818 turning radius

[Buzz Skyline]

The turning radius on my 818 is huge. Who has tried to improve the turn radius of their cars? What did you do and how did it turn out?

[AZPete]

Rather than measuring the turning radius, I've been looking at the steering wheel turns from lock to lock. Jacked up with no wheels I get 2 1/2 turns lock-to-lock. With wheels & tires, I get 2.1 turns.
Anyone know the lock-to-lock for a stock WRX? (our standard?)
Anyone know the 818 lock-to-lock with 215/40/17 on 8", 40mm offset wheels? (FFR recommended max)

I have 215/45/17 on 8", 35mm offset wheels as listed in early manual, later revised to 215/40/17.
More info on lock-to-lock with no wheels, various tire sizes and offsets would be useful to many. Assume front alignment done for street.

[Bob_n_Cincy]

Rather than measuring the turning radius, I've been looking at the steering wheel turns from lock to lock. Jacked up with no wheels I get 2 1/2 turns lock-to-lock. With wheels & tires, I get 2.1 turns.
Anyone know the lock-to-lock for a stock WRX? (our standard?)
Anyone know the 818 lock-to-lock with 215/40/17 on 8", 40mm offset wheels? (FFR recommended max)

I have 215/45/17 on 8", 35mm offset wheels as listed in early manual, later revised to 215/40/17.
More info on lock-to-lock with no wheels, various tire sizes and offsets would be useful to many. Assume front alignment done for street.

Hi Pete,
My 2 donors, 06 impreza wagon and 04 forester XT.
Lower control arms mounted in wagon holes.
Current wheels 16x6.5 55et OEM
Current tires 225x45/16 toyo R888 23.8" diameter
Both cars 3 turns lock to lock with or without tires. No rubbing
Camber -2.5* caster +2.5* toe 0.
Firewall clearance was about 3/4" a while ago. But I have played with alignment since then.

You can see in the video where I go to steering rack lock right after my spin. The wheel in up-side-down.
Bob


https://youtu.be/GM-tN_g2HIA

[AZPete]

Good info, Bob. It's interesting you're getting 3 turns.

[Mechie3]

Different year WRX had different steering ratios. The base impreza was different too IIRC.

[Buzz Skyline]

Bob, I am utterly mystified. We have the same size tires and wheels, but my car has a miserable turn radius. The only difference is that you have '06 wagon donor control arms and I have '02 sedan arms. Could that be the key? If so, I will gladly track down a pair of wagon arms.

[Bob_n_Cincy]

Bob, I am utterly mystified. We have the same size tires and wheels, but my car has a miserable turn radius. The only difference is that you have '06 wagon donor control arms and I have '02 sedan arms. Could that be the key? If so, I will gladly track down a pair of wagon arms.

Buzz
The length of the LCA has nothing to do with the turning radius.
Only 3 factors determine turning radius.
#1 travel distance of steering rack
#2 length of front knuckle steering arm.
#3 Vehicle wheel base.

This chart shows what you should be getting. 17.7 feet.

http://thefactoryfiveforum.com/attachment.php?attachmentid=41730&d=1430965419

I believe that AWD and FWD vehicles typically have higher turning radius because the CV joint is the limiting factor.

Edit:
From the info above you can calculate that the Non turbo is a 16.66:1 ratio. The WRX is 15:1 ratio. The STI is 15.24:1
Bob

[Bob_n_Cincy]

Buzz
On some of the early 818 the steering rack was not in the middle of the car. You have to put your steering rack in the exact middle of travel and then adjust your toe on each wheel without moving the steering rack. If you don't do that, you will get poor turning radius in one direction.
Bob

[Buzz Skyline]

Thanks, Bob, I'll check that. But last time I worked on it, the limiting factor was the tires jamming against the frame when the steering was turned to the limit in either direction, and it seemed identical on both sides. So I can't see how it could be a misaligned rack. Still worth checking.

The LCA could be the issue if it is longer and allows more clearance between the tire and frame. It's not that it changes the turn radius per se, but It would allow full range of motion if it holds the wheel farther out.

BTW, did you have to trim the threads on your upper control arms to achieve that much camber?

[Bob_n_Cincy]

Thanks, Bob, I'll check that. But last time I worked on it, the limiting factor was the tires jamming against the frame when the steering was turned to the limit in either direction, and it seemed identical on both sides. So I can't see how it could be a miaaligned rack. Still worth checking.

The LCA could be the issue if it is longer and allows more clearance between the tire and frame. It's not that it changes the turn radius per se, but It would allow full range of motion if it holds the wheel farther out.

BTW, did you have to trim the threads on your upper control arms to achieve that much camher?

Buzz
You did not explain that you poor turning radius was caused by rubbing tires. I thought you were just hitting steering lock. Post tire and rim specs and a picture of your front suspension so we can figure out why they are rubbing.

Yes, I trimmed about an 3/4" off each of the longer upper ball joint mounting studs.
Bob

[Buzz Skyline]

I should have been more clear, but think most people who are having turn radius problems are dealing with frame interference. I currently have the same wheel and tire set up as you, Bob. I can't take pics now because I have temporarily replaced the front wheels with some steelies with 175 width tires.

