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    1. #141
      Join Date
      Apr 2009
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      san diego
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      5,102
      Country Flag: United States
      What about on tighter and slower autocrosses?

      Example: not alot of straight aways to accelerate therefore not a lot of braking to get the car to dive.

      How does a low roll/ high travel setup work under those conditions?



    2. #142
      Join Date
      Nov 2012
      Location
      Sacramento, CA
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      Quote Originally Posted by SSLance View Post
      Are you being easier on the brakes to keep the car from diving and unloading the rear tires on corner entry? Basically letting the car settle back to ride height before initial turn into the corner?
      No. I'll outline below.

      In other words, with this type of setup, where in the corner do you want the weight to transfer to the front, then the outside, then the rear on exit?

      I'll outline the optimum driving style for both common suspension set-ups;

      ---------------------------------------------------------------------------------------------------------------------------------

      For a Conventional Low Front Travel/High Roll Set-up:

      You can drive this set up deeper on corner entry because the stiffer front springs will prevent the car from unloading the rear tires too much or too quick.

      You need to drive this set-up deeper on corner entry ... and brake HARD ... to get the front end to compress as much as it can ... to get some loading on the front tires for cornering grip.

      If you don't brake hard enough ... the front end won't travel enough to properly load & grip the front tires ... and the car will push once you really start to turn it.

      If you brake too short ... or too soft ... you will have a mid-corner push.

      If you brake hard too early ... and get off the brake too early ... the front springs will push the front end up too early & push bad in the middle of the corner.

      If you brake hard too early ... and stay on the brakes long enough to prevent the front springs from pushing the front end up too early ... to avoid pushing bad in the middle of the corner ... you will have braked too long ... killing the corner speed.

      Because this set-up is more prone to mid-corner tightness, push or understeer ... the car doesn't get turned or "rotated" soon enough ... and you have to wait on picking up the throttle.

      If you pick up the throttle much before the car is turned or "rotated" ... it will push on exit ... until the front tires grip and snaps the rear of the car loose.

      ---------------------------------------------------------------------------------------------------------------------------------

      For a Modern High Front Travel/Low Roll Set-up:
      You can not drive this set up as deep & brake as hard on corner entry ... because the softer front springs will unload the rear tires too much, or too quick ... unloading & ungripping the rear tires ... and the car will be loose once you really start to turn it. This is easier to do because of the softer front springs and/or higher ride heights.

      You need to brake a little earlier on corner entry with this set-up ... and brake substantially softer, but hard enough to get the front end to compress ... to load the front tires for cornering grip. This is easier to achieve with softer springs and/or higher ride heights.

      If you brake too long ... you will kill the corner speed. Overall, you will need to brake less ... to keep the corner speed up ... to obtain the lap time advantage. This set-up will corner well at higher speeds. The same cornering speeds that would cause a push in a conventional set-up.

      If you brake too soft or too short ... the front springs will still push the front end up too early & push in the middle of the corner ... just less than a conventional set-up.

      Because this set-up is more likely to turn well in the middle of the corner ... you can pick the throttle up sooner ... and roll it on harder.

      ---------------------------------------------------------------------------------------------------------------------------------

      Make sense?


    3. #143
      Join Date
      Nov 2012
      Location
      Sacramento, CA
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      Quote Originally Posted by Bryce View Post
      What about on tighter and slower autocrosses?

      Example: not alot of straight aways to accelerate therefore not a lot of braking to get the car to dive.

      How does a low roll/ high travel setup work under those conditions?
      Frankly, with how soft the front springs are ... it happens plenty quick. Also with the stiffness of the rebound valving ran in successful set-ups ... it is not coming all the way back up to ride height.


    4. #144
      Join Date
      Aug 2012
      Location
      Peoria, AZ
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      Yeah, I gotcha...that makes sense. You need to time the braking to load the front tires at the optimum spot, but don't brake for too long or it'll scrub off too much speed.

      This will be a big change for me at my next road course track day. I'm typically an easy braker on the road course, more coast into a corner then power out of it. My last instructor was trying to get me to charge the corner harder, brake more aggressively, then roll the corner faster.
      Lance
      1985 Monte Carlo SS Street Car

    5. #145
      Join Date
      Nov 2012
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      Sacramento, CA
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      Quote Originally Posted by SSLance View Post
      Yeah, I gotcha...that makes sense. You need to time the braking to load the front tires at the optimum spot, but don't brake for too long or it'll scrub off too much speed.
      Yup !

