//<86TA>\\

iTrader: (14)

I remember there being issues with fitting a wider front wheel/tire. Is this solely related to the steering arm? or something else? Any racecraft owners chime in?

Pablo

iTrader: (1)

I myself have been wondering if the racecraft spindles for the rack and pinion setup will allow the steering knuckle to fit inside of a 17" wheel and work with the standard steering linkage.

It would be neat if we could talk racecraft into manufacturing these spindles with maximum ackerman assuming the arm/rod end fit inside of the wheel.

//<86TA>\\

iTrader: (14)

That where I'm going with this.

I seem to remember the rack ones not working either. My current steering arm mod has gained me a "positive" akerman angle, maybe too much really, but the steering even with 295/18 front tires is greatly improved. In a tight slow turn, there is no noticable hop or push in the front end, so it seems I'm going in the right direction.

tvc 15

Sorry to be a dumbass. But I thought ackerman was when the inside tire turns more than the outside wheel? And if so are do you want more of it or less of it?

//<86TA>\\

iTrader: (14)

Your on track, but these cars have anti akerman steering, the intersection of the steering arms is about 10 feet in front of the car, where is should be somewhere around the center of the axle, + or -. This work would be to move the steering arm to correct this issue, but wheel and rotor clearance is the problem.

Changing the angle will.change how the wheels turn in reation to each other, making them both turn at the proper angle for their respective turn radius, or making the inside or outside tire toe in or out in realation to the turn radius. All will affect who the car reacts in a turn, for better or worse. There is no real right or wrong once you are in the ballpark, but changes can he made to change feel and I'm sure under and oversteer to an extent, but I'm still learning too and don't know al the in's and out's yet. And anything is better than what the cars have stock.

If Dean hasn't bailed out again, maybe he will chime in on this, I'm sure he can explain it better than I can

Pablo

iTrader: (1)

What did you do to gain ackerman? I'm not sure its possible to get past parallel steering on these cars. Maybe a tiny bit.. but you'll hit the brake rotor or the wheel before you get too much.

Picts?

I have really bad hop and push with my car because of the stiff sidewall tires and rear axle moved forward.

Pablo

iTrader: (1)

The thing about ackerman is that you have to account for the slip angle of the tires. Something tall and loose will generate a lot of slip angle in a turn so that would probably explain the anti ackerman built into our cars. They were designed in the late 70s for tires of that era.
Fast forward to the early 90s and look at an E36 BMW with essentially the same front suspension, they built in at least parallel steering, possibly some pro-ackerman in there. The big difference was the tires. Less slip angle.

You want to set things up so that you are at the peak of the slip angle curve with both tires as it generates the maximum amount of grip. So the stiffer and shorter the tire sidewall the more ackerman necessary so you don't get on the backside of that curve.

I would say that with the tires available today, every thirdgen built for handling could benefit from moving away from anti ackerman. This of course is only a big deal if you are making a lot of tight turns, like on an autoX course. If you are on a big road course that doesn't require a whole lot of steering angle it probably wont make much of a difference.

tvc 15

From my understanding of ackerman our cars have it. Ackerman is when the steering arms are not straight infront of the spindle pivet point. Our steering arms are slightly turned in from the pivet point causing one spindle to go over center faster than the other thus causing the inside wheel to turn more than the outer. That is what I was told ackerman was. But maybe I'm wrong.

Pablo

iTrader: (1)

Our cars have anti ackerman. When the arm is inward of the pivot and in front of the wheel the front wheels toe in as the wheels are turned. 100% ackerman would be if the inside and outside wheel matched the arcs of their turning radii perfectly. In order to do that the steering arm has to be far enough outboard (if in front of the ball joint) that a line drawn through the tie rod end centerline bisecting the ball joint would hit the center of the rear axle. This is not possible with the arms in front. Arms behind the wheels makes this possible. Old corvettes for instance have their arms set up this way.

Lots of stuff online about this, google.

