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Thread: The Rear Grip Thread: Ride Height, Spring Rates, Anti-Squat

  1. #76
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    I think I have 850s on my car (rear), and they feel great. Only a little over 300hp through a slushbox though, so who knows how that translates... Really does feel right though.

  2. #77
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    Length?

  3. #78
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    Well thus is where I ended up after installing offset RTABs backwards lol, we’ll see how she does next weekend.
    Last edited by Novablue454; 11-11-2017 at 09:26 PM.

  4. #79
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    This Thread was really helpful for me to understand Anti-squat and forward grip. Can we add a discussion about side bite? What effects side bite? what exactly are we looking for beside the car returning to straight faster?

  5. #80
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    Overall grip (front/side) are mechanical in nature. Purely changing side bite tends to be a tire characteristic.

    Status: Someone put glitter in my oil. Wait. Why's all my oil outside the engine? What's that knocking?

  6. #81
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    lack of sway bars in the rear help with side bite too.

  7. #82
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    Quote Originally Posted by blake261 View Post
    This Thread was really helpful for me to understand Anti-squat and forward grip. Can we add a discussion about side bite? What effects side bite? what exactly are we looking for beside the car returning to straight faster?
    Tire pressure, compound, and alignment. More toe-in in the rear will increase side bite, as well as lower tire pressure or a stickier tire (or both).

    Quote Originally Posted by protomor View Post
    Overall grip (front/side) are mechanical in nature. Purely changing side bite tends to be a tire characteristic.
    +1 This is mainly a tire change. Lower pressure and toe-in can increase it, but putting on a sticky tire will have a far more dramatic change than anything else.

    Mike
    IG: @mikevanshellenbeck

  8. #83
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    Also wider tire. But usually whatever affects side bite will affect forward bite.

    Status: Someone put glitter in my oil. Wait. Why's all my oil outside the engine? What's that knocking?

  9. #84
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    I sometimes wonder about all this since I think controlling wheel speed has a huge roll to play aside from just setup. My thoughts on this are partly my own experience and from what I have heard around the pits in FD. Also last weekend at FD I heard whispers that HGK has an algorithm that tells them the optimal wheel speed % over ground speed to create optimal bite.

    In some cases I think backing down the power can be advantageous to speeding up the car in drift. Lets say for just for discussion sake that +20% wheel speed over ground speed is optimal for forward grip but at any given time you have enough power to maintain +50% over ground speed. That extra +30% wheel speed is not helping you go fast so learning to pedal the car or lowering power level of the car can increase grip. With a lower power to grip delta in theory could make it easier on the driver since there would be less pedaling and he would just have to keep his foot mashed to the floor and be right around the optimal grip level. Most likely this will be more of a handful to drive in tandem though since you won't have any power in reserve if the need arises.

    We had an idea about doing some testing to find the optimal wheel speed % over ground and writing a simple program that would work on a Racedash like system where the rev counter would serve as a wheel speed % / ground indicator. Where staying in the middle of the graph will produce optimal forward bite. Using GPS data for vehicle ground speed. This way in the lead position the driver would have a indicator in his peripheral vision as to how much he should pedal back the throttle. In chase it would only become a factor to pay attention to if the lead starts pulling away.

    Anyways I've been thinking about this a bit lately and figured I'd write it down here.

  10. #85
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    @Piner that's a pretty cool idea. I know for a fact that something like that could easily be implemented with a Motec. (And likely other dashes, I just happen to be familiar with Motec). I wonder how long teams would get away with doing that before FD makes GPS illegal on competition cars.

  11. #86
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    Yeah at the moment there isn't anything in the rule book that outlaws it. It would be easy to hide as well since its just an indicator on the dash while you're driving.

  12. #87
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    Seems like too much to think about while driving. Might be more useful during practice sessions to get good data.

    Sent from my SAMSUNG-SM-G930A using Tapatalk

    Status: Someone put glitter in my oil. Wait. Why's all my oil outside the engine? What's that knocking?

