1987 FC road race pushy!
 

Good day!

I finally got my 1987 FC on the track. it has some older tokiko Blues, stock springs, stock swaybars, Star Spec tires, Hawk black pads. The car has mostly stock bushings (old)

For alignment:

Front 1/8" toe out. 2.8 deg front camber
Rear 1/8" toe out. 1.5 deg rear camber

The car is REALLY pushy! I don't think I could spin the car if I tried!

I added some circle track spring rubber to the rear springs to stiffen them up a bit. This helped a good bit, but didn't solve it entirely.

I know most people take the rear sway off the car. This would make it push even more! How are you guys getting your cars to turn?

This is for a budget limited class. Anything I do needs to be cheap!

Thanks!

Rob R.

Rear should be toe in.

If I toed in the rear wouldn't that make it have even more rear grip? WE started with 1/8" in and it got better when we went out.

I'm going to go out on a limb and say the stock springs and sway bars are a big part of the problem.

Things i would try.

Spacers up front.

Use white shoe paint and paint outer edge of front.tires. if it doent.wear. you possibly have to much negative camber up front.

Try more air.pressure on rear tires only.

New bushig for.rear only.. ehehe

The outer edges of the front tires are worn more that the rest. I was thinking I needed MORE front camber.

What do you mean by spacers up front?

What spring rate would you use on the rear? What swaybar on the rear?

Its gotta stay CHEAP!

Thanks!

Rob R.

what pressures are you running? put more air pressure in the front tires, they're probably rolling over onto the sidewalls

you could probably do more front camber, I run -3.5*

are you running stock wheels/tire size?

anything you can do to stiffen the front end would help, be it either springs or a sway bar. (one of the reasons you're probably understeering is you're bottoming out the front suspension because it's so soft.)

front is too soft, you would need like neg 5 deg of camber in the front and that may still not be enough for stock springs and bars. Stiffen up the front springs and bar...and lower the front end at the same time

what does the car weigh with driver?

Dont mess with the rear till you get the front stiffer...or you are just balancing the car by decreasing overall grip. It sounds counter intuitive but until you are using the full front contact patch the usual handling adjustments don't really apply that much.

yep, start there.

The car weighs about 2450# with driver.

Tire pressures are 38 hot front 37 hot rear on 205 50 15 star specs. Stock wheels.

Any cheap easy ways to increase the front stiffness?

This. Dollars to donuts the camber and grippy tires are allowing enough side loading to make the front suspension corner on the bump stop, a recipe for understeer if there ever was one.

how cheap are we talking? you could probably get used coilover springs and collars pretty cheap.

I'm running these sleeves on the front of my car:

Here is my game plan for now....

I am going to run 200# front springs on adjustable collars. I am going to take 1/2 a coil out of the rear and add a spring rubber (My math says this should make the rear spring rate about 125 #).

I am adding front end camber for a total of 3.5* per side.

I plan to drill a new hole in the sway bars (front and rear) about 1" away from the current mounting hole (making the moment arm shorter).

Any other cheap / free suggestions? Anybody have any reasons why this wouldn't work?

Thanks,

Rob R.

I'd run stiffer than 200#.... I have 600 lbs/in on my car. Most track guys run ~400 lbs/in in the front.

for a roughly 2400-2600lb car (includes driver) you want to be at around 400lbs springs with a pretty good size sway bar. With this you can run right around 3 deg negative and achive a pretty good front wear and even tire use.

400# Springs??

Is this not WAY too much? I am having snap loose issues in my FB and I am trying to learn as much as possible about the front skipping/chattering going on in our car. We run 125# springs, but the highest I have heard people running is a bit over 200#s. Does anyone else have some knowledge they can share about spring rates/suspension set ups in an FB?

Thanks guys!

Also, wvumtnbkr, do you have any photos of the car in the corner? We learned a ton about how out of whack our setup was from photos. It sounds dumb, but you tell whether you are pulling the inner front tire off the ground etc.

the old pro7 spring setup was 350/175... not saying its the perfect spring setup for an FB or anything, but its pretty normal.

FC's are typically 300-450 in the front...

