DIY Corner Balance And Ride Height Adjustment - Page 6 - LotusTalk - The Lotus Cars Community
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post #101 of 140 (permalink) Old 05-30-2011, 06:59 AM
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Welcome to production vehicle set up. Yes in the perfect world each corner would weigh the same. Such as my DSR. But that is a dedicated race car. The lotus is a balance nightmare. Way too much weight in the rear, very light in the front and the driver sits off center line. The only way to change the balance is to move weight or add it. For the most part neither are an option for us. So you live with what you have.

Yes to increases cross percentage the RF and LR will weigh more than the LF and RR.

The more the imbalance fore aft or left right the more it will sacrifice handling. So a 500lb guy in the drives seat vs a 150lbs guy will be at a handling disadvantage.

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post #102 of 140 (permalink) Old 05-30-2011, 08:27 AM
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Ok, right. A 500pds guy should go cycling and not driving around with cars !
Just want to say, all right with me! it's just a extreme sample.
*
Unfortunatly not with my 2-11:
Now after after putting in a new upper wishbone (front right) and a new steering rack (2,4turns) I need to do all the wheel alignment. What's the right order: First weighing wheels, second wheel alignment? Or how would you do this?
Is there a significant difference of wheel allignment between 50 or 56% cross weight?
I can imagine, you can feel most of it while driving, how you have to change cross weights.

It's really amazing how the car oversteers, when lifting the pedal while cornering, or accelerating as well . And as well the differences with or without a passenger. I agree, a wheel scale probably isn't really necessary, just good to get basic adjustments. Or if you know the weights for a specific track and you really want to set up quickly.
But I'm not racing, I just go out for a couple trackdays a year...
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post #103 of 140 (permalink) Old 05-30-2011, 08:51 AM
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If you want the car corner balanced it has to be done in concert with the aliment. Every adjustment affects corner weights and adjusting corner weights affects the alignment.

Corner balance is very crucial to how the car handles.

54% is a very extreme balance. Most tracks seem to like 50.5% to 51%.

Your over steer on and off power is more likely due to the shock valving. Hence why we developed the V2 spec valving.

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post #104 of 140 (permalink) Old 05-31-2011, 01:27 AM
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Now I got it. I checked the pictures of the scales again (in this thread). I did a error in reasoning.
Crossweighing is dividing the overweight you have on the left side (driver) to front an rear in the right way. This means leftfront>rightfront and leftrear>rightrear. Still possible to get equal crossweights !
All clear now!
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post #105 of 140 (permalink) Old 07-11-2011, 10:34 PM
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Just tossing this into the mix and bringing a good thread TTT

I hadn't seen it mentioned yet, but you can take a lot of the guess work out of which corner to fiddle with by quickly deriving the calculated corner weights.

Works like this:

1) Bring the car to the correct ride height while being reasonable about the spring positions. ie. you're not drastically different on one corner vs the other. You can be off a lot and this method still work great.

2) Drive on to your scales and take the weights. Use your spread sheet to make this easier. Jot down your 4 corners. You know the total of each end and sides are Ks.

3) Do the math or enter the numbers in the spreadsheet. Figure out the total left side and the total right side. Let's say that total on the left is 1033 and on the right is 999 (total=2032) with driver of course.
LF:401
RF:407
Total front:827
LR:632
RR:573
Total Rear:1205
(these are obviously "before" figures. Cross delta is 84lbs or about 4%)

4)Now figure out the percentage of the left side is to the total. In this case, 1033/2032=50.84%. You only really need to calculate the weight for one side. Take 827 (the total of the front) and multiply by the left side percentage, 50.84%, which equals 420lbs. That's the LF target weight. To get the right side, just subtract 420 from 827 and yet get 407 obviously. That's the RF target.

5) Do the same for the rear

Now you know where to go to add and subtract weight with your spring perches. I like this strategy because it takes a bit of the guess work out.