  13. #88
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    Launch control systems work very similarly, in that about 110% of ground speed is the ideal wheel speed for forward grip. I forget where I read up on the study of forward grip with slip speeds, but it was clear that some slip was beneficial in terms of thrust that can be gotten out of a tire. It would be crazy to see a rear wheel speed controller that is able to limit the wheel speed to where you get the most grip out of the tire. Then maybe have a pedal override, that if you go more than 50% down on the pedal it'll override the setting for a while if the driver needs the wheel speed mid drift.

  14. #89
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    Bringing this thread back! I'm having some issues with balance (grip vs Power) and wanted to get some advice.

    My car is 700HP/700tq, Turbo LS and with the help of this thread, I've been able to dial in a huge amount of grip in the rear. Problem is, now, out of boost, my car will straighten instantly. This makes following people very difficult, but makes my lead runs outrageously fast.

    Currently, I have a JK40 trans (CD009 from a 370z), and a 2.91 welded rear diff. My turbo is huge, 1.32 AR T6 twin scroll, 75mm (Borgwarner S475). I know this makes it super laggy even with 6.0L's pushing it. but hey, it was cheap AF. Before all this grip, it was very easy to spin the rears with the 2.91 diff out of boost and with a 3.38, I was hitting 5th gear, on very small tracks.

    I was considering adding nitrous with an RPM switch to get her spooling a bit sooner. But honestly, I feel the car is much more powerful than it needs to be, and adding this down low may just add more reliability problems, and possibly drivability problems. Basically a lot of effort that could potentially hurt me in the next rounds of E10Drift. I need to manage what I have better.

    So I started thinking about a 3.15 large case diff as a happy medium. with the 2.91, on Pro-am tracks (larger tracks) I am in 3 for most, if not all of the run. I can easily clutch-kick 3rd in boost from basically a dead stop, and not bog, it's when I'm sucking up on someone and have to slow after is the issue and fall out of boost. Left foot braking can help on the larger turns, but not in the tight ones.

    What do you think? both roads are similarly priced, but I think gears may solve my problems better than more power. lowering my wheel speed would also provide more grip, so maybe I can stay just as fast in the lead...

  15. #90
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    Looks like you want to start messing with gearing if you don't want to get a smaller turbo or nos down low.

    Status: Someone put glitter in my oil. Wait. Why's all my oil outside the engine? What's that knocking?

  16. #91
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    Quote Originally Posted by protomor View Post
    Looks like you want to start messing with gearing if you don't want to get a smaller turbo or nos down low.
    ok, so you agree then. Can't really change the turbo out with redoing everything so that's out of the question.

  17. #92
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    at that power level yeah I'd say look at a winters quick change rear end
    instagram @andyitslit

  18. #93
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    Quote Originally Posted by blake261 View Post
    Bringing this thread back! I'm having some issues with balance (grip vs Power) and wanted to get some advice.

    My car is 700HP/700tq, Turbo LS and with the help of this thread, I've been able to dial in a huge amount of grip in the rear. Problem is, now, out of boost, my car will straighten instantly. This makes following people very difficult, but makes my lead runs outrageously fast.

    Currently, I have a JK40 trans (CD009 from a 370z), and a 2.91 welded rear diff. My turbo is huge, 1.32 AR T6 twin scroll, 75mm (Borgwarner S475). I know this makes it super laggy even with 6.0L's pushing it. but hey, it was cheap AF. Before all this grip, it was very easy to spin the rears with the 2.91 diff out of boost and with a 3.38, I was hitting 5th gear, on very small tracks.

    I was considering adding nitrous with an RPM switch to get her spooling a bit sooner. But honestly, I feel the car is much more powerful than it needs to be, and adding this down low may just add more reliability problems, and possibly drivability problems. Basically a lot of effort that could potentially hurt me in the next rounds of E10Drift. I need to manage what I have better.

