ITT you will teach me to corner balance my car & I might not hurt you
 

I understand the concept of adjusting ride height to get cross-weights close...but what about spring preload and other things that I'm leaving out which is certainly a long list considering this post is only one sentence long.

Everyone around here wants from $400-1200 to corner my car, so I think buying a set is the right idea.

http://forum.miata.net/vb/showthread.php?t=381226

Buying a set...... Of scales?

I have the Proform scales coming in tomorrow and will let you know if they are worth a $shit or not. If they are, they were just a hair over 700 sitting on my doorstep.

1200? Tell them to DIAF.

Sure would be nice to have a decent scale set-up available. Wish I had the time to get to West End while I was in LA.

I too want to learn a cheap way to do this.

Buy my old scales I picked up on here a few years back that's still sitting in the box I got them in, then youtube cross weight


http://www.youtube.com/watch?v=eZhZS...eature=channel

Um... how much for the scales?

Tuner/race shops are expensive here too, but there must be a SM racer near you who has scales and won't rape your wallet. I had mine done along with a minor alignment tweaking for $100 up at Summit Point. I don't mind paying that on a very infrequent basis, though I'd like to own scales some day.

Longacre scales + Accu-line alignment plates + ICM string box
 

I have a set of these Longacre scales, but I think I paid about $1200, so either their prices have gone up or I bought them through vendor at discount. It was about 5 years ago, so my memory is fuzzy.

I use Accu-Line bolt on alignment plates and the ICM alignment strings + digital camber gauge when I do my corner balancing and then alignments. The plates were a bit pricey(like $600), but WELL worth it. I have used the scales and alignment plates about 20 times, mostly during tech days to help other people corner weight, but just in the savings to myself of doing my own setups everything is almost paid for in savings alone.

The plates are awesome because:

• no need for setup jacks to get undercarriage clearance for accessing the alignment bolts
• easy access to coilover collars for cornerweighting, so no need to remove the wheels each time you make a change(major PITA savings)
• No need for roll on/off pads(built in locking sliders)
• SUPER accurate - no variables introduced by tires or wheels
• easy to level the corners using a DIY pvc water pipe setup(built in water scales)
• incorporated toe plates on ALL 4 hubs allowing you to CW, then align and then recheck CW before slapping the wheels back on.

So far, no issues with the scales - I am very happy I bought them.

I've thought about buying that alignment stuff to save cash in the long-run.

http://images.harborfreight.com/manu...5999/45742.pdf

I can't find them on the site though. They are an expensive alternative to stacked wax paper and tile flooring.

I have Smart Strings sitting in a box waiting on the scales to get here. Again, if you wait a couple days, I'll let you know how they work and take pictures of the setup. With the smart strings, your supposed to be able to mount them on any car, which will save money in the long run even with DD's that the morons at the alignment shop can never get right.

I bought the lifetime alignment at brake check, so everytime i fubar my suspension, or change it, they put it back to the specs i want.

Most of the places around here who align cars for less than $300 will tell me the car is "done" with up to 1* variance in any measurement.

that sux balls. i sit in mine while the guy is doing the adj. and he shows me where it's at and asks if i'm happy. my variance is 0.1* on the newest hunter alignment setup.

Around here, all we get are toe and go shops.

I tip my alignment guy, it goes a long way.

Word. I'm using NTB who has a Hunter machine and techs that will do what you ask within the adjustment limits. I tip them after they are done so they are helpful next time I come in.

Get some wireless scales so you can sit in the car with the display box. Also I have this great xls sheet where you plug in your current numbers and it will tell you what to do.

Holy S!

NFW would I pay that. ~$150-200 gets me aligned & corner balanced, to my specs, with me in the car. Plenty of discussion about it too, if I want, including a review of previous setups I've run.

Takes a couple of hours to do it with a lift, turn plates on tables, and John Beam setup, can't imagine how long it would take at home . I've spoken to racers who have spent an entire weekend with strings, and only ended up tired, po'd, and unsure of their setup.