      This will be a big change for me at my next road course track day. I'm typically an easy braker on the road course, more coast into a corner then power out of it. My last instructor was trying to get me to charge the corner harder, brake more aggressively, then roll the corner faster.
      That didn't quite sound right. You will need to brake softer.

      What your instructor was teaching back then ... is for a more conventional set-up.


    6. #146
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      Aug 2012
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      Peoria, AZ
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      What I meant was, he was trying to teach me to charge the corners and brake harder...which I was working towards near the end of our session.

      Now it sounds like with the high travel\low roll set up I'll have to back away from that a bit. And that's okay really as it might fit my more natural driving style better anyway.
      Lance
      1985 Monte Carlo SS Street Car

    7. #147
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      Nov 2012
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      Sacramento, CA
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      Quote Originally Posted by SSLance View Post
      What I meant was, he was trying to teach me to charge the corners and brake harder...which I was working towards near the end of our session.
      You got it. I was just twisted up with the wording This is for conventional stiff front spring/low travel/high roll set-ups,
      where the goal is to charge the corner entry hard ... drive deep ... and brake hard.


      Now it sounds like with the high travel\low roll set up I'll have to back away from that a bit. And that's okay really as it might fit my more natural driving style better anyway.
      Yup. With modern, soft front spring/high travel/low roll set-ups, where the goal is to carry more corner speed, you brake a "bit" earlier, brake softer & a little longer ... but overall using less braking to keep corner speed up.
      Then get'er turned & giddy up.


    8. #148
      Join Date
      Mar 2013
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      4
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      So after reading this thread and being absolutely blown away by the amount of useful information on here I feel the need to thank Lance for having the courage and wherewithal to post his handling problems in a logical manner. Also I'd like to thank Mr. Sutton for answering the questions in such a way that even guys like me understand it and can hopefully start to apply it to my truck.

      So...

      Thank you guys for the support you have shown to the members of this forum.

      -Adam

      Also, I have some questions for you Mr. Sutton but I will PM you. I don't want to hijack the thread with my own questions.

    9. #149
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      Nov 2012
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      Quote Originally Posted by AJohn6 View Post
      So after reading this thread and being absolutely blown away by the amount of useful information on here I feel the need to thank Lance for having the courage and wherewithal to post his handling problems in a logical manner. Also I'd like to thank Mr. Sutton for answering the questions in such a way that even guys like me understand it and can hopefully start to apply it to my truck.

      So...

      Thank you guys for the support you have shown to the members of this forum.

      -Adam

      Also, I have some questions for you Mr. Sutton but I will PM you. I don't want to hijack the thread with my own questions.

      Thanks for the kind words. PM your questions & we may start our own thread.


    10. #150
      Join Date
      Aug 2012
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      Peoria, AZ
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      Making a little bit of progress this week so far. Tuesday night I pulled the driver side LCA and coil spring out and put the DSE LCA with Howe tall ball joint in place with no coil spring. I then used the lift and some car ramps to cycle the suspension to the bump stop limits up and down while recording the shock length and fender height measurements every inch along the way. This will aid us when the time comes to set the adjuster height on the spring to dial in final ride height.

      Here is the passenger side at current ride height and all of the old pieces still in place



      and here is the driver side at same height but with new LCA and BJ in place



      Notice the different tie rod end angles.

      This picture shows the UCA bump stop on the passenger side



      And here is the driver side UCA bump stop with new parts in place



      Both pictures at current ride height as measured by the fender.

      I then put a tape measure on the outside of the frame rail and measured to a tread block on the front of the tire (and also a second measurement to a framing square up against the outside of the tire) as I cycled the suspension from full compression to full extension to document how much bump steer is happening with the new LCA and the old tie rod end. That's where I stopped last night.

      As it sits the tie rod adjuster contacts the frame just as the LCA bump stop hits the frame. Ron asked me to remove the bump stop and tie rod and cycle the suspension even further up, see what hits next and record shock and fender height measurements as I go...all to further document the new suspension travel points. Then I'll put the bump steer correction kit on the drivers side and measure the new bump steer travel at all points. Once armed with these measurements, Ron will direct me on how to set up the bump steer kit for optimum correction.

      I've also been sourcing the needed parts and tools to correct and remount the LCA bushings in the cross member. Since this car is Metric, this was a bit of a difficult task. I ended up going to two local fastener stores and placed mail orders with 2 more stores to get everything I need. hopefully I'll have everything in hand by Friday and can make some serious progress this weekend.

