Adjustable A-arms..?

[GregR]

Does anyone know of a company that manufactures adjustable upper A-arms, ideally for the 5th gen Prelude? I'd like to get a pair if they're made, otherwise I need to design my own and get a local shop to make me a few pairs. I'm thinking about the type that would let you unbolt the spindle, then turn a rod end to either extend or shorten the arm length (thereby adjusting the camber in half-turn steps, which hopefully would be 1/4-degree or so), then bolt the spindle back on. Anyone make such a thing?

[Marsh]

Greg there, as you are discovering, there is virtually nothing available for the 5th Gen. The only effective camber kit I know of for the Prelude is the Ingals. Unfortunately it's too tall and smacks the strut tower in bumps. Dave P. had some nice holes in his from these.

BTW The best places to ask this question would be Prelude Online:
http://www.preludeonline.com/index.php?

Hond-Tech.com
http://honda-tech.com/

Or even the Toronto Prelude Club
http://www.hondaprelude.to/

[GregR]

Yeah, I've noticed. Some of the other Prelude folk don't like the Ingalls for noise reasons (that might be the hitting you're talking about). Plan B was (and looks like will be) to make my own custom upper A-arms with rod ends for the spindle. What do you think of such an idea? Feasible? Preferably aluminum due to weight and rust (less and none). Being a suspension guru, what's your take on that?

[Marsh]

I wouldn't use alluminum. You have to use so much of it to elliminate fatigue concerns that it ends up being not much lighter. I would use steel. I've thought of this. If you've never made such a piece it can be quite challenging. I have and I wouldn't look forward to it.

The biggest trick in my opinion would be to accurately measure the existing A-arm. The other trick is to adapt the rod ends to work with the existing ball joint mounts. Although I presume there are off the shelf parts for that. If you do try it I'd love to here how it goes and see some pictures of what you come up with.

[Dave]

Greg, I know of a few shops in the GTA that modify stock upper a-arms for camber adjustability (Mantis Racing in Oakville did this on Henry's ITR I believe). They use a similar method as the Skunk2 arms you may be familiar with for Civics and Integras. If I'm not mistaken you're up in Ottawa, so I can't offer much help but perhaps Tapp Auto (http://www.tappauto.com/) can do this or will know a shop in the area that can.

I also know of a 5th gen Prelude owner in Texas who special ordered a set of A-Sports camber adjustable a-arms. A-Sports doesn't normally make Preludes kits but they do special order items but be prepared to pay through the nose for these. They are very trick pieces though...here's a picture of one of their Integra a-arms

http://www.aj-racing.com/Products/ASports/images/DSCN9395a.jpg

Like Marshall said, the Ingalls kit on my car had major clearance problems. On a stock ride height Prelude they might be ok, but if you've lowered your car much you will run into serious shock tower clearance problems. But hey, if you don't care about a few dents (or holes even) then let them "modify" the shock towers until they fit :) It'll just add to the character of your car...

[DirtyLude]

Anybody other than aj-racing sell those A-Sports in NA? The only other dealer I can find on the web is Japanese.

[Dave]

kHF can probably source them for you, but the A-Sports arms are ridiculously expensive...the DC2 ones are $1300 from A&J, so you've got to figure the special order BB6 ones will be a fair bit more than that. But if you want the best and money is no object, I personally love the design of the A-Sports arms. Having the adjustability built into the rear mounting points like that is brilliant.

On the other hand, having the OE arms slotted at Mantis Racing costs about $250 I think and from what I've been told they work well.

I'm surprised nobody has started to make knock-offs of the A-Sports design. How hard could that be?

[ctheo]

Holy Chit, those things are art! I'd use transparent fenders just so I could admire them.

Mmmmmmmmmmmmmmmmm, functional bling bling.

[ctenche]

That looks really really beautiful but I'm not sure how practical it would be. I'm imagining what it would take to make adjustments.

First you'd have to remove the bolt that go through the spherical bearings at the end of each arm to disconnect it from the anchor bolts that connect the arm to the chassis. This might necessitate dropping the shock because everything is really cramped in there.

Once you have that disconnected you would loosen the nut that secures the rod end to the arm. Then you'd need to thread the rod end in or out a set amount to make your adjustment. But how much do you turn it? Half a turn? Quarter turn?

Also keep in mind that you need to do this to both sides of the arm otherwise the castor will be ALL over the place.

Finally, reconnect it all. Settle the suspension, measure and then rinse and repeat until you get the settings that you want.

What a PAIN!!!

[Dave]

Caius, why couldn't you just jack the car up and put a wrench on the adjuster nut without disconnecting the bolt through the spherical bearings? I can't envision why they'd need to be disconnected like that.

[rpr]

Dave, something has to turn, the nut is just a jam nut, the whole bearing has to turn, thus the arm has to come out, or at least the bolts holding the arm do.

[ctenche]

Hmmm...okay maybe.

