+ Reply to Thread
Page 2 of 3 FirstFirst 1 2 3 LastLast
Results 21 to 40 of 51
Like Tree7Likes

Thread: How to do an alignment with a string system?

  1. #21
    http://www.trackhq.com/Banners/yellowsitesponsor.gif
    Join Date
    Jul 2012
    Posts
    151
    Liked
    51 times

    Default

    Joe!!!!!! Good to hear from you.

    The big take away from your email for everyone IMO is the commitment you guys had to making changes to the car at the track for what the driver was experiencing. Whatever method anyone uses, the important thing is repeatability and consistency in process. This allows you to establish a baseline that can be used every time you set the car up and give you consistency and confidence when moving away from that baseline as the track and driver demand a change.

    My go to setup adjustment at the track is rake/derake, adjusted at the rear. Has minimal impact on camber, toe, cross weight. After that, rear bar and front toe. I try hard not to use tire pressures too much to correct handling. I may be able to correct the problem for an ideal lap, but at the expense of overheating a tire on a long run. That said, tire pressures adjustments are my weak spot and I have probably settled into my method to mask that deficiency. Something I need to work on more.

  2. #22
    Senior Member fatbillybob's Avatar
    Join Date
    Sep 2008
    Location
    by the beach
    Posts
    1,958
    Liked
    1562 times

    Default

    Quote Originally Posted by Joe jordan View Post
    Hey James and Brett, you probably remember Joey and I doing a bazillion alignments a weekend at the track. .
    Joe,

    Can you comment on what you try to achieve with a bazillion adjustments? What exactly does that mean? During practice do you say to yourself I want more top speed in T8 @WSIR because I'm in that turn a long time. So you dial in more negative camber on the left side and see if the lap time falls? If so how do you decide or prioritize goals?

  3. #23
    Member
    Join Date
    May 2012
    Posts
    77
    Liked
    65 times

    Default

    Quote Originally Posted by fatbillybob View Post
    Joe,

    Can you comment on what you try to achieve with a bazillion adjustments? What exactly does that mean? During practice do you say to yourself I want more top speed in T8 @WSIR because I'm in that turn a long time. So you dial in more negative camber on the left side and see if the lap time falls? If so how do you decide or prioritize goals?
    It is very track dependent, but we usually talk about the most important corners of the track before the weekend and dial in the car to those corners, I am an old tire guy so I am very comfortable messing with the tires, I use contact patch as a key tuning element and also consider the tire a spring IE the lower the pressure the softer the spring, higher pressure the higher the spring. We always ran higher tire pressures than almost everyone else except at lower grip surfaces like Mazda raceway Laguna Seca.

    In regards to the bazillion adjustments, this was on test days, we would always start by making one adjustment at a time, so we would literally align the car 5-10 times a day on a test day, people thought we were crazy most of the time... We would dial in the most important corner on the track, for example at Willow springs we would say turn 9 because it connected the two longest straightaways. and try not to give away anything in other parts of the track, we would then dial in the second most important corner on the track without giving up anything for the most important and so on. I felt rake and cross weight were bigger adjustments than toe and tire pressures, Once we got to know a track like Willow springs and or MRLS we would run asymmetrical setups with less camber on one side of the car than the other to help it go through left handers at MRLS and Right handers at Willow Springs.

    We very rarely worried about top speed except at Cal Speedway and or Road America or someplace with really long straightaways, spec miatas were all so close we did not get hung up on that and chose to focus on corner entry minimum speeds as we learned that exit speeds were all very similar but how you got to them was different, in many cases when you watched our car race it appeared that the car gave up under braking, but actually he was transitioning to the throttle before most to gain the time between braking and full throttle if that makes sense.

    Hope that helps

  4. #24
    Member
    Join Date
    May 2012
    Posts
    77
    Liked
    65 times

    Default

    James,

    We all have our strengths and weakness areas! I have a longtime tire background so I am very comfortable with them. In regards to rake we changed it very little and actually used camber mostly in the rear to tune the car for specific corners, as you may remember Joey liked a car that turned in quick and that was very loose, so many of our adjustments were standing up rear tires and tire pressures. Rake and or cross weight were too big an adjustment usually for Joey. He was looking for small changes, we knew the car so well from racing them from 94-99 in the Speedvision cup (now continental series, one time I knew how many racing miles we had in miatas in those years and it was something like 72,000 race miles!!! Several 24 hour races and all endurance racing) Will Rodgers like the car a touch tighter but not much, but some would say the car was undrivable lol.....so everyone has their own way and the key is to not be afraid to try anything.

