cars really benefit from big bars.

Ah, I see. How much spring were you running with the Elantra, if you don't mind my asking?

Believe he's using a progressive street spring in that car. His general statements are correct, though i'm not sure that his personal experiences with his car translate to yours.

It's really all down to chassis.

I'm not sold on the FWD Macstrut = huge rear bar rule of thumb, if i must be honest. But that's likely because i own two Mazdas that prefer a huge FRONT bar, and not so big of a rear bar. Adding a 1" rear bar to my MX6 made it a bit ermmmm "interesting" to deal with.

Progressive springs ... ah. That makes sense.

I'll bet your Mazda has a really low front roll center. Wonder if they make RCAs for your car?

I've modeled my Nubira and, honestly, I really like the design over all. It's got a good for a strut camber curve, especially in the front, the mounting is rigid and I have some pretty high roll centers that allow me to get away with not that stiff of a suspension and not much roll either. 9kg/mm really isn't that extreme for a 2500 lb car. The way Daewoo setup springs/bushings/swaybars to go along with this pretty good hardware was beyond awful, but the underlying design has made me a fan of high roll centers.

This is a picture of the beast in the aforementioned high mu, cambered corner. The car is rolling at 2.7 degrees.

A few random thoughts:

• Would a larger rear bar help with turn-in, due to increasing rear weight transfer vs front at sub-wheel-lifting cornering forces?

• Would a larger rear bar help with power-on understeer, in that the rearward weight transfer would help take advantage of more of the rear stiffness than off-power weight distribution? (I.e. more weight on rear means more potential weight transfer before inside lifts)

Sorry if it's been covered before, but I didn't see it in a quick skim: Is the rear a Chapman strut, or something else that has the similar 1:1 spring:wheel motion ratio to a Mac strut? You said you were running 500 lb/in springs all around, but what are the wheel rates?

A larger bar would probably help with turn in. Good point.

The car is a four wheel McStrut design. The wheel rates are about 440 lbs at the front and about 460 lbs at the rear. Nearly 1:1.

DaewooOfDeath wrote: Progressive springs ... ah. That makes sense. I'll bet your Mazda has a really low front roll center. Wonder if they make RCAs for your car? I've modeled my Nubira and, honestly, I really like the design over all. It's got a good for a strut camber curve, especially in the front, the mounting is rigid and I have some pretty high roll centers that allow me to get away with not that stiff of a suspension and not much roll either. 9kg/mm really isn't that extreme for a 2500 lb car. The way Daewoo setup springs/bushings/swaybars to go along with this pretty good hardware was beyond awful, but the underlying design has made me a fan of high roll centers. This is a picture of the beast in the aforementioned high mu, cambered corner. The car is rolling at 2.7 degrees.

Probably. The roll center of the MX6 is likely about 8 feet underground.

If it's a strut, it's also probably giving you an awesome "gains positive camber under compression" dynamic as well.

Up until the point you get jacking, I can't think of a good argument against high roll centers on struts.

BTW, was it you who turned me onto the no-swaybars MR2 guy?

DaewooOfDeath wrote: If it's a strut, it's also probably giving you an awesome "gains positive camber under compression" dynamic as well. Up until the point you get jacking, I can't think of a good argument against high roll centers on struts.

You're right again. To the point that at rest it has 1 degree of positive camber on all four corners.

I need to get those cam bolts in there.

I tend to prefer to make MacStrut suspension work by making them.... not work. Then stuffing a gargantuan tire under it. It's easier, and the end result probably isn't much different.

And no, that wasn't me with the no-sways MR2.... but i was in that conversation and remember it pretty well.

I've been trying to apply that MR2 setup to my Woo and so far, it's working pretty well. Considering my cornering speeds with the Nubira and the big bar setups I've had on cars before before, I think he might be onto something with the "bars reduce mechanical grip" angle.

DaewooOfDeath wrote:

wbjones wrote:

DaewooOfDeath wrote:

White_and_Nerdy wrote: On top of all the other wonderful suggestions (more rear bar FTW), learn and practice left foot braking. Technique alone can get the rear to swing around a bit if you get it right. Massive rally style drifting won't be the fastest way through the corners, but if you moderate it you could at least transfer weight to the front to help with the understeer problem.

Is this a good idea in a 107 hp car? I've never tried it in anything but high power cars.

I left foot brake in my ( mostly stock motored) CRX all the time

What situations? I'm fascinated.

seems to help in 2 ways... a: you're muchmuch quicker off throttle on brake then back on throttle, than if you try to use your rt foot back and forth... in quick transitions sometimes a quick stab with the left can help tuck the front ( loosen the rear ?) ... just don't hesitate or around you'll go.. sometimes I'm even on both throttle and brake ( that quick stab) same thing in long sweepers ... you can control the attitude with a quick lifting of the throttle, or once again that quick stab/brush of the brake pedal.. I'm sure others with far more experience can add a lots more to this answer

Am I right in assuming this mostly comes from autocross, and mostly autocross courses that keep you in 2nd gear?

I've used left foot braking before in autocross, but on track, when I'm going up and down through the gears, I haven't figured out a practical way to use it. That said, there is one stretch I could probably use the left foot in for, if even briefly.

You can go to stiff on a rear bar. On my ZX2SR I installed and adjustable 22mm bar. On the short arm , it felt like the suspensionwas was binding or something. Did not handle well. On the long arm, it was quite neutral and I could throttle steer throught a corner.

DaewooOfDeath wrote: Am I right in assuming this mostly comes from autocross, and mostly autocross courses that keep you in 2nd gear? I've used left foot braking before in autocross, but on track, when I'm going up and down through the gears, I haven't figured out a practical way to use it. That said, there is one stretch I could probably use the left foot in for, if even briefly.

yes and no... depends on the track... at VIR I down shift to 3rd going into 3 and use my left foot for any braking until I finish the flat esses ... also once I whoa it down at the end of the back straight and start down the roller-coaster, it's all left foot 'till I roll on the throttle going into hog-pen

at CMP I'm able to use my left foot between 11 and 12... it does save time... but yeah it does take practice and you do have to concentrate to make it work... but it is worth the effort with bringing the rear end around