//<86TA>\\

iTrader: (14)

my hub and brake package moved the rotor out considerably, so i have more room than most, but there is still some room with more "stockish" brake and hubs setups. the rod end for my steering is about 1/2" from the rotor

this is my experiment bracket, its pretty beefy, but i dont trust it to hold up without flexing once i start pushing it really hard, it was made as an experiment, so aesthetics were not of a concern at the time. the hole close to the stock tie rod pickup point was the first attempt at moving he arm, a little movement, nothing big, but i forgot to test fit the wheel before making it, and well, it did not fit...., so i left the sleave in there to keep it from distorting, and pressed soem bronze bushings into both sides to act as a rivet of sorts.




its all 3/16 steel, pinned to the stock tapered end of the spindle and the dust sheild bolt on the arm with a grade 12.9 bolt. Its a pretty drastic change in angle. Not the cleanest looking piece, buts its solid. Thats a 5/8 bolt for the steering arm. This all allows the tie rod adjuster to just clear the sway bar link at lock.

so the plan would be to take the racecraft spindle, cut the arm down, weld a serrated akerman block to the end and that would make me happier than this bracket currently does as far as strength, and it would allow some adjustment of the angle itself. It has survived so far without issue, but no more than some overly spirited driving on the street to test it with as of yet.

the only thing i dont love about the racecraft spindle is that its a 2" drop. I would be happier with a 1" spindle, or even a 1.5. I may look into moving the balljoint boss on the spindle as well, to lessen the drop since i dotn plan on running the front of the car in the dirt.

tvc 15

Thanks Pablo. I took a refresher coarse via google on ackerman steering. And what I was missing is when the steering arms are pointed in it only produces ackerman on rear steer cars. If the car is front steer the arms need to be pointed out. PS I love this place.

Pablo

iTrader: (1)

Love what you've done here!
I had mentally thought of doing the same thing but never took everything apart to see if it was feasible. I didn't think it was, but it looks like you pulled it off.
The only question is strength and stiffness. I don't think the fasteners are the weak point since you are more or less dividing the force between two of them now. The only one that would be questionable would be the smaller dust cover bolt. I don't know how deep those threads are. Would it also be possible to drill and tap that hole for a larger size fastener?
Only thing I would be worried about would be the potential cantilever action trying to twist that sleeve around the steering arm. The lackluster FEA program in my brain would say the top and bottom edges of the weld on the sleeve, and the top and bottom edges of the rear mounting tab would likely be the areas with the most stress. Everything forward of that looks pretty beefy.

How much clearance do you have from the tie rod adjuster to the A arm? I was concerned that the steering arm being too short would touch the A arm under the right conditions.
How much has the steering ratio been affected? Big difference?

I really like this idea. I might have to steal this from you which would make this the second thing I've taken. I used your posts as inspiration for my own mini tub though I did mine a little differently.

rlewi771

Yes, the racecraft issue is solely based on the steering arm location. I have them and have fought with this a ton. No solution i've been able to come up with so far other than adding the width towards the outside of the car and running fender flares or a custom widened fender

I've called in an talked to Racecrafts tech's which were very knowledgeable and explained the issues, and asked if the design of the rack and pinion spindle would gain me anymore clearance and he thought it might even be worse.

//<86TA>\\

iTrader: (14)

well, if you want to offload them for some stock ones.....

and for Pablo,

i agree complete with the possible cantelever issue with the tube. The pics dont show the bottom, and there is much more meat down there, so the only issue would be the top being pulled out or pushed in under load. I got brave and tossed the car through some of my favorite twisty back road turns, and one high speed one, nothing happened, and i did not die! SO they are pretty strong, but still not ideal.

i dont know what kind of room there is to do this with stockish brakes, those hubs are over 1/2" further outboard than a stock rotor/hub. the dust sheild hole is 8mm 1.25 (pitch IIRC). Not a huge bolt, but at grade 12.9, pretty strong. There is plenty of meat in that area to increase it to 3/8 without any issue.

i have to measure the tie rod to a-arm clearance. Its not close to the tubular arm i have, but may be to a stocker, which i dont have to verify. Steering is about 1.5 turns lock to lock, maybe a tad less. Its awesome, i dont even need to take my hand(s) off the wheel to make a turn, since the wheel never goes past 3/4 in either direction. I have no noticable change in steering input either, even with the large front wheels. The PS pump is not happy though, and i may have to find something stronger or have mine rebuild with different valving

