Sway feeling when cruising

CammedS197 said:

Hahaha thanks

Is there a better set out there or OEM just fine or a good aftermarket? I believe I do need a bump steer kit. Replacement pretty easy?

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No, you don't need to do a bumpsteer kit. Steeda and the other vendors like to act like you absolutely must have that stuff, but you really don't unless you're chasing tenths.

If you're on a budget, just get some OEM or Moog units.

Norm Peterson said:

Even if the rear upper was in rough shape, it wouldn't have contributed to the swaying problem.


Norm

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Okay thanks Norm! Won't worry about too much then.

Sky Render said:

No, you don't need to do a bumpsteer kit. Steeda and the other vendors like to act like you absolutely must have that stuff, but you really don't unless you're chasing tenths.

If you're on a budget, just get some OEM or Moog units.

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Alright thank you. Did not want to spend $100+ for them lol. I'd rather pay less than $50 and swap out and be good to go. Any shock strut recommendations? Can't afford the koni yellows which is what I really want but I may be able to spring the oranges. I hear they are pretty much the yellows on the soft setting. True?

I'd lean towards a set of Bilstein struts/shocks.
http://www.vorshlag.com/product_info.php?cPath=141_142_179&products_id=642

If you're looking at lowering your stance, consider a set of Vorshlag's street pro setup.
http://www.vorshlag.com/product_info.php?cPath=141_142_179&products_id=559

As Sky Render noted, you don't need a bump steer kit.
OEM tie rods are just fine, probably better than moog since I've seen some terrible QC on moog of recent.

oldVOR said:

I'd lean towards a set of Bilstein struts/shocks.
http://www.vorshlag.com/product_info.php?cPath=141_142_179&products_id=642

If you're looking at lowering your stance, consider a set of Vorshlag's street pro setup.
http://www.vorshlag.com/product_info.php?cPath=141_142_179&products_id=559

As Sky Render noted, you don't need a bump steer kit.
OEM tie rods are just fine, probably better than moog since I've seen some terrible QC on moog of recent.

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Oh really? There's a guy in classifieds selling a set of moogs and I may buy them. Are the one's on AM's site the OEM? I know lowering messes with camber but does it also mess with toe?

oldVOR said:

I'd lean towards a set of Bilstein struts/shocks.
http://www.vorshlag.com/product_info.php?cPath=141_142_179&products_id=642

If you're looking at lowering your stance, consider a set of Vorshlag's street pro setup.
http://www.vorshlag.com/product_info.php?cPath=141_142_179&products_id=559

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As he noted, he can't afford Koni Yellows. Bilsteins look to be about the same price these days, so I doubt he'll be able to afford the Bilsteins.

Like the OP, I've heard that the Koni Orange (STR.T) units are the equivalent of Koni Yellows on full soft. Aside from experience, the only way to know if the Koni STR.T units will properly control the springs the OP has is by examining the spring rates of the springs and the damping rates of the dampers.

The only values I can find for the SR springs are 230 lb/in up front and 200 lb/in in the rear: http://www.moddedmustangs.com/forum...owering-springs-really-worth.html#post4888919

I don' t know how accurate that is, but it's all I've got to work with. So, critical damping of 230 lb/in is about 50.5 lb/ips ("ips" is "inches per second"). The Koni Yellow rate up front at full soft is about 28.5 lb/ips, which for 230 lb/in is about 56% of critical. You'd presumably want 65% or so for truly proper control of the suspension, so 56% may be a bit soft.

HOWEVER: the advertising claims that these springs are progressive, so that 230 lb/in figure is incomplete, to say the least. It may be that the curve is such that you'd get good control over nearly everything but the last bit of spring compression, or it may be that most of the spring is near that rate, etc. Tough to say.