      Parts and tools purchased

      M12-1.75x110 Socket Cap Screw 12.9 (2) (shoulder is 0.4685, ID of bushing is 0.4750)
      M12-1.75x120 Socket Cap Screw 12.9 (2)
      M12x24x3mm const. flat washer hard zinc plate (8)
      M12-1.75 All Metal Top Lock ZP Nuts (4)
      3' piece of 12mm drill rod
      Flat Washer, Thick, Blk Oxide, Fits M12, Pk5 (2)

      The last item being the hardest to find. Here is how they are described, Flat Washer, Extra Thick, Case Hardened Steel, Black Oxide, Fits Bolt Sizes M12, Inside Dia 13mm, Outside Dia 26mm, Thickness 5mm, Thickness Tolerance +0.4/-0.5mm, Rockwell Hardness C40, Load Distributing, For Use With Die And Jig Fixture Setup. Finding an extra thick, case hardened, M12 washer locally proved to be an impossible task.

      I'll use the drill rod to put through the crossmember holes and LCA bushings and elongate the holes in the crossmember to place the control arms in the preferred position. The thick, case hardened washers will be what gets welded to the crossmember to hold the control arm bolts in place once the new positions have been set. Then the new longer bolts with tighter tolerances to the ID of the bushings will be used to hold the control arms in place while not restricting the movement of the control arms up and down.

      That's where I'm at now, will update once again once more progress is made. Wish me luck on it all going smooth...

      Lance
      Lance
      1985 Monte Carlo SS Street Car

    11. #151
      Join Date
      Jul 2005
      Location
      Grain Valley, MO
      Posts
      92
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      Nice work Lance! I might have to step up to 315s when we race next season.

    12. #152
      Join Date
      Aug 2012
      Location
      Peoria, AZ
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      1,758
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      This will be fun Patrick, the 2013 KC Region ESP and SM Champions going head to head in SMC in 2014!!

      Are you going to be in a Camaro or a WS6 is the only question?
      Lance
      1985 Monte Carlo SS Street Car

    13. #153
      Join Date
      Feb 2013
      Posts
      38
      Country Flag: United States
      On moving the lower control arm. I slotted mine a 1/8 to 3/16 and got about 9/16 at the ball joint. It stayed within the steel sleeves in my circle track solid bushings. I also put a come along and pulled the a frame forward while tightening the bolts to help in distorting the frame. Made my own .125 thick washers but not hardend. The stock bolts were long enough to fit everything. How far are you shooting for?
      Slotted with die grinder and carbide bit

    14. #154
      Join Date
      Aug 2012
      Location
      Peoria, AZ
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      It is amazing to me how much just a little of movement at the bolt translates to a large movement of the ball joint, still trying to wrap my head around that.

      Ron will have to answer specifically how much we are looking to move the holes, but I think our first objective is to get the passenger side to match the driver side in lower ball joint placement and to get all 4 holes in the cross member on each side perfectly in line so there is no bind to restrict the up and down movement of the LCA, then go from there for more built in caster. I have room in the wheel well to move the tire forward as it sits back of center now. The further forward we go, the more adjustability we'll have with the upper control arm mounts. The downside of going further forward is greater bump steer movement and possibly clearance issues with the tie rods and sway bar.

      We'll have to see how it all shakes out, but in the back of my mind, I'd love to see both sides exactly equal and 9+ degrees of positive caster with the inset slugs in my UCA cross bar offset back and be able to swap that slug to center or forward to have less positive caster (and bump steer) for daily driving. Easy changing from an optimum track setup to a street setup would be an ultimate goal for me, it remains to see if that goal can be reached though.

      This exercise has been a great learning experience for me, I'm really starting to recognize how it isn't just a toe setting, or a camber setting, or even caster or KPI angle...it is how all of these settings work together as the suspension cycles up and down and the steering wheel is turned. We are trying to maximize all we can with all of these settings while working with the parts we have and the platform already in place. I can't wait to see how it all turns out.
      Lance
      1985 Monte Carlo SS Street Car

    15. #155
      Join Date
      Nov 2012
      Location
      Sacramento, CA
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      Lance & I have discussed moving the lower BJ forward a total of .800" to gain 4° of caster "potential". The LCA from DSE moves the lower BJ .400" forward ... so we'll get the other .400"+ through LCA pivot modification.

      In the end, you want the LBJ on both sides to be in identical in X & Y distances. And you want the pivot of the LCA to be 100% true, which most are not from the factory.