I appreciate the info man. I am very much a rookie with finding good spring/suspension setups. We are finally to the point where we can work on these things, rather than worrying about power etc.

the fc is very pushy from the factory and even modified unless drift knuckles and other tricks are implemented. i didnt read the whole thread because its late...but pm me for handling and suspension advice. i can help you..

you dont need knuckles or other exotic geometry horseshit to make an FC handle well. Just needs a lot of spring. I'm at 700/500, with an ST front bar on stiff, no rear bar, staggered tires, and its a little loose.

<*sigh*>
So much misinformation, so little time.

Do a search through this forum - FC suspension has been discussed many times. Here is the condensed version.

400# springs front, 225# rear, Racing Beat front sway bar, no rear bar. Shocks/struts were usually something like a koni yellow. A KYB-AGX was about the minimum needed given the front springs. Car is lowered. Camber adjustment plates front, adjustable center link in rear. You should be able to set at least 2.5* neg camber in front an a little less in the rear. Rear steer bushing setup should be eliminated.

This is kind of a "base" setup for an SCCA ITS-level car (around 2680# w/ driver, about 170rwhp). 225/45r15 tires on 15x7 rims. You need the front stiff to prevent roll (and associated camber loss) and the rear soft to let you put down power.

With the above set up, my car is fairly neutral. Over/under steer can be adjusted for with shock settings and tire pressures. A couple psi change front-to-rear can make all the difference.

Good luck,

-b

Good info in this post. Suppose you're trying to improve a Lemons car and can't spend that much money (or look like you've spent that much money). Are there any lowering springs available that come close to the suggested spring rates? Or do you pretty much have to go to a perch/sleeve set up so you can choose your spring rates? It looks like all the springs out there are somewhere around 150 lb fronts - pretty far off from the suggested 350-400 lbs suggestions. Is there a cheap way to put linear springs on the front of these cars, maybe with some slight modification to the perches? And how much negative camber is possible without getting camber plates?

comparing spring rates between different cars (or between different generations of cars in this case) is an apples and oranges exercise.

do some interwebs reading on motion ratio and subsiquent effective wheel rate...

The right spring rate for a given weight on an FC will not be the same for an FD nor will it be right for 1st gen...

Further anyone pushing spring rates as ideal without any real consideration of the weight of the car should be ignored.

Nevermind... I had typed up a reply but realized you were just making a general reply to the thread, not my question a couple replies up.

I just read elsewhere in the forums that Racing Beat springs are linear. On RB's site, they specifically mention that the FD springs are linear but do not mention the springs for the FC application being linear. I sent them a note to find out for sure. Though ideally we'd choose our spring rates based on the weight of the car, it's a Lemons car, so it's got to be done on the cheap.

So Racing Beat's springs for the FC are linear, but they said that for track use we would probably want to look around for a stiffer spring - but couldn't tell me who made any that would drop in without moving to a perch/sleeve set up. Can anyone tell me if there is a company who makes a stiffer linear spring set that will work with the OE shocks on an FC? Something stiffer than Racing Beat's 156 lb front and 128 rear.

you can get a used (or ebay lol) set of coilover perches for way less than RB springs... or any other new lowering spring, I don't understand why you're pushing stock style springs. There are none that are stiff enough.

Mainly to look at stock as possible for Lemons...

What perch/sleeve set would work and require the least amount of modifications? I only know of the Ground Control kits, and couldn't find any others doing Google searches. We're all very new to this car and don't know about the cheaper options that will fit. GC is too expensive for this program.

they don't have to be car specific, just measure the diameter of your strut and make sure their ID is more than that... you can fill up the gap with duct tape (I'm serious :) )

I run these on my custom front coilovers (not stock struts):

Custom coilovers

Snap loose mid-corner in an FB is usually due to unweighting the inside rear tire because the front suspension is too soft and the rear suspension doesn't like to articulate.

Solution - throw away most of the rear suspension in favor of something that moves, or stiffen up the front suspension so it doesn't move much either.

Stiffening the front may also get rid of a good deal of understeer, as well. Suspension on its bump stop has infinite rate.

