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Horrible understeer

TeeLew

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The M1 owner's manual publishes (page 339) 211#/in front and 742 rear for the handling package. So the rear is already pretty close between the two cars.
I guess I wasn't too far off...
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TeeLew

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I wonder if my 800# rear springs are too much?
I think that's still in the range of reasonable. BMR has their 1000# rears, which would probably be as high as I would ever venture on a very smooth track with really good tires (race slicks), but that's just my preference.
 

bnightstar

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I wonder if my 800# rear springs are too much?
They are just perfect. I run 515 lbs front with 800 lbs rear and don't have understeer. You have something else going on.
 

bnightstar

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And that something is 200lbs springs with race slicks at 43psi and not enough camber.
Yeah this front rates are way off for racing slicks without camber. You will need like 4" or more camber to run slicks on that springs the body roll will not be good. Front Sway as discussed will help big time. Even at my front springs I don't think I have enough spring to run slicks.
 

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...

Okay so I'm picking up some new street wheels and tires tomorrow. When I change them out I'll count the coils on the struts and confirm the diameter and spacing and then order those spring rubbers. And thanks for the tip on the hardness. That part I hadn't predicted.
I looked into spring rubbers further. My front springs have 4 coils, 6" diameter, and 1.75" spacing when compressed (estimated). RE Suspension largest product is 5" dia, 1.5" tall. Each rubber has to be slit apart to follow the spiral. They recommend against keeping them in and running them on the street because they will deteriorate faster.

At this point, $90 spent on spring rubbers may be better spent towards $120 for new springs. Rubbers can be put in for track day, and then removed for nice DD ride after. ~200# springs is a permanent choice. And I want to be sure that I don't hate the DD ride because of them.

And I refuse to lower my car, so next I need to find 200# springs that do not lower, or source spacers to control the height. (Are spacers for front springs available?)
 

gone_n_60

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In my experience these cars don’t like maintenance throttle. Avoid it at all costs.

Also just added a note about camber to my post above. Take a look. Don’t know how camber would be fine with your setup if you’re driving the car near the limit.
Was rereading this post again, after 4 HPDE Novice track days now 3 with instructors, I've been schooled that with your feet you are either braking, doing throttle maintenance or rolling on the gas when tracking out. The goal is never to be coasting, so if there's no throttle maintenance what are your feet doing? The OP has stated he knows how to drive track and is seems to be driving HPDE type events. Curious on the statement.
 

Scootsmcgreggor

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Was rereading this post again, after 4 HPDE Novice track days now 3 with instructors, I've been schooled that with your feet you are either braking, doing throttle maintenance or rolling on the gas when tracking out. The goal is never to be coasting, so if there's no throttle maintenance what are your feet doing? The OP has stated he knows how to drive track and is seems to be driving HPDE type events. Curious on the statement.
Good question and I should have clarified that my statement was specific to 2nd and 3rd gear corners. High speed corners maintenance throttle is sometimes needed and unavoidable.
 

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gone_n_60

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I guess it means practicing trail braking more for the slower corners.
once I learn that new skill, LOL. Have to say the 10R80 feel much better in Track mode vs, Sport+. my first instructor recommended Sport+ until the last few sessions we switch to Track mode, much better shift points.
 
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tosha

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once I learn that new skill, LOL. Have to say the 10R80 feel much better in Track mode vs, Sport+. my first instructor recommended Sport+ until the last few sessions we switch to Track mode, much better shift points.
I think that overall, the problem that OP is describing, is specific to very advanced skill and car level. At the beginner level, there are lots of other things to focus on. Listen to your instructors, if they are good, they know best 😄
 

gone_n_60

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I think that overall, the problem that OP is describing, is specific to very advanced skill and car level. At the beginner level, there are lots of other things to focus on. Listen to your instructors, if they are good, they know best 😄
Totally, again I was rereading the thread and that statement about avoiding maintenance throttle just jumped out to me... now that I'm learning these skills.
 

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Totally, again I was rereading the thread and that statement about avoiding maintenance throttle just jumped out to me... now that I'm learning these skills.
With OEM suspension maintenance throttle does more harm then good. My instructor (N24 class winner) says that when I'm doing maintenance throttle in a specific corner I'm unbalancing the car so I needed to learn to brake deeper into the corner and obviously later (still trying to do that) and trail brake instead of maintaining my speed via gas pedal. That way the car will actually turn better and will not have the weight balance away from the front wheels causing it to understeer mid corner and making my exit worse. Obviously the thing is we need to do more trail braking than stoping before the turn and maintaining speed through the apex. In fast corners is a bit different obviously because if you are not on the gas you are losing time.
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