      .

    16. #156
      Join Date
      Aug 2012
      Location
      Peoria, AZ
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      28 year old rubber bushings...









      New parts, full droop





      Full stuff





      Video of wheel travel with all new parts mocked in place.

      New wheel travel - YouTube

      Still don't have my drill rod or washers so no modification on control arm bolt holes done yet.
      Lance
      1985 Monte Carlo SS Street Car

    17. #157
      Join Date
      Jul 2011
      Location
      NC
      Posts
      461
      Country Flag: United States

      Need a little help figuring something out

      Awesome work Lance! Thanks for documenting everything so we can all learn! I hope to be there doing the same very soon.
      Josh
      "Schism"
      69 camaro

    18. #158
      Join Date
      Aug 2012
      Location
      Peoria, AZ
      Posts
      1,758
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      Since I was still waiting on my drill rod and right sized washers to get here, I didn't any parts to work with Sunday, I built some homemade alignment tools.







      Custom fender height measuring device...



      Slide plates...




      Everything still need a bit of tweaking and I need to reposition my camera differently, but here's a video of them in action for the first time.

      New homemade wheel alignment tools in action - YouTube

      I think it will view better if I have the camera stationary, not stuck to the car and I need to find out if my digital angle finder has a back light. Also I'll figure out a better way to measure the toe change with more accuracy.

      Notice the two pieces of laminate under the tires, had them kicking around...cut them up and they slide on each other real nice. Should be able to hang a tape measure across the front and back of the 1/2" steel rod to measure and set toe real easy by myself and can also measure camber pretty easily as well. If I can figure out a way to set the upright part of the tool in line with the ball joints (can't see them from the outside) I can measure caster with them as well.

      Anyway, that's how my Sunday went, hope all or yours was good too.
      Lance
      1985 Monte Carlo SS Street Car

    19. #159
      Join Date
      Nov 2002
      Location
      state of confusion
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      1,499
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      Alternatively (and probably easier) just sweep the wheels from some known angle right to the same angle left, take the algebraic difference between camber readings taken at those positions, and multiply by a factor that depends on what that angle right and left was. Most of the commercially available camber gauges use ± 20° and a 1.5 factor is built into the caster vial, but you could also use ± 15° where the factor = 2.


      Norm
      '08 GT coupe, 5M, suspension unstockish (the occasional track toy)
      '19 WRX, Turbo-H4/6M (the family sedan . . . seriously)
      Gone but not forgotten dep't:
      '01 Maxima 20AE 5M, '10 LGT 6M, '95 626, V6/5M; '79 Malibu, V8/4M-5M; '87 Maxima, V6/5M; '72 Pinto, I4/4M; '64 Dodge V8/3A

    20. #160
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      Aug 2012
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      Peoria, AZ
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      There has to be an easier way Norm, right?

      Some progress tonight. Got my drill rod and washers in today. After having the washers turned out to 0.475 ID I headed home to put the rods and washers in place. As Ron warned me, I had to ream out two holes on the driver side and one on the passenger side to get them all lined up in a row straight enough to get the rod through. After some finagling, I got the rod and washers in place. A couple of the holes could have used a bit more work, but since it's all coming apart and more work on the holes needs to be done, I left it for the night.

      Some notes in case anyone else wants to do this on a metric chassis. The stock LCA bolts are 12 mm. I ended up with a 12 mm drill rod, and 7/16s case hardened extra thick (5mm) washers which we turned the inside out to 0.475 ID which is also the ID of the bushings in the control arms. The 12 mm washers I ordered first had 1 mm of play between the washers and drill rod which isn't acceptable.

      Anyway, here's the pics of the rods in place.














      Also had some time to try out my new laser pointer to check the bump steer. I started at 26" fender height which might be where the ride height ends up, then dropped it by 1", measured, then 1" and measured, then raised it to 27" and measured. I had the graph paper up against the front of the inner fender and was using a marker and there wasn't any room between the marks, so I moved the graph paper up 7 feet in front of the car and remeasured.

      7' in front of the tie rod ends, the toe moved out 3/4s of an inch with the 2" of suspension compression, and a 1/4" in with the inch up from ride height...and was the same on both sides. Someone better at math than me might have to help figure out how much it's moving at the tires...I know this though, it ain't much.







      That's it for now. Up next is the moving of the holes and welding the washers in place.
      Lance
      1985 Monte Carlo SS Street Car

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