I was thinking that the rod end looked like the first one from the left.

http://www.bakerprecision.com/images/aurorpic.jpg

If that is the case, the brass coloured nut is simply a tigthener to make sure that once the set it will not change. If my assumption is correct, then you would need to disconnect the arm so that you can thread the rod end into or out of the A-arm to make the adjustment.

If on the other hand the rod end has a female end (second rod end from the left) and a threaded bolt goes into it then yes, your method would work. In other words, the bolt has a fixed adjustment nut (ie. like the toe adjustment on Hondas) that you can thread it into the spherical bearing to get more negative camber or out of the spherical bearing to get more positive camber.

But looking at the image of the AJ arm it's hard to tell just how much room there is for negative adjustment. Does there look like there's enough body in the rod end to get something screwed into it?

[rpr]

I think you're assumption is correct, the one on the A arm is a male threaded bearing.

[Marsh]

IF your making your own there is a way to do with without removing the A-arm. Our upper rear arms on the SAE car are infinitely adjustable (within their range) and you only need to remove the wheel to adjust it. Caster is not adjustable by this method. We adjust caster on the front by making a seperate part on the spindle. Caster is adjusted by swapping different brackets. Camber is adjusted by placing spacers between the bracket and upright. I can't seem to find any picture right now so I'll take some at school today.

BTW those rod ends are loaded in bending. I think that design could be improveda little.

[Dave]

Hmmm, I still don't see any reason why you couldn't just throw a wrench on the adjuster nut.

http://www.hadamotorsport.com/HondaUpperArm.JPG

As you can see from the diagram, the bushing or spherical bearing in question is just a pivot point, not an achor point. So as long as the wheel is still on the ground or supported some how I don't see why you couldn't loosen the adjuster nuts without any problem. The A-arm wouldn't move or pivot on that bushing so you should be able to apply plenty of torque to the adjuster lock nuts, no?

[rpr]

I'm probably missing something in the visualization, so I refuse to embarrass myself further. :)

[ctenche]

Ack more confusion.

There are two parts to the stock suspension. The A-arm itself and the anchor bolts that contain a bushing at the bottom which connects to the A-arm and a bolt that connects the assembly to the chassis.

The AJ A-arm looks to replaced the OEM A-arm plus the bushing that was originally part of the OEM anchor bolt. The spherical bushing allows the arm to pivot up and down as the car goes through bump and rebound.

I have no idea how the anchor bolt connects to this. It's obvious that the OEM anchor bolts can't be used so I'm guess there must be some other joint that connects through the bushing up to the chassis.

I'm bored so let me see if I can diagram this out in my next post.

[Dave]

I think it's safe to say that the A-Sports arms must anchor to the existing chassis mounting points in the same way as the original arms do. I can't see how else they'd mount them. I suspect the picture I posted early is simply an a-arm from a different car, maybe a non-Honda (the horror...). The image says "available for DC2..." but it doesn't say that the image is actually the DC2 unit.

[ctenche]

Here's what I mean...

http://www.pbase.com/image/13777107

So how do attach this to the chassis? You need some sort of joint that would take the place of the anchor bolts. And there's still the issue of adjustability.

Of course, if the image of the A-Arm is not the Honda kind then I'm gonna have to come over there and kick you in the butt 'cause that throws this entire discussion out the window.

Still, it's been fun. Certainly much more fun than writing a monthly project status report :)

[Marsh]

Sigh...

Dave has posted a picture of the stock rear suspension. The front mounts the same way as the civic etc.

Dave you can't turn the nut to adjust it, because the nut is not what adjusts it. The rod end is actually threaded into the A-arm. To adjust it you must remove the A-arm, loosen the nut, rotate the rod end, re-tighten the nut and re-install.

The solution is to not thread the rod end into A-arm, but rather thread it into another nut on the back of the tube. What we did on the SAE car is made a threaded sleeve that the rod end threads into. I'll post a picture when I get home in a few hours.

[Dave]

Sigh...sorry Marshall, guess again :) The picture I posted from my shop manual IS of the front upper a-arm for all 92-95 Civics, which is exactly the same as the front upper a-arm on all 94+ Integras. God knows I've swapped this arm on and off my car enough times to know what it looks like.

BUT, I think I do finally see the point that you guys have probably been trying to make all along. It's not the nut that adjusts camber, it's the threaded rod that goes into the a-arm that adjusts camber! Yeah, it makes sense to me now why you'd have to disconnect the arm to adjust the camber. That sucks though. Definitely a drawback of the design, though it's probably a much more robust design than the Skunk2 arms like I have that are prone to slipping because the cheesy little allen key bolts come loose and the ball joints tend to go bad quickly too.

[ctenche]

While the Skunk2 arms are GREAT for ease of adjustability the design of the locking mechanism sucks. All that force held together by 6 cheep nuts using nothing but friction. To top it off forces are applied in the same direction as the range of motion.

Still, if I'm gonna play around with different settings then this is the one I'd want. I just can't imagine how much work (and therefore $$$) the AJ arms will take to adjust on an alignment rack.

I remember some people on honda-tech.com mentioning how they changed the screw mechanism on the Skunk2's to make it better. Wish I would have saved that thread.

