Here's the story. I have a N*Getrag 85/86, Held Slalom front end, currently stock rear with RCC bumpsteer kit. Front spring rate is standard for Held, rear is a RCC Coilover 350 lb" (what was recommended for N* conversions). Tires are Firestone Firehawks 225/50/16 F 255/50/16R. Car is lowered about 1 1/2", battery is up front. Addco heavy duty front bar in front, stock front bar in rear.

This past weekend I entered an autocross in New Orleans. Bad news. Car had severe oversteer. I've noticed this on the street to some extent but haven't pushed it. Anyway I was the first car to spin around on the sweeping curve. Even the chicane was tough cause the rear kept trying to slide out. I posted 4 slow times. 4 seconds off the 911, but really beat by Miatas and BMW and such. Even another Fiero beat me by 1.5 sec (3800 auto).

Now some of this was driver experience, which I lack. But the car was like it was on skates. Video showed that the rear was rolling a lot. The front was stable.

My plan to correct this is to increase the rear dar diameter to 15/16", install Koni's on the rear (have both) and change the rear springs to some softer level. Any suggestions as to what should be done here and what spring rate I should go to? BTW the weight of this car is somewhat lower than stock, but the N*/getrag rear weight is the same as the 2.8.

The plan must not include a tire change just yet. I want to tune this car to the fastest possible time in full street trim.

Very simple fix---------I think your wheel allignment is way off . Mine handled just as you describe .My alli. was screwed up by the local goodyear place . Sears made it handle great again with a laser type machine . Good luck !!!!

If you increase your rear bar the oversteer will get worse. The Koni struts should help you dial out some of the oversteer. Try adjusting them to keep the weight from transferring when you let off the gas. Maybe try a constant speed through the turns, not slowing down through them.

Do you have the 1 1/4 bar up front?

An alignment might help too. Maybe even lower the rear tire pressure a bit and raise the front pressure? Maybe you are just going too fast ? Maybe even losen the rear endlinks for the swaybar.

Remember if you decrease the rear spring rate the rear bar will have an even bigger effect of their spring rate.

This is the funnest part of racing: Dialing it in!

[This message has been edited by SCCA FIERO (edited 01-30-2002).]

Before you try anything EXPENSIVE, try removing the rear stabilizer bar, and see if the car will drive neutral around a small skid pad.

(Just find a deserted parking lot and try going in tight circle at a steady speed, gradually increase speed until one end of the car starts to squeal the tires.)

The front should squeal first, unless you have REALLY improved front traction. If the rear squeals first, you DON'T need the rear bar.

If the front squeals first, you probably need a SMALLER rear bar than the current one, and believe me, you will get MUCH faster times if you can keep the rear hooked up to accelerate with.

You can make a very satisfactory and inexpensive small bar by buying a 1/2" crome moly solid bar, get a welding shop to heat and bend the ends (and quench them in oil) with a torch, and mount it with collars and heim joints in the same location the other rear one was.

Hope this helps ya.

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Gerald Storvik (8shark.com)

Hey man, 350lb springs are *way* too heavy! Try 275s or so. That may be the real cause...

Konis will help too. A lot. Especially if you have really 'stock' dampners there. there was NO STOCK COMPRESSION DAMPING! (!!!)

That, and if you run rear toe-out, you have to run LOTS of front toe-out!

Try different compound tires? (are the firehawks good sticky no-treadlife stuff?)

Best!
Ben.

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Ben Cannon
88 Formula, T-top, Metalic Red. "Every Man Dies, not every man really Lives"
88 Formula, Northstar, Silver, In-Progreess. -Mel Gibson, "Braveheart"

were you totaly off the gas when it oversteers???? or mostly anyway??
try a little more gas+ lite on brakes [trailbraking]
before the apex note this is race only not a street tactic as you can over heat brakes quickly and wear them out
the other biggie is smoothly lifting and braking to keep car stable and not braking rears lose [eazy to say hard to do!]

