Today i had my digital camber gauge on the car to set camber and my friend turned the steering wheel... I was shocked to see that the camber went from an agressive 2 deg (wheels off the ground.. usually 3 when on the floor) to 0 with the steering about 3/4 way turned.

Now my question is, when i am racing, and turn the wheel does this mean that i lose all the camber?? When turning i know you get camber gain with compression but is it less than what is lost? Also, when i check at the caster reading, when turning the wheel it goes to positive caster..

I am learning this stuff slowly but it seems that loss in camber is part of my understeering problem.

 

What kind of car was this measured on?

If I understand the front suspension geometry of the typical Civic / Integra, there should be no caster change from steering input. However, other cars with a "multi-link" type of front suspension (like an Audi) do change caster with steering input.

In general, if you have positive caster (and all cars should have at least a little), then the outside tire should gain negative camber, while the inside tire looses negative camber (gain positive camber) while turning.

Caster is wonderful, until you factor in steering effort, the fact that turning now raises the front of the car up on its suspension (gives you that nice self centering when you let go of the wheel though), and loads the outside rear tire (bonus feature for FWD imho).

Also, keep in mind that you generally won't ever have the steering wheel turned 3/4 to full lock except in parking lot maneuvers, where the speed is low enough that camber and traction aren't an issue.

 

The car is a civic EG. Forget about the caster comments i made earlier because i was just looking at the reading from the guage and not actual caster.

I know for a fact that the car has 0 caster (verfied when i did my alignment on a proper laser rig). The real question is that i lose camber turning left or right so if the tire is centered then i have 2 deg.. when i turn left it goes to nearly 0 then when i turn right it also goes to nearly 0.

 

You should be less concerned with the actual mesurement of camber and more concerned with your tire temperature. You add camber to optimize your traction patch. To do this you will measure your tire temperature at 3 points across the tire: inside/middle/outside. You will want the temperature to be hottest on the inside and loose about 10 degrees as you get to the outside. Inside is hotter by more than 10 degrees to much camber. If the outside is hotter than the inside not enough camber. Remeber when tuning suspension that you try to optimize the contact patch.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BRN12345 &raquo;</TD></TR><TR><TD CLASS="quote">I know for a fact that the car has 0 caster (verfied when i did my alignment on a proper laser rig). The real question is that i lose camber turning left or right so if the tire is centered then i have 2 deg.. when i turn left it goes to nearly 0 then when i turn right it also goes to nearly 0.</TD></TR></TABLE>

This behaviour you're describing is due to your kingpin inclination (KPI). Think of it as caster when viewed from the front. It is the angle from vertical of the steering axis when viewed from the front and it will add positive camber to both tires when steered in both directions.

There are a few reasons for this angle, including packaging reasons for double wishbone front suspensions with tall steering knuckles. Also, when combined with caster, it could affect the grip of the tires since at different loads (i.e. inside vs outside loaded tire in a corner) the tire will operate best at different camber angles. And finally, for front wheel drive cars especially, this angle allows the suspension engineers to adjust the scrub radius, minimizing it, or slightly negative (steer axis intersects ground outside of tire centreline) to reduce brake and acceleration feedback to the steering. Actually, that's not all, but those are the main reasons. Enough info for you?


Modified by bsclywilly at 11:18 PM 5/5/2008

 

Well to tell the truth its not enough info

You see i am trying to figure out why my car understeers so badly even though i have tried everying that i can think of to fix it. I also posted here many times and had many suggestions that i tried out, to no avail. My mechanic is telling me the tire is bending over in the turns and he can see it in the many pictures of the car that we have. The reason for this post is that i discovered that camber is lost when the wheel is turned. I guess in simply terms, is it normal to lose camber when you turn the wheel? if so on a race car is this something you want? Again if so how do i minimize camber loss when turning.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BRN12345 &raquo;</TD></TR><TR><TD CLASS="quote">i have tried everying that i can think of to fix it. I also posted here many times and had many suggestions that i tried out, to no avail. </TD></TR></TABLE>

Well, now that is a different question than your original post. Why don't you tell me what you have tried so far that hasn't worked?

