Aftermarket Steering Rack?

[Scargo]

Has anyone looked into an aftermarket steering rack? I'm wondering whether they could be pounds lighter, have a quicker ratio or include provisions for a steering damper.
Seems like a steering damper on the stock unit would be needed. Is it in the kit?
Any recommendations?

[Erik W. Treves]

does not come with the kit and not sure why you would need one.

[Scargo]

I'm not positive I need one, but I have owned several Porsches, VWs and other cars/trucks that have them. I'd think that a car with a light front end and steering without power assist (to dampen and help control the wheels), might need one. I've had some horrible DTs from steering with a shot damper!

[Wayne Presley]

A steering dampener is a band aid for a poorly built/aligned car. The 818 does not need one.

[Scargo]

Just came across this from a Road and Track article (http://www.roadandtrack.com/first-drive-factory-five-racing-818-r-track-day). It might bolster my position/question/suggestion that the car might benefit from adding a steering damper.

They say, in the article, "This race-car thrill ride isn’t without compromise, however. On Gingerman’s occasionally ragged track surface, the Factory Five tramlines and hunts out imperfections with an alacrity that is something alarming. Kickback through the steering wheel can be violent. It should also go without saying that a mid-engined car with 43/57 weight distribution, a turbocharged engine, and a complete lack of power assistance or electronic driver enhancements must be treated with respect at all times. "

I have read that tramlining can be caused by weak or ineffective power steering. I do believe that a damper would help in this non-power steering design.
I really want to hear from FFR's engineers.

[Rasmus]

The texture of a road surface is what determines if a car will tramline. Tramlining can be magnified by a car alignment and tires. Neutral toe will see more movement. Toe out and you'll fight to keep the car on the road. Triple so if the toe out's in the rear. Certain tire tread patterns and some tire compounds will want to tramline more than others.

Ineffective power steering doesn't cause it. But boy would you get a workout if you had to fight it without power assist.

[metalmaker12]

Absolutely no need to dampen this steering IMO

[AZPete]

Scargo, you can keep the donor power steering with only a little money to extend the hoses. Build it as you want it.

[Scargo]

The texture of a road surface is what determines if a car will tramline. Tramlining can be magnified by a car alignment and tires. Neutral toe will see more movement. Toe out and you'll fight to keep the car on the road. Triple so if the toe out's in the rear. Certain tire tread patterns and some tire compounds will want to tramline more than others.

Ineffective power steering doesn't cause it. But boy would you get a workout if you had to fight it without power assist.

I agree with what you are saying as things that will magnify tramlining. I can cite several car owners who said fixing their power steering cured their tramlining issues when they had tried everything else to solve it.
Then, as I have stated, I have experienced severe shaking steering wheels and wheel balance related issues solved with a new damper. This was on my non-power steering cars. They use them on motorcycles.

[Xusia]

I will probably never own another motorcycle without a damper - regardless of how well the designers engineered it, and regardless of how well it's been set up . However, the steering dynamics of a motorcycle are completely different, and I'm not sure the reasons I'd want one on a motorcycle are valid for a car.

[visaliaman]

road and track mentioned the kit could benefit from a steering damper. i wonder if filling one side of the built in ps ram with hydraulic fluid and porting it to the other side the way the factory recommends but with proper hydraulic fittings and hose would effectively be a damper? varying the grade of fluid could affect the damping effect.

visaliaman

[Scargo]

We got way off my original questions and nobody has contributed towards those.
Which is: Anyone using an aftermarket rack and what ratio should I be looking for? I have read that the 818 steering is quick, yet many Subie people, especially if they autocross, get a faster ratio Q-rack (11:1), and swear by it. I, personally have not seen a need for a faster ratio with my road race STi. The Q-rack's price is ludicrous...