Strangely, based on the dyno plots, the lower-speed damping of the stock Brembo dampers would do a better job of controlling rebound of the SR springs than Koni STR.T dampers would. The problem with the stock Brembo dampers is that they look to me like they're underdamped in high speed rebound, and ride quality suffers as a result. And if they're underdamped in high speed rebound for the stock Brembo springs, they're definitely going to be underdamped there for something firmer, and thus I wouldn't expect terribly good ride quality from them. Here's the dyno plots comparing the stock Brembo dampers against the Koni Sport dampers on full soft and full firm: http://www.s197forum.com/forum/showpost.php?p=2240528&postcount=165

Stock Brembo dampers can be had for $82 each: http://parts.autonationfordwhitebea...ont-suspension-cat/struts-and-components-scat (look for the "performance package" struts).

I don't know of any other reasonable option available to the OP, given his budget limitations. It looks to me like the STR.T dampers would be the way to go if ride quality is the primary goal, while the OEM "performance package" dampers would be the way to go if low speed rebound control is the primary goal. Given the OP's use, I suspect that ride quality would win, but it's a personal choice.

CammedS197, you may want to give Sam Strano (http://www.stranoparts.com) a call on this. He may be able to steer you towards other, better options than either of those, given your budget. You'll just need to be clear on what your goals are. I'd normally also suggest a call to the guys at Vorshlag (http://www.vorshlag.com), but I don't see anything in their inventory that is anywhere close to your budget here.

CammedS197 said:

I know lowering messes with camber but does it also mess with toe?

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Yes. When camber is changed, the knuckle at the steering arm height also changes. Since the length of the rack & pinion unit as measured from outer tierod end to outer tierod end is fixed (until you adjust it), the tires end up being steered slightly. Usually, when camber goes more negative, toe goes in the 'out' direction, IOW from 'in' to 'less in', maybe zero, or possibly all the way to 'out'.


Norm

kcbrown said:

HOWEVER: the advertising claims that these springs are progressive, so that 230 lb/in figure is incomplete, to say the least. It may be that the curve is such that you'd get good control over nearly everything but the last bit of spring compression, or it may be that most of the spring is near that rate, etc. Tough to say.

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Ride quality-wise, it's the rear spring/shock combination that's more important. Certainly in a stick-axle car.

I suspect that the SR springs (and most other springs billed as 'progressive') are really dual-rate (or very close to it). Where the closely spaced coils open/close up and the rate abruptly softens/stiffens could matter, and as long as the advertising claim of 200 lb/in rear is not intentionally misleading this is probably the working rate over more than half of the normal range of suspension travel. The close-spaced coils will be closed up at static ride height, and they'd drop to the 'soft' rate somewhere in rebound where the axle has dropped relative to the chassis. Per Sam some years ago when I was considering them, Vogtland springs are like that, as are the 220 lb/in BMR Handling springs I now have (can't even force a thin feeler gauge blade between the close coils at static ride height).

If STR.t's truly are like yellows at full soft, I suspect that ride quality with STR.t's for 200 lb/in springs would be mildly bounce-y as opposed to slightly harsh. Yellows at maybe a quarter turn up still allow a small but noticeable (to me) amount of bounce with dual-rate springs listed at 220 lb/in, but the ride is still quite good over most roads (I was surprised how good). It gets too harsh over expansion-jointed concrete at about half a turn up.


Norm

Hey Norm, thanks again for that info on the toe and camber. As a DIY'er I have never done that before but I've seen someone I know do the toe by measuring the length from outside point on the front of the tires and then the rear. Is here an easier/smarter way to do it and what should I be looking for on toe for pretty much 100% daily driving except for maybe 1 track day a year and some spirited driving?

Yeah mainly going for more on comfort side for dampening. Will talk to Sam Strano.

Personally, I would hold off on other mods, save, and find the budget to get a set of Bilsteins or Koni yellows. They often show up lightly used on the classifieds for around $500 or so, and I think the extra $200 over lesser new shocks is well worth it. The rear axle is heavy and all unsprung weight and high end shocks just make a dramatic difference in the day to day stability of the car. I like Bilsteins for their quality, monotube construction, and digressive valving. But either one will be way better than what you have.

