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High speed stability with 3rd gen steering box swap?

3K views 9 replies 4 participants last post by  Greg O 
#1 ·
I have done a ton of reading and see that lots of people have done the 3rd gen swap. My question is about high speed stability with the quick ratio box?

Today i have the "pinkie steer" factory power steering. Now that I am going 115 at the top end of the track I am looking for stability. With the easy steering a little bump in the track quickly turns into a sway. My first thought is to go to a factory manual box. It's slower ratio means that if I hit a bump and move the wheel an inch or two it unsettles the car less.

The 3rd gen box requires more effor to move, but a 1" move will "turn" the car a lot more right? Just wondering how that will be on the top end.
 
#3 ·
The fastest ratio available in Gen III Camaros were power steering gears with 12.4:1 gear sets. If you are concerned that it might be too fast, there was an intermediate fast ratio gear with a 14:1 ratio during the Gen III years that might be a better fit for your race car.

I have a listing of all these 14:1 power steering gears that were used in production in the Gen III Camaros.
1982, 83, 84 Level IV suspension 14:1 ratio 27 inch-lb valve effort 70 degree output
1985 Level II suspension 14:1 ratio 27 inch-lb valve effort 70 degree output
1986 thru 93 Base Camaro 14:1 ratio 23 inch-lb valve effort 70 degree output

Now the problem is whether or not the aftermarket rebuilders have these exact gears available. I sometimes have doubts that the rebuilders take a lot of care in trying to match the actual production gears. (I shouldn't just complain about the aftermarket people, I am sure that the General Motors Service Parts people restrict the actual number of gear boxes that they make available as well.)

I think the best thing to do is to actually check the ratio of a gear that you might purchase from a rebuilder. Go out and purchase a cheap plastic protractor and carefully tape it to the output shaft of a new remanufactured gear. Carefully measure the total sweep of the output (pitman) shaft. The total sweep should be 70 degrees. Now measure the rotation of the input shaft as you turn the gear from full lock to full lock. You should rotate the input shaft 2 3/4 turns (actually 2.7222 turns). That would be a 14:1 ratio.

BTW here is the calculation for steering gear ratio:

Pitman sweep (70 degrees) X gear ratio (14) / 360 = input shaft rotation
70 X 980/360 = 2.7222

Now the bad news. As much as you can actually measure the sweep and ratio, you will not be able to check the valve effort built into the gear. Certainly the effort should not be "pinky finger" light. A 23 or 27 inch-lb valve should provide moderate steering effort. I don't know how to quantify it any better than to say moderate. Gen I gears had valves that were in the 18 inch-lb range. Valves in the 23 to 27 inch-lb range should feel to have significantly higher effort.

There was a Gen III power gear for the Berlinetta (1982-85) that had a variable ratio (15:1 on center and 13:1 near full lock.) Unfortunately, this gear box went back to the "pinky finger" (17 inch-lb) effort found in the early Gen I years. So I don't think your really want this one.

Good luck,
Jim
 
#4 ·
Thanks for the valuable info. I see your location....did you work for Saginaw by chance?

I did some looking at O'rielys as they cary the Cardone brand. It looks like the 27-6550 is the 12.4 high performance one. That is the one most people go for but they are looking for handling feel and performance. i am more straight line.

The other part number they list is a 27-6530 for the "soft ride" option on the same year Camaro. Should that be the 14:1? I dont see a separate part number for the 27 vs. 23 inch-lb 14:1 box looking at the different years. they may have combined the part numbers. I think i will go for the 14:1
 
#5 ·
Yes, I worked in the engineering department (steering section) for 39 years before retiring in 2001.

I don't know what Cardone calls their various Camaro gears. I am not sure what "soft ride" means. If it is the Berlinetta gear then the steering may feel very light. (But you won't know that until you bolt the gear into your Camaro. I would order what you think is the 14:1 gear and check the ratio by rotating the input shaft and measuring the output as described.

Wish that I was of more help,
Jim
 
#7 · (Edited)
I'm pretty sure a 1979 Z/28 used a stiff feel 14 to 1 box, that was the first year GM stopped offering variable ratio steering.
If you want to get a couple more MPH at the end of a quarter mile, correct the bumpsteer. When the front comes up at speed, the wheels toe-out.
 
#8 ·
Man this stuff will drive you nuts when dealing with the aftermarket. i looked at every different 1982 Camaro part number at O'Rielly's to see if there was a separate part number for a Berlinetta and there is not. Cardone 27-6530 is the part listed for all 82 Camaros AND the 79 Camaro AND the 85 Z/28 without the special suspension. So i guess it is a bit of pot luck as to what you might get in the box. Might be the VR 'pinky steer' berlineta box or the one i want...the 14:1 higher effort piece. i guess the only way to be sure I get a stiff feel box is to get the special suspension piece. It is 27-6550.
 
#9 ·
I would contact a rebuilder & get specifically what you want. I have concerns a Cardine box would actually be what the listing says it is.
I would buy a box from AGR, they make other ratios than 12.7 with stiff valving if you contact them. Also a 12.7 box can be slowed down by using a short 5.25" pitman arm, & longer outer steering arms will slow it more. I drove the One Lap Camaro 155 mph at Road America last year with great stability & it has the fast ratio box with fastest combo of steering arms. I do think for a drag only Camaro slowing the steering with the short pitman is a good plan.
 
#10 ·
Getting Lee's to rebuild it is $300+ as is the AGR box. You can get a Cardone piece for $116. I guess it is the balance of "you get what you pay for" but i can't see paying triple. I appreciate the feedback on the 155 MPH with the high ratio box. I think I will go that route. If i am unhappy with it i'll be much happier if i only invested $120 vs. $350.
 
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