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Old 06-12-2011, 06:34 PM   #1
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Default Setting up suspension

As discussed in the suspension forum, my car sits higher on one side than the other:


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Originally Posted by saboteur View Post
Hi,

I have my TEIN Super Streets set right at the bottom at the front, and 20mm up from the bottom on the rears. These are Japanese Super Streets so I have heard the springs are 50mm longer than the US ones, but it doesn't seem crazy low anyway.

My problem is that, although both left and right fronts are wound down as low as they can go, the car seems to be 10mm higher on the right than the left. The same applies on the rear but it isn't as extreme (7mm).

Do you know WTF could be causing this?

Cheers
Would you guys typically dial it in so it sits even, or just set both shock collar adjustments to be the same?

At the moment the pinch weld measurements are:
  • FL 128mm
  • FR 118mm
  • RL 128mm
  • RR 121mm

I'm going to jack it up a bit so it sits ~6mm higher at the rear as suggested by 949 Racing.

BTW I put a shock collar on your girlfriend.

Cheers
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Old 06-12-2011, 07:10 PM   #2
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Dial it in at the pinch welds. Not the amount of thread left on the collar.

If you autox/track your car but still drive on the street I suggest a 4.5'' F/4.75'' R measurement from the most forward and most rearward parts of the pinch welds before they start curving up. I am running as low as 3.75''/4'' with my 13's on but that's a different case.

In MM it would equate to 114mm front/ 120.4mm rear.


Just FYI, my car is even all around but the collars are all a little off.
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Old 06-12-2011, 07:56 PM   #3
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If one's pinch welds were pretty much FUBAR'd, is there another reliable point to measure corner heights? I know the fender lips are not reliable enough, especially since I have flares on the rear, and my frame rails are ground down from speed bumps and therefore not even either....
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Old 06-12-2011, 07:58 PM   #4
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The correct way is to set the approximate height you want then dial in the corner weights, but making it even with your weight in the seat is reasonably close for a street car.

Then have it aligned...
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Old 06-12-2011, 09:09 PM   #5
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And then have it corner weighted again... And then aligned again. If you REALLY want to do it right.
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Old 06-12-2011, 11:08 PM   #6
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Originally Posted by falcon View Post
And then have it corner weighted again... And then aligned again. If you REALLY want to do it right.
True... it's how we set em up at work. A little overkill for a primarily street driven car though.
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Old 06-12-2011, 11:14 PM   #7
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Well I figured since this is the race section.... As for another place to measure I would try the rocker panels a bit higher than the pinch welds. Make a tiny mark or something for measuring purposes. But you would have to figure out the proper heights...
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Old 06-12-2011, 11:27 PM   #8
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Mine is a non-registered track only car but with these shocks I might aim for that height anyway.

Thanks for the feedback!
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Old 08-30-2011, 03:49 PM   #9
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We played with the shock stiffness last event and found with all 4 set to the 'middle of the road' setting the car would get crazy oversteer on rebound. After dialling up the rear shocks a bit (very minor adjustment) the car seemed to have shittier turn in but it was more stable and faster.

Is this kind of compromise fairly typical?

The suspension is just left over from my street car - Tein SS with 6/5kg springs. I also have MSM/SE swaybars and an MSM/SE tower brace.
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Old 08-31-2011, 02:27 AM   #10
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Oversteer is typical with 6/5 springs and stock sways, yes.

You don't need shock adjustments, you need different front and/or rear springs, a much larger front sway, and at least 6mm of rake in the car.
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Old 08-31-2011, 10:19 AM   #11
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I have still never driven a Miata with uncontrollable oversteer. Understeer on the other hand is much more prevalent.
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Old 08-31-2011, 10:47 AM   #12
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It's controllable, it just results in slower laptimes.
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Old 09-11-2011, 09:53 PM   #13
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Well after reading your posts I think you may be overlooking a problem. You mentioned turning the collors all the way to the lowest setting, you also mentioned crazy over steer.

With these two statements I would guess that you are on your bump stops.

Start by raising the coils up two turns at a time untill you dont hit the stops on hard corners or bumps. Then get it on the flattest and most level peice of pavement you can find with scales under each wheel.

