Is There a Car With an OEM Quick Ratio Rack?

[HectorM52]

You know how the third gen F-bodies have quicker ratio boxes than some of the others?

Well is there a stock vehicle out there that has a quicker ratio than others?

If you know of one...is it up to the task of turning wide tires/wheels? Meaning we probably don't want something from a Geo Metro since its used to turning 3" wide tires!

Anybody?

[MrQuick]

4th gen Trans am? they offer 3 different ratios IIR

[Bryce]

in the mustang world it is common to use a j-car rack. rock auto shows a quicker ratio as an option. However, its a rear steer rack.

[Matt@BOS]

I know a lot of the aftermarket subframes, and rack and pinion conversion kits, use a rack from an '80s Mustang. After I broke mine I replaced it with what I believe is for an '84 SVO Mustang. They're cheap and work pretty well.

Matt

[HectorM52]

Thanks guys...I'll definitely be researching the 4th gen F-bodies.

And i guess I gotta find out what a J-car is...


What's the difference between a rear-steer rack and a front-steer rack?

I didn't say, but this will be custom-mounted in my S10 so if it's just placement then it probably won't matter much...

[FULMNTE]

All 83-88 Monte Carlo SS had quick ration boxes...

[HectorM52]

All 83-88 Monte Carlo SS had quick ration boxes...
Yeah, there's a quick ratio box on my truck.

But I'm looking for a quick ratio RACK!! :)

[GeoffP]

I've got a 4th gen Z28 rack that is of no use to me if you're interested. PM me if you are. I'll let it go for very reasonable price (or will trade for other parts). BTW, J Body cars would be like the early 80's Pontiac 6000's, Sunbirds, etc (if that's what he's talking about above).

[Rhino]

Since you're looking to retrofit into an existing chassis it's not quite as simple as choosing a ratio and making it fit.
Two measurements you'll need to know when researching a rack. The inner ball joint to inner ball joint, and the linear throw.
It is absolutely crucial that your inner ball joint to inner ball joint measurement works with the track width and other suspension components you have in mind. It's pretty difficult to modify an OEM power rack so you're usually stuck with whatever you find.
Where the throw comes into play is your turning circle. When planning my suspension, I found the 4th Gen rack worked ok, however didn't provide nearly the throw I needed to attain a near stock turning circle. I can't speak for putting one in an S-10, however most people who retrofit them into 1st Gen Camaros are rarely happy.

As was previously said, the fox body racks work well for quite a few installations. I ended up purchasing a 15:1 AGR rack for a late fox.
The early SN95 racks can also be a pretty decent fit. Similar IBJ to IBJ as the fox, with a little longer tie rod ends.

A rear steer rack will throw the opposite direction of a front steer rack. If you visualize what needs to happen with the steering arms you'll understand what I mean. When turning the wheel clockwise on a front steer rack, it will move the arms to the right. On a rear steer rack, this would move the arms to the left.

With all that said, I (personally) wouldn't retrofit a rack into an existing suspension. There always seem to be too many compromises. In this situation, a well designed box usually trumps a rack in both ease of installation and performance.

[HectorM52]

Wow, thank you sir! That's the kind of info I've been searching for. Right in one post!!

If you wouldn't mind bearing with me and answering some more questions I would really appreciate it...

I completely understand the front-steer vs. rear-steer thing. Must have been late when I posted above. Duhhhh.

Okay...IBJ to IBJ measurement. Are you talking about where the tie-rods connect to the spindles? Or where the inner tie-rods connect to the drag link?

Basically...the reason I ask is because I'm wondering if it would be possible to do the following:

1 - yank the "stock" rods off of the output shafts
2 - make a big "C" shaped rod that you will weld to the now naked output shafts
3 - jump off of that "C" with a bracket which will essentially mimic the drag link from MY stock steering setup.

https://static1.pt-content.com/images/pt/2010/07/Naked_Rack-1.jpg


https://static1.pt-content.com/images/pt/2010/07/Modded_Rack-1.jpg

[HectorM52]

Basically, what I'm trying to do is get back to a point where I can mimic all the locations of IBJ or OBJ or just generally place the system in the correct "plane" in all the X, Y and Z axes...

[Rhino]

The IBJ to IBJ measurements are what you're left with after removing the tie rods. Essentially the center section that you're referring to.

I understand where you're going. That may be the best way to fit a rack into your existing setup. I'd start by researching what the mustang guys do to retrofit a rack into their rear steer setup. The J-car rack is widely used since it already has a center mounting that can be used in the exact manor you're describing.
This is a similar install method that may give you a good jumping off point. http://www.crankshaftcoalition.com/wiki/Swapping_to_rack_and_pinion_steering

I have no practical experience, however I've heard that this method of mounting a rack can get some significant play after a number of miles.

Is your truck front or rear steer?

[Bryce]

The only other center-take-off rack that I know of is the TCP rack designed for mustangs and other 60's fords.

The other thing to keep in mind is an OEM rack designed for a commuter car with no performance in mind is probably not the best donor rack.

[HectorM52]

The only other center-take-off rack that I know of is the TCP rack designed for mustangs and other 60's fords.
Yikes!! That's more than the Unisteer setup that's specifically made for my application!




The other thing to keep in mind is an OEM rack designed for a commuter car with no performance in mind is probably not the best donor rack.
Yeah, which is why I might TRY the J-car rack (on someone else's truck :) ), but I can't imagine it being the rack I'm looking for.

Again, I'm looking for a QUICK-RATIO rack. Typically, when a manufacturer makes either a rack or box into a faster ratio, it's due to being a performance-version of it's former self.

...Sooooooo...I'm hoping when I find that quick-ratio rack then it's going to automatically be faster ratio. I'm wishing myself good-luck right now!!

[Jim Nilsen]

Check into the 84 Corvette steering boxes. They had a 2 turn lock to lock progressive ratio box from what I have been told. Very different to drive than a standard rack from what I have been told and will turn a corner and you don't need to take your hands off the wheel at all. Not all 84's had them so they may be hard to find or just plain expensive. Do some google searching and you may find all the info you need.

[HectorM52]

The IBJ to IBJ measurements are what you're left with after removing the tie rods. Essentially the center section that you're referring to.

I understand where you're going. That may be the best way to fit a rack into your existing setup. I'd start by researching what the mustang guys do to retrofit a rack into their rear steer setup. The J-car rack is widely used since it already has a center mounting that can be used in the exact manor you're describing.
This is a similar install method that may give you a good jumping off point. http://www.crankshaftcoalition.com/wiki/Swapping_to_rack_and_pinion_steering

I have no practical experience, however I've heard that this method of mounting a rack can get some significant play after a number of miles.

Is your truck front or rear steer?
Mine is front-steer.

And I read that article. Very interesting. Gives me some great ideas.

Thanks for all your help so far!

[vette427-sbc]

As Jim Nilson was saying, look into C4 corvette racks (not sure if that was a typo Jim, but since '84, corvettes used only steering racks, no boxes).
Early C4's with the Z51 option had very quick ratio racks for a street car. I think they were somewhere around 2.25 turns lock to lock (They are front steer also). Anything quicker than that might feel a bit too twitchy.

[HectorM52]

I definitely will have to find one of those old racks. Though I imagine it will be too wide since those Vette's are MUCH wider than my little truck.

Though maybe that could be fixed??? Hmmmmm...