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Question wonder and be wierd

Another SM2 Fiero!! Welcome. You should join the racing list and see what they have to offer.

I have not been able to answer your e-mail., so will answer your questions in this forum.

I agree it is likely your alignment. But, for autocrossing, your alignmnet should be a lot more aggressive than for the street. There are several different driving styles, but I can give you a setup that will get you in the ballpark. Then you can make your own adjustments to suit your driving style as you progress in your Solo driving skills.

Try using these alignments. they ARE aggressive, as I mentioned. I have been told they will tear tires up, I haven't noticed a huge tire wear (and all my street Fieros have had an autocross alignment on them, including the 4.9)

Anyway - - for a dual purpose car I would suggest neutral front toe and 1/8" toe IN on the rear (I actually put about 1/8" toe OUT on the front of mine, but it gets twitchy at speed).

For camber I would suggest you start with 1.3 to 1.5 degrees negative camber at each corner (I run 1.6)

Have you ever ridden a motorcycle? Remember the "choppers" of our youth with the long front ends and extreme rake? Great for cruising, but couldn't get around a corner very well. Remember - even watching "Easy Rider" drives that point home.

Well, changing a car's caster does about the same thing as changing the rake angle on the neck of a chopper. If you want stable straight line cruising, a lot of caster will do it. If you want quick turn in (as in Solo II) then decrease it. I would suggest - for a dual purpose car - about 4.0 degrees to start. (I run 3.5 degrees positive caster).

I also agree that you may have your rear suspension too tight. Instead of switching swaybars, try just putting the rubber bushings back in to loosen it up. The 22mm rear bar shouldn't be too much with the 1" front bar.

The Ryane slolum I had on the Q4 came with 300lb front springs. Most 2 1/2" springs, such as the ones Ryane/Held put on, are marked with their rate somewhere. You should find either a metal tag with the rate, or it will be painted on the coils themselves. If you don't find the spring rate on the front springs, I would e-mail or call Dave and ask what rate he sold you. I used to keep a few different rates around to adjust for track conditions, but you probably want to keep it dual purpose so you don't have to mess with the car on race day.

Changing from the Bilsteins to the Koni's will make a world of difference, I would not set the Koni's too stiff, however.

Hope this helps.

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George Ryan

A pair of 4.9 Cadero's

This '85 SE daily driver:

4.9
5 speed
'88 cradle
Koni's/Eibach/Addco/Prothane
complete Mr. Mikes interior

[This message has been edited by cadero2dmax (edited 02-05-2002).]

Just install that Getrag with Torsen, and stay slightly on the gas through the corners

In addition to Cadero2dmax, Slammed Fiero is a good source of autoX info. And check out the Fiero racing list on yahoo groups.

First of all, thanks to all who replied. There is a wealth of experience in there and I'm sure it will all help.

But I guess I'm still wondering what's wrong. This is essentially the same setup I ran with the v-6 and that was a better handling ride. I'm going to tackle this as a spring rate/rear bar/alignment before I get too serous. Thanks again.

Hi George, what front springs are you running? I'm assuming he's only running 275 or 250lb on the front (and the front spring rate is about 1.6 of the wheel rate on an early car iirc.)

The Koni struts are rebound-damping only? I could swear they're both compression and rebound, with the ajustments simply modifying both? Am I nuts?

Wish there were Yellow Konis that fit our cars

Wcapman: do you have off-the-shelf Konis, or Held's Konis? (not sure of the exact differences, but I know he uses a slightly different strut body.)

On alighment, I simply defer to george's recomendations. He knows those early front ends! (wheras I do not at all...) (toe-in rear even with the bumpsteer kit that replaces that rubber with a rod-end? I've no idea, just thought I'd bring it up.)

I know your spindle swap will tighten up the rear end in a *big* way, but untill then, the car should at least turn right.

This is a bit of a werid one, like you said, just start playing with the easy stuff and see what it does.

