Road race/autox setup
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Well, the Details are different between Road-Racing and Auto-X.
The Biggest Diffences, IMO, are with Alignment and with Sway-Bars.
For Auto-X, you want a car that will really "Rotate" for you.
For Road-Racing, Too much Rotation will have you Backwards in a Hurry. The Higher the speed you're Traveling, the easier it is to generate oversteer. A BIG Rear Sway bar, with a Small Front one will help alot for Auto-X, but might get you killed in a 90MPH Sweeper.
There ARE Good Compromises, depending on how much you want to spend, and how much time you spend doing one or the other.
What's your Budget, and where is your Emphasis?
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BTW, WELCOME to Focaljet!!!!
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The Biggest Diffences, IMO, are with Alignment and with Sway-Bars.
For Auto-X, you want a car that will really "Rotate" for you.
For Road-Racing, Too much Rotation will have you Backwards in a Hurry. The Higher the speed you're Traveling, the easier it is to generate oversteer. A BIG Rear Sway bar, with a Small Front one will help alot for Auto-X, but might get you killed in a 90MPH Sweeper.
There ARE Good Compromises, depending on how much you want to spend, and how much time you spend doing one or the other.
What's your Budget, and where is your Emphasis?
BTW, WELCOME to Focaljet!!!!
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3,350 Posts
What Michael said is right-on...Also, are there any preparation/rule limitations that we/you need to be aware of--or is this a no-holds-barred, cost-be-damned approach?
My budget is limited........... I just want something that will handle GREAT on rails...........myabe koni adjustables and some h&r springs for starters, or is stock better? (hey, stock hanldes great, you never know). Maybe a sway bar later on? let me know thanks.
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3,350 Posts
Oh yeah. Big difference , and shouldnt "scrape"...but the H&R race springs may knock the fillings outta your teeth
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Does ride heigh affect spring rates or is it the case that whatever the spring rate is, determines it's characteristics and height of spring has nothing to do with it's characteristics after that?
Sorry if that doesn't make any sense and if it's a stupid Q.
Asking because I know the f is dropped 2.0 inches and the rear only 1.7 with the race springs. Rates for front are 325 and rear is 375.
I've been thinking for quite some time now about ditching the spax coilovers and just going with the koni/hr race setup with progess and few bushings (front control arms, rear sway bar, etc.) as you mentioned Michael.
What size is the progess bar anyway? It was either that setup or I was going to stick with the Spax and then get an eibach front (22mm) and rear (25mm). The Spax does have adjustable dampers.
With the front only lowered about an inch or inch and a half and the rear dropped quite a bit from stock (although at the highest level possible with the coilover springs), and rears set at full firm and fronts set at mid-full firm, and nothing else done for suspension, the setup feels quite nice. Rotation is nice and I can get the rear to swing out on turns nicely. But thing that is weird is that I'll have to turn the wheel quite a bit to get it to rotate. At times I need to turn it alot just to get it to rotate...or else if I don't turn the wheel enough, it feels like it's not wanting to rotate much.
Is that normal or a sign of a poorly tuned suspension setup?
Also, I must note that I don't have much a basis for comparison.
Any thoughts?
Sorry if that doesn't make any sense and if it's a stupid Q.
Asking because I know the f is dropped 2.0 inches and the rear only 1.7 with the race springs. Rates for front are 325 and rear is 375.
I've been thinking for quite some time now about ditching the spax coilovers and just going with the koni/hr race setup with progess and few bushings (front control arms, rear sway bar, etc.) as you mentioned Michael.
What size is the progess bar anyway? It was either that setup or I was going to stick with the Spax and then get an eibach front (22mm) and rear (25mm). The Spax does have adjustable dampers.
With the front only lowered about an inch or inch and a half and the rear dropped quite a bit from stock (although at the highest level possible with the coilover springs), and rears set at full firm and fronts set at mid-full firm, and nothing else done for suspension, the setup feels quite nice. Rotation is nice and I can get the rear to swing out on turns nicely. But thing that is weird is that I'll have to turn the wheel quite a bit to get it to rotate. At times I need to turn it alot just to get it to rotate...or else if I don't turn the wheel enough, it feels like it's not wanting to rotate much.
Is that normal or a sign of a poorly tuned suspension setup?
Also, I must note that I don't have much a basis for comparison.
Any thoughts?
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3,350 Posts
Progress is 22mm and then there are a couple of bars at 22.4 (7/8") and then some really big ones like Eibach and Steeda... A larger-than-stock bar will help, IMHO.
No, the ride height does not directly affect the spring rate. BUT, you have to remember the bumpstops have a rate from 100-1000lb/in. If you hit the bumpstops, your wheel rate goes huge. That's why riding low isn't very smart.
As to the original question, I suggest you check out Apex suspension kit. I've got it, and I'm VERY pleased. It handles AMAZING.
As to the original question, I suggest you check out Apex suspension kit. I've got it, and I'm VERY pleased. It handles AMAZING.
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3,350 Posts
Rob, What are the APEX spring rates?
height is a direct result of spring rate and spring height. ie a 10" spring that was rated at 325 lb/in would collapse 2 inches if your car weighted 3000 lbs and was 50/50 balanced (750 lbs on each corner) Spring rate is weight (in lbs) needed to compress spring 1 inch. In your example, 325 rate would drop 1 inch for every 325 lbs you stacked on them. 325 front, 375 rear
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???? I guess I'm confused why you want stiffer springs in rear, when they don't have as much weight to carry. Sounds kinda stout for a 2800 lb car too. Seems my '91 Mustang used 425-530 progressive fronts and 200-300 progressive rears, and it weighed 500 lbs more
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2,949 Posts
motion ratio= ratio of "free" spring rate of the spring sitting on your coffee table versus actual wheel rate dictated by that spring installed and articulated by the suspension geometry.Please do elaboratedon't forget about motion ratio......![]()
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<- newb just trying to learn![]()
a spring has its "free rate".....the one that a spring rate tester would reveal. A car has its front and rear "wheel rates".....this is the real "working" spring rate because of lever-arm action within a given suspension geometry not to mention the additional rate from anti-roll bars.
Easy translation.....on a Focus the front suspension's motion ratio may be closer to 1:1, that is the given "free" spring rate translates to similar rate at the wheel, while on the rear, because of the geometry it takes more "free" spring rate to equal the wheel rate of the front.
Therefore a disparity of F/R spring rates on "paper", do not have as much of a disparity as applied in the Focus suspension.
Pulling #s out of my arse for discussion purposes--
A front "free" spring rate of 325 may translate to into an effective wheel rate of 300 because of the given geometry, while a rear "free" rate of 375 may translate into an effective wheel rate of 275 for example.
Begs the question.....is there a "better" or "best" motion ratio? Well not really. One could say that a ratio that would allow the highest rate at the wheel would allow the lightest spring to be used. Always a desireable trait. However, most final motion ratios are just the end product of suspension packaging goals, or other suspension characteristic goals - NVH, camber curve, toe change/control etc.
I'll leave it to geeks far superior to me to share what the Focus' exact motion ratios are front and rear, as well as even provide examples of other cars' motion ratios....Mustangs etc.
I'm just a surfer for fawk's sake
Right you are Murph, Forgot about the rear linkage setup. Does make sense. Much like the higher rates needed with the Griggs setup on my Mustang. Just hadn't thought about it. Still if stock is 129 Front/ 157...300/375... about the same ratio...sounds kinda skittery on the street.IMHO
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How much track experience do you have (open track)?
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