rack n pinion front steer ackerman issues...explain...

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turbofreek

turbofreek

batcrap crazy racing team
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Why is there so much hoopla about improper ackerman angle and dangerous handling if one wants to put a rack on an abody? Is it not just as simple as making new ends to face forward to attach the rack to the spindles? Why does everyone jump and say its dangerous but never explains why it is or you cant so it. You have to buy a 4000 dollar k member etc... one even said that the stock spindles would be "shorter" if front steer. I dont know how they shrink personally. if i didnt use my shrink ray but that is the going rate of return for switching to a rack n pinion.
So. I have been trying to find why the fear and misguided misdirection to guide one away from going to a rack n pinion is so previlant? Can anyone with experience and most important knowledge on this matter be of some help here?
I am currently having a custom tubular kmember made. It will include a front manual steering rack n pinion with the use of stock spindles and tubular arms single lower control arms and coilovers for drag racing with street driving use. Not a corner carver. With all the stories i heard it truly scared the crap out of me. I am no steering expert but i am a very fast study on things and i learned quickly. What they talked about was absolutely mind boggling.

Thought if we got enough solid great information on the matter. A sticky could be useful for future people who dont have thousands to buy a fancy kit like hdk etc..
 
A LOT of it comes from people simply trying to throw around terms to make themselves sound more intelligent than they are.

Aside from that, the need for Ackerman geometry is imperative to prevent tires from slipping around turns.

Pretty simplistic explanation to get everyone on the same page in case you don't know what Ackerman geometry is.

https://en.wikipedia.org/wiki/Ackermann_steering_geometry

Since the wheels track different diameters in a turn, it's necessary to allow one wheel to turn at a different angle than the other to avoid wheel slip. It's all in the article above and very easy to understand.

Why people make a big deal about is probably because of the reason I stated. There's nothing setting steering up correctly.
 
I would be much more concerned with bump-steer for drag-racing.
Just watch some U-tubers coming off the line, to see some radical toe-change as the front ride-height changes. Scary stuff.

I wonder if the stock lower BJs with integral steering arms would be the best choice for front steer. I cant see it working very well for Ackerman or bump-steer; but then I suppose a drag-car isn't overly concerned with turning. Still, if the car gets sideways at half-track or speed, I imagine you would want the car to steer at least somewhat predictably!
Good luck in your engineering.
 
Looking at real world examples can help too. A late model front steer Ford is a good one. Their engineers needed the tie rod end so far outward that a hole though the brake dust shield was required.
 
I have a 1940 ply. coupe. One day I got a bright idea lets put a 360 6 pack in it. So I took the car apart. Install motor mounts trans mount and the motor. When I tried to bolt the steering box to the frame it didn't fit. Not enough room between the engine block and frame. Looking on the web I'm not the only one with bright ideas. I found 3 different ways to install a rack and pinion steering on older Plymouth & Dodge. They all used a 89 to93 cavalier rack & pinion. :eek:ops: Will update when install is done.
 
jockeyshift said:
I have a 1940 ply. coupe. One day I got a bright idea lets put a 360 6 pack in it. So I took the car apart. Install motor mounts trans mount and the motor. When I tried to bolt the steering box to the frame it didn't fit. Not enough room between the engine block and frame. Looking on the web I'm not the only one with bright ideas. I found 3 different ways to install a rack and pinion steering on older Plymouth & Dodge. They all used a 89 to93 cavalier rack & pinion. :eek:ops: Will update when install is done.
Click to expand...


Rear steer or front steer?
 
AJ/FormS said:
I would be much more concerned with bump-steer for drag-racing.
Just watch some U-tubers coming off the line, to see some radical toe-change as the front ride-height changes. Scary stuff.

I wonder if the stock lower BJs with integral steering arms would be the best choice for front steer. I cant see it working very well for Ackerman or bump-steer; but then I suppose a drag-car isn't overly concerned with turning. Still, if the car gets sideways at half-track or speed, I imagine you would want the car to steer at least somewhat predictably!
Good luck in your engineering.
Click to expand...