Best!
Ben.

quote Originally posted by cadero2dmax: First, the 350lb spring with his setup is stiff, but not "way too heavy". That is what I have on the rears of mine, now. Also, the Koni's are a rebound shock, same as the stockers. It is just that the rebound rate can be adjusted. There are double adjustable Koni's out there, but bring your checkbook - we're talking the exotic racing crowd now!! Front toe IN is what you need for a tight autocross course, fairly neutral for a street machine or dual purpose, and toe OUT in the front is only good for road racing/high speed touring. Toe OUT will wear tires even more than toe IN will on the front. On the rear, a definate toe IN is advisable, especially on the early chassis. It helps with bump steer. The 14" tires I run on the street are Firehawks, the SS10 series. Not the most aggressive tire out there, but a solid, long wearing performance tire none-the-less. These tires were actually the spec tires for the Firehawk series of racing a few years ago. Hope this helps G

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Ben Cannon
88 Formula, T-top, Metalic Red. "Every Man Dies, not every man really Lives"
88 Formula, Northstar, Silver, In-Progreess. -Mel Gibson, "Braveheart"

I have just a hair shy of 300lb springs (measured) on the front. These are a set of red Eibach lowering springs cut about a full coil, for a total of about a 2 1/2" drop. Before they were cut, they measured right at 275.

I will betcha a cuppa coffee Koni's adjust rebound only. That includes Koni yellows, also. Both could be converted to double adjustable for enough $ bills, and the Porshe crowd has them done a lot. But that is not the way they came!!

G

I'd first make sure that you're not toed out in the rear,then,try it without the rear swaybar.
The best way I've found to setup spring rates is to allow a difference of 25-50 pounds between the front and the rear,with more in the rear of course.Then only a small bar should be necessary to dial it in.
I once had a set of the older Konis on my 4 cyl car,they worked incredible,rode a little rough,now I use some Bilsteins from a Golf/JettaII,inside some housings I made with threaded collars ontop.I like the Bilsteins even better,and they fit perfectly inside the original bumpstops.I also turn the upper strut mounts upside down for more travel(bottom out=rapid oversteer).
What's that motor weigh,is it all aluminum?
If not you'd be better to stay closer to the 50 pound difference between the front,and rear.

quote Originally posted by lowCG: I'd first make sure that you're not toed out in the rear,then,try it without the rear swaybar. The best way I've found to setup spring rates is to allow a difference of 25-50 pounds between the front and the rear,with more in the rear of course.Then only a small bar should be necessary to dial it in. What's that motor weigh,is it all aluminum? If not you'd be better to stay closer to the 50 pound difference between the front,and rear.

Just checked the alignment. I'm toe out rear, toed in front. Yech! Back to Firestone. Good thing I bought a lifetime alignment. The front suspension is the Held Slalom, which has 2" longer a-arms than stock. The inner pivots are further inboard. The front springs are 300 #. The N* weighs in exactally (within 5 lbs) of the 2.8. This car should setup and balance just like any other Fiero.

Just talked to Dave Helm. Dave says to ditch the rear bar (formerly the front bar) and go with one with longer arms. I'll have to bend that later. I may go with a slightly smaller diameter while I'm at it.

The standard Koni's have a larger body diameter that do KYBs or Bilsteins. Therefore I will need 2 5/8" springs (AFCO) and will need to make my own spring seat. I don't need the coil over once I get the right height.

This is going to be fun.

longer arms = thinner bar both may be toooo much together.
if you go to coilovers you can tune the spring rates eazy plus use wider tyre
and if your buying springs and doing custom mounts can't that much more????
will they let you sit in car to get real weights and ridehight when doing alignment??

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Question wonder and be wierd

There are more than one that have used the Ground Control kit with the Koni and 2 1/2" springs. I may be wrong, but I think Slammed Fiero might be one of them.

I DO know for sure that a couple of people on the FieroRacingList have done it, and it should be chronicled in the archives for that list.

G

Hey again, I'd swear the Konis can wear very standard 2.5" springs (just have to do a bit of grinding to slip the threaded collar over.)