Look at the weights of each wheel and adjust the coils until the fronts weights are equal side to side and the rears are equal side to side. While doing this you will notice that a adjustment on one corner will affect the weight on the other three corners, pay attention to this. Dont worry if they are a few pounds off they will be when you do the next step. Once close add the opposite corners diagnolly and adjust to try to acheive equal cross weight. You can do this with you in the car or you and your navigator.

Once the corner weights are set drive it and put it back on the scales to check that the weights have not changed. Then get an alignment from someone that will set it to your specs. (Settings can be found on this site or over at Mnet) Dont use the quickie $75 alignment shops, they usually check your settings and if they are in a range considered acceptable they wont make a change.

Then adjust your sways to help with over or understeer.

Once this is done start adjusting the shocks, start with the compression then do the rebound.

From here if you need to adjust the ride height you can turn the coils equally and the corner weight will stay close to the original weight but you will have to change your alignment.

Good luck

Greg
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Old 09-12-2011, 12:59 AM   #14
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Quote:
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With these two statements I would guess that you are on your bump stops.
Doubt it. His ride heights don't suggest that at all. His oversteer is caused by a huge spring rate mismatch and stock sways - no amount of setup will cure that.

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Then get it on the flattest and most level peice of pavement you can find with scales under each wheel.
There isn't a slab of pavement in the world that's level enough to accurately scale a car. If you don't have adjustable scale pads and a way to level the scales (either a 10ft bubble level or some other way) you may as well not bother with scaling the car at all. If you are 1/4" off over a distance of 10ft, the scales will be totally inaccurate.

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Dont use the quickie $75 alignment shops, they usually check your settings and if they are in a range considered acceptable they wont make a change.
San Luis Obispo must be the mecca of good, cheap alignment shops. There are multiple <$100 shops in town that will let me pull the car on/off the rack, stand around and watch the tech work, hit my numbers with absolutely no discussion or drama, and do it all with a smile.

If you give your race car to the tech and sit in the lobby reading a magazine, you can expect a shitty alignment, but with a little oversight and $10 in the right shirt pocket, anybody with a laser alignment machine and a few box wrenches can produce a perfect alignment in about 45 minutes.
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Old 09-12-2011, 01:06 AM   #15
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Corner balancing is something you do 6-months after you feel like you have the car right. Been there, done that.
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Old 09-12-2011, 03:06 AM   #16
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i made a deal with the alignment shop i go to. told him i might be getting as many as 4-5 aligments per year and i would send all of our car club members to him from now on. also that i would give him my alignment #'s and be sitting in the car while it was being done. i paid $89 first alignment and usually pay about $60 including said tip now. the mechanic even lowers the car a little when it's done so i can see the screen to see if it's okay. kinda like when the barber turns you around so you can look inthe mirror after a haircut. lol... like i've said before, you have to make connections with people to get **** done right and for a fair price if you can't do it yourself.

as far as the op saying he dial'd upped the rear and it helped? shouldn't have unless they were underdamped to begin with. Sav is right about the spring rates, they suck, they are too close together. in the mean time to help counter that oversteer, he should stiffen the front to a little below full stiff in the front and remove the rear sway bar. also, there is no such thing as msm/se sway bars. if they are not red, they aren't msm. if they aren't msm they're not really worth having. big RB (hollow) frt. sway with (real) msm rear sway is a proven set up.
one last thing, aren't the tein independent height/preload adjustable? if so, that could explain why the car doesn't seem low and is higher on one side, etc..
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Old 09-12-2011, 03:30 AM   #17
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Originally Posted by spoolin2bars View Post
also, there is no such thing as msm/se sway bars. if they are not red, they aren't msm.
Australia got the MSM labeled as a Special Edition car, hence the MSM/SE designation from Australian members.
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Old 09-12-2011, 04:30 PM   #18
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If they are red than they should be decent non marked eibach sways with poly mounts. As said above pull that rear sway for now and start the process of getting the correct f/r bias of rates on the car.
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Old 09-12-2011, 04:41 PM   #19
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Quote:
Originally Posted by jacob300zx View Post
As said above pull that rear sway for now and start the process of getting the correct f/r bias of rates on the car.
keep the rear sway and get at least a 7/8" front sway...I think that would be the better choice.
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Old 09-12-2011, 08:32 PM   #20
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pull rear sway = free and fast
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