Exactly. And once again, all of this is covered in The Mopar Suspension Manual, but no matter how much you preach it, people will not listen.

:banghead:
 
AJ/FormS said:
I would be much more concerned with bump-steer for drag-racing.
Just watch some U-tubers coming off the line, to see some radical toe-change as the front ride-height changes. Scary stuff.

I wonder if the stock lower BJs with integral steering arms would be the best choice for front steer. I cant see it working very well for Ackerman or bump-steer; but then I suppose a drag-car isn't overly concerned with turning. Still, if the car gets sideways at half-track or speed, I imagine you would want the car to steer at least somewhat predictably!
Good luck in your engineering.
Click to expand...

Your ackerman is all wrong if one trys to just flip stuff around back to front on these things im told. That is what is most complained about. Which makes one wheel turn much more than the other at travel extention while in a turn. Seems most do not know how to fix this issue. Blame is always place somewhere else besides the ones doing the thinking. So if you like hard fast turns it makes it much more difficult to go around turns smoothly at good speeds.

So the outer wheel doesnt turn as much as the inner wheel does and drags and pulls the car away from the turn outwards. In drag racing that would be prefered cuz would wants to follow the turn into the wall anyways? Not me

That about sum it up?
 
Yeah, that manual taught me more stuff then I could have imagined it ever would, when I purchased it, way back when................
If every person here had one,and studied it, FABO would/could take on a completely different character.
 
turbofreek said:
Why is there so much hoopla about improper ackerman angle and dangerous handling if one wants to put a rack on an abody? Is it not just as simple as making new ends to face forward to attach the rack to the spindles? Why does everyone jump and say its dangerous but never explains why it is or you cant so it. You have to buy a 4000 dollar k member etc... one even said that the stock spindles would be "shorter" if front steer. I dont know how they shrink personally. if i didnt use my shrink ray but that is the going rate of return for switching to a rack n pinion.
So. I have been trying to find why the fear and misguided misdirection to guide one away from going to a rack n pinion is so previlant? Can anyone with experience and most important knowledge on this matter be of some help here?
I am currently having a custom tubular kmember made. It will include a front manual steering rack n pinion with the use of stock spindles and tubular arms single lower control arms and coilovers for drag racing with street driving use. Not a corner carver. With all the stories i heard it truly scared the crap out of me. I am no steering expert but i am a very fast study on things and i learned quickly. What they talked about was absolutely mind boggling.

Thought if we got enough solid great information on the matter. A sticky could be useful for future people who dont have thousands to buy a fancy kit like hdk etc..
Click to expand...

There's been threads here and "all over the internet," and some --who have tried--- have offered real world examples. Some guys who've tried a backyard approach describe a car that is nearly impossible to back up...........the steering geometry is so screwed that one tire squals terribly trying to back up around a corner. Another guy used his primarily for drag racing.....and got it to handle well straight ahead and for occasional street use.

But when you get into hard corners, tight corners, and so on, this requires a LOT of engineering, that most of us don't know about.

Seems to me the answer......if you just hafta........is completely different spindle design, whether you go to a Stang front end, make your own, or whatever
 
RedFish said:
Looking at real world examples can help too. A late model front steer Ford is a good one. Their engineers needed the tie rod end so far outward that a hole though the brake dust shield was required.
Click to expand...

I've done that..........about 3 years ago. "A quick look" under my Ford Ranger confirmed my worst fears.........there is no way you'd ever change a Mopar spindle to accommodate that
 
My '67 has power rack & pinion steering, stock K member, and '74 Valiant disc brake spindles. I have a custom built oil pan on the 360. Yes it is rear steer. The torsion bars are gone in favor of coil-overs and the upper control arm pick up points have been modified to correct the geometry.
The key to a properly working system is that rack be mounted at the right height to eliminate bump steer and the tie rods are the right length.
remember that the correct rack WILL come from a rear steer application. unless of course you want to learn to drive all over again.
You have to put your thinking cap on and think outside the box to get it to come together. I can tell you from experience. this car is a true "canyon carver" and a dream to drive with 15X8 wheels on all four corners.
 
turbofreek said:
Yep stock spindle.
Click to expand...