I'm thinking of going with 215s and perhaps some spacers to move the wheels farther out, but I will have to take a few measurements before I do it.

[Buzz Skyline]

There's probably a great reason not to do this, but what if I mount the sedan control arms in the wagon control arm positions? That would both increase tire clearance and provide more camber.

Has anyone tried it? What could be the problem with doing it?

[STiPWRD]

There's probably a great reason not to do this, but what if I mount the sedan control arms in the wagon control arm positions? That would both increase tire clearance and provide more camber.

Has anyone tried it? What could be the problem with doing it?
You may end up putting too much strain on the bushings if the sedan arms don't line up well with the wagon holes.

[Bob_n_Cincy]

There's probably a great reason not to do this, but what if I mount the sedan control arms in the wagon control arm positions? That would both increase tire clearance and provide more camber.

Has anyone tried it? What could be the problem with doing it?

Buzz
One of my cars is like that now.
Two problems:
#1 Shock is to short. Not enough travel in the extend.
#2 Steering rack is to short. Not enough thread engagement on tie rods.

Take some pictures anyway so I can look at all the "A" arm adjustments and rear bushing mounting.

Spacers will move the tire out and increase the swing radius. Causing a worse problem hitting the firewall. Imagine putting a 1 foot wheel spacer in. The tire would hit the door.

Bob

[xxguitarist]

There's probably a great reason not to do this, but what if I mount the sedan control arms in the wagon control arm positions? That would both increase tire clearance and provide more camber.

Has anyone tried it? What could be the problem with doing it?

We were going to do this, but the stock steering endlinks would be over-extended. There's about 2 inches of thread, and we use almost as much as I'm willing with our aluminum arms in the sedan position.

[Bob_n_Cincy]

We were going to do this, but the stock steering endlinks would be over-extended. There's about 2 inches of thread, and we use almost as much as I'm willing with our aluminum arms in the sedan position.

Craig made me some adapters over a year ago.
Bob
41734

[STiPWRD]

As another point of reference, I've got almost too much thread on the steering end links with the 02 wrx rack and sti aluminum arms. The nut that locks the tie rod to the steering link has about 4-5 threads left on the inside of the link for adjusting toe-in.

[Pearldrummer7]

Craig made me some adapters over a year ago.
Bob
41734

Oh that is so cool.

Does Craig sell these? ZDB, I need your help!

[Frank818]

Subscribing

[RM1SepEx]

Oh that is so cool.

Does Craig sell these? ZDB, I need your help!

We had to add those to only one side of the rack to equalize the bump steer on both sides when straight. Bob and I identified the problem looong ago. Our racks are offset to the left. I don't know what frame # had the frame change. We were told to just adjust our steering off center so that there would be enough threads engaged on the right side.

[Santiago]

I'd also like to know if Craig has plans to offer these.

Bob, what range of travel were you looking for in extension?

Best,
-j

[Bob_n_Cincy]

I'd also like to know if Craig has plans to offer these.

Bob, what range of travel were you looking for in extension?

Best,
-j

I only added one to the passenger end of my rack. I believe it was 20mm.
This does not change the travel of the steering rack. I my case it just made the center of the steering rack match the center of the car.

It also had the added benefit of giving me more thread engagement on the tie rods.
Bob

[Santiago]

Oops! I think I didn't make my question clear Bob. I was referring to the #1 problem you noted below regarding a loss of shock travel. I was curious how much you thought was "not enough" travel for the shock before you were tapped out in extension?

Best,
-j




Two problems:
#1 Shock is to short. Not enough travel in the extend.
#2 Steering rack is to short. Not enough thread engagement on tie rods.

Bob

[Bob_n_Cincy]

Oops! I think I didn't make my question clear Bob. I was referring to the #1 problem you noted below regarding a loss of shock travel. I was curious how much you thought was "not enough" travel for the shock before you were tapped out in extension?

Best,
-j

I have not measured this accurately.
But at normal ride height the standard shock travel is about 2" each way.
Using the wrong holes (wagon holes) you get 3" in bump and 1 inch in rebound. I suspect my inside wheel may be fully extend the shock during a hard turn.
To me, hitting the shock extension end stop is unacceptable.
Bob

[Buzz Skyline]

I'm sure you'd blow the shock pretty quick hitting the end stop like that. I wonder how hard (and expensive) it would be to find a suitable shock with the right length and travel, though.

Extending the reach of the steering rack doesn't seem like that difficult a problem to solve.

[Santiago]

Thanks Bob.

They do make shock extensions for the upper mount like these QA1 pieces (http://www.qa1.net/suspension/street-performance-racing-suspension-accessories/shock-mount-accessories/aluminum-shock-extensions). I'm not sure if they match the Koni thread, but if not we may know a guy who fabs up adapters... ;)

I know I've also seen whole separate shock eyes that have the extended length built into them as one solid piece. There are options here.

Best,
-j