OK, I read that the STi ratio is 15:1 and the WRX is 16.5:1.
Found this 15:1 Flaming River rack (http://www.amazon.com/Flaming-River-FR1520-Manual-Mustang/dp/B003LVQZ4U/ref=sr_1_51?s=automotive&ie=UTF8&qid=1390921889&sr=1-51&keywords=Manual+Rack+and+Pinion) for $300.
This Southwest Speed unit for $325 (http://www.southwestspeed.com/?sec=view_part&id=835). Don't know the steering arm length so I don't know how it compares. Says, 2.50" MEANS WITH 1 REVOLUTION OF THE PINION, THE SHAFT MOVES 2.50"

[Bob_n_Cincy]

Measuring a rack and pinion as a "RATIO" like 15:1 does not make sense. I think this type of measurement goes back to steering gearbox that had arms on them.

Rack and pinion should be measured distance/revolution.
I don't know the Subaru value but it's pretty easy to measure.
Method #1: Rotate steering wheel one rev and measure distance rack moves.
Method #2: Count teeth on pinion gear. Measure length on rack of that many teeth.

Sweet Manufaacturing has rack from 1 7/8" per rev to 3" per rev
https://sweetmfg.biz/home.php?cat=1

Hope this helps
Bob

[Scargo]

I am back at this again, especially since I am actually working on the car. I just sent an email to Dennis of Palatov Motorsport (http://www.palatov.com/) to see if I can get somewhere with incorporating his GTS upright for the front suspension. It would lop off at least 22 pounds of unsprung weight! If you go with inboard shocks it would be even more.
I know there is interest in an aftermarket rack and pinion for the car. I feel like I am at a chicken or the egg stage on the front end.
I don't know how the stock WRX steering arm length compares to a Mustang II or the Palatov unit and whether or not the differences would have a significant impact on the steering ratio you might choose.

[Scargo]

Dennis just said he wanted some time to think about offering an adaptation of his GTS upright for the 818R. He said, "sounds like a project i might be interested in." Might not hurt for other interested parties to let him know that you would like to see it adapted.
Dennis Palatov, dp@palatov.com Suspension page. (http://www.palatov.com/products/suspension.html)

[Slatt]

Might not hurt for other interested parties to let him know that you would like to see it adapted.

Done. Thx.

[chikoo]

I have read that tramlining can be caused by weak or ineffective power steering.



The texture of a road surface is what determines if a car will tramline. Tramlining can be magnified by a car alignment and tires. Neutral toe will see more movement. Toe out and you'll fight to keep the car on the road. Triple so if the toe out's in the rear. Certain tire tread patterns and some tire compounds will want to tramline more than others.

Ineffective power steering doesn't cause it. But boy would you get a workout if you had to fight it without power assist.


I agree with what you are saying as things that will magnify tramlining. I can cite several car owners who said fixing their power steering cured their tramlining issues when they had tried everything else to solve it.


I came across this forum, and this post by Scargo when I was googling for tramlining and weak power steering.
Why was I googling this?

Well, it so happened that I have had been experiencing for the last 3 months or so a very bad case of tramlining, and the steering wheel being jerked from left to right as I go over the undulations on the back country road to my home. I had my alignment checked thrice, but it barely made any difference. As part of the alignment check, they even Ok'ed the control arms, bushings and tie rods. I also checked my tires which are bridgestone RE760 sports. They have 50% tread left. So I started thinking about changing my tires. Maybe the tires are just not keeping up as they get old. Then it so happened that I noticed a couple of spots of oil on the driveway. So I took my e46 330cic to my mechanic and he put it up on the rack, removed the belly cover, and found that the power steering hoses were weeping. So he goes ahead and replaces the hoses, and the belt.

Then as I drive back home, I notice none of the tramlining or the steering going left and right vigorously on the very same roads that I drive daily. Funny how it all disappeared right after fixing the power steering. This led me to arrive at a conclusion, as unbelievable as it sounds, and I had to google it to confirm if this is for real (or not).

so there you have it. Scargo, add me to your list of people who can confirm that a weak power steering does indeed lead to a bad case of tramlining. In other words, a good power steering fights the effects of tramlining for you, and keeping it from you having to fight it.

[Scargo]

Well, OK. I feel a bit flushed-faced, but perhaps it's from the scotch. I appreciate the affirmation.
I do think it is important to have a damper OR power steering in many circumstances, as combinations of tires and tread designs and grooves in the road can really wreak havoc on the steering. Perhaps in a perfect world it is not required. Just run slicks, because "race car"!