Wanna share that spreadsheet??

Here is an article on corner weighing.

Also, this website is AWESOME. I recommend a full read.

http://farnorthracing.com/autocross_secrets11.html

^good info

A friend of mine has a set of longacre scales for $600 with case and laser level. I have no part in the sale but if anyone is interested PM me and I can give you the guys email.

Now you speak up..... At 850, its not worth it. At 600, it is.

Buy scales, you won't regret it if you think auto racing is lifetime hobby for you.

I always start with a $20...but that doesn't get me anywhere at the Porsche shop.

I buy the guy shit mexican food at the place next door, and he pretty much lets me do it.

hmmmm scales or HANS? hmmm???

Lol why a hans, you don't even wear a fucking driving suit.

Huh? Two completely different modes of protection.

Is it required in your class or sanction? I'm not up on the SCCA/NASA track rules.

If its not, a good neck brace should keep your cervical vertebrae inline while the harness keeps you locked into the seat. Just make sure your harness is installed correctly so it doesn't do more harm then good if the time were to arise that you actually needed it.

Just because it isn't required, doesn't mean your melon isn't worth the extra money spent on safety. Well we are talking about hustler here though....

scales

I still don't know when to adjust spring pre-load vs. ride height.

Right now I have steady-state understeer (I think its worse on left turns). I don't know if I should crank valving, increase rear preload to raise rear spring rate, or something I don't currently understand.

Did you try tweaking the tire pressures?

I didn't want to screw temps becuase they were as good as they were going to get.

Jump onto M.net and PM Perryrace. He's one of the guys I've been going to for all my newb questions..... Which appear to be the same ones you have. They are the same questions I had walking into my high performance steering and suspension class years ago..... which taught me NOTHING.

As far as pre-load vs ride height-

If you have the option to adjust them independently, you want the optimum up/down travel you can get being set with pre-load, then the bottom adjusters to fine tune the ride height. PLEASE scold me if I'm wrong, as that is the only way it makes sense to me currently. Without testing and playing with the car on the scales, this is all just speculation on my end :cry:

While your PM'ing him, can you ask him about adjusting the valving on the shocks? What symptoms to look for to determine that you have them too soft where its not controlling the spring at all or too stiff where its dampening too much? That was the other big question I had in that class, that yet again got me no where.

if it's understeering, soften the frt. shocks a couple clicks, take a few laps see what it feels like. the softest setting that still controls the spring motion is always gonna give the most mechanical grip.

But inside the car, how do you monitor the spring control?

My take on preloading
 

Right now I have steady-state understeer (I think its worse on left turns). I don't know if I should crank valving, increase rear preload to raise rear spring rate, or something I don't currently understand.[/QUOTE]
I assume you already corner balanced? You may have a bit of "wedge"(>50% weight on the LR and RF corners). It may be a simple issue that you need more -camber on the front end.

There is a shitload of variables, so I have some questions:

• Have you verified your tire temps as measured outside/middle/inside immediately after hot lapping? You want to see slightly higher temps on the inside of the tires(especially on the fronts).
• Do you have adjustable sway bars?
• What shocks and spring rates are you running?

I am NO suspension guru, but I have picked a lot of minds over the years, so here are my thoughts on the subject:

If you increase the preload it will make the car sit higher and increase shock travel while static. To compensate for a higher sitting car you should then shorten the shock body(if you have adjustable body length shocks).

Preloading the springs is HUGE in the offroad and rally car world, but I am not sure how many road racers or autoxers do it. I have not experimented with it yet, but the optimal goal for every vehicle is to maximize traction, so it makes a lot of sense that the off road cars that catch a lot of air and hit tons of dips and bumps would want to use spring preloading coupled with SOFT springs to optimize the traction.

That said, people that are running FM's AFCO suspension seem to be putting down some pretty good lap times, so maybe there is something to be said for running softer springs, but having shocks with TONS of travel(coupled with spring preload to keep the static ride height).

