FormulaIntegra

So, I'm now in the process of measuring my ES poly bushings, and drafting plans for the machine shop to recreate them all out of delrin, plus offset the UCA ones for increasing negative camber for my 95 ITA Civic Coupe.

I've been told by an experienced friend that I should leave no less than an 1/8" of material on the outside edge of the offset bushings. My question being, with delrin, do I still need to use the steel sleeve that came with the ES poly bushings for the pivot bolt, or is delrin dense enough to be able to forgo the sleeve?

I'm questioning this because it will determine, not only the size of the holes that need to be bored through, but will also determine just how much offset I can get with those that will be eccentric.

It's for a race car, but if this question would be better suited for the suspension forum, please let me know, and go ahead and move it, Stinky.

beanbag

Have you read any of those Delrin design guide pdf's out there that have charts of the compressive strength, creep/flow, etc? While poly can flex a little, Delrin flexes very little, so you had better be sure that the joint moves in exactly the way you expect. Using a sleeve helps because
1) it spreads out the forces on the delrin
2) it can be made smoother than a bolt so is better when it rubs on the delrin
3) when you torque down the suspension bolt, it's much better for it to squeeze on the sleeve than bare delrin.

Why not brass or sphericals/roller?

For the offset bushing, how will you prevent them from rotating out of place?

Andy Hollis

This ^^

Most of the bushings on a Civic are designed with multi-axis motion. Delrin can't do that. That's why you usually jump from urethane straight to bearings (assuming your rules allow).

--Andy

Battle2.0Eg

Andy didnt you have some special bushing/sperical setup in your Sts car ?

I would like to get some of those

Andy Hollis

If you mean the ST Civic, nothing special there. Just ES, and a few Prothane pieces.

My track Civic has pimpy bearings everywhere.

Or maybe you mean my old STS(2) Miata? That one had Delrin, yes. But a Miata does not have multi-axis motion in the control arms, so Delrin works perfectly there. Sourced it from Mazdaspeed.

--Andy

Jenkinsal2

Just curious is this still in refference to your camber adjustment bushing ideas? If you end up following through with those I would be interested in a set.

slammed_93_hatch

For the EG/DC you can (I wouldn't) run derlin in the UCA joints, front inner LCA, and front compensator.


But I wouldn't.

You can_not_run derlin any where on the rear of a EG/DC. Look for pictures of Zsolts snap shock as a result of the binding.

Wicked tunning sells an OEM front LCA with SB for the EG.

Chris over on RRax does the UCA and compensator.

Johnny Mac

The upper control arm on the EF, EG, DC, EK, ect. only requires one degree of freedom and thus no sphericals (three D.O.F.) or sliding sphericals (like rear trailing arm bearing requirement) are required for the UCA's operation. However, the spherical bearing is a convenient bushing for many of these applications due to its inherent stiffness and relative ease in machining the bearing housing. You could use a needle bearing also for it's stiffness and free rotation (i.e. virtually no stiction) also.

Delrin works well but has a few drawback for this application. Number one, you should have what is known an ANSI standard "clearance locational fit" of either LC3 (H6 hole tolerance of +.0007 in, -.0000) and (h5 shaft clearance of +.0000 in, and -.0005) to LC5 (less expensive to machine than LC3 due to larger tolerances) so you don't just want your machinist to give you their typical tolerances of +/- .010 for this item. Because if they do, the impact loads on the delrin will soon hammer it to oblivion. Machining the part to LC3 to LC5 (you can get a good introduction to fits in Machinery's Handbook). Remember the proper fits take into account the bearing material's properties, the bushing material's properties, and various costs and expected bearing life.

The other thing about the delrin has to do with which way you are going to run the orientation of the eccentric hole in the bushing. Are you using it to remove negative camber or are you adding negative camber. Removing negative camber means that the thin section of Delrin cross section will be located toward the center of the car. In a heavily loaded corner say a right hander, the leftside UCA goes into tension to counter act the moment of tire contact patch (lateral grip moment is CCW on LW in RH corner) and moment due to vertical tire load would be a small CW moment about say the wheel bearing. The result of all of this is a larger tensile load in the LH UCA in a RH corner combined with a smaller compressive load in the RH UCA. As a result of all of this is that the thin eccentric section - assuming of course you have rotated the delrin bushing to give full positive camber change) of the Delrin is in the highly loaded side (LH).