Fwiw, im sitting on tanabe gf210 lowering springs. They are 3k front and 2.5k rear. They really woke up the cars handling (along with a full set of older tokico blue struts).the springs are $190 shipped off ebay an lowered the car damn near 2" (it says 1.5" but mine dropped more than that). A friend of mine has pbm coilovers under his car 10k front 8k rear and i honestly believe its far too stiff. If mine were much stiffer i would be dissatisfied. I do need some xambrr plates up front though.

Can someone explain what those adjustable perches do? Im confused by them lol.

3k is 169 lbs/in which probably isn't much more than stock. your handling improvements are because your riding around on bump stops... which isn't the right way to make a car handle.

the adjustable perches allow you run run universal 2.5" race springs so you can run whatever spring rates you want. They turn normal struts into coilovers...

how stiff a car feels has a lot to do with the damper valving. I run 10.6k/7.5k springs on my car and it's pretty easy to drive on the street.

Hmm there is still plenty of travel if you push down on the car, so can't be riding on the bump stops. It feels much stiffer than the old stock stuff. It also has a much lower ride height, maybe the larger improvement is from the lower center of gravity. I don't know, but feels a lot better than it did lol. Im really interested in those collars, how do they work? I understand they turn regular struts into coilovers but what is they are actually doing? (Compressing the spring to make them stiffer? They can't be stiffening the actualy strut are they? Are there different settings, like if i want the fronts to have a rate of 400#, is there a setting for that?) thanks a lot!!!

Btw, yea 160# is not as stiff as i would think. I did the co version last night. Im not a math wiz so i didnt try it myself, but after using the mighty math god google i figured it out lol.

the height adjusters just put the bottom spring perch on a thread, so you can raise and lower it.

think of it like changing the length of the spring

And by compressing the spring it stiffens the spring rate correct? If so i am hooked on this idea, then add camber plates up front. I am so glad i read this.

No, the spring stiffness is entirely determined by the spring, the height is entirely determined by how much unsprung weight there is pushing down on it. The adjuster collar is to set the ride height and cross-weighting.

Look at it this way - springs are sold as X diameter/Y length/Z rate. For what we're concerned with, we're dealing with 2.5" diameter. Length and rate then are the things we need to worry about. Generally springs are sold in 6, 8, 10, 12, and 14" lengths, and rates at every 25 pounds from 75 to over a thousand.

So say you're playing with 10" springs and you're using 200lb rate. You go to 250lb rate. The spring is the same unloaded length, the car is staying the same weight, so the stiffer spring will make the car sit higher. So you have to lower the collar to compensate. Then you decide to try 275s and change things again. And on and on.

Ok that makes a lot more sense. Thank you for breaking it down for me to understand it easier. So with that being said, imany recomendations for a stiffer spring set than what i have? Honestly, the fronts feel nice and stiff but the rear feels too soft, whats the proper way to test a strut to make sure its still good? The rear just feels too soft while attacking a corner.

To the OP, what have you tried so far?

(Sorry not tryin to thread jack)

personally:

replace bushings with cheap polyurethane bushing kit
replace stock springs, i run 600/400 which has been a pretty proven number in e-rpod, so keep that ratio and dial it down for tokikos
reduce front tire aspect ratio, also buy used R compound tires

turbo II rear swaybar minimal. i wasted years of my life racing around with no rear swaybar on fd's, fc's, and s2k's. always liked it more when i put the sway back on (i would take it off if you are having massive oversteer problems and need to tune). might as well neuter a stud (not having a rear bar).

make sure the wheel makes the front wheel bearings happy, retain stockish offset and go inboard with the wheel pretty far.

keep a square wheel setup

2.8 camber front and 1-1.5 rear

1/16 toe out front, 0 to 1/16 toe in rear depending on oversteer qualities

do not lower the FC excessively. doing so will result in roll center problems and bump steer, which lead to loss of front grip. it handles good at near stock ride heights.

more gas in tank helps the rear come around

drive the car like a grand touring car. its not a small car, and takes lots of hacking to make it snappy.

try a LSD if you dont have one.

increase both swaybars to reduce body roll and increasing the rear bar will bring that big square butt around faster.

increase frame rigidity and tune it to be stiff in the rights spots that bring the car around.

tune brake pads to have high endurance in the front and bite in the rear. this helps the bias bring the car around under braking. its hard to overheat the rear brakes, too.

thats all i got right this second.