I have a Steeroids set up on the 65. I like it but the steering is a little quicker than I than I would like. Right now it is 2 1/2 turns lock to lock. My undretsanding they use a "sport" rack. Anyone running a standard rack with 2 3/4-3 turns lock to lock? Impressions?
Another Steeroids Question
- Thread starter Sky65
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mrvette
Phantom of the Opera
Yes, but it's on my own install done a year before Steeroids came out, same thing, essentially 2.7 turns, feels great to me.....I use a '88-91 vette serp setup/pump, and with the '72 valving that came with the car....
I don't see that small variation to be anything to worry over one way or another...
but nothing is stock about my car either, in that dept. the wheels are tires are obviously the most important, and they are 17x9.5 '89 vette wheels...
255 /50/17 up front and 275/50 in the rear...
:beer:
I don't see that small variation to be anything to worry over one way or another...
but nothing is stock about my car either, in that dept. the wheels are tires are obviously the most important, and they are 17x9.5 '89 vette wheels...
255 /50/17 up front and 275/50 in the rear...
:beer:
On Saginaw rack and pinion gears built between 1988 and 1998 there were two different pinion ratios. Standard model gears had 2.1 inches of rack travel for each revolution of the pinion. The other R&P gears were sport models with 2.4 inches of travel for each revolution of the pinion (handling, sport, W56, Uplevel, etc). So you can take a ruler and have someone rotate the pinion (steering wheel) one complete revolution. Carefully measure how far the tie rod moves. That will tell you if you have a standard model (2.1 inches per rev) or a sport model gear that moves further-faster (2.4 inches per rev).
Now you also have to be aware that these same gears could have two different amounts of total travel. They could have 6 inches of total travel. Or they could have 5.7 inches of total travel. These gears can be identified by the total number of pinion revolutions or by just measuring the rack travel as the pinion is rotated full lock to full lock. Now 0.3 inches (just a hair more than 1/4 inch) doesn't sound like much. But it could make the difference of your tires hitting the fenders, frame, etc at full lock or not. So to be safe it would be best to find a R&P with the same total travel as the one you currently have in your Vette.
The standard model gears will have 2.7 to 2.9 number of revolutions of the pinion (or steering wheel) from full lock to full lock (depending upon the amount of total travel built into the gear). The sport models will have 2.3 to 2.5 total turns full lock to full lock.
So as you state your rack and pinion gear has exactly 2.5 revolutions full lock to full lock. This would mean that you have a sport model gear with 2.4 inches of travel per revolution. This would also mean that you also have 6 inches of total rack travel.
So you will want to find a standard model R&P gear from a 1988 through 1994 Cavaliar, Sunbird, Skyhawk, Skylark, Grand Am, Corsica, Beretta, or Achieva. These would be slower with 2.7 (5.7 inches of total travel) to 2.9 revolutions lock to lock (with 6.0 inches of travel).
I could be wrong but I think that all models of Saginaw R&P gears were fast ratio after 1994 so stay away from them.
Jim
Now you also have to be aware that these same gears could have two different amounts of total travel. They could have 6 inches of total travel. Or they could have 5.7 inches of total travel. These gears can be identified by the total number of pinion revolutions or by just measuring the rack travel as the pinion is rotated full lock to full lock. Now 0.3 inches (just a hair more than 1/4 inch) doesn't sound like much. But it could make the difference of your tires hitting the fenders, frame, etc at full lock or not. So to be safe it would be best to find a R&P with the same total travel as the one you currently have in your Vette.
The standard model gears will have 2.7 to 2.9 number of revolutions of the pinion (or steering wheel) from full lock to full lock (depending upon the amount of total travel built into the gear). The sport models will have 2.3 to 2.5 total turns full lock to full lock.
So as you state your rack and pinion gear has exactly 2.5 revolutions full lock to full lock. This would mean that you have a sport model gear with 2.4 inches of travel per revolution. This would also mean that you also have 6 inches of total rack travel.
So you will want to find a standard model R&P gear from a 1988 through 1994 Cavaliar, Sunbird, Skyhawk, Skylark, Grand Am, Corsica, Beretta, or Achieva. These would be slower with 2.7 (5.7 inches of total travel) to 2.9 revolutions lock to lock (with 6.0 inches of travel).
I could be wrong but I think that all models of Saginaw R&P gears were fast ratio after 1994 so stay away from them.
Jim
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mrvette
Phantom of the Opera
Jim, why did they bother changing all that around, for such a minor variation??
5.7" travel vs 6" for instance....why bother??
:drink:
5.7" travel vs 6" for instance....why bother??
:drink:
I know that it sounds like an insignificant amount (it does calculate out to a 14% increase in rate of travel). But from 1988 through 1994 the ride and handling engineers at the car divisions thought that there was enough difference to justify sport versus standard steering in their vehicles. As I mentioned after 1994 all the GM gears were fast ratio.
BTW, it is not really correct to call a R&P gear fast or slow ratio. A R&P gear translates rotational motion of the steering wheel to linear motion of the rack. So the correct engineering term is to call it the C-factor. A slow C-factor of 2.1 inches per pinion revolution (or 53.48 mm per rev) or a fast C-factor of 2.4 inches per pinion revolution (or 61.75 mm per rev.)
The overall vehicle steering ratio is the amount of travel of the steering wheel for the equivalent travel of the front road wheels (i.e. 14:1).
Jim
BTW, it is not really correct to call a R&P gear fast or slow ratio. A R&P gear translates rotational motion of the steering wheel to linear motion of the rack. So the correct engineering term is to call it the C-factor. A slow C-factor of 2.1 inches per pinion revolution (or 53.48 mm per rev) or a fast C-factor of 2.4 inches per pinion revolution (or 61.75 mm per rev.)
The overall vehicle steering ratio is the amount of travel of the steering wheel for the equivalent travel of the front road wheels (i.e. 14:1).
Jim
Check to see if your rod ends are mounted in the front or rear holes in the steering arm. If mounted in the front (power steering) hole, you could "slow" it down by mounting in the rear (manual steering).
Thanks Guys.
I had already checked the total rack travel. I have 6.1". I want to keep that because I have no clearance issues and the turning radius is already less than stock. I don't want to reduce it any more. I thought of moving the tie rods to the outer, manual, positions but that wouldn't that reduce the turning radius?
mrvette
I am running the same size tires on 17X8 front and 17X9 rear wheels. Not much about my car is stock either! :bounce:
Jim
Do you know a specific year/model that I could go to my FLAPS and order and get a 2.7-3.0 lock to lock with 6.1" of travel?
Thanks
Tom
I had already checked the total rack travel. I have 6.1". I want to keep that because I have no clearance issues and the turning radius is already less than stock. I don't want to reduce it any more. I thought of moving the tie rods to the outer, manual, positions but that wouldn't that reduce the turning radius?
mrvette
I am running the same size tires on 17X8 front and 17X9 rear wheels. Not much about my car is stock either! :bounce:
Jim
Do you know a specific year/model that I could go to my FLAPS and order and get a 2.7-3.0 lock to lock with 6.1" of travel?
Thanks
Tom
mrvette
Phantom of the Opera
Ain't hot rodding GRAND?? fun challenge to me, but I don't have tons of bux to toss after some concept, so for me, it's junkyards all the way....
like for the last couple daze, mornings out hunting parts for another project....
:rofl::rofl:
Yeah, I'm a budget roddder myself. I bought the Steeroids used, 6 months, and paid less than half new price! I don't have a welder....yet....so fabrication for me is limited.
I have posted the table of General Motors slow c-factor center take-off power rack & pinion gears over at the Corvettefaq.com websight. Here is the address:
http://jimshea.corvettefaq.com/wp-content/uploads/2009/10/1988-94cto53rpgears.xls
If anyone is interested in the fast c-factor cto R&P gears, here is the address:
http://jimshea.corvettefaq.com/wp-content/uploads/2009/10/1988-98cto62rpgears.xls
Jim
http://jimshea.corvettefaq.com/wp-content/uploads/2009/10/1988-94cto53rpgears.xls
If anyone is interested in the fast c-factor cto R&P gears, here is the address:
http://jimshea.corvettefaq.com/wp-content/uploads/2009/10/1988-98cto62rpgears.xls
Jim
Jim - Can the T-bars be interchanged?
JimL82. Thanks for the details.
I assume the c-factor effects the mechanical advantage. The semi common complaint with the R&P conversion is a lack of road feel. I think you've commented before that the torsion bar size is a prime causal factor. Now that we know where the bigger bars were originally used, is there some external indicator of what size bar is in a specific ass'y? In the rebuilt world things may not be as controlled as they were at the OEM.
If we have a desire to increase the feel is the T-bar something that can be changed out or do we just have to try and buy the correct assy?
Grampy
JimL82. Thanks for the details.
I assume the c-factor effects the mechanical advantage. The semi common complaint with the R&P conversion is a lack of road feel. I think you've commented before that the torsion bar size is a prime causal factor. Now that we know where the bigger bars were originally used, is there some external indicator of what size bar is in a specific ass'y? In the rebuilt world things may not be as controlled as they were at the OEM.
If we have a desire to increase the feel is the T-bar something that can be changed out or do we just have to try and buy the correct assy?
Grampy
Just for comparison, C4 to C3:
C3
3.75 turns lock to lock
Total travel 7.6 inches (2 in/rev)
Steering arm centerline to tie rod: 7 inches (manual) and 8 inches (power)
C4
2.6 turns lock to lock
Total travel 4.7 inches (1.8 in/rev)
Steering arm centerline to tie rod: 5 inches
Compare (From Jim's chart)
1988-94 GM Slow Ratio
2.9 turns x 53.48mm = 6.15 inches
1988-94 GM Fast Ratio
2.5 turns x 61.75mm = 6.07 inches
I can see now why Steeroids does not have the turning radius that a Corvette gear does.
Jim, great information. Thank-you
C3
3.75 turns lock to lock
Total travel 7.6 inches (2 in/rev)
Steering arm centerline to tie rod: 7 inches (manual) and 8 inches (power)
C4
2.6 turns lock to lock
Total travel 4.7 inches (1.8 in/rev)
Steering arm centerline to tie rod: 5 inches
Compare (From Jim's chart)
1988-94 GM Slow Ratio
2.9 turns x 53.48mm = 6.15 inches
1988-94 GM Fast Ratio
2.5 turns x 61.75mm = 6.07 inches
I can see now why Steeroids does not have the turning radius that a Corvette gear does.
Jim, great information. Thank-you
You cannot determine the T-bar size without tearing down the gear and then disassembling the valve. I do not know if you can disassemble the valve and have any chance of getting things back correctly together again. (During the manufacturing process the valve was originally set in a machine where it was hydraulically balanced and pinned.)
I will try and contact one of the retired Saginaw engineers and find out if it is possible.
Jim
I will try and contact one of the retired Saginaw engineers and find out if it is possible.
Jim
mrvette
Phantom of the Opera
You are correct, it doesn't...but it's still tighter than a '87, C4....I found that out making a certain U turn into a gas station up north....
:noworry:
Twin_Turbo
Der Maulwurf
- Joined
- Mar 5, 2008
- Messages
- 7,579
No way the steeroids junk is tighter than a C4 rack. A C4 rack is very right and has a good feedback...not overassisted at all. The steeroids...well...it's junk...that's all it is. If yours wasn't tight it was most likely worn.
mrvette
Phantom of the Opera
Nope, it was fresh rebuilt, the OEM leaked, so replaced, I was talking of steering radius of the car with wheels all the way over to the left, as in taking a U turn the 87 always needed about 4' more road than the curb allowed, I had to get used to going into the middle of the intersection as a result....
this shark with the stock steering would leave 4' off the same curb, for about 8-10' tighter turning....dunno why, just was...I attributed it to the wider 16" tires...and even with the wider C4 rims on the front of the '72 shark, it was still a tighter/narrower radius....AFTER I restricted the radius a bit....which actually worked out fine when the rack came along some 6 years later....
I just talked to my engineering retiree about valves. He says to not even think about disassembling a valve and trying to put it back together (regardless as to how careful you are in doing it!)
There is a hardened pin that holds the t-bar to the input shaft. Once the pin is driven out of the valve you can never get it back in place so that the pinned connection will "live" without loosening.
Jim
There is a hardened pin that holds the t-bar to the input shaft. Once the pin is driven out of the valve you can never get it back in place so that the pinned connection will "live" without loosening.
Jim