    So I started thinking about a 3.15 large case diff as a happy medium. with the 2.91, on Pro-am tracks (larger tracks) I am in 3 for most, if not all of the run. I can easily clutch-kick 3rd in boost from basically a dead stop, and not bog, it's when I'm sucking up on someone and have to slow after is the issue and fall out of boost. Left foot braking can help on the larger turns, but not in the tight ones.

    What do you think? both roads are similarly priced, but I think gears may solve my problems better than more power. lowering my wheel speed would also provide more grip, so maybe I can stay just as fast in the lead...
    It sounds like your car is pretty serious as is, so in this instance a quick change diff is probably your easiest route. I certainly wouldn't add nitrous to solve it. I would definitely put a smaller turbo on it, but if that's out of the question completely, just gear it shorter. Also just slip the clutch some to stay in boost more as long as you have a stout clutch. You can keep it spooled relatively well being on the ebrake in a tight chase and no LFB if you're slipping the clutch enough to keep the RPMs up.

    Mike
    IG: @mikevanshellenbeck

  19. #94
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    Quote Originally Posted by blake261 View Post
    Bringing this thread back! I'm having some issues with balance (grip vs Power) and wanted to get some advice.

    My car is 700HP/700tq, Turbo LS and with the help of this thread, I've been able to dial in a huge amount of grip in the rear. Problem is, now, out of boost, my car will straighten instantly. This makes following people very difficult, but makes my lead runs outrageously fast.


    Left foot braking can help on the larger turns, but not in the tight ones.
    What do you mean it can’t help in the tight turns? Lifting off the throttle is clearly your problem, it has nothing to do with the left foot braking.

  20. #95
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    Stock for the cd009 is like a 3.5. So 2.9 is stupid longer. Makes sense it would exit boost.

    Or like down shift. Or dont lift lol.

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  21. #96
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    2.91 is absurd, I'm running 4.10s with 650whp and a Z32TT trans. I run almost every layout in 3rd, sometimes with a quick clutch kit on smaller tracks or a quick hit of 4th on bigger ones. Looks like in my trans that's a 1.30 3rd gear, so that would put you in your 1.271 4th gear. I think you're E36 so 3.91s are easy to find and cheap.

    This is pretty much the exact reason I went SC instead of turbo.

  22. #97
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    Thanks for everyone's input. Of course, I can always do more while driving to work through it (don't lift, left foot brake small corners, downshift, etc.). When I'm on my own, the car feels fantastic, but in the chase runs, it's really difficult. I want to make it easier to drive and in turn, more consistent, without slowing it down too much.

    I made a mistake in my last post, with a 3.91, it was in 5th on small tracks and constantly shifting. That may be different now with all this grip, and I have two 3.91's at my house already.

    I'm picking up a 3.23 this weekend to test out. if it's not enough, maybe I can keep dialing up the grip and move back into the 3.91. The speeds of a 3.91 with a T56 is nearly identical to a 3.15 on a CD009.

    If I were to do it again, I would do a SC, but I couldn't resist the 2500$ LS turbo!

    (if it really cost 2500$ I could have bought about 8)

  23. #98
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    You were in 5th gear with a T56 and 3.91 diff?

    Status: Someone put glitter in my oil. Wait. Why's all my oil outside the engine? What's that knocking?

  24. #99
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    Quote Originally Posted by protomor View Post
    You were in 5th gear with a T56 and 3.91 diff?
    No, it was just for comparison. I never had a T56

    As in, "maybe I can get back to the 3.91, but a CD009 with a 3.91 will be shorter than a T56 with a 3.91"
    Last edited by blake261; 06-07-2019 at 03:22 PM.

  25. #100
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    IIRC factory diff with the CD is a 3.4 rear. The T56 has a ~3.7. So a .2 bump on the T56 (3.9) would be a 3.6 on the CD009. At least that's how my shade tree mechanic mind does it.

    Status: Someone put glitter in my oil. Wait. Why's all my oil outside the engine? What's that knocking?

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