I can add a gusset to the top, back to the stock location to brace the arm, but i dont think its the solution because of the angle it would be at and im just adding even more weight at this point.

you are welcome to steal this idea, maybe we can come up with a solution that would aid the 3rd gen community with this. I plan to fiddle with the racecraft piece, i just hate having to spend the 600 bux if i mess it up. I dont have the tooling to build my own spindle, which would be ideal, but it will still cost many times more than the racecraft piece when figuring in all the tools parts and equipment needed. (or machine shop costs)

The other option is cutting and welding the stock spindle, but welding cast iron is a hit or miss deal, and even a beautiful weld can be weak. since this is a "life and limb" part, i dont like that route at all.

Pablo

iTrader: (1)

I agree that gusseting the top would be better. In my mind I envision two plates - one top, one bottom- laid horizontally, and clearanced/formed around the arm, and a third plate vertically on the outside of the arm tying the two together. Holes drilled in the top and the bottom to slide the sleeve through and welded. Left would just be a flipped version of the right. I think this would provide more support against the cantilever action.
Honestly I think this is a better idea than what you are giving it credit for. It seems like it should be plenty strong if not an ideal distribution of load. As far as weight goes, consider that different wheels can vary by several pounds as well as brakes. These are further out on the A arm which is a greater moment arm than this bracket which is a bit closer. I don't imagine this weighs more than a couple of pounds.
I think you'll see your greatest stress just turning the wheel back and forth while stationary. Is there another bolt hole you can tie in for a third mounting point? I dont remember the placement of the dust cover bolts exactly.
Wish I lived nearby, I'm sure we could set up a dial indicator on there somehow and measure deflection just yanking the wheel left and right while stationary. Maybe you can try this with an assistant?

I run the stock A arm and I think the rolled lower lip may start to get close, or it may not considering that the pitman/idler moves forward with more steering input. Worst case scenario I'd cut off the rolled lip and weld in a small gusset underneath. Should weigh the same.

I'm definitely going to look at doing this. I have stock brakes so I'll have less room but I'll see what I can do. This steering arm length/angle looks very much like my E36 bmw

BTW I too am very hesitant to cut and weld on the cast iron spindle. I know one guy has done it but I feel more comfortable with what you have done vs doing that.

//<86TA>\\

iTrader: (14)

That makes sense, and I think I may try you arm design before I go the route of the racecraft piece. I have a pile of spare spindles so mocking new pieces up is no problem.

I can get a buddy to help with the deflection test.

I will have to take a look at myy other car, it has c5 brakes, and see what kind of room is in there for this kind of work

Pablo

iTrader: (1)

Did you have to go to a different length tie rod adjuster sleeve? IIRC you said you had previously gone with a 9" sleeve. Is that still the recommended length?

I am going to start getting some parts together to do this.

//<86TA>\\

iTrader: (14)

its longer now, currently its a 12" sleeve, but 11 would probably work better, 12 is about bottomed out on both ends.

the sleave length with depend on how far you move the pickup point, so i would not buy that until you have something together. I have a bunch of different length sleeves i can use for mockup.

tvc 15

After figuring out I had it backwards I might be interested in doing some modifed spindles also, cool idea. But what I was wondering have you checked the bump steer after making the tie rods longer. Or maybe with the limited travel it doesn't matter so much.

FlyDoc

OK for the question asked in this thread before it went off into left field, good info.

this is a racecraft spindles for a rack&pinon steering, I'm running 18x9.5 wheels. as you can see there is only 1" for the tie-rod end. which will not allow the use of a stock type tie-rod. this is how I solved this issue.

I had 1/2"milled off the bottom of the tie-rod mount, drilled square (taper removed)and used 5/8" rod-ends with the bolt head milled down. this package fits inside the wheel. there is no way to use a stock style tie-rod, unless you are running piazza cutters.

