This is why you don't run stock suspension...

Discussion in 'Road Racing Forum' started by domesticpower, Jul 28, 2019.

  1. Norm Peterson

    Norm Peterson Corner Barstool Sitter

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    Dunno why people seem to look at pitch and roll motions as separate problems unto themselves.

    Domestic's post #1 picture does show a rather extreme amount, but it apparently didn't constitute much of a handicap even though the car might be on the bump stops.


    Norm
     
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  2. Norm Peterson

    Norm Peterson Corner Barstool Sitter

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    I'm wondering how much "anti-rise" is really necessary or desirable. Stock is pretty poor at something like 30% anti-squat (the related parameter that's easier to determine).

    I've had what domestic's car shows (picture might have been taken on the run where I sent a Camaro back to paddock ;) ). It's better now with about 50% more rear spring (and about double the OE front rate). But I may be in the market for UCA adjustability and don't want to overdo the anti-squat/anti-rise thing. Something about geometric load transfer possibly being too rapid for street tires if there's too much of it . . . vs how much rear spring might be too much for other reasons.

    2012_run_to_the_shore_start_stop_squared10a.jpg


    Norm
     
  3. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

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    I blame the aftermarket. ;)

    Not really sure I should get into a serious answer on this.

    Absolutely agree. I had about the same initial reaction.

    'Necessary' and 'desirable' are hard to quantify when the trade-off might be the ability to put power down.

    "Don't overdo" is a good place to start. Unfortunately, most UCA brackets don't have much room and adjustment to work with, and LCA brackets usually start at a 2" lower position. Makes it easy to overdo on the adjustments without control over spring/ride height.
     
  4. Norm Peterson

    Norm Peterson Corner Barstool Sitter

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    Don't hold back on my account. I see inertial motions as being consequences, not causes.


    Makes sense. Would probably make the best solution for me different from what would be best for domestic. I suspect that a 4.6 car is always going to be something of a "momentum car" compared to any Coyote-powered car.


    "Don't overdo" is exactly what I'm looking for. More as an anti-squat % target than "which hole combinations to not use".

    Adjustment capability is that coarse only as long as one limits his thinking to using the adjustment locations provided with those brackets in their "out of the box" condition . . . or even with just another set of holes added.


    Norm
     
    Last edited: Aug 7, 2019
  5. blacksheep-1

    blacksheep-1 TMO Addict

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    I think you will find that the shocks are going to be key, and unfortunately, I don't know what to tell you guys because of the expense, there is a guy named Carter Schrader, who works at Hoosier Midwest that has gotten into the shock biz, you might give him a call, drop my name if you want. Basically the cars are built around the shock package.
    I'm seeing a lot of body movement down to the bumpstops, a lot of guys are going to bumpstop cars these days, besides the stock car crowds, but with it comes a lot of body movement in order to make it all work. one then must manage all that movement which is why the shock package becomes so critical.
    The statement about stock 200TW tires and would this suspension work with them, all I have to say is that, like everything else, it's all good..up to a point, then the tire overloads and you go into a big push, so you need to build up to that max level and you do this mostly with the shocks and springs. AJ was a master at this, he would make rate changes in as little as 15 pounds. It's very hard to do this as a one man show, you need at least one other person just to collect tire and temp data, that's why I think it's a false economy to go out and buy the newest, trickest.. stuff..but yet you have no data to back it up. You'd be way better ahead to run a baseline setup, collect data, revue it, make a change for session 2 and go back and do it all over again.
     
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  6. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

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    Well said Rob.

    Collecting data *is* hard as a one man show. So is learning how to set tire pressures by charting, etc...and learning how to adjust spendy dampers...adjustable suspension parts...same thing. It has been and continues to be a bit of work.

    It's been fun and educational work, but somewhat detracts from the effort to simply work on better driving. I find more and more that I'm inclined to tell people to drive their cars stock longer and only start to mod to fix specific issues or to work with upgrades in tire compound or sizes...or when it's really the car that's limiting lap times.

    Agreed, and it's not you or any single person I'm concerned about. Maybe if the topic comes up again later.
     
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  7. Coz

    Coz TMO Race

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    Congratulations!
    You just made Vorshlag's latest email (with the 08 photoshopped out!
    Screenshot_20190807-230735.png
     
  8. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

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    LOL. There you go. Exactly what I was getting at Norm. ;):D
     
  9. Norm Peterson

    Norm Peterson Corner Barstool Sitter

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    For sure . . . and I caught OP's new-found fame myself.

    I've even got my own pic from a few years back, from a speed-stop-squared run (good chance it was the run that got a Camaro sent back to paddock ;) )
    2012_run_to_the_shore_start_stop_squared10a.jpg

    Obviously, there's such a thing as too much motion, that either runs the suspension out of bump travel or perhaps just takes a bit too long to happen. That said, the tone I keep picking up in most everybody's complaints (and in much of the advertising copy) is that if there's enough inertial movement to see, that's itself the definition of "too much".