Looks like rather than flipping the spindles they probably just cut the steering mount off the ball joint and then made arms to attach to the rack. I've heard a lot of people say to flip the ball joints, I would guess that's where the issue comes into play.
 
HemiDenny said:
Rear steer or front steer?
Click to expand...

Denny, I believe the 40 is rear steer. the kits I have seen are all rear steer for the 40's Plymouths.

I have contemplated adapting the A body steering to my 47 Plymouth more than once.
just seems like a lot more work than a Mustang II based kit.
 
heres a few pics of a-body,rack and pinion,stock mopar k-frame,if done right works
 

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other pics of a-bodys ive collected,i have a aje under mine and its been 5.82,with a junk motor,with no problems
 

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vitamindart said:
Denny, I believe the 40 is rear steer. the kits I have seen are all rear steer for the 40's Plymouths.

I have contemplated adapting the A body steering to my 47 Plymouth more than once.
just seems like a lot more work than a Mustang II based kit.
Click to expand...

Thanks.....just wondered.

The only time I use a rear steer is flipped upside down for my friends down under....takes it from a rear steer LH to front steer RH drive .......works like a charm.

The rear steer rack Unisteer sells is interesting. I saw one at Mopars at the Red Barn in a Challenger. The steering shafts had some serious angles going on......I can only imagine the degree of difficultly in putting one in an A body.

Have you looked into Fat Man Fabrications for the 40s and 50s hot rods?.
 
yeah, the Plymouth can be somewhat of an Odd duck since it had independent suspension from the factory. even the mustang II swap usually involves a stub for the Plymouth. they sell dropped uprights and rack kits. I just don't know that they will fit my bill.
I would really like to add some handling to the old girl and some stopping power.
the mustang II kits offer plenty of brake choices.
 
440outlawdart said:
heres a few pics of a-body,rack and pinion,stock mopar k-frame,if done right works
Click to expand...

Man that ackerman angle is so bad. Has to be extremely dangerous to drive. Just ask the experts that required me to start this very thread. Some people just drive me nuts some times with ideas they know nothing about. Thank you very much for proving my point. This is doable and safe to use and works. I very much appreciate it more than you could ever know.
 
Dr dan said:
My '67 has power rack & pinion steering, stock K member, and '74 Valiant disc brake spindles. I have a custom built oil pan on the 360. Yes it is rear steer. The torsion bars are gone in favor of coil-overs and the upper control arm pick up points have been modified to correct the geometry.
The key to a properly working system is that rack be mounted at the right height to eliminate bump steer and the tie rods are the right length.
remember that the correct rack WILL come from a rear steer application. unless of course you want to learn to drive all over again.
You have to put your thinking cap on and think outside the box to get it to come together. I can tell you from experience. this car is a true "canyon carver" and a dream to drive with 15X8 wheels on all four corners.
Click to expand...

Have you ever posted this, details, photos, what rack you use?

I've thought about a rear rack. In fact, I have a "rear steer" rack. Big problem for me was figuring a good way to deal with the extreme column to U joint angle to get to the rack.

A set up like this, tho "properly done" would not have the issues the OP was talking about.
 
67Dart273 said:
Have you ever posted this, details, photos, what rack you use?

I've thought about a rear rack. In fact, I have a "rear steer" rack. Big problem for me was figuring a good way to deal with the extreme column to U joint angle to get to the rack.

A set up like this, tho "properly done" would not have the issues the OP was talking about.
Click to expand...

You just need a way to hold the steering shaft in a set location once you move it south at the extreme angle. Not a big deal at all. Many chassis builders do this all the time regularly.
 
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