I searched your previous post https://honda-tech.com/zerothread?id=2217605 and to be honest if you've tried what's been suggested, you are probably hopeless and it's not a car issue. The main changes that I would reiterate from that post would be to reinstall your front bar. You describe the car as slugish turn in so adding that front bar and perhaps stiffer front rates will help that. You also mention horrendous tire roll over, and those changes will also improve that situation. the V700 you run are quite camber sensitive from what I've read so there should be a very noticable difference. Now, did you try those things already and what were the results?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BRN12345 &raquo;</TD></TR><TR><TD CLASS="quote"> I guess in simply terms, is it normal to lose camber when you turn the wheel? if so on a race car is this something you want? Again if so how do i minimize camber loss when turning.</TD></TR></TABLE>

You should have some caster (stock is 1 deg?), if you can't get it back to stock then you know what to fix. If you can add more caster, the more the better. With so little caster when stock, I wouldn't be surprised that there is small positive camber gain on outside wheel (not ideal) and more on the inside (okay).

To minimize camber loss add caster.




Modified by bsclywilly at 5:53 AM 5/6/2008

 

Here is a dumb question. Did you make sure your camber gauge was still perpendicular to the floor when you did this? Also, what is the point of measuring camber when the car is off the ground?

As for your understeer, let me make a few guesses. You've removed the front bar, you're running the car really low, you have over 2 degrees negative camber on the rear axle, you're running equal size tires all around, and your front spring rates are 400lbs/in or so? Let me know how close I am. I'm pretty familiar with making an EG handle. I can give you some tips that always work. Half of them don't even require a wrench.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by solo-x &raquo;</TD></TR><TR><TD CLASS="quote">Here is a dumb question. Did you make sure your camber gauge was still perpendicular to the floor when you did this? Also, what is the point of measuring camber when the car is off the ground?

As for your understeer, let me make a few guesses. You've removed the front bar, you're running the car really low, you have over 2 degrees negative camber on the rear axle, you're running equal size tires all around, and your front spring rates are 400lbs/in or so? Let me know how close I am. I'm pretty familiar with making an EG handle. I can give you some tips that always work. Half of them don't even require a wrench. </TD></TR></TABLE>

I'd be happy to hear those suggestions and as to the main post and the problem at hand(BRN12345). You have to take into consideration that you are driving a FWD car and it doesn't take a dergee in enginering to figure out that the car will understeer and it will feel like it understeers horribly when your exiting a corner and applying the power. As was suggested before put on your front sway bar and put a bit stiffer spring in the front if you can. Bump up the front tire presure to releive some of that tire roll and make some test runs and see what happens. I don't mean to insult you at all but sometimes the simplest solutions tend to be the best ones. Before you jump into a ton of suspension thoery use some common sense and take a look at what your doing. After all, you may just be over driving the car.

For Solo-X, I saw a few people running different size wheels and tires on their cars last weekend at AutoX, whats the scoop with that?

 

I'm running 275's up front and 205's out back on my new car, a DSP ITR. I do this for several reasons.

1. The front has so much weight and power it needs as much rubber as it can get.
2. The rear is along for the ride. A narrower rear tire actually gives a more predictable level of rear grip in a Solo situation because it warms up quicker and closer to the rate the front tires warm up.
3. The rear doesn't need as wide of a tire to have the same tire width to corner weight ratio. In reality, the rear actually has a higher ratio of tire to corner weight then the fronts do, ie, I could still go narrower with the rear tire or wider with the front.
4. A narrower rear tire is lighter.

D-SOHC 05 kinda hinted at the number one cause of understeer. The loose nut behind the wheel. As long as nothing is bent in your front suspension, don't worry about fussing with it. There is more to be had in the driver if you can't get a straight chassis EG to rotate with springs, bars and alignment.