Yep, toe out rear, toe in front will be a problem!

Ok 300front, 350 rear isn't too bad. You may drop the rears to 325lb though if the problems persist. (or just for grins, 2.5" springs are CHEAP! and easially changable.)

I'm almost done with my motor mounts, next step is fitting my cradle into the car!!!

These cars sure are fun indeed.

PS: George, read you on the ajustable rebound damping only, but don't the Konis also have at least *fixed* compression damping? (stock fiero shocks have NO compression damping afaik.) I haven't heard of converting a koni to fully independant ajustable, got any urls/pointers?

quote Originally posted by wcapman: Just checked the alignment. I'm toe out rear, toed in front. Yech! Back to Firestone. Good thing I bought a lifetime alignment. The front suspension is the Held Slalom, which has 2" longer a-arms than stock. The inner pivots are further inboard. The front springs are 300 #. The N* weighs in exactally (within 5 lbs) of the 2.8. This car should setup and balance just like any other Fiero. Just talked to Dave Helm. Dave says to ditch the rear bar (formerly the front bar) and go with one with longer arms. I'll have to bend that later. I may go with a slightly smaller diameter while I'm at it. The standard Koni's have a larger body diameter that do KYBs or Bilsteins. Therefore I will need 2 5/8" springs (AFCO) and will need to make my own spring seat. I don't need the coil over once I get the right height. This is going to be fun.

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Ben Cannon
88 Formula, T-top, Metalic Red. "Every Man Dies, not every man really Lives"
88 Formula, Northstar, Silver, In-Progreess. -Mel Gibson, "Braveheart"

Ben

The OEM/OEM replacement(like Gabriel, etc.) shocks/struts simply have holes in the piston that meters the flow in both directions when fluid or gas is forced through these holes to the other side of the piston.

Thus all shocks and struts have some sort of compression dampening. Some even have a tapered metering pin, much like aircraft use. The "automatic" adjusting shocks/struts (like Monroe has - can't think of the name)use this principle.

What the Koni's have is a metered compression damping (much like the OEM/OEM replacement) but they do offer a little stiffer compression, but at a fixed rate. They also adjust the rate of return flow (rebound).

I have somewhere in my archives an addy for the Koni double adjustable conversion. But I am told any dealer that offers a Koni rebuild can get the conversion done. Check with your dealer. Frankly, I've never paid much attention to this process because that costs BIG bucks. I am talking in the neighborhood of a grand for converting both shocks. Not needed, IMHO

G

Hi George, cool, thanks for the info!. I may look into this double ajust conversion, maybe it can be done cheaper with a friendly machine shop (then again, maybe not if you have to drill into a high pressure N2 cylinder..) If we could get the cost down to a few $hundred for 2 struts it may be worth wile. (hrm, MORE stuff to ajust and balance with the rest of the car, that's all I need.)

Back to welding the cradle!

Best!
Ben.

quote Originally posted by cadero2dmax: Ben The OEM/OEM replacement(like Gabriel, etc.) shocks/struts simply have holes in the piston that meters the flow in both directions when fluid or gas is forced through these holes to the other side of the piston. Thus all shocks and struts have some sort of compression dampening. Some even have a tapered metering pin, much like aircraft use. The "automatic" adjusting shocks/struts (like Monroe has - can't think of the name)use this principle. What the Koni's have is a metered compression damping (much like the OEM/OEM replacement) but they do offer a little stiffer compression, but at a fixed rate. They also adjust the rate of return flow (rebound). I have somewhere in my archives an addy for the Koni double adjustable conversion. But I am told any dealer that offers a Koni rebuild can get the conversion done. Check with your dealer. Frankly, I've never paid much attention to this process because that costs BIG bucks. I am talking in the neighborhood of a grand for converting both shocks. Not needed, IMHO G

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Ben Cannon
88 Formula, T-top, Metalic Red. "Every Man Dies, not every man really Lives"
88 Formula, Northstar, Silver, In-Progreess. -Mel Gibson, "Braveheart"