Roostmeyer

iTrader: (3)

Quoted for the truth. Different tires behave differently of course, so in a road racing environment it may be difficult to justify or quantify like you said.

Just two points I want to add.

From my days in FSAE, a short wheelbase/wide car can really benefit from this. Ackerman steering increases the slip angle on the inside tire and with that increased slip angle there’s a proportional increase in drag. This drag helps rotates the car around the front inside tire.

In general if a car responds positively to more toe out, more ackerman in the steering should help. Ackerman can get you the toe out condition, without the drag penalty in straight line. Woodward has a nice PDF you can download that describes this better than I can.

I sent an email to a guy from racecraft asking for this exact thing (shorter arm, more ackerman), even offering to model it and help develop, but he wasn’t interested. Hopefully if there’s more than one nut job asking for it he may be interested…

If a custom spindle is being made, seems like we could change the strut angle to gain wheel clearance there as well, maybe even make room for coil-overs. This would lengthen the FVSA length some as well, not sure if that’s a good thing or not.

//<86TA>\\

iTrader: (14)

so what are you saying

i have yet to hear back on my inquiry with racecraft, if i get some time, i will start mocking up a new bracket, it seems like the most economical route

FlyDoc

see #20.

Pablo

iTrader: (1)

Flydoc, thanks for posting the pictures. That helps. Kind of disappointing to see that this setup would likely not fit in a 17" wheel. It does seem like they may have improved the ackerman some from what I see in your pictures though its hard to tell for sure. My eyes could be deceiving me.
A good thing about the racecraft piece is that I assume its made out of regular steel so modifying it would be a lot easier than modifying a stock spindle. That would be if you really want the 2" drop and unsprung weight reduction they claim.
If you are just after improved ackerman and wheel clearance then I don't see why we shouldn't move forward with 86TA's bracket concept.
I am proceeding in this direction. Just ordered up some parts. With stock brakes I don't have much room so I am going with a 1/2" bolt instead of the 5/8ths. I think the bolt itself should be plenty strong.

DBLTKE

iTrader: (1)

I sent an email to Racecraft as well. I would LOVE to have a set of drop spindles and I also want a quicker steering ratio plus more steering angle. But I also want to run an 11" wide front wheel with the option of being able to use a 17" diameter wheel.

You may already know this but TGO member Luv2Drift has voiced interest in designing and fabricating completely custom drop spindles that have shorter than stock steering arms. You should contact him and voice your interest, maybe he'll try and get on that sonner rather than later.

83 Crossfire TA

iTrader: (2)

This was what I was trying to generate here:
https://www.thirdgen.org/forums/susp...ring-arms.html

I also have a thread about brakes on racecraft spindles, since the person linked to on their site as selling adapter brackets for them that work with their spindles is MIA and I can't seem to get an answer if the normal adapter brackets will work.
https://www.thirdgen.org/forums/susp...-brackets.html

FWIW, I have bought a set of racecraft spindles to cut up and try exactly that.

I like what you did there. I played with cutting up the stock spindles and welding them, I've done some cast welding, some with good luck, but I don't know that I would like to put my life in the hands of a welded cast piece. OTOH, a welded piece with a brace bolted to it, maybe. WRT to your design, I'd probably just make it wrap the top and bottom of the arm, possibly with a small bolt to keep the 'wrapped' parts from moving relative to the arm.

I'm another one that spent quite a bit of time talking to the guys at racecraft, including the guy responsible for designing them and the guy that puts them together. They have no faith in the "drag" versions for R&P working for the kind of application that we're talking about, besides the geometry issues, they say that they're just not strong enough for that use. I will say that they have a pretty good handle about the design constraints on this thing, and you can talk all this with them with reasonable knowledge, but I don't think you'll actually get anywhere WRT to getting them to make something like what we're talking about because of their design constraints. I'd bet that at this point I have some info about their stuff that isn't public knowledge, but probably shouldn't get into what that is, at least not without confirming with them first.

83 Crossfire TA

iTrader: (2)

One thing I'd love to understand is what GM was thinking when they designed the suspension on these cars with the instant center and ackerman that they have, it just doesn't seem to make sense on no matter how I look at it.