 

First thanks for the comments.. I do have to clear up though that this is a road race civic and not autoX. I started with 450f/600r spings and now i am running 800f/1000r. I have a 22mm ITR bar in the back. The car is not too low, its about 6" from the jacking points. And i dont hit the bumpstocks (checked with zipties). My understeer is not on mid or corner exit, on the contrary the car tracks perfectly there.. my problem is on high speed corner entry.. secter times show that i am the slowest car on the grid going into several of the highspeed turns! The problem is that as soon as i turn the wheel the car pushes (and this is off throttle) once it slows down it turns and then i am on the gas. People have said i come in too fast but to prove that i dont i got another driver to try my car and he ran off course in several turns and came back and said something like "*#$^(@$^ understeer pig". I see the other Hondas taking the corner entry MUCH faster than i do and some are running front bars and some are not.

Regarding the camber gauge being perpendicular, yes it was.. there is a nice bubble level on top to make it perpendicular. The point i was trying to figure out in the begining of the post is the following:

When the wheels turn on a EG civic do you lose camber? If so by how much? Also, is this something you would like to minimize?

Solo-x also asked about rear camber, its at 1 deg now. The front bar is removed. Car is not running low. yes equal size tires but so are all others in my class. Front is 800 rear is 1000.

 

I've said it before, but if you can't get a fwd car to turn in you are a) going into the corner too fast b) missed the setup on the car or c) have a welded front diff.

How do you have -3* of front camber if you are that high? All the on the market camber adjusters cut into available travel dramatically. They also really screw up the front geometry. What modifications have you made to the control arms and knuckles? I haven't charted changes with offset delrin bushings to see if they screw up bump steer as well, but it wouldn't surprise me.

I've never measured camber change with the wheel turned. Looking at the car on the ground with the wheel turned, the inside definitely goes positive, the outside doesn't look to change much. I have measured bump steer with modified upper control arms and it wasn't pretty. Honda did a really good job mitigating bump steer and small changes to the uca length or ball joint location really f things up.

How much rake are you running, and is it front high or rear high?

 

Have you taken any tire temps?

 

IMO your setup isn't that "aggressive" for road racing.

What is your minimum weight?

Do you have any incar video?


what shocks are you running?

 

whats a good height for track only eg civic front and rear, weight around 2000lbs

 

It sounds like you need a lot more camber in the front. Tire temps should NOT be even across the tread, unless you are doing testing around a skidpad. The inside of the front tires should be about 10-20 degrees hotter than the outside. This is due to the acceleration and braking done which heats up the inside of the tire faster due to the camber. Do you want tire life, you do you want to go fast?

 

Great to see this discussion as it is really helping.

Solo-x I can get much more than -3 on the front, i think we got it up to -4.6 the other day just testing... I run adjustable UCA that came of a ex jdm car. No modifications whatsoever in the front other than the adj UCA. I checked last night and both my inside and outside tires go to near zero camber when turned.

MightyMouseTech: Yes i have and they are not even across but very close to 160-163-168 out-mid-in.

Slammed_93_hatch: minimum weight is 2450lbs. Not allowed to run in car due to promoters rights. I am running Koni race yellows(8041-1152 front and 8041-1164 rear) with GC 800f/1000r springs.

 

you need a front bar on the car

you need to increase your rear spring rates by at least 300lbs.


You still didn't answer what a "high speed" corner is.


Run an incar for testing and host it. It will tell us a lot.

 

Like Slammed said, put a front bar on the car. The stock 21mm bar is a good start, but the 24mm ITR/GSR front bar is better. I'd also bump the front spring rates to 1000lbs/in and run some 1200's out back. Dial rear camber down to -.5*, ditch those stupid adjustable uca's and lower the car until you have -2.5* to -3* front camber which is about 4" to the jack tabs on 23" diameter tires. Put some 205's on the rear wheels and keep the 225's up front. Oh, and try not to spin it on turn in your first session out.

ps. if that rear alignment setting is too aggressive you can run a little more rear negative camber.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by solo-x &raquo;</TD></TR><TR><TD CLASS="quote">Like Slammed said, put a front bar on the car. The stock 21mm bar is a good start, but the 24mm ITR/GSR front bar is better. I'd also bump the front spring rates to 1000lbs/in and run some 1200's out back. Dial rear camber down to -.5*, ditch those stupid adjustable uca's and lower the car until you have -2.5* to -3* front camber which is about 4" to the jack tabs on 23" diameter tires. Put some 205's on the rear wheels and keep the 225's up front. Oh, and try not to spin it on turn in your first session out.

ps. if that rear alignment setting is too aggressive you can run a little more rear negative camber.</TD></TR></TABLE>

His intial turn-in is where he's having problems. Why would he go to a stiffer front spring?
Why lose the adjustable lower control arms? Just cause he lowers the car 4" doesn't necessarily mean that both left & right sides will gain the same amount of neg camber.
And for road racing, putting skinnier tires on the rear definately would increase steering response but may be too aggresive for road racing (high speeds compared to auto-xing)

Did you check the basic alignment settings such as toe? if you're at 0* you might want to try -1/16" of toe out to get that initial turn-in you want....or slow down entering a turn.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BRN12345 &raquo;</TD></TR><TR><TD CLASS="quote">
MightyMouseTech: Yes i have and they are not even across but very close to 160-163-168 out-mid-in.
.</TD></TR></TABLE>

That is not much of a spread. I like to see about 20 degrees across the face with LSD, and 30 without.

I really think you need to crank up that front camber. I would set it to 3 degrees and then maybe go a little more if required by the tire temps.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by solo-x &raquo;</TD></TR><TR><TD CLASS="quote">Like Slammed said, put a front bar on the car. The stock 21mm bar is a good start, but the 24mm ITR/GSR front bar is better. I'd also bump the front spring rates to 1000lbs/in and run some 1200's out back. Dial rear camber down to -.5*, ditch those stupid adjustable uca's and lower the car until you have -2.5* to -3* front camber which is about 4" to the jack tabs on 23" diameter tires. Put some 205's on the rear wheels and keep the 225's up front. Oh, and try not to spin it on turn in your first session out.

.</TD></TR></TABLE>

This is not an autox car.

 

i have been running the staggered setup for the past few weekends (actually 3 out the last 4 races). Honestly i think the car initially feels better, that is i just put the 225s up front with no real changes. The car feels great, turn in is great and it is much easier to go 30 minutes with out "overworking" the front tires. It can be done on the 205s too, but most of the time i would make too many mistakes and overheat them.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MightyMouseTech &raquo;</TD></TR><TR><TD CLASS="quote">

This is not an autox car.</TD></TR></TABLE>

Yep. And it doesn't matter. The idea that vehicle dynamics change because you call it a "road race car" is terribly flawed.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by solo-x &raquo;</TD></TR><TR><TD CLASS="quote">I'm running 275's up front and 205's out back on my new car, a DSP ITR. I do this for several reasons.

1. The front has so much weight and power it needs as much rubber as it can get.
2. The rear is along for the ride. A narrower rear tire actually gives a more predictable level of rear grip in a Solo situation because it warms up quicker and closer to the rate the front tires warm up.
3. The rear doesn't need as wide of a tire to have the same tire width to corner weight ratio. In reality, the rear actually has a higher ratio of tire to corner weight then the fronts do, ie, I could still go narrower with the rear tire or wider with the front.
4. A narrower rear tire is lighter.

D-SOHC 05 kinda hinted at the number one cause of understeer. The loose nut behind the wheel. As long as nothing is bent in your front suspension, don't worry about fussing with it. There is more to be had in the driver if you can't get a straight chassis EG to rotate with springs, bars and alignment.</TD></TR></TABLE>

Makes sense.