So let's look at the large compressive load in the thin section of the delrin - as this will govern the design. Keep in mind that the thinner you make the delrin (the offset of the hole factor) the larger the stresses in the delrin will be due to fact that the thinest sectional slice of delrin will be stiffer and carry more load than the other slices. Thus, the amount of eccentricity and hence camber compensating offset that you can get will be governed by the strength of the delrin in compression.

chrisb

I have a box of delrin stuff I have pressed out of customer's front LCAs when I replaced it with sphericals. Maybe even the UCA I will have to check. I will send all of it to you free if you send me money for shipping. But at a cost of nothing you will still be getting ripped off. Delrin is garbage and has no business on a race car. But seriously, I really do have a shitload of delrin crap you can have for free if you want it.

P.S. I also do the inner pivot and lower shock mount along with UCA and compliance but thanks for the mention! :-)

Chris

FormulaIntegra

Well, to basically answer everyone's questions at once, it seems I keep running into roadblocks with trying to increase negative camber legally for an ITA car (no camber adjustable arms/plates/etc.) Bushings are open. I had a thread several months ago asking how to legally increase negative camber (top of wheel leans towards the center of the car) for an SCCA ITA car, and it basically came down to either run offset bushings on the upper control arms, or bend the knuckle (which technically isn't IT "legal", but can be construed as damaged caused by hitting curbs too hard, and just happens to help the car handle better.

It all comes down to tire wear and temperatures. I have -1.5 degrees of camber up front just from lowering to the class minimum ride height. I'm running Nitto NT-01s, and am having to over-inflate the tires to try to keep them from rolling over and cording the outside edge before the inside even shows a hint of wear, and temperatures are always way higher on the outside than on the inside. They're a unidirectional tire, so I can't just flip them on the rim like you can with RA-1s. Every book I've read on suspension setup and reading tires says I need more negative camber.

Now, my friend (who has raced spec944s for years) tells me I actually need more positive caster (upper ball joint moved rearward) because in braking dive, as well as turning (compression on outside corner), more caster will take care of the camber issue, and keep the contact patch flatter in both circumstances. Having read up on that, however, seems to show problems with an increase in bump steer, as the radius rod pivot point at the knuckle moves downwards in relationship to the steering rack.

I'm not sure why I'm so leery of just bending the knuckles in a press, but for some reason, I feel like I'm leaving it as a last resort. People say, you gotta get rid of the factory rubber bushings for racing, but then others s*** all over poly bushings (which is what I've got on the car right now, and I've got to say, I have not had any issues with them yet, and they're not that expensive to replace if they last a couple of seasons). I spoke with Lyonel Kent some years ago, and he swore by delrin bushings, but I haven't talked to him recently, so I don't know if he's changed his tune. I think I may have said in my original post here that I was planning on swapping everything over to delrin, but I know that's not a good idea, as alot of the LCA's need to be able to move multi-axially, so I'm really only just concerned with the front upper control arms.

So, in a nutshell, my intention was to move the inside pivot point of the front UCA's inward, increasing static negative camber, and hopefully creating a more even tire wear and temperature across the tread. I have heard that drilling and tapping for a set screw would be plenty enough to maintain the orientation of said bushing. If there's a better way to do this with sphericals, I'm all ears, but I don't have the experience, tools, or facilities in my garage/shop to fabricate something like that myself.

Chris, do/can you make offset spherical bearings for the front UCA's on an EG? If so, let me know, I'm interested.

beanbag

Are you allowed to slot the holes where the UCA mounts to the shock tower, thus moving it inwards? Or fab your own UCA to shock tower mount? or add spacers between the UCA mount and shock tower (gives a steeper camber curve)?

There are all kind of dirty hacks, I just don't know the "rules".

FormulaIntegra

Definitely "no" to everything except the spacers.

In SCCA IT, only MacPherson strut cars are allowed to slot the upper strut holes, as that is the ONLY way to adjust camber there, and no aftermarket control arms, whether off the shelf, or homemade, are allowed. With double wishbone, the rules specifically state that eccentric/offset bushings can be used. Hardware is free, however, so I would assume adding washer "spacers" to the UCA mount would be legal, and I've thought about doing that, but wasn't sure what the negative consequences to a steeper camber curve would be. Anyone have info/empirical data on doing that?

FormulaIntegra

Here's the SCCA IT rules on suspension:

d. Suspension Mounting Points
1. Cars equipped with MacPherson strut suspension may
decamber wheels by the use of eccentric bushings at
control arm pivot points, by the use of eccentric bushings
at the strut‑to‑bearing‑carrier joint, and/or by use
of slotted adjusting plates at the top mounting point. If
slotted plates are used, they shall be located on existing
chassis structure and may not serve as a reinforcement for
that structure. Material may be added or removed from the
top of the strut tower to facilitate installation of adjuster
plate.
2. On other forms of suspension, camber adjustment may be
achieved by the use of shims and/or eccentric bushings.
3. All forms of suspension may adjust caster by means of
shims or eccentric bushings. Additionally, MacPherson
strut‑equipped cars may adjust caster at the upper strut
mounting point/plate.
4. Independent rear suspension mounting holes may be
slotted and reinforced for purposes of camber and/or toe
adjustment. Material may be removed from the top of the
strut tower to facilitate installation of adjuster plate.
5. Cars may add one (1) front stayrod, located in one of the
following areas:
A. Between lower suspensions mounting points.
B. Between the upper strut towers on Mac-Pherson strut
equipped cars.
C. Between upper front shock absorber mounts on cars
with other forms of suspension.
6. Bushing material, including that used to mount a suspension
subframe to the chassis, is unrestricted. This includes
the use of spherical bearings, so long as no suspension
component is modified to facilitate their installation. Retention
of spherical bearings by use of tack welds is allowed,
as long as the welds serve no other purpose.
7. Rubber bump stops may be removed, modified, or
replaced, but their chassis mounts, brackets, etc., may
not be altered in any way.
8. No other relocation or reinforcement of any suspension
component or mounting point is permitted.
9. Hardware items (nuts, bolts, etc.) may be replaced by
similar items performing the same fastening function(s).

FormulaIntegra

So, I can slot the body mounting point of the rear upper control arm to lower it, and increase negative camber, but that will do the same as shimming the front upper control arm, and increase the camber curve, too. What are the ramifications of this?

beanbag

ok then, how about angled spacers ( a wedge with a hole in it)? That will move the uca mounting point both downwards and inwards.

My guess is you want more camber curve and not more static camber.

You might want to read the rulebook more carefully. There may be special exceptions on the third friday of every month, due to options expiration.

Jenkinsal2

[QUOTE=beanbag;42123895]Are you allowed to slot the holes where the UCA mounts to the shock tower, thus moving it inwards? Or fab your own UCA to shock tower mount? or add spacers between the UCA mount and shock tower (gives a steeper camber curve)?

There are all kind of dirty hacks, I just don't know the "rules".[/QUOTE

civichb20

A little of topic what would happen if you just machine just straight metal bushing out of aluminum or steel ? I understand that Honda suspension is multi axis would this spell disaster for handling or could this me a affortable alternative?

It also sounds like you need to jump ship and move to NASA
Have you try talking to the east coast ITA guys like OPM they have tons of experience in the Honda area . Good luck

FormulaIntegra

I have not spoken to OPM or any of the east coast ITA guys (unless they've piped up in here).

I can see where lowering the inner UCA pivot points would increase the camber curve, and be benificial in a body-roll, cornering state, but I believe it would be detrimental in a straight-line, brake dive state, where as the nose goes down, negative camber would increase, reducing the size of the contact patch, and therefore, overall braking traction. Is this where the trade off is going to be with my car?