    Do you suppose that's because most people are subconsciously indexing "on track" amounts of inertial motion against their normally mild street driving where there's hardly any "nose dive" or roll?


    FWIW, my car isn't quite that bad now, guessing about half as much dive up front and maybe 2/3 as much rise out back . . . so maybe down to about 60% as much pitch. It was the time element involved - it started feeling like it was taking too long to happen - that finally drove the spring change rather than the amount of pitch itself. Wheel rates now are roughly comparable to the current GT350R, still fully streetable. Even my wife doesn't mind, as long as for any longer rides or rides over roads known to be in rough shape I dial the dampers back a bit from where I put them for my own driver-only street use.


    Norm
     
    Last edited: Aug 8, 2019
  10. domesticpower

    domesticpower Track Addict

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    I really enjoy how discussions evolve on this forum. Whether or not I (or others) agree with other opinions, it's refreshing to see that people here seem to have arrived to their conclusions after doing some critical thinking instead of just reading something somewhere. I find this rare in online forums.

    I completely agree that the impact of body roll and pitch is very exaggerated online... and I took advantage of that that with my post for views lol... sorry.

    The biggest issue like Rob said has always been overloading tires. This is becoming less critical as new tires are getting developed, thanks to factory 4,000 lb. track cars which sounds like an oxymoron! Tire weight capacities and grip seem to continue to go up despite the weight, where that wasn't possible just a few generations ago. I think tire manufacturers are responding to heavier performance cars so optimal grip points are getting pushed higher and higher (relative to weight) to make them work on heavy cars (and "track" SUVS! like a 5,000 lb. X5 M or Trackhawk). Another really big problem with that amount of body movement is the delay, which is where good dampers with a well matched spring rate shine. Generally speaking, softer suspensions allow more body movement but weight transfer is not complete and suspension isn't loaded until the body is settled. That makes transitions slower (in terms of response and possible speed as a result). Smooth driving and tracks without tight or quick transitions don't suffer as much but it will ultimately still be limited by the suspension.
     
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  11. domesticpower

    domesticpower Track Addict

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    Driver mod!! ;)

    In seriousness, the platform is very capable and the vast majority of people in my experience, even fast drivers, don't learn to drive their cars to the limit, instead relying on improving the car and continue to drive up to "only" 80-90%. I find that it's one thing to be comfortable with speed (approaching a corner at speed and braking late, carrying a lot of speed into a corner, etc.) which is where most fast drivers end up in my experience, and something else to get used to truly driving a car at the limit, where it will tend to move around a bit. Not to many people are comfortable with the latter.


    Haha thanks for sharing! Any credit or mention by any chance in the rest of the email?

    I think you're absolutely right that the tone is "if it looks too much, it is too much" but I don't think that's true. If the tire isn't getting overloaded and you don't find yourself having to wait for delayed weight transfer, it's as stiff as it needs to be. Super stiff suspensions are really only needed because of aero and the massive loads they generate. On most tracks that aren't meticulously maintained and absent big aero, relatively softer is always better IMO.
     
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  12. blacksheep-1

    blacksheep-1 TMO Addict

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    Well, I'm going to go back to the pic that many of you have seen before, this is the pole run at VIR a few years ago. Contrary to popular opinion, this car is dialed right in. squat, wedge, body roll and all, this car is using ALL of it's suspension and is launching off that corner.

    [​IMG]
     
  13. ChrisM

    ChrisM No bad days.

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    I hope they at least left the watermark on that picture.
     
  14. blacksheep-1

    blacksheep-1 TMO Addict

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    The Phoenix car is on a poster too....

    [​IMG]
     
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  15. Coz

    Coz TMO Race

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    Oh boy. I just assumed they checked with you before using it. No credit that I can find and it looks like it was cropped and the watermark was in the portion deleted.

    Didn't intend to stir up a hornet's nest...
     
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  16. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

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    @Fair @modernbeat
     
  17. 302BOB

    302BOB TMO Addict

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    Hornet's nests ARE never a good thing to mess with!!!!!....I came in contact with one, yrs back while trimming my bushes and paid the price..............dearly!!!
     
  18. blacksheep-1

    blacksheep-1 TMO Addict

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    so how did we go from suspension setups to copyright infringements?
     
  19. Coz

    Coz TMO Race

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    Any autographed versions available?

    Blame me...
     
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  20. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

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    ..not like the email wasn't blasted to a bunch of subscribers.
    Business As Usual. Welcome to TMO. ;)

    Always glad to hear it! Consensus and group-think are always great...except when it's not. :D ;)
     
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