Pablo

iTrader: (1)

In the book "Camaro, The Third Generation" they go over a lot of the engineering considerations in the design of the car. They don't get specific about instant center and ackerman but you can see that most of the work happened in the late 70s. The design staff had a completed prototype that looked exactly like the production car as early as december of 1978.

In the case of ackerman, that design time frame was probably a good 8 years before 16" wheels even entered the picture. In the book they have a chart with cornering coefficient vs slip angle for the top of the line goodyear 215/65R-15 tires on the '82 Z28. The cornering coefficient seems to peak at 5 degrees of slip angle, possibly more (they cut off the chart data beyond that point). That's a lot of slip angle for such a small amount of grip.
Considering that the car still had to be stable and predictable with the base model wheels and tires, I would not be surprised if they purposely put in enough ackerman to ensure that even the base model contact patches would not go toe out in a dynamic situation. Base models tires probably had huge slip angles.
A compromise would have given both the base model and Z28 less than 100% dynamic ackerman (if I can call it that) with the Z28 in effect having less considering the smaller slip angle of the goodyears (which is large by today's standards) over whatever weak tires the base model had.
Pure speculation on my part but that's the only way I can make sense of it.

Pablo

iTrader: (1)

I should also add that if I am understanding things correctly, it take a lot less force to generate those slip angles on those old goodyears than it would on a newer, stickier tire. So under much slower driving conditions you'd be more likely to twist the tire to its maximum slip angle than you would with a newer, stickier tire. Even if their slip angle curves peak at the same amount of degrees.
Please correct me if I have this wrong.

//<86TA>\\

iTrader: (14)

that sounds like an interesting book, i may have to pick it up.

//<86TA>\\

iTrader: (14)

i had some time this evening to mess around with a new bracket. Im growing more confident in the original one now that i have had more time with the car. I've been pushing it harder to see what happens, and i am yet to have any noticeable bending or damage to the brackets, i even ended up with some pad knockback, which i think was in the rear, after the last "tuning" session. I need to look into that a bit.

I did some measuring on the car and i looks like i found the "sweet spot" with the first arms. I cannot move the steering pickup point closer to the balljoint or the tie rod adjuster will hit the sway bar mount/a-arm. And i cant move it away from the balljoint much more than 1/4" or things start getting too close to the inside of the wheel. This is with the center of the rod end mounted 1/2" lower than stock to make up for the tall balljoint. this all may create an issue with a 17" wheel.

here is the start of the next design rough pieces, some trimming, bending and such will still be needed.


it goes on somthing like this









now this is only part of the bracket, there will be a bottom piece, and im planning to triangulate everything at the piece of tubing back to the balljoint, triangulating everything. I may or may not add a small gusset back to the dust shield bolt as i did before.

Pablo

iTrader: (1)

Wow, nice, that looks really beefy. Attaching it to the ball joint stud seems like a better way of doing it. The only thing that might be a concern is the weight. What do you expect them to weigh in total?
I was also wondering how you drilled the large hole (1" ?) Huge regular bit or was it a hole saw?

DBLTKE

iTrader: (1)

Also of you want to get some idea's do a search on google or some Nissan sites for "steering angle kit." here's a couple that I've found...

Pablo

iTrader: (1)

At first glance I thought "wow nissan suspension looks almost exactly the same as my 318is". Turns out those are indeed E36 bmw parts.

Very interesting way of doing it. Definitely gives me ideas. Thanks for posting.

//<86TA>\\

iTrader: (14)

The issue with those style parts on our car would be the sway bar link.

//<86TA>\\

iTrader: (14)

That's an interesting way of doing it. And that's a really long monoball stud. It might not work realy well on a 3rd gen without some serious time at the machine shop. The bmw seems to have the balljoint and the tie rods all mounted on the same plain, the 3rd gen does not, they are different heights and at an angle to each other. The best place to move the tie rod pickup point would aftually be along the steering arm itself, requiring the arm to be cut off and rebuild/welded, and that's what I'm trying to avoid.