    I don't think we ever made a sway bar adjustment after the first few events and did do some testing with no bars to see if we could improve grip... To help you with tires, think of tires like a spring rate, they actually do have a rate that Toyo or Hoosier can provide and it does change with pressure. We ran most of the time as close to 50.0 cross as we could. Every time I dialed in some cross that I thought would work he would complain the car was not consistent and it made him hesitant to go all out like he wante, he wanted a car balanced in what it felt like in every corner and the small changes to air pressure and camber and toe would give him enough to go fast with confidence.

    I was open to sharing any of our setup with anyone that asked, i'd tell them what we did and most did not believe the toe settings and tire pressures we ran, they thought I was lying, but I wasn't it just worked for us!

  5. #25
    Senior Member
    Join Date
    May 2017
    Location
    South FLA
    Posts
    116
    Liked
    5 times

    Default

    Great info guys. So I invested in some hub-stands and made a string rig along with having a camber gauge.
    I understand that in order to get the toe of a wheel I need to take a measurement from the string to know point on the rear and front of the wheel ? The goal is to have the toe amount equal on both side of the car.
    I came up with a spread sheet just to understand this better. Can someone please confirm I am on the right track?

    I also read above that hub-stands gave a different measurement that with the wheels on ? That makes sense, but its not a bad thing is it?

    Last edited by FoxSTI; 05-10-2017 at 07:40 PM.

  6. #26
    Senior Member
    Join Date
    May 2017
    Location
    South FLA
    Posts
    116
    Liked
    5 times

    Default

    Another question, when you guys add or subtract camber or toe (most importantly) at what increments do you do this?
    I remember when racing 8th scale nitro RC cars we would work on 1/2 degree increments.

  7. #27
    Senior Member fatbillybob's Avatar
    Join Date
    Sep 2008
    Location
    by the beach
    Posts
    1,958
    Liked
    1562 times

    Default

    Quote Originally Posted by Joe jordan View Post
    I was open to sharing any of our setup with anyone that asked, i'd tell them what we did and most did not believe the toe settings and tire pressures we ran, they thought I was lying, but I wasn't it just worked for us!
    1st sorry for the side-bar but this is really interesting stuff. Joe, are you basically tuning with akerman creating more over steer torque to get turn-in and corner entry and seeing what your data says is faster? If so how much of that is really driver dependant? If a guy is not a trail braker you need more akerman. If a guy trail brakes you need less because trailing improves turn-in. What about tire pressures now? I think of tire pressures to achieve max lateral grip. But I suppose you can use tire pressure to alter loads and thereby induce more yaw under braking to improve turn-in for one direction like the entry of turn3 at ACS. Is this the kind of tuning you are getting at with toe and tire pressure?

    What does this level of precision net you in regards to lap time? Are we talking this improves 10ths or a is there a whole second to be found there or even more???

  8. #28
    Member
    Join Date
    May 2012
    Posts
    77
    Liked
    65 times

    Default

    FOX STI, yes I believe you are on the correct path. I don't think it matters if it's different at the wheels, but you need to understand the differences. For example I love hubstands for scaling the car and initial setup, but feel it takes to long at the track to set them up so I get down and dirty to achieve speed in changes at the track.

    Most guys that I see don't spend a ton of time tuning their alignments at the track they use rake and or cross to tune the car.

    JJ
    Last edited by Joe jordan; 05-11-2017 at 12:12 PM.

  9. #29
    Member
    Join Date
    May 2012
    Posts
    77
    Liked
    65 times

    Default

    Quote Originally Posted by fatbillybob View Post
    1st sorry for the side-bar but this is really interesting stuff. Joe, are you basically tuning with akerman creating more over steer torque to get turn-in and corner entry and seeing what your data says is faster? If so how much of that is really driver dependant? If a guy is not a trail braker you need more akerman. If a guy trail brakes you need less because trailing improves turn-in. What about tire pressures now? I think of tire pressures to achieve max lateral grip. But I suppose you can use tire pressure to alter loads and thereby induce more yaw under braking to improve turn-in for one direction like the entry of turn3 at ACS. Is this the kind of tuning you are getting at with toe and tire pressure?