Oh well, this has been a fun discussion.

[GregR]

I think that the idea of having the rod ends at the anchor point to the chassis sucks because there's a lot of removal AND you need to do both at once. I would prefer a method with the rod end at the spindle side, so that all you do is drop the spindle, turn the rod end half a turn either in or out to tweak the angle, and slap the spindle back in. Similar to the Skunk2 version, but instead of a sliding bearing it's threaded.

[Dave]

cool idea Greg! I like it. Instead of a sliding balljoint held down with a few cheesy little bolts perhaps an a-arm could be designed such that the position of the balljoint is adjusted with threaded rods that run down each side of the balljoint. Know what I mean?

Anyway, it has been a fun little thread and I'm sure none of us will be buying the $1300 A-Sports arms so it's kind of a moot point :)

[GregR]

I know exactly what you mean. I thought about that right after seeing the Skunk2 units. But I see a trade-off that maybe someone with more knowledge will be able to solve.

A threaded rod end going right into the A-arm is lighter, but is limited in its travel (effectively camber degrees) by the length of the threaded bolt since you don't want 80% of it sticking out of the A-arm.

A sliding bearing on two parallel threaded guides is heavier, but can have WAY more adjustment range and be more fine-tuneable since you don't have to do it in 1/2-turn steps.

Marsh or anyone else? Any take on the benefits of one over the other?

[Marsh]

OK! here are the pictures

As you can see with this system the rod end isn't threaded into the a-arm. Instead it's threaded into a seperate female piece that inserts through the other end of a short piece of tube. To adjust camber to any point you want you simply loosen the lock nut and turn the end with a wrench. On a lift you might even able to do it without removing the wheel.

http://www.cockyracingguy.com/pictures/Misc/SAE-susp-01.jpg
http://www.cockyracingguy.com/pictures/Misc/SAE-susp-02.jpg

What we do on the front is this:
http://www.cockyracingguy.com/pictures/Misc/SAE-susp-03.jpg

The nice thing about this is that adjusting camber has no effect on toe so there is no need to go back fixing toe later. It also has no effect on caster or anything else. Plus you can now change Caster and Ackerman by simply making different brackets (which is really easy if you have a mill).

Dave, sorry I thought the front of a civic was the same mounting system as the front of a Prelude. The system you showed is VERY week and I would think Honda would risk it with drive loads? It is how the Prelude mounts in the rear, but the front uses horizontal bolts in double shear (like the A-arm you posted). So I'm curious: How the hell do you bolt those a-arms to the stock mounts on a civic, since that's what those a-arms are supposed to be from. (The point Caius was trying to make I think?)

[Dave]

Marsh, it was confusing of me to use a Civic/Integra a-arm to illustrate my point when this thread started out as a Prelude discussion.

Here's a diagram from Majestic Honda's online catalogue of parts that'll give you an idea of how the front hub/knuckle attaches to the balljoint on the upper a-arm.

http://www.hondaautomotiveparts.com/catimgs/13SR30_J08.gif

The shock actually passes thru the u-shape of the upper a-arm and then bolts to the shock tower, so the shock is really only indirectly connected to the upper a-arm via the knuckle. The bottom of the shock is connected to a fork that drops over the driveshaft and connects to the lower control arm (which connects to the hub/knuckle assembly via a balljoint). Here's another picture from Majestic to illustrate what I mean.

http://www.hondaautomotiveparts.com/catimgs/13SR30_J11.gif

This suspension design seems to be quite strong given all the road race use its had on the countless Integra Type R's that have dominated the Speed World Challenge for example.
The Skunk2 arms have been knocked for the weakness of their camber adjustment system, but I've never seen a stock system break on a Civic or Integra. It is interesting that Honda went with such a different front and rear suspension design on the Prelude compared to the Civic and Integra. It would be cool to find out why Honda's engineers went this way with the Prelude.

[Marsh]

No, I'm not implying it would break, I'm implying there is way too much flex. The stock upper A-arm attaches to a simplified rod end that threads verticly into the chassis. But the suspension loads are more horizantal (by definition the loads must be co-planare to the A-arm). This means those rod ends are loaded in bending. You NEVER load a rod end in bending. This would mean that they are twice as strong as they need to be in order to take the bending load. Honda obviously does this for simplicity or to reduce cost, but it's a bad way to do it.

This the the Prelude front A-arm:

http://www.cockyracingguy.com/pictures/Misc/lude-susp-01.jpg

Note that the mount is a flange welded to the chassis. Nothing is in bending and it's significantly lighter AND stiffer. I was very surprised to see that Honda would do this on the Prelude (and I think the Accord is the same?) but not on the Civc/Integra. I wonder what the reasoning is?

[Dave]

interesting stuff. I wonder if they went with this design on the Prelude/Accord because of the higher curb weight of those cars? Or the heavier front ends? A 97-01 Prelude is about 300 lbs heavier than an 94-01 Integra GS-R (2668 lbs) but maybe that's enough to require the stronger a-arm attachment system?