In the above case, I pretty much know where I need to go to fix the corner balance issue without throwing my ride height off into limbo land since I know what the finished product will look like. If I'm creeping up on the target weight and I still have a ways to go, then I best move to a different corner or my ride height is going to go funky. It's EASY and pretty quick. This is to attain a 50/50 cross balance. At that point, you can then tweak it for the track or whatever...

Cheers,

Phil

PS- It's nice to use a person when weighting the car. Makes a big difference in the weighting just moving feet, your head, etc.... At some point, it's just ridiculous. I'm not as anal as Andy is about this After all weight in the car is dynamic. I've tried and tried and I can get sweet talk the fuel into staying in one place in the gas tank for anything! LOL


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Last edited by turbophil; 07-11-2011 at 10:52 PM.
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post #106 of 140 (permalink) Old 07-12-2011, 06:54 PM
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FYI guys. I'm now selling roll off leveling pads on the TrakkTape site. Home Page.

They are $500 for a set that is very similar to Longacre's $900 set. I was checking on buying used scales and found some good deals, but YIKES!, when I looked at roll off levelers.

Also, check out Longacre's Refurbished list on their web site. It's at the far right on their main menu with Products. Lots of good deals there. That is where I finally bought my scales.

We're working on some other alignment oriented tools like a toe gauge and caster/camber gauge. Will keep you posted. We're trying to develop some good quality items for serious track/race guys with less than NASCAR budgets.

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post #107 of 140 (permalink) Old 07-13-2011, 07:25 AM
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Coolness, thank you for sharing ... keeping an eye on this.

I've often thought about building my own alignment rig, making sure it's easy to transport to/from the track. Given some of the inconsistancey with my LSS and Rac's and C71 tires, I think this is going to be much more important for me in the future ... I've never experienced a simple wheel change costing me 4 seconds a lap before.

EDIT: worse case with my Hoosiers on same rim sets was 1 second drop-off which is suggesting the C71 turn to crap after only a few heat cycles (has obvious regular use implications and costs, I'm thinking a Hoosier R6 (or A6) might actually be a better tire for LC series, it's consistant down to the cords and has better tire size options for 16/17 runners).

Rob

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Last edited by robains; 07-13-2011 at 07:36 AM.
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post #108 of 140 (permalink) Old 07-13-2011, 07:39 AM Thread Starter
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FWIW Rob, I ran on Friday at LS with SpeedVentures on a set of C71s with >10 heat cycles... ran a 1:36.050... my best time of the weekend was on the second heat cycle of a new set during the Time Attack: 1:36.012
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post #109 of 140 (permalink) Old 07-13-2011, 07:41 AM
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I know, has me puzzled ... I know Hankook had a series of issues with these tires that got corrected, I'm just wondering if I got an older set ?

I did run the "bad" set in wet/dry track once ... but I don't see how exposure to water would have caused this drop off.

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post #110 of 140 (permalink) Old 07-13-2011, 09:39 AM
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Quote:
Originally Posted by robains View Post
Coolness, thank you for sharing ... keeping an eye on this.

I've often thought about building my own alignment rig, making sure it's easy to transport to/from the track. Given some of the inconsistancey with my LSS and Rac's and C71 tires, I think this is going to be much more important for me in the future ... I've never experienced a simple wheel change costing me 4 seconds a lap before.

EDIT: worse case with my Hoosiers on same rim sets was 1 second drop-off which is suggesting the C71 turn to crap after only a few heat cycles (has obvious regular use implications and costs, I'm thinking a Hoosier R6 (or A6) might actually be a better tire for LC series, it's consistant down to the cords and has better tire size options for 16/17 runners).

Rob
I built a rig for my car similar to what Andy uses. I'll post photos soon. It was so simple that, frankly, it's not even worth making into a separate product. I'll show enough detail that anyone can build one wiht one trip to Home Depot or Lowe's.

