Steering ratio difference? - Suspension and Brake Forum

Forum Post / Reply
You must log in before you can post or reply to messages.
Steering ratio difference?
Friday, April 27, 2012 2:09 PM
Something I've never noticed before was that there are 2 different steering ratios available for our cars stock(at least the sunfire i know does)

15.7:1 for the GTs and 1SC PEG package(03+)
14.7:1 for the SE/sedans and 1SA/1SV & 1SB PEG(03+)

Resulting in an end to end steering of 2.83 turns for the 15.7:1 and and 2.66 turns for the 14.7:1

What does this actually mean?
Is the steering tigher on the 14.7:1 since you only need 2.66 turns to go lock to lock(less)? Or does it just have less of a turning radius because of different parts that lowers that number? I would think that the tighter steering would be on the GTs and 1SC package.

What is the actual difference in terms of which one will turn your tire the most, with the least rotations of the steering wheel?
Is it the rack that makes the difference?

If its even possible, what would happen if you put a 14.7:1(whatever parts necessary) on a GT with the 205 width tires, rather than the 195 tires(I only ask because stock they would've never been mated together)? Does the tires or tire width even matter?

Ive never really messed with steering components other than direct in and out parts that are exact stock replacements.

Re: Steering ratio difference?
Friday, April 27, 2012 3:49 PM
The 14.7 ratio was the standard rack on the 3rd Gen Cavalier Z24 models. The difference between it and the 15.7 ratio rack is only the number of turns from lock to lock. The turning circle and distance the wheels travel is the same. The 14.7 will turn the wheels right or left faster than the 15.7. I believe the only difference between cars equipped with each is the rack itself. The tires have no bearing on the mechanical function. I have a 14.7 rack I plan to retrofit my 'vert with in my next life. - MarkC


markc50...formerly 1of7627 but that login doesn't work anymore.
Re: Steering ratio difference?
Friday, April 27, 2012 4:28 PM
That answers most of my questions, but if this is correct then, why would they give the 14.7:1 rack to the Z24 cavalier and the 15.7 to the Sunfire GT?
There has to be a reason, because the base model Sunfires, and sedans got the 14.7:1. Why would they put the lesser of the 2 in the GT?
Re: Steering ratio difference?
Friday, April 27, 2012 4:29 PM
I checked the cavaliers and I think you might be misinformed Mark. the Z24s got the 15.7:1(at least in 02)

Cite: http://www.new-cars.com/2002/chevrolet/chevrolet-cavalier-specifications.html
Re: Steering ratio difference?
Monday, April 30, 2012 6:34 AM
The z24 is supposed to have 2.5 turns lock to lock, base model is 3.
Re: Steering ratio difference?
Monday, April 30, 2012 7:10 PM
thats what i said lol. its actually 2.83 and 2.66. Duralast lists 2.75 and 2.5 or 2.6 for stock replacement and are listed as FE1(soft ride) and FE2(ride and handling) suspensions.

That was part of my initial question. Both car have the same turning radius(uturn) but the racks change the lock to lock. So why would you have to steer the GT/z24 cars MORE than the base models for the same amount of turning? shouldn't it be the other way around? More responsive/tighter steering in the better car?

This is actually a semi active discussion in another section. http://www.j-body.org/forums/read.php?f=2&i=476425&t=476388#476425 heres the link if you want to participate because I don't really want to have to double post everything.
At this point idk what is 'right or wrong' im still just fishing for information and opinions. Its coming across though as everyone who responded so far 'knows' the answer, or at least has the 'right' information, or thinks it doesn't matter.
But nobody can actually explain anything helpful to my initial questions(which is my goal lol i want to learn the difference, and why its different. not just know that there is one. And I'm not retarded lol at least i didn't think so before I brought this topic up. I'm just amazed that I searched and nobody has ever brought this up, and even a few of the guys ive talked to who've been around awhile didn't even know there were 2 racks/ratios
Re: Steering ratio difference?
Tuesday, May 01, 2012 9:59 AM
15.7:1 is the faster ratio.

for every 1 turn of the steering wheel, the pinion gear will turn 15.7 times.

in other words, the pinion gear will travel a farther distance on the rack per turn with the 15.7 resulting in a lower number of turns lock to lock and ultimately quicker steering.



Re: Steering ratio difference?
Tuesday, May 01, 2012 10:51 AM
strat81 is right. I was backwards in my description. I've always known there were two different racks as the 3rd Gen Z24 brochures mentioned the coupes firmer suspension and faster steering. (The Z24 convertibles didn't get the same thing.) I apologize for the error. - MarkC


markc50...formerly 1of7627 but that login doesn't work anymore.
Re: Steering ratio difference?
Tuesday, May 01, 2012 12:20 PM
Cadillacin wrote:Something I've never noticed before was that there are 2 different steering ratios available for our cars stock(at least the sunfire i know does)

15.7:1 for the GTs and 1SC PEG package(03+)
14.7:1 for the SE/sedans and 1SA/1SV & 1SB PEG(03+)

Resulting in an end to end steering of 2.83 turns for the 15.7:1 and and 2.66 turns for the 14.7:1

What does this actually mean?
Is the steering tigher on the 14.7:1 since you only need 2.66 turns to go lock to lock(less)? Or does it just have less of a turning radius because of different parts that lowers that number? I would think that the tighter steering would be on the GTs and 1SC package.

What is the actual difference in terms of which one will turn your tire the most, with the least rotations of the steering wheel?
Is it the rack that makes the difference?

If its even possible, what would happen if you put a 14.7:1(whatever parts necessary) on a GT with the 205 width tires, rather than the 195 tires(I only ask because stock they would've never been mated together)? Does the tires or tire width even matter?

Ive never really messed with steering components other than direct in and out parts that are exact stock replacements.


