Suspension guys-a question of "feel"

[vanzuuk1]

My 69 camaro has dse arms and leaf springs ,carrera adjustable shocks,1 1/8 swaybar, dse st box, about a half inch of rake.

I run about five degrees caster and 1 1/2 dgree camber, 1/4 toe in.

Springs are 600 front and 175 rear.



The issue I have is that the car handles great in an autocross situation but feels twitchy on the open road,it takes a lot of effort to drive alongside another car on a two lane road, feels like I am going to clip mirrors.

This is NOT a traction issue, the car is neutral once its in a corner.


I have a 14 inch steering wheel, would a slightly larger wheel "dumb down" the steering a little.

Will the box loosen a little with time?


Any thoughts? I can adjust the shock and tire pressure,would softer in the front help a little?

[Lowend]

Based on your setup it sounds like a bump-steer issue.
Look here (http://www.thedirtforum.com/bumpsteer.htm)for more info on the subject but Baer makes a set of shimable outer tie rods (called Baer Trackers) which will allow you to correct the problem.

[Mean 69]

Also seems like a lot of toe-in, you might play around with the steering alignment a bit and see what the response is. First gen f body cars don't have terribly good Ackerman, so a band aid for that is often to go with a bit of toe-out to help initial turn in, which will make the car darty on the street in most cases. A small change to neutral, or a slight amount of toe-in makes them a lot more stable. I would guess that 1/4" is too much though. But as Lowend states, it very well could be a bump steering issue. When you make a change and feel a difference, please make sure to post back here so others can learn from the experience.

Mark

[MrQuick]

I agree, try playing with your toe adjustment. A 1/4" in is a lot but not with certain tire sizes also combined with that camber it might be negative.

[parsonsj]

Piling on here: I'd start with changing the toe to 1/16 in or 0. My toe settings make a huge difference in twitchiness ...

jp

[vanzuuk1]

Thanks for the replies, I will check the toe in. Tire pressure and shock settings are free, so I will do those this week. Then loosen the sway bar ends, then off to the alignment rack.

Then I guess i will measure bumpsteer even if it feels better.

[David Pozzi]

I agree, work with the toe. With 1.5 deg neg camber, you could run 0 toe or even 1/16" out.

I think you really need the firm valved PS box to make it complete. If you allready have this box, then check your steering box free play and make sure that's OK.

[vanzuuk1]

I have the dse box, I will set the toe at close to zero.

[David Pozzi]

Check the box for free play, even if it IS a DSE box.

[vanzuuk1]

The box seems fine, I even think some free play might help this time.

I actually had a little more than 1/4 inch toe, knocked it down to 1/8. So far the car seems better,need to drive it on some of the same roads to confirm. Not as twichy for sure.

One annoying side effect has been bringing the car to my buddies gm dealer for alignments, my friend john is awseome but the comments from the other workers are endless, lots of "experts" standing around.

[Rick Dorion]

Dirk, I'm not running the camber you are (I have -.5*) but with 5* caster and zero toe I have a stable tracking car. Also have the DSE box. Keep the updates coming!

[vanzuuk1]

My friend who does my alignments would kill me but I want to adjust the toe in my driveway using the old tape measure method.

[Randy67]

I've done the tape measure toe alignment on 2 different daily drivers. Neither has had tire wear issues and drove straight and both were autocrossed as well. I put 25,000+ miles a year on each. So I say go for it, certainly cheaper to try it yourself.

[pitts64]

I prefer the straight edge method. Don't forget to have wax paper under the front tires to free the suspension up (unlike the photos).

[MrQuick]

...or on two peices of cardboard. So they can slide on each other. I picked up a laser level kit at home depot for pretty cheap. Works real nice.

[Damn True]

My friend who does my alignments would kill me but I want to adjust the toe in my driveway using the old tape measure method.

Do you need the procedure?

[wendell]

Dirk,
Don't be afaid of using a tape to set toe. Like the other folks said, put something under the tires (I use two sheets of news paper). After an adjustment bunce the front end up and down and wiggle the wheel before measuring again.

get my PM?

[vanzuuk1]

Hey wendell... yea i got it, we got to hook up at lrp one day.

[vanzuuk1]

No True, I have the tech, just been lazy I guess.

[Rick Dorion]

Check the box for free play, even if it IS a DSE box.
I experienced the twitchiness too just recently when driving on roads that have been patched along the sides. I jacked up my front end and can wiggle the wheels side to side a bit. I see this translate to some steering box arm movement. I assume this is the play being referenced(?) I don't detect any play in the compenents (tierods, BJ's, idler arm, etc) which are fairly new. Anyone else experience some looseness in the DSE box? I'll have to read up on adjusting. It's disconcerting to feel like the steering is a bit disconnected.

Dirk, have you made any progress?

[vanzuuk1]

I thought I would update this...it was never an issue of anything feeling loose,in fact the steering felt tight and twitchy,darty.


The dse box is a faster ratio, so thats one thing that could make me think the car was twitchy.


I took out some toe,that helped. Ran a little less tire pressure in the front, that helped. Tightened the wheel bearings, one was loose,that helped.