    I have not thought of it in the way you describe, but after talking to many guys I respect who coach and are top drivers themselves they consistently told me the speed between a fast guy and pretty fast guy was all before the apex of the corner. So speed was gained with higher minimum speeds and getting on the gas just slightly sooner. Exit speeds were always very similar. The gap between a slow guy and fast guy were much more pronounced. This philosophy is why we focused on turn in (toe ackerman) and to the apex with our tuning and didn't really focus on much else other than balance. We also went with some radical to most set ups like asymmetrical camber, different camber on every corner on some tracks and whacky tire pressures, most also though we ran way to much toe out in the front! We also ran a lot of toe out in the rear of a FWD car....

    In regards to tire pressures, I think speed is created through driver confidence so the consistency of the contact patch is the most important especially to a newer driver, as the driver develops they can handle a changing contact patch. Higher pressures create a more consistent contact patch even if sometimes it's smaller contact patch than low pressures.

    In regards to trail braking, my driver my kid did do a fair amount of trail braking, but what he was most concerned with is the initial turn in, after turn in he has very quick hands and if you watch his in car he is always correcting not the classic slow hands smooth approach, many have commented about this in his videos which I find funny, because most of the ones negatively commenting about that aren't driving at the absolute limit. Also the different tire pressures were used to get the car through a specific corner for example at willow springs mostly right handers the car may have a slight push in turn 1 so we would raise the RR tire pressure to compensate for that, the car most likely had a degree less negative camber in the right side than the left to get through the left handers faster.... the slightly higher tire pressure would stiffen up the car for that specific corner without negatively affecting the speed through the other corners. Does that make sense?

    Here is a video for your entertainment. This was a borrowed car as we hurt our car in qualifying, so it's not completely our normal setup but you can see his hand movement.

    Watch This Spec Miata Driver Go From Last to First in Just One Lap


    One other note, the Norcal crew tend to run lower tire pressure as they run on low grip tracks like MRLS and Sears Point frequently, my opinion is the more squirm in the tire, lower pressure helps create heat in the tires and thus grip at those tracks, so we would run lower than normal pressures for us. Sears Point especially is a track that local knowledge is king, we would always do pretty well there but not as well as we did at Thunderhill that has more grip and our higher pressures seamed to work better and most did not change pressures depending on the track. I think this is also why some spec miata guys say some tracks like old tires and some like new tires, they just arrive at their findings differently.


    What does this level of precision net you in regards to lap time? Are we talking this improves 10ths or a is there a whole second to be found there or even more???
    When we first started and he was developing as a driver the times gained were significant 1 second or more as he become more refined and a better driver less time was gained. We see anywhere from a .1 to .5 per lap from the the first session (baseline) settings to the last after many changes or a few depending on the track. In spec miata that is a big swing. I think James and Brett can attest to that.
    Last edited by Joe jordan; 05-11-2017 at 08:13 AM.

  10. #30
    Member
    Join Date
    May 2012
    Posts
    77
    Liked
    65 times

    Default

    I have no clue how I answered the above in a quote sorry about that. I tried to highlight it in bold with edit feature, I can set up a car, but I'm an idiot on the forum

  11. #31
    Senior Member fatbillybob's Avatar
    Join Date
    Sep 2008
    Location
    by the beach
    Posts
    1,958
    Liked
    1562 times

    Default

    Quote Originally Posted by Joe jordan View Post
    I have no clue how I answered the above in a quote sorry about that. I tried to highlight it in bold with edit feature, I can set up a car, but I'm an idiot on the forum
    Your commentary is way more important than format. Thanks for your insights. Is there an issue of trying to chase good setup as the tire degrades? Can you find 10ths without keeping other parts of the setup the same like new tires?

  12. #32
    Member
    Join Date
    May 2012
    Posts
    77
    Liked
    65 times

    Default

    Quote Originally Posted by fatbillybob View Post
    Your commentary is way more important than format. Thanks for your insights. Is there an issue of trying to chase good setup as the tire degrades? Can you find 10ths without keeping other parts of the setup the same like new tires?
    There are big disagreements on this, some say you can only setup on new tires, but the bottom line is I'm a cheap bastard and would usually setup older tires. We got good enough to know how the new tires would help the car and it usually just made it much easier to drive but not that much speed... Also since I was always trying to make the setup work for the end of the race used tires were good enough. The key was not dead old used tires but decent old used tires, (still some life left in to them)

    Also that is track dependent, at Willow Springs new tires are always faster, turn 2 and 9 tear up tires! New tires will beat old tires every time at Willow Springs. The rougher the track or course surface the more new tires come into play.