I just looked this up and it seems a GT rear axle weighs about 175 pounds. Wow. All unsprung. I knew it was heavy but.... And the shocks have to control all that weight flopping around. No wonder mediocre oem shocks don't leave a real secure feeling.

CammedS197 said:

If I'm on a very small budget what shocks/struts should I get? I really wanted to save for the koni yellows but man that is so far away its not funny! I could do maybe $300.

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AM.com has SR shocks & struts for $260 if you want to match brands with your springs. And for $300 you can get a set of KYBs which are also good OEM replacements.

I would avoid Koni STR.Ts solely because they did not last very long for me. They began leaking after 35k miles of use and had very little rebound left when I took them out at the 40k mile mark. For a daily driver, 40k is not much. They gave me a firm, planted feeling when they were new though.

CammedS197 said:

Hey Norm, thanks again for that info on the toe and camber. As a DIY'er I have never done that before but I've seen someone I know do the toe by measuring the length from outside point on the front of the tires and then the rear. Is here an easier/smarter way to do it and what should I be looking for on toe for pretty much 100% daily driving except for maybe 1 track day a year and some spirited driving?

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For a street car with almost no track time, 0 toe would be best to minimize tire wear. For spirited driving, 1/16" of toe out is a good starting point. The theory is that a slight toe out can help turn-in. You could split the difference and aim for 1/32" toe out. Some alignment shops measure toe in degrees so I'm not sure what that translates to in inches or mm.

Thanks for the toe info 13726548. Hmm will have to see how those are holding up for people. Will definitely talk to Sam Strano and get his insight and see if there's a reliable and perform better than the oem and ride better.

CammedS197 said:

Hey Norm, thanks again for that info on the toe and camber. As a DIY'er I have never done that before but I've seen someone I know do the toe by measuring the length from outside point on the front of the tires and then the rear. Is here an easier/smarter way to do it and what should I be looking for on toe for pretty much 100% daily driving except for maybe 1 track day a year and some spirited driving?

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I've always checked toe via "parallel strings". You stretch strings at axle height down each side of the car that are parallel to each other. Then measure the offsets from the strings to the front and back edges of the wheels. That way, I can get individual toe readings and do a better job of centering the steering wheel all at the same time. Plus, the flanges of undamaged wheels are more uniform surfaces to try to measure to than anywhere on a tire with a scale graduated in 0.01" increments. I don't trust tire sidewalls to be accurate enough, as they have all kinds if information molded into them and may even have raised styling elements as well.

I don't have any pictures of my two separate strings setup, but it's sort of similar to the 'Smart Strings' toe device, except I also need to verify the distances between the strings as being the same in front of and behind the car to guarantee parallelism. About 2/3 of the way down the page is a plan view sketch. Instead of having the strings attached to lateral sticks (and any of the rest of that framework), I've got jackstands sitting where the ends of the sticks are.

http://www.smartracingproducts.com/smartstrings.html


For street use, I'd shoot for just a tiny amount of toe in, maybe 0.03" or 1/32" total toe.


Norm

Okay thanks. Will be much more helpful and beneficial than how I was going to try it lol.

13726548 said:

For a street car with almost no track time, 0 toe would be best to minimize tire wear.

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Maybe, but...

If you're sensitive to tramlining, and, as discussed earlier, tire design and road surfaces can accentuate this, I'd do a slight amount of toe-in, to help directional stability. I run 1/16", and my Pilot Sport A/S show totally even wear at 18K miles. Car tracks arrow-straight.

If you're not actually racing your car much, you should go with stock alignment specs, which does have a slight toe-in to help with tramlining.

Increasing caster can also increase tramlining.

Thanks for all the great info guys. Yall are the best when help and info is needed, again thank you.