I like the suspensions that use helper springs of decent stiffness) - this makes preloading the shocks irrelevant(unless the helper springs are not stiff enough, like under 100ft/lbs).

The results to spring preload is:
1. Less preload your suspension will have less droop and down travel.
2. More preload will add more droop and suspension down travel.

The compression/rebound damping of the shocks have TONS to do with how well they react over big bumps/dips, so spring rate + shock damping need to be taken into consideration if you are contemplating adding preload to the springs.

I played with some shocks years ago that did not have adjustable body length, but they did have adjustable ride height via spring preload. The spring rates were quite low so in order to get a decent ride height I had to add a SHIT TON of preload(like 15 full turns on each collar) which ended up causing the springs to coil bind under hard compression. It sucked.

On a track or autox miata I would NEVER go below 375/250 front/rear spring rates, unless you have fairly stiff helper springs on the coilovers.

[QUOTE=hustler;594160]I still don't know when to adjust spring pre-load vs. ride height.

The problem is steady state. I played with them at Hallett and fixed turn-in but it was fail mid-corner.

No, the car is not balanced
I have uneven temps because 2.75 and 2.6* camber is not enough
sway bars are not adjustable (rb front and stock rear)
I have tein flex

I have 550/390lb springs

stiffen the rear, again, only a little at a time, too much and you will have oversteer. i was trying to fix that problem at h2r once and i adjusted the frt. down and it helped some but not 100%. finally i tried stiffeneing the rear shocks a little and it was just right.

when i adj. the frt. on mine it helps turn-in and steady state. just to make sure you're not creating the problem, mid corner what's happening with the throttle?

if you're slowing down too much before the corner to the point that you can add a bunch throttle mid corner, then you are creating understeer. when you give it a bunch of gas you're transferring weight off the frt. to the rear. might not be what your doing, just saying.

Mid corner it will understeer even at full throttle in 3rd or so (big time understeer in 5 and 6 at Hallett. I had a bit more grip in #1 but could use a little less understeer there too. I stiffened the rear down to 4-clicks until the car started skipping over bumps and sliding that way, lol.

Right now understeer is limiting my corner entry speed. I'd like to soften the valving overall and seriously thinking I have too much weight up front.

Put an adjustable bar in the back. I'm still not understanding the small/no sway bar stiff spring combo the Miata suspension guru's say works well.

I agree, add an adjustable rear bar and start with the outer hole first. OR, put in stiffer rear springs. I would do the following, in this order:

1. Corner balance the car, don't preload the springs. Add more negative camber - how much depends on what temp differentials you are seeing on each corner.

still have front end understeer?

2. Add an adjustable rear bar(I would try to borrow one for a track event so you don't invest in something you may not need).

still have front end understeer?

3. Up the rear spring rate to 8k.

FWIW, I run JIC FLTA2's on the track car with the standard 9k/8k spring rates w/RB hollow front bar and NO rear bar. I am contemplating dropping the rear to 7k and adding a stock bar back in because on sweepers the sway bars would be beneficial. The rear wing helps keep the ass planted, so it is not much of an issue except when I am pushing it to the limits.

I also adjust the crossweight(~2%) depending on the track configuration - ie, Infineon is clockwise so I reduce the crossweight, but Laguna and Thill are CCW so I ADD crossweight. It noticeably helps turn in and steady state without much affect on opposite direction turn in.


I like having stiff rear springs because I like to dorifto and I like to snap oversteer the rear end using the throttle or under trail braking.

This sheet will help you bigtime if you have 4 scales and need to figure out how to get the car to 50%.

Put in the current weights and it will tell you how much you need to add/remove to each corner.

I had the RB rear bar but it was wayyyyyyyyyyyy to much rear bar. Last time I had too much oversteer everyone told me to switch to the smaller sway bar, lol. I have camber maxed with ride height, which is really low to the point of tucking the tire a bit in the front.