  13. #33
    Senior Member
    Join Date
    May 2017
    Location
    South FLA
    Posts
    116
    Liked
    5 times

    Default

    Are you guys then suggesting setting up the car is better with tires than on hubstands?

  14. #34
    Member
    Join Date
    May 2012
    Posts
    77
    Liked
    65 times

    Default

    Quote Originally Posted by FoxSTI View Post
    Are you guys then suggesting setting up the car is better with tires than on hubstands?
    Both or either will work. I use hubstands at the shop or garage and strings at the track. It depends on what you want. The hubstands are definitely the best for the initial setup after a new car or major component build, but like anything in racing their is more than one way to skin the cat.

  15. #35
    Senior Member
    Join Date
    May 2017
    Location
    South FLA
    Posts
    116
    Liked
    5 times

    Default

    Joe, do you not use strings to set your toe and angle the the hub stands? Where can I see how that I done ? or how to you do it with out strings ?
    My stands have these "toe bars" But what do I reference their ends to - you know?

    Honestly the strings are a PITA in my small garage.

  16. #36
    Member wagnerov's Avatar
    Join Date
    Mar 2014
    Location
    Sunnyvale, CA USA
    Posts
    67
    Liked
    45 times

    Default

    Quote Originally Posted by FoxSTI View Post
    Another question, when you guys add or subtract camber or toe (most importantly) at what increments do you do this?
    I remember when racing 8th scale nitro RC cars we would work on 1/2 degree increments.
    Ahhhh, memories of my 1/10 and 1/8 nitro on-road R/C days. Most people are surprised (for better or worse) at how much carries over from little car setup tools and tricks to big cars. If only I could fit a complete Hudy setup on my Miata. Hub stands put one halfway there.

  17. #37
    Senior Member
    Join Date
    May 2017
    Location
    South FLA
    Posts
    116
    Liked
    5 times

    Default

    ^ When I first talked to Brion (BBX) I told him, "you know? I had something similar from Hudy when I used to race RC cars when I was younger"

  18. #38
    Senior Member
    Join Date
    May 2017
    Location
    South FLA
    Posts
    116
    Liked
    5 times

    Default

    Are you guys familiar with the ART Laser String II Four Wheel Alignment kit?
    $1600.00 MSPR.

    Any one have experience with it? seems pretty logical and comparable to strings, it is worth the money / I maybe I should ask, why is it so expensive.
    MK Technologies - ART Laser String II

  19. #39
    Senior Member
    Join Date
    May 2017
    Location
    South FLA
    Posts
    116
    Liked
    5 times

    Default

    I was looking at the laser method and I leaner that what you need is a LASER LINE device, not a "pointer" (so the process now makes sense.)
    I really like what ART has done, but the system is a but our of my budget at the moment.

    However, I have made a car specific rig for my cars to use strings, but if I place a Bosch GLL (+/- 1/8" @ 33 ft.) on each end and just square them to the wheel hubs (or a know point for that matter). No different than string, however I only need to place the fixture of one end of the car (unlike smart strings) and there is not string to deal with.
    I did a little layout in CAD to see what the margin of error would be with a car that has a 10' wheel base.

    Turns out that the front wheel I would be +/- 0.0076 " and Read +/- 0.0455" (this is mount the fixture at the front bumper (just like strings).

    There will always be human error in these approximations, but I am wondering if starting with that margin of error makes sense.

    The one thing I like about my setup in that lasers are attached to the car, not the floor, and I do not need a 3rd laser. Any thoughts?

  20. #40
    Senior Member albertg's Avatar
    Join Date
    Feb 2010
    Location
    Long Beach, CA
    Posts
    148
    Liked
    35 times

    Default

    I think most alignment shops reference toe to a 24in wheel, correct? The hubstands come with a toe bar that is 24in. So if you measure toe at the ends of those bars, you will likely be speaking the same language to most when they describe their toe settings.
    1990 S2 SuperMiata

+ Reply to Thread
Page 2 of 3 FirstFirst 1 2 3 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts