Black R

Yes I searched.

I'm interested in hearing from people who autox or road race and have swapped the upper A-arms left to right (and vice-versa) to get more caster.

Please share your alignment numbers if they're not top secret.

Is it a worthwhile endeavor?

Did you notice a significant drop in lap times, steering feel, responsiveness, turn in, etc?

How much is too much caster for an EF civic?

Black R

OEM Suspension measurements (courtesy of bus driver J):

Caster:* * * * 3.0 +/- 1

Camber:* F* *0.0 +/- 1
* * * * * * * R -0.3 +/- 1

Toe:* * * *F* *0.0 +/- 3
* * * * * * *R* *0.2 +/- 2

Front Track 57.1"
Rear Track 57.3"

185/60/14

redzcstandardhatch

hm...i've though about this before...never tried it though. i'd bet everything would work fine, geometry-wise, but i'm curious what happens..

Black R

A lot of people used to do it locally for sts in the Atlanta region.

Its supposed to increase camber while cornering.

Since I'm playing with my suspension settings anyway and trying to max out caster adjustment, I may go ahead and try this trick also.

I'm curious what 6deg of caster will feel like.

meb58

you get an increase in camber with an increase in caster angle, BUT...

An SLA set up gains camber anyway...increasing caster will increase steering effort by reducing mechanical leverage, increasing caster will dilute SAI returnability, increasing caster will throw weight onto the wrong rear wheel in an opposite lock slide...so if your setup dances the oversteer knife's edge this may not be helpfull at all.

If I had my druthers I would begin with zero mechanical trail and 2 maybe 3 degrees caster angle...but this requires heavy modifcation of body and suspension linkages.

fireant

Why doesnt anyone make threaded radius rods for this kinda thing?

Super79Dave

They make adjustable radius rods for this if you buy a traction bar setup.

I made my own adjustable ones for the ef, I used 83-86 honda prelude radius rods and cut sleeved and machined for length and adjustability. I found this was better as u could lengthen and shorten the anchoring point at the front of the cross member. Works good you can actually put 5+ degrees of caster into the car but it loads the heck out of the front sway bar. Best balance is about 3.25 degrees of caster for my road race car.

I made a set once as well using 93-96 toyota corolla rear radius rods. they have a threaded setup identical to a rear camber adjuster for hondas. They are also hollow so i cut the stock radius arm and machine it in the lathe and then inserted it into the adjuster and then pinned cut for length and sleeved and rewelded. This worked however under heavy loads i found that the lock nuts would untighten and start to adjust you had to check it after every session. This system was for easier adjustment but i found that once i had it set i didn't play with caster as much.

Being able to play with caster let me run less negative camber decreasing tire wear. Used to run 2.5-2.8 front camber and am now 2.0-2.25 with 3.25 caster.

hope this helps

I read an abscure reference once that said 90-93 accord radius arms fit and are adjustable but was unable to confirm and i remeber those having a wierd bend in them for oil pan clearance.

Black R

I have a jimfab traction bar, and there is some adjustability there, more than you need because it can pull the hubs toward the front of the fenders quite a bit.

Jaker

I just threaded the OEM radius rods for their full reduced diameter length (where they go through the bushing), and run them with locknuts on both sides of the spherical bearings that are in the crossmember. I was running 4.5 degrees of caster, but the steering was "quite" heavy. I'm down to 3.25 degrees right now, but that's not enough anymore.

Once I install power steering, I'll go back to the increased caster.

Black R

Well seeing as how stock is 3 +/- 1, then I should be able to run 4deg without issue.

With the 275 Hoosiers, this will be fun.

I've actually been contemplating retrofitting power steering also!

Jaker

You're gonna need it. I was running 285/30-18s on 10.5" wheels at the time, and the steering was incredibly heavy. Stupid heavy in fact. My arms were aching after a 50 second run. That was with the Quaife internals though (2.4 turns lock to lock). Needless to say that made it very difficult to place the car precisely.

JBrettHowell

Yep, back before aftermarket control arms were legal in SP, the only way to adjust caster and camber (beyond what lowering provided) was off center bushings. When I was replacing the front bushings with delrin I had them machined to take advantage of the available slop in the control arm to chassis joints in order to add as much caster as possible. In addition to generating additional negative camber on the outside wheel, caster also generates positive caster on the inside wheel - an ideal combination. The increased steering effort is one by product, and such a setup also de-wedges the car as the steering wheel is turned further which can produce some strange handling traits until you get used to it.

Big front Hoosiers + Kaaz diff + add'l 2.5 degrees of caster + slow manual rack = real need for power steering.

meb58

I'll add...an autoX setup should not be the same as a road course setup...and if you are setting up a track only car you will likely have a notes for individual tracks or autox circuts.

AutoXing requires some fairly aggressive tuning - out of the box to just plain odd - and road course is suited to a more conventional approach. Here I personally hate a lot of caster angle and would opt for zero trail if I could get it. That way the CASTER angle and trail don't dilute or over-power the messages coming from the tire. Sometimes you have to trade of pure cornering power for a more pure sense of feel. From my experience feel helps consistency. But this too is like a glass of wine; we all tatse something a little different from the same elixir...

In any event, increasing caster will slow steering repsonse and i'm not sure you want that in an autoX setup...I woouldn't. I think caster is at time a convenient conciet. Try reducing caster an see what happens...you might be surprised.

JBrettHowell

I agree with almost everything here. Especially the part about unconventional wisdom and autox. With a nose-heavy chassis and the need for maximum front grip for transitions and direction changes, I have always focused on maximizing front grip and tailoring rear grip as needed for balance. If I find the car is understeering then I typically look initially for ways to address it by adding more front grip rather than adding rear roll resistance/more spring to the back end. With the big 255's in front on the Pebble (or 275's on the Snot Rocket) and the transitional nature of autox, I like the result with some caster up front (and I've tried it both ways on the same car with basically the same setup - just OEM caster then the additional 2.5 degrees of caster). My opinion, and opinions are like ********...

meb58

...i edited my reply above...CASTER is in caps. I wrote camber by mistake previously.

I agree that there are no smoking gun solutions. The path we choose is basically determined by some of the fundamnetal choices we make...some are good and some are bad. I decided to opt for a little less front end grip - road course - in lieu of better feel and consistency. Over-all this worked but it was not the outright fastest setup in mant areas of some of the track I drove on. But I was hugely comfortable driving the car...and it had strock caster...so so much for my long winded reply above.

joenationwide

I like the additional caster from swapping the upper A-arms.

I find the on center feel it gives you is very helpful in an autox run, since it can be difficult to know where your front wheels are pointed during transitional elements.

meb58

I experimented with many caster angles on my 99Si and wound up going back to stock. I felt the added caster was a bandaid for very poor steering feel, so I understand your point for sure. In my case I felt the increase in caster angle destroyed turn-in and actually made 'feel' much worse near tire saturation - close to losing grip. Caster's self centering force can quicly over-ride other tingly little messages...but speeds are much higher on a road course.

I spent a fair amount of time trying find my tire's centroid axis and then tried to get SAI and caster within that region of the contact patch. This required making some track wdth alterations which may not be allowed in some classes. But that was 10 years ago...

I get intensly involved with preserving feel...perhaps at the outright expense of some cornering grip. Oh well.

slammed_93_hatch

When allowed most teams run a good bit of positive caster up front:

https://honda-tech.com/attachment.ph...1&d=1275433402

from here https://honda-tech.com/forums/road-racing-autocross-time-attack-19/claudes-pics-mosport-2010-a-2785132/ in case the link doesn't work.

That's something over 5 degrees.

meb58

Nice photo!

I think caster is a personal choice geometry. Adding a lot can diminish some aspects of handling and feel while at smaller angles can help balance other inadequacies. It is probably more suited to mac struts since these lose camber in bump...but the stop watch doesn't lie.

redzcstandardhatch

so..if i decided to do this to my 90 hatch, and aligned it the same, with the same tires, what kind of expected change would i see, theoretically?

i would like a bit more grip, mid turn, in a couple turns, and almost ever track i visit.. i KNOW a bit more camber would help...and AERO is in the future...is this something i should try?

meb58

Hope you don't mind a response that reads more like teaching /preaching...I'm not talking down to your question, just trying to be thorough by offering my thinking path. I'm sure it won't work for everyone.

To your first question...caster will aid grip but grip is also tethered to camber and these are optimized by a given roll angle - spring rates and bar rates affect roll angle; soft rates and you might expect to use more camber and caster...more roll angle requires more camber compensation. Caster will aid straight line stability, reduce turn-in leverage, potentially will wash out some of the self centering effect from SAI (caster's self centering is in straight line only) so you have to decide if you like a slightly more vague steering wheel when negotiating turns. And, more and more caster will transfer more and more weight onto the wrong rear wheel in an opposite lock slide...I imagine this experience can range from fun to scary dpending upon the speed and your intentions.



To your second question...not in any particualr order

I make a check list that highlights anything that can potentially help or hurt grip...while keeping a keen eye on the fact that most of these cars started life as fairly mundane pieces.

Since we are discussing geometry, I would pay attention to bushing compliance. Great static geometry/alignments can turn to crap on a track if the bushings are not up to the task.

Optimize roll center locations - very hard to do...but the most important thing to do in my humble opinion. RC location will determine how much weight is transfered, where it is transfered - proportioned between front and rear wheels, and, the speed of weight transfer - high RC loads tires faster in transient for example but is kinder in steady state.

Super-duper spring rates add lots of control but can at some threshold reduce grip by causing a tire to saturate quickly.

Dampers...digressive dampers can hurt grip at some level but usually help heat tires faster...progressive is just the reverse. I just learned this from a suspension engineer...didn't really know the fine line between the two.

Body flex can become a big pig when spring and damping rates are increase by 'some' amount.

Aero...very,very complicated stuff...easier to remove weight...incidently, some of those under-body flaps that come with these cars from the factory actually help aero a great deal despite the fact that they are nearly perpendicular to the wind. Unless you are installing a full undertry with diffuser and spoiler all designed to work together, I would retain those pieces. As a related aside, sometimes a poor rivet job performed on a very well designed diffuser can ruin its effect. Aero is very sensitive and requires a wind tunnel and fairly smart folks to get right...there are brilliant winners and losers among the F1 crowd...seperated by aero for the most part.

redzcstandardhatch

hehe

maybe i should just do a before-after at an open-track test-tune...haha

obviously suspension and aero are rather complicated setups.

but i'm not particularly new to this car (10 years with it), and my setup isnt exactly goofy...its been done, and i'm kind of using what works.

anyways...on this particular car, what change happens when you flip the arms? anybody done it with a direct before/after?

meb58

I've never swapped arms...but if you can try it without hurting yourself and log the changes, I would be interested to see/read the results. I am no longer setting up Hondas...or anything these days, I am just curious.

Black R

After maxxing out my caster on the traction arms and living with it a while, I can say I've noticed these things:

Turn in feel is diminished

Return to center is increased - it literally snaps back (I'm also running a wider track - 15x7 zero offset, which compounds this effect)

Understeer is worse in wet conditions.

I'm going to get a full alignment and see what my settings are at before getting more caster out of the upper a-arms.

meb58

...you've done two things here that can add to understeer. Increasing front track increases front roll resistance and this will increase initial turn-in understeer. BUT!!! the increase in track width also reduces the front roll moment relative to the back so you also get more potntial mid corner and late corner grip - front end grip.

More caster effectively increases wheel base and this INCREASES polar moment.

What do you mean by zero offset? How mant mm?

Caster is a very animal to wrestle with. And as I wrote above, if you have an SLA front end it already gains camber in bump...you might find that less caster is actually better. turn-in will improve, return to center will improve at slow speeds and steering feel will also improve...too much caster can help you to over-drive your car at some level since it can wash out a lot of steering feel fidelity.