I wonder if its possible/practicle to cut the arm completely off and buid a new one that bolts on somehow?

wretched737

Phil if you dont mind some annoying company i'd love to come by and help/learn a bit more about what is going on here, some really neat **** is happening

//<86TA>\\

iTrader: (14)

I will be working in the garage most of the evening, have some work to do on the yelow car and some work on these brackets. If you want to swing by for a bit your welcome. Remeber where I am? Pm me if you need my number

//<86TA>\\

iTrader: (14)

sorry i missed this one Pablo, i used a 7/8 carbide tipped hole cutter i use at work for making holes in electrical equipment, they are nasty and cut beautiful holes the tubes i have a 7/8" OD and that just happens to be a standard size for 1/2" conduit knock outs. DRill slow, little oil if you want and they leave no bur like a hole saw will.




I have made some progress on the new set, i layed out a piece to tie back to the boll joint, but its hard to package and i dont think it will prove much sice it will be rather thin, so for now i abandoned that part. Basically i redesigned what i alrady have to make it a bit beefier and lose the extra material at the old tie rod pickup point.







before welding, they are sitting at 1.25lbs. I expect to add a few ounces with weld, but after finish grinding and opening the speed holes a bit in places, i may be able to keep then at 1.25 lbs if not less, which in reality is not bad considering the good these will be doing. I moved the new steering pickup closer to the steering arm by about 1/8" and about 1/4" toward the front of the car.

The first design has a lot less material, and has held up admirably so far, so im pretty confident in the strength of this setup.

Pablo

iTrader: (1)

Those look pretty darn robust, and surprisingly, 1.25 lbs is lighter than I expected. Are you going to measure if these flex at all?

paul_huryk

Phil, nice design & fab work - want to see it in person when you are done.

//<86TA>\\

iTrader: (14)

Yes, I will rig up something to check for deflection once they are done.

Pablo

iTrader: (1)

Did you ever get these finished up? Anything new to report?

//<86TA>\\

iTrader: (14)

lol, no i have not. They are all tacked together still, but no progress. Been really busy with work and its been too hot to work in the garage for the last few weeks. Soon i hope, but nothing right now.

The first design is still on the car and working admirably.

Just need some time to weld them up, fit them and rig up a deflection test of some kind

scooter

iTrader: (11)

Is this what you wanted to use my welder for?

//<86TA>\\

iTrader: (14)

yes sir, mine does not have quite enough power to penetrate the 3/16 as well as i would like

TEDSgrad

iTrader: (4)

Phil, very cool idea. This will be helpful in the future. If you can reach flyinbye, he'll have the brackets, if you're still looking.

TEDSgrad

iTrader: (4)

Phil, any news with this?
Did you need the mod to fit the 295/18's, or could minor shaving make them work? How close? What about bump steer kit?

Brian

Pablo

iTrader: (1)

To fit 295s you dont need to do this. You can actually fit 315s up front on a 17" wheel but it cuts it very close and sticks out slightly depending on your ride height. Even once you fix the tie rod end issue you don't have much room before you get close to the strut.
I have some parts to build my bracket so that I can tuck my 315s a little better and get some ackerman, especially since my rear axle is moved forward.

I have really wanted to get started on this but we have a new baby and time has been crunched.
I have been thinking of adding a set of U bolts to clamp the bracket in addition to the two bolts. Placed horizontally on each end of the rod end bolt tube clamping a plate or bar to the other side would probably reduce the chance of failure and strain (flex).

//<86TA>\\

iTrader: (14)

Hey guys. I have not had much time to mess with this more, but I will say that the first pieeces I made are still holdijng up and honestly, I think they are good enough to leave alone for now. I will put the 2nd style on the shelf. I'm exploring another more expensive route route now, but if it works out, will be much better.

295/35/18 will fit the front perfectly with a properly spec'd wheel. Only mod would be to lengthen the steering stop a little to keep them from hitting the back of the a-arm. And yes, people run 17x11 with 315 commonlhy on the front, but they stick out a little more since they don't clear the strut and tie rod as well a most 18" wheels.