The change that seemed to help the most was to ditch the 13 inch wheel and get a big stupid 15 inch flat wheel from speedway. I had to redrill the wheel to bolt to the grant adapter and the turn signal stalk was trimmed to get it out of the way. The final touch was a big stupid pad to cover the redrilled center section. It looks like a bumper car steering wheel now but its muuuuch better.

My car seems to like tighter turns,it feels more like an autocross/donut/drift car than a high speed oval track car. That suits me fine, I would rather hit an exit ramp a little hard than push it around 100 mph sweepers.

The next time i autocross I will put on the smaller wheel for the day to make it turn super quick again, but for street or track day the big wheel makes the steering much more user friendly.

[gt1guy]

What ratio is the box?

Kevin

[vanzuuk1]

You had to ask the one question I could not answer...its a dse box, faster than my stock one. I will check the paperwork later.

[hotrdblder]

12-1 ratio

[vanzuuk1]

Thanks.

[JEFFTATE]

My car also has the "twitchy" feeling.
I'm gonna set the toe a little different.( Maybe to 1/16" or 0" )
Currently it is at 1/4".

[hotrodf1]

I have been told that the more neg. camber you run, the less toe you need. If you run -1.5 camber, you may need 1/16th OUT. Pretty sure D. Pozzi and Fred Puhn would agree.

Camber thrust has to be accounted for when you run that much neg. camber. at -.5 degree camber, 1/16th should do it. Maybe the extra toe is generating lots of "extra" forces and the road surface irregularites bring it out more.

The 1/4" toe is the original spec for the camaro with bias plies on it, no need for that much toe any more. Regular radials and camber = 1/8" toe.

[silver69camaro]

Currently it is at 1/4".

Whoa, that's alot.

Things to resolve twitchy steering:
1. Alignment
2. Steering linkage/box adjustment
3. Wheel bearings
4. Pump flow

I'm willing to bet the original poster of this thread needs to reduce the flow of his PS pump. It will make the car feel extremely sensitive to steering inputs.

[ls1 nova]

Just out of curiosity, What steering arms are you running. Short,med,or long. Could the short arms(already quick steering) coupled with a fast box cause this?

[David Pozzi]

With 1 1/2 deg neg camber, I'd play with more toe reduction, including some toe OUT up to 1/8" - 1/4" total.

[JEFFTATE]

Whoa, that's alot.

Things to resolve twitchy steering:
1. Alignment
2. Steering linkage/box adjustment
3. Wheel bearings
4. Pump flow

I'm willing to bet the original poster of this thread needs to reduce the flow of his PS pump. It will make the car feel extremely sensitive to steering inputs.

You know what ?
I think I posted that wrong.
I've actually got less toe-in than that.
2' negative camber.
and 4.75' - 5.00' of positive caster.( One side has a little more than the other to compensate for the crown in the road )
I'll have to look at the alignment spec. sheet to make sure.

[70bird]

The dse box is a faster ratio, so thats one thing that could make me think the car was twitchy.
I think you hit the nail on the head!
IMO, 12:1 (actually DSE box is 12.7:1) is too quick for a primarily street driven car, and will require more steering corrections while driving in a straight line. Higher speeds will make the twitchy feeling worse, and any bump steer problems will be more noticeable at the steering wheel. The larger steering wheel effectively slowed the steering ratio, which is why it feels better.

I used a 12:1 box for a while, and after 4 alignments trying to cure this problem, I changed the box to a 14:1 ratio and the car is now a pleasure to drive.

[the camtender]

When I had AGR build me a steering box (quick ratio 1 3/4 lock out to lock out) I told then that I do alot of high speed stuff and street , so they changed the valving in the box which slowed the the flow down I guess.They said that's the set up they sold to nascar (truck) guys. It feels like a manual rack kind of.I like it! works perfect for me,I couldn't image a better feel than what I have now.

Jerry

[CarlC]

There may also be some "getting used" to the car. I know that I have to switch gears in my head when driving the Camaro vs. my daily driver. The Camaro will track fine, but it is not as easy to keep in-line with other cars as the DD. More tire, agressive alignments, stiffer springs, etc. all add up.

However, I do agree that toe-OUT should be in the neighborhood of 1/8" for -1.5* camber/+5 caster. I had good results with this, even on the street.

[Rick Dorion]

I have zero toe with 4.5* caster and -.5* camber. With the DSE box it tracks well.

[JEFFTATE]

You know what ?
I think I posted that wrong.
I've actually got less toe-in than that.
2' negative camber.
and 4.75' - 5.00' of positive caster.( One side has a little more than the other to compensate for the crown in the road )
I'll have to look at the alignment spec. sheet to make sure.

Well , I've actually got :

3/4' of neg. Camber on each side.
4.5' + Caster on the Drivers Side & 4.75' + Caster on the Pass.Side.
and 1/8" Toe In.

I was trying to achieve the alignment specs from the Guldstrand Catalog and from the Stage Three setup from Global West.
That's as close as I could get it.

[John Wright]

Like the other folks said, put something under the tires (I use two sheets of news paper). I have used two mild steel plates with grease between them...seems to work OK