[LT]

Ok guys and gals I'm looking for opinions on steering box ratios for the street. NASCAR uses 16:1 and 14:1 for stability at high speed. Dirt Track and Asphalt use 6:1 and 8:1 for quick whipping. GM fast ratio in the Performance cars is 12.7:1 which is 2.5 to 2.75 turns lock to lock . I see Sweets Manufacturing makes a 10:1 = 2 turns l2l. I plan to put an overdrive in the 71 Bird and I have Protouring F Body GenII upper and lower A arms with 700 in/lbs sings up front. I'm not planning to see over 140mph but to plan to see that for a brief period. Would the 10:1 be to quick at high speed? It would be nice in the turns. Is 1 wheel turn worth 700 buck? 12:1 is $450, 8:1 is $750 and 10:1 is $1150. Give me some thoughts, thanks LT-

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[b-man]

I love my 12.7 box, I have it in my Tempest canyon-carver.

Best upgrade for street performance driving.

Some say they're too twitchy on the highway or freeway, I don't agree.

Anything quicker is a waste of money, and you probably wouldn't like it much for street driving.

I also have a 14:1 box, for my Le Mans convertible cruiser.

[LT]

That is what came in IROC s and Monte SS right? Did second gen Trans Am have the same box?

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[b-man]

Yes, the 12.7 box came in the Monte SS and IROC Z.

Second-gen WS6 T/As had the 14:1 box, that's where mine came from.

[LT]

Thanks b-man that makes sense now, the 14:1 was the one I was missing and I'm use to using (after 11 T/A's in the late 80's you could buy nice ones with 75-80,000 miles for $1200 wish I didn't commit them to the bone yard, oh well) but I always wanted just a little quicker on the ratio.

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[STEELCITYFIREBIRD]

Be sure to figure in steering arm length of the spindles of each type of vehicle for a true ratio comparison.

With our Dirt Late Model's over the years, the faster the speed of the track the slower the steering we use. The spindles we use have 2 or more mounting points for the tie rod ends on the spindle steering arms. Allowing you to adjust ratio (and/or ackerman) if you choose.

A difference in hand speed/feel and not ratio can be achieved with a larger or smaller diameter steering wheel.

If quicker is what your after, you could add a quicken-er to the steering shaft. http://www.colemanracing.com/Steerin...ers-P4753.aspx

[b-man]

Both of my cars have the original huge steering wheels in them, that's the way I like them to look.

It's great having only 2.5 turns and 3 turns lock to lock instead of the factory 4.5 turn power boxes.

[LT]

My poor 71 box leaks like a siv and has the dredged tough click just off center to the left.

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[LT]

Nice point Steelcity, what about valving? .185 vs .210 or .235? I see .185 is easiest and .250 gives the most "road feel". What do you suggest?

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[Steve C.]

When it came time for me to put power steering back on my '70 Trans Am I choose to not use the origional factory steering box. Instead I bought a AGR box with 12:1 ratio and upgraded from the standard 210 valving to a firmer 220 valving. Absolutely outstanding out on the open road ! The upgraded valving provides a firm road feel, like what you might find in a modern pick up truck or BMW, yet for my needs it's adequate for around town and related parking.


http://www.agrperformance.com/Chevro...otorsports.htm

.

[LT]

Great info thanks!

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[STEELCITYFIREBIRD]

I'd give Sweet a call, our "stock" car years ago was years ahead of what is the norm now on a good "stock clip" chassis. We used a mix of factory spindles, different length ball joints, custom length tubular control arms, and a custom centerlink (now available off the shelf). They, Sweet, know what works together best to produce the optimum roll center,for dirt or asphalt, camber gain, and bump steer for lots of traction and great feel from a front end.

As far as assist, all my recent experience is with dirt late models, on 14" wide tires.. no one uses a .250, .210- .220" dia torsion bar is the norm on the assist, but we run rack and pinion steering on the DLM. Again, steering arm length is an issue in feel because of leverage, so that likely won't be comparable to a street car.

I would call Sweet with your specific parts, application, and desires.

For Myself, I would consider an integral rack depending on the originality of the car.
---------------
B-Man, the rule of thumb for steering wheels on circle track cars is use the largest wheel your belly will allow! Had a driver try a tiny little wheel once, and he vowed never to do that again.

[Squidward]

Originally Posted by b-man

I love my 12.7 box, I have it in my Tempest canyon-carver.

Best upgrade for street performance driving.

Some say they're too twitchy on the highway or freeway, I don't agree.

Anything quicker is a waste of money, and you probably wouldn't like it much for street driving.

I also have a 14:1 box, for my Le Mans convertible cruiser.

I am one of those that says too twitchy. I will most likely get a bigger steering wheel down the road to give even less road sensitivity.

For me, 14-18 would be ideal. 22+ was too much. 12.7 was too little.

[leeklm]

I originally had the mid 70's big car "slush box" in my 66 GTO, and upgraded to a 12.7 box from a newer trans am that also had a firmer feel to it. VERY NICE upgrade and was never "twitchy" on the drag strip at 112mph. If i ever decided to put pwr steering in my 73, I would go to that same box.

In the meantime, my biceps get a workout with manual steer and about 100 turns lock-to-lock

[RocktimusPryme]

Are those IROC boxes an easy swap? I would think they are everywhere. I also seem to remember jeep grand Cherokee boxes being super common swaps. Not sure of the reason for that particular model.

[Squidward]

Originally Posted by leeklm

I originally had the mid 70's big car "slush box" in my 66 GTO, and upgraded to a 12.7 box from a newer trans am that also had a firmer feel to it. VERY NICE upgrade and was never "twitchy" on the drag strip at 112mph. If i ever decided to put pwr steering in my 73, I would go to that same box.

In the meantime, my biceps get a workout with manual steer and about 100 turns lock-to-lock

On the dragstrip I am always "locked on" to the task. When I am cruising on the street, I like to relax a little bit. I don't want to worry about sneezing and then find myself changing lanes. A little exaggeration, of course, but just sayin'...

Maybe I need some more suspension/alignment work, because my steering doesn't hold center as well as other cars I have owned. IDK. I don't like 1st gens handling. But I always loved the handling of 2nd gens, so I can understand OP's desires.

BTW, I am running the JGC conversion. In retrospect, not worth it for my personal preferences.

[Will]

Does anyone make fast variable ratio boxes? The original box in my formula was a 12.7 variable ratio. Best of both worlds - not twitchy at speed but still only 2.5 turns lock-lock.

It's been replaced with a 12:1 constant ratio box which is still fine. I've had the car up to 145 mph and didn't feel the steering was overly sensitive.

Lots of positive caster is your friend.

[Schurkey]

Originally Posted by Squidward

I am one of those that says too twitchy.

What is your caster and toe measurements? Toe, especially, makes a car steer abruptly and semi-uncontrollably.

[Steve C.]

Will,
AGR makes a box that has firmer valving and 16/13:1 variable ratio gearing for better handling and drivability at highway speeds. Maybe other ratios, not sure. Ans as we know there are other companies out there.

.

[72projectbird]

I run the IROC box. Its very tight, a little heavy and stiff, and really responsive. Cant beat it for the price!

Very easy swap. They bolt in like any other box. You'll need to change the rag joint to adapt the box to your stock column, and the fittings for the power steering hose are metric. You can either get metric to standard adapters to fit your stock hose on, or take the threaded fitting out of your stock PS pump and thread in a metric fitting from a newer pump. They'll thread right in and allow you to used the PS hose from an IROC.