[Tamra]

I think most of the 818 platform's tramlining issue is due to bump steer problems, assuming your alignment is already correct. I'm sure power steering can help cover up some problems.

Based on our recent measurement of bump steer problems on this car (about 3/4" of toe in at 2" of travel), I imagine a lot of 818S owners are experiencing extreme toe changes under bump travel.

The resulting alignment change wouldn't be present at static ride height, so your alignment shop would probably say you are fine... but then you hit a bump, and your alignment is nothing like it was, resulting in severe toe changes and tramlining.

We are running 500lb springs on the front of our 818, so it impacts us less due to the fact that we are getting less travel due to the stiffer springs. But if you are running softer springs, I imagine it would be amplified.

The 818R manual has a bump steer fix included, but nothing is mentioned in the regular manual.

[matteo92065]

I think most of the 818 platform's tramlining issue is due to bump steer problems, assuming your alignment is already correct. I'm sure power steering can help cover up some problems.

Based on our recent measurement of bump steer problems on this car (about 3/4" of toe in at 2" of travel), I imagine a lot of 818S owners are experiencing extreme toe changes under bump travel. ....l.

I definitely have bump steer. Supper annoying, but controllable. On roads that I travel frequently, I know all the spots (bumps/dips/manhole covers) where I will have to be ready to take actions to stay in my own lane.

[RetroRacing]

Install an electric power steering piece like this one http://www.ebay.com/itm/02-07-SATURN-VUE-05-06-EQUINOX-ELECTRIC-POWER-STEERING-PUMP-MOTOR-ASSEMBLY-OEM-/151978771017?hash=item2362a40249:g:ocgAAOSwXshWsRp d&vxp=mtr and a Rheostat to dial in the amount of power steering help you want, when you want it. Really great to dial it up for help in and out of the pits, then trim it down for on track feel.

[Scargo]

...Based on our recent measurement of bump steer problems on this car (about 3/4" of toe in at 2" of travel), I imagine a lot of 818S owners are experiencing extreme toe changes under bump travel.
The resulting alignment change wouldn't be present at static ride height, so your alignment shop would probably say you are fine... but then you hit a bump, and your alignment is nothing like it was, resulting in severe toe changes and tramlining. ...
Thanks for that information. That is dramatic and serious. I was shocked when, years ago, I was driving a loaner Mini at speed. When I went around a curve and hit a bump the car almost completely changed lanes. Sounds like a serious compromise in the suspension geometry that needs to be addressed on all 818s.

[Hindsight]

Wow, 3/4" toe change at 2" suspension travel seems extremely high. What's the fix on the R model and could it be applied to the S? I don't want to deal with a lot of bump steer like that but I also don't like the typical bump-steer solution.

[RM1SepEx]

I think most of the 818 platform's tramlining issue is due to bump steer problems, assuming your alignment is already correct. I'm sure power steering can help cover up some problems.

Based on our recent measurement of bump steer problems on this car (about 3/4" of toe in at 2" of travel), I imagine a lot of 818S owners are experiencing extreme toe changes under bump travel.

The resulting alignment change wouldn't be present at static ride height, so your alignment shop would probably say you are fine... but then you hit a bump, and your alignment is nothing like it was, resulting in severe toe changes and tramlining.

We are running 500lb springs on the front of our 818, so it impacts us less due to the fact that we are getting less travel due to the stiffer springs. But if you are running softer springs, I imagine it would be amplified.

The 818R manual has a bump steer fix included, but nothing is mentioned in the regular manual.

you are running an S at R height tho IIRC. Did you measure bump steer at normal height?

[Tamra]

We are pretty close to a 4" ride height with our street tires on, but the toe change is severe enough that I don't think it would eliminate the issue if we were 1/2" taller.

[Hindsight]

I guess some taller ball-joints and possibly the Baer bump steer kit may be in order for me. I like the idea of the ball joints since it means that much less space you have to put between the tie rod ends and the spindles.... the less the better IMHO.

[lance corsi]

The FFR suspension setup is suspect IMO. Personally, I'm installing a C-4 corvette suspension all around. If you want a proper suspension, you must get away from the hokey repurposed MacPherson strut suspension and erector set upper a arms.