I guess I can try shimming the UCA to lower the inboard pivot point for my next event and see how that affects tire temps and treadwear. Can't be any worse than what I'm used to dealing with now. I will need to adjust the resultant toe-in back out from doing this, correct?

chrisb

Sorry for the late reply. My UCA sphericals are centered in the sleeve only right now. The circular bushing housing that bolts to the chassis is so relatively small and the bolts so large that I think it would be hard to get much meaningful offset with a spherical. One kind of sketchy hack that I know some SCCA people have done is slot the UCA where the bolts pass through to get more camber then tack weld a washer when you get the camber equal side to side. Should get you pretty close to where you need to be. Might not stand up to a protest though. Which is stupid since you can damn near reinvent the top end of your suspension with a MAC strut POS but you can't slot a damn hole on an A arm car?

Lo-Buck EF

i have the compensators. very nice pieces.

slammed_93_hatch

The "problem" doesn't happen with the front runners because they tend to run hoosier which don't need near the camber that a R888/ra1/NT01 do.

FormulaIntegra

I talked to Tom from OPM. He said a couple of interesting things, but mostly, I need to get more negative camber by whatever means I can within the ruleset of the class. -1.5* just ain't gonna cut it, and I need to be, at the very least, in the -2* to -3* range. He said stiffer springs will help cut the necessary negative camber down a little, but not eliminate it entirely. I'm currently running 10k/8k f/r respectively. Thinking about putting 10k's in the back and possibly leaving the 10's up front or going to 12's. Haven't played with spring rates much at all yet.

He also said something that struck me, in that, understeer will cause excessive outside edge tread wear which can be mistaken for not enough camber. This almost feels like something I have been experiencing due to a test day last season where I was messing around with shock bump settings and rear bar settings for each session, and in one session, had extreme corner entry oversteer, causing me to dial it waaaay back, and I think I've been running for too long on the safe, understeer side. At my last race, due to a blown head gasket (don't worry, Jimmy, the motor's fine, just had coolant leaking into 2 cylinders because the cooling system bleed screw fell out and overheated the motor. Got it shut down in time to avoid major damage, but spent the rest of the day, and most of the following changing the headgasket and then tracing down a spark plug wire issue) Barely made it on track for the second race of the double having only done the practice session the day before, started at the back of the pack on a completely guessed at suspension set up, as I hadn't been able to run any of the sessions previously, and although it was a much looser set up than I've been running, I actually was getting better at keeping it under control and my laptimes were dropping significantly.

I'm going to try swapping my UCA up front right to left for my next race, to gain some camber, as well as see if I can get another set of 10k and some 12k springs. Tom also said to check with Nitto, because although they are a directional tire, so are the Toyo R888's, and OPM has never had any problems flipping the tires to extend the treadwear life. My only other thought with the UCA's is to try shimming the inside pivot downwards as Kiwi had suggested in another thread. It will put me into a steeper section of the camber curve, which will help cornering, but sacrifice a little contact patch in brake dive, but hey, it's an ITA FWD Honda. I'm learning I don't actually need to brake as much for alot of the turns I go into anyways, and sometimes, even just feathering off the throttle is enough to carry speed through the corner, like Turn 9 at Big Willow.

Thanks for the opinions, insight, and technical knowhow. I'll try to remember to report back after next month's event at Buttonwillow and take it from there.

Cheers.

Dilbones

bump,

what results did you see? Did you end up using the delrin?

dirty19

iTrader: (1)

LOL you bumped a old thread with the last post of 6 years ago.
Formula integra hasn't posted in two years.
Lots of great info here, but some of it is dated.
Nonetheless still good info.

FormulaIntegra

A lot of really good info here.

Sorry I've been away for awhile, guys. Life and less money has me only racing about once a year now for the last 4 or 5 years, so as long as the car runs and makes it through the weekend, I really haven't had much chance to try to make it go faster.

Never did go the delrin route. I did end up swapping the front UCA's from side to side for the added caster, which did help with turn in negative camber. I also bumped up my spring rates to 12kF/10kR, and I think that made a huge difference in tire wear and grip. The biggest difference, however, was to go back to running Toyo RA-1's and Toyo RR's. The NT-01's were nice (mostly because they were free), but they just weren't able to run a full 30 minute sprint race without getting greasy and losing a ton of traction about 2/3's of the way to the checkered flag.

Other than needing to get some race-valved Konis, I'm pretty happy with the suspension setup at this point. Hopefully this year, after some financial situations will get better, I can get out to the track more and reconnect with this forum again on a regular basis.

Cheers!

Darren