Interesting topic.
For staters, going by my old GM records the 1995-1997 Js all had the the slower reacting 15.7:1 .
This is a quote from 1997 Cavalier...
Quote:

Power-assisted rack-and-pinion steering (15.7:1 ratio) is standard on all Cavalier models. Rack-and-pinion steering provides precise control under demanding driving conditions. The steering rack is mounted on the front suspension cradle to provide a solid feel while improving isolation from road disturbances.


1995-1997 Specs were:
Quote:

Type Power Rack-and-Pinion
--------------------------------------------------------------------------------
Ratio (overall) 15.7:1
--------------------------------------------------------------------------------
Turns stop-to-stop 2.88
--------------------------------------------------------------------------------
Turning diameter curb-to-curb (ft.) 35.6
--------------------------------------------------------------------------------
Turning diameter wall-to-wall (ft.) 37.2


It wasn't until 1998 GM decided to put the faster 14.7:1 on their base model all the way to 2005. Also the specs in general changed overall too.
Quote:

Steering
--------------------------------------------------------------------------------
Type Power Rack-and-Pinion
--------------------------------------------------------------------------------
Ratio (overall) 14.7:1, 15.7:1 (uplevel)
--------------------------------------------------------------------------------
Turns stop-to-stop 2.6, 2.8 (uplevel)
--------------------------------------------------------------------------------
Turning diameter curb-to-curb (ft.) 35.6


Now why would GM decided to put the slower steering on the FE2 cars? Well it's GM!
Seriously, although on paper it does look better to have faster 14.7:1, BUT when it comes to real world. The side to side transitions as the car settles will be more linear rather than abrupt, in other words, less slop. I say this because on the these cars, body roll is VERY apparent even with the FE2 suspension. So with the quicker steering... body roll will be even more noticeable as the steering reacts like a "knee-jerk" to your input. In a "performance oriented" car (Z24, GT, LS Sport) you do not want that at all. Now if GM really wanted to do it right and tie in the quick 14.7:1 ratio steering with stiffer shocks and at least a 26mm Front stabilizer bar with 25mm rear. Now the side to side transition or any transition is quelled with beefier tuning done by what I just mentioned.

Now, I used to have the SE and still the GT Sunfires, and I did notice immediately that the SE had heftier steering effort and it was tad quicker in response. But I remember reading back in the day that the GTs had a "variable effort" unit while the SE had a conventional power steering unit. What that means at parking lot speeds it is giving more assist, while on the road, it gives less assist stiffening up the steering. I've searched everywhere for that bit of info and I could not find it. It maybe in my old brochures.

You have to look at the bright side, if your power steering fails, you will be putting less effort at parking speeds. And your power steering pump doesn't have to work as hard either. lol



>>>For Sale? Clicky!<<<
-----The orginal Mr.Goodwrench on the JBO since 11/99-----

Re: Steering ratio difference?
Tuesday, May 01, 2012 12:26 PM
I looked up on how GM did the Cobalt's tuning and well... they did what I was suggesting. ^^
From GM on a 2009 Cobalt...

Chassis/Suspension
LS & LT
SS

Front:
independent strut-type suspension with stabilizer bar
MacPherson independent strut-type with direct acting, 24mm solid stabilizer bar

Rear:
semi-independent torsion beam with stabilizer bar
semi-independent torsion beam with montoube gas shocks; 24mm solid stabilizer bar

Steering type:
electric, speed-sensitive, variable-assist rack-and-pinion
electric, power-assisted variable-speed rack-and-pinion

Steering ratio:
16.63:1
14.8:1 (variable)

Steering wheel turns, lock-to-lock:
3.6
2.75

Turning circle, curb-to-curb (ft / m):
37.4 / 11.4
39.4 / 12





>>>For Sale? Clicky!<<<
-----The orginal Mr.Goodwrench on the JBO since 11/99-----

Re: Steering ratio difference?
Tuesday, May 01, 2012 2:19 PM
Thank you so much. I'm seriously beyond ecstatic to see somebody actually able to finally explain this to me so that I can understand it.

Re: Steering ratio difference?
Tuesday, May 01, 2012 7:51 PM
Mr.Goodwrench-G.T. wrote:I looked up on how GM did the Cobalt's tuning and well... they did what I was suggesting. ^^
From GM on a 2009 Cobalt...

Chassis/Suspension
LS & LT
SS

Front:
independent strut-type suspension with stabilizer bar
MacPherson independent strut-type with direct acting, 24mm solid stabilizer bar

Rear:
semi-independent torsion beam with stabilizer bar
semi-independent torsion beam with montoube gas shocks; 24mm solid stabilizer bar

Steering type:
electric, speed-sensitive, variable-assist rack-and-pinion
electric, power-assisted variable-speed rack-and-pinion

Steering ratio:
16.63:1
14.8:1 (variable)

Steering wheel turns, lock-to-lock:
3.6
2.75

Turning circle, curb-to-curb (ft / m):
37.4 / 11.4
39.4 / 12


Im not sure if this is for all cobalts or if GM changed during differant years, but I've driven a 07 LS and a 05 LS and the 05 had TONS of slop in the steering, I found I had to constantly move the steering wheel like an inch back and forth on the highway. The 07 was not too bad though, My old 06 SS had amazing steering and loved the way it handled.


2000 Cavalier Z24 5spd - Intake, Dynomax muffler, Hawk Pads, Powerslot rotors, Sportlines/Koni reds, Neon Coil, MSD 8.5 Wires - **SOLD**
2014 Kia Forte Koup SX 6spd - 1.6L Turbo - My new car
2015 Kia Sorento EX V6 AWD - Wifes Car

Forum Post / Reply
You must log in before you can post or reply to messages.

 

Start New Topic Advanced Search