Most of the fast Miatas in Cali run the same springs and sway bar set-up that I'm on. I think I have too much weight in the front with all the turbo crap.

I wonder if zero bracing in the rear (1.6 car) is part of the problem?

Too much weight on the frt? No, all of us have turbo's. from what you're describing, it sounds like your driving. you need wags to take a ride with you. If you were going fast enough mid corner, you wouldn't be anywhere near full throttle until track out point or close to it. Like I said, when you give it gas you're transferring weight to the rear which is taking weight OFF your front end. to regain traction you must lift off the throttle which puts MORE weight to the frt. Same thing Aero would be doing, adding weight to your tires through the downforce generated. (Or reduction of lift)

Too much weight...maybe you need moar hole saw?

A few thoughts from watching the discussion...

If the front is understeering, fix the front, don't make the rear grip less to fix the issue (which is what stiffening the rear springs/rear bar will effectively do).

If you're serious about going fast the first thing you'll do is get corner balanced and then retest... you honestly can't get a usable baseline until you do this.

If you continue to have a steady state understeer problem, check tire temps across the tread immediately after you come off the track from hot laps... you MUST have someone else do this in the hot pits just as you come to a stop or the results are skewed. A contact pyrometer is the correct tool, IR temp gauges aren't terribly accurate for this.

My guess is you need more front camber, if you need more than you can get now buy offset bushings.

I guess I'll balance the car and go from there. If it were any other track, I'd entertain the possibility that its driver error, but I have not had this problem in my car previously nor when driving John's car at that track. Turn 1, 5, and 6 are throttle steer corners there where the faster I enter, the more curbing I grab and more throttle I put down to rotate the car. I'm not going full throttle in either corner, but I'm grabbing a lot of loud pedal there.

When I had the big bar in the rear I had fear/scary oversteer.

That is why I kept lowering the spring rate in the back end. When I bought the car, it had 500/375 springs in it. It now has a more spec miata ratio of 430/220 with the rear bar on full stiff. Again, no real track experience, just auto-x and off ramp testing.

...and softer rear spring means less weight in the front on the loud pedal. If anything I should go stiffer on the spring and remove the sway bar.

Ah ha, that is why they suggest ditching the bar and going to a stiffer spring.

yeah, he doesn't have the oversteer anymore, now it's understeering.

good thread:
http://www.lotustalk.com/forums/f91/...59/index2.html

I think increasing the rear spring rate is the way to go to reduce acceleration over-steer and not affect steady state cornering as much by jacking with sway-bars.

So apparently I can increase spring rate by increasing pre-load independently from ride height. I'm going to do this in the rear because right now the body and spring perches are sammitched together. I'll have to increase preload by raising the spring perch, then lower the body to compensate.

I kind of wish I didn't have adjustable body length because it adds another variable to the mix. What are everyone's thoughts on lowering the bodies all the way down and only adjusting preload for height adjustment?

Ok time to dispel this whole "preload" myth....

Unless you have the spring cranked up so far that you've maxed its travel (and therefore have zero droop travel), you aren't "preloading" the spring, all you're doing is holding up more of the cars weight.

What body length adjustable coilovers (like Flexes) are able to do is to adjust bump/droop travel at a variety of ride heights which is something normal coilovers can't. The tradeoffs are more complexity as you noted, and more unsprung weight.

IMHO, if you know what height you want and order your coilovers accordingly there's no advantage to body length adjustables. I've yet to see a purpose built road racing car use a body length adjustable shock, up to/including F1 cars.

To answer your original question, no... you need to buy the correct rate spring, install them and reset your corner weights/alignment.

Thanks...it really sucks that each time I change something I have to pay $300 for a new alignment so I want to make sure I get everything right before I fuck with it. I don't really know what spring rate I have in the rear because the swift springs part number is a sticker and its gone.

I wish i had money for JRZ or Xida.