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post #111 of 140 (permalink) Old 10-10-2011, 08:23 PM
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Just getting into my first major corner weight. Have done alignment before with good results. So now is the time to do all of it together.

Two quick questions.

When you use the marker to level scales ( I used an old socket with a piece of tape on it marked to 10mm), doesn't the scale deflect a bit when the car's weight is on it? Do you recheck for level once the car is on the scales? Otherwise, won't that affect ride height measurements?

Next, how close should I try to get left and right front weights to each other? I have heard 2-4% is good, but is that a percentage of the total weights of both sides or what? Can someone give an example on that?

Thanks!


2006 Elise, Graphite Grey/Red leather, Sport Elise Suspension, Cup airbox, ECU ref lash, MonoBalls, etc. etc.
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Old stuff gone: Ferrari 275GTB/4, '69 1275 Cooper S. '72 500 Fiat, old Jags, etc. Never bought a boring car.
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post #112 of 140 (permalink) Old 10-10-2011, 08:39 PM Thread Starter
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Yes, the scale does deflect, but only by 1mm or so, depending on the design of the scales and pads. Since each scale deflects, it doesn't effect the "level" of the set up significantly. I do remeasure the height of each pad below the laser and make a note of each, using that number to calculate the overall height at each corner.

If you're only ballasting the driver's seat, you will not be able to get the left and right sides weight equal without shifting weight around; adjusting the spring perches will not help. I'm generally concerned with setting the cross weights to be equal so that's my goal during the corner balance.
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post #113 of 140 (permalink) Old 10-10-2011, 09:02 PM
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Thanks for the help, Andy.

BTW, I assume you met David MacMillan at Infineon. He was the guy with the red 2-Eleven that blew up early in the weekend.

He is a friend and bought the car after he experienced the light weight charms of my Elise. I put lots of miles in it at Chuckwalla last year. What a great car! You are a lucky guy! (as well as one putting the car to proper use!)

Also, if Carl sees this, Longacre is now making a toe gauge similar to the one he has. I just ordered one. Can't have too many tools!

Thanks again,


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Old stuff gone: Ferrari 275GTB/4, '69 1275 Cooper S. '72 500 Fiat, old Jags, etc. Never bought a boring car.
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post #114 of 140 (permalink) Old 10-10-2011, 09:35 PM Thread Starter
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You're welcome. Yes, I did meet David at Infineon...
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post #115 of 140 (permalink) Old 10-11-2011, 03:52 PM
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Out of curiosity, Ones must have adjustable eyelets on their shocks so the length could be adjusted to do corner balance? You cannot just adjust the shock perches on the shocks (ie:Track pack) because it will mess up the preload?
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post #116 of 140 (permalink) Old 10-11-2011, 04:32 PM Thread Starter
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Out of curiosity, Ones must have adjustable eyelets on their shocks so the length could be adjusted to do corner balance? You cannot just adjust the shock perches on the shocks (ie:Track pack) because it will mess up the preload?
It would be ideal if you could adjust the shock's length independently from the preload... but many shocks (including the track pack shocks) are only adjustable from the spring perch. So you have to compromise on which you feel is more important... preload or ride height/corner balance.

You could add helper springs if you thought that lowering the car reduced preload too much.
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post #117 of 140 (permalink) Old 10-11-2011, 09:22 PM
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The Nitron GT3 Package has adjustable eyelets. Of course I would recommend the V2 Valving.

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post #118 of 140 (permalink) Old 10-13-2011, 07:24 PM
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Thank you for clarifying guys! =)
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post #119 of 140 (permalink) Old 08-05-2013, 04:22 AM
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Hi guys ... thanks for info.

I found this useful Corner Weight Calculator ... it's simple to check balance.
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post #120 of 140 (permalink) Old 05-22-2015, 01:24 AM
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Did I miss out something?

50/50 for cross weight & left vs right.

How about front vs rear?

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