Xian

What I've convinced myself of is that... after (or at) rear lift-off, you have a change in how roll occurs. The chassis can still roll "more" but the roll is partly on the lateral axis (what I think we all consider "roll") and partly the vertical axis as the outside front compresses and the inside rear corner of the car rises. This chassis movement allows for additional weight transfer from the inside to the outside (and largely on the diagonal). Once the rear wheel goes air born, you may still be able to get quantitatively m0Ar grip from the chassis but it's the front end that's having to handle all that additional weight transfer... which means more outside front compression and more lateral roll... which also means decambering the outside front... which means, eventually, less total grip. "But what about the outside rear!?" you say? It's still there... and quickly losing camber and grip.

Now this isn't to say that some people haven't won important races and made very fast cars from setups that hike the inside rear waaaay into the rear but I am saying that I think that they could have gone even faster with additional front roll stiffness.

And let's not even talk about tire to tire sensitivity differences to camber and loading...

Agreed... and in your pics with the inside rear skimming on the ground, I'll bet 2 things: #1- you're on the gas. #2- that corner is almost completely unloaded.

As we progress as a driver/setup person... we tend to be on the gas more in corners, not trailing the brakes, and generally carrying more speed while also being smoother and blending entry to midcorner to exit. And then we point to pictures of our car(s) and say "See!!! The inside rear is just barely on the ground and it's perrrrrrfect!" But is this observed behavior really a function the setup? Or driver? Or maybe... it's both.

Christian, trying to enjoy the road to FWD enlightenment and not focus quite so much on the destination.

Robin6

Great read. Thank you Xian.

Xian, are your saying its personal preference as it relates to rear inside lift?

Xian

Thanks

Hopefully my conclusions are... well... errrr... correct. I'll defer to the Soooooper Genius or Claude or the other Smart Guys on this stuff for any corrections.

The amount of inside rear lift can be a "preference" in that some folks may do better with their inner ear measuring out the chassis roll through the front end of the car. I don't think that a big inner rear lift is ultimately as fast as one that stays close to/barely on the ground at WOT. What I don't want is a car that has the inside rear 6" into the air at mid-corner when I've been at WOT since turn-in...

RR98ITR

The amount of inside lift is a CHOICE made in the selection of springs and bars. A soft car with a fast fwd setup (bias) will lift moar. A stiff car with a fast fwd setup (bias) will left less, even to the point of barely not lifting.

I maintain that no driver ever came off the track sweating a disruptive event traced back to lifting, "fixed" it, and went back out and on return said "That's better". Just doesn't happen. For DECADES, Cortina, Alfa, Porsche, DKW, Mini, Rabbit/Golf, and Honda drivers have been lifting the inside wheel on one end or the other trying to keep some weight on the inside driven wheel.

Scott, who 99% of the time doesn't care where the inside rear is so long as the car feels good...but there is a correlation that can't be denied....

Robin6

All good stuffs guys!

More than just FWD have rear lift...

StatGSR

Here are my thoughts...

Avoid this...

Robin6

^^^yup

vtecjj

HI-LARIOUS!!!

Xian

If you say "Ghettoracer" 3 times while looking at that pic, Frank will pop into the thread...

Ev

Ya, I know it's not a Honda, but



Tripoding it is the only way to get an FWD car to turn...

gringotegra

Thanks! i know i asked a very general question. Trying to sort through the noise and take in the data here ...

Myles, a drag racer turned road racer and total noob on driving in corners.

Lo-Buck EF

Christian- I have watched video from cars behind me and people have watched my corner entry where everyone lifts a tire. My car (this year with the new setup) doesn't lift a tire.

SCoupe 5sp

My ek went to no lift this year as well. From 600lb front to 800lb front, from 800lb rear to 1000 rear. No lift.

Xian

Very interesting ^^^ regarding the two "no lift" scenarios. I know the somewhat limited pics I have of my old ITA sedan (700/1000 speedway rear bar) all showed the inside rear planted. My ITR (750/500 even larger speedway rear bar) also appears not to lift an inside rear much or possibly at all. I'll have to ask folks who've been behind me what here seeing...

I still wonder if some of the lack of inside lift isn't due to evolving driver style couple with the setup changes. Almost a chicken and the egg type scenario where the lack of lift is not due to one or the other but a combination of the two.

Lo-Buck EF

the evolving driver style is a possibility too. i know with this new (slower) engine i make a point to be on the gas as early as i can. but i've seen dudes like kevin helms be WOT in T10 at summit with the RR up in the air and perfectly still all the way to the outside gators. and that dude is no slouch in a honda.

SCoupe 5sp

I'd like to think my driving style improved yielding a more planted car. But this particular change was like throwing a switch. It lifted Saturday, it was stuck on Sunday and never came back.

There were no vestiges of the chassis lifting ever again, not one instance. (video from cars behind me and the usual track photographers planted around the appropriate corners with their zoom lens.)

We are creatures of habit and you'd see some flash of the old style every once in a while in the corners and braking of a ten to 15 lap sprint race. imho.

So I'm not down with that explanation because it was too sudden and non-recurring...

Calif_Kid

I just wanted to post some old pictures from Laguna Seca. The pictures are from the inside of turn 5, and for some, I was using a fairly slow shutter speed. - Jim

RR98ITR

Ah, very good...gotta love it when the magic wand is waved: "evolving driver style". That's good - I like it. Explain how the faster style that holds the inside rear down YET fills out the traction circle MOAR fully (you know, maximizing those psymoaltaneous braking and turning-in g's). Because it seems Really Clear to me that the combination of pitch and roll corresponding to minimum load and/or maximum lift on the inside rear is closer rather than farther from the perimeter of the circle.

Scott, who did just, to be fair, read yet another high level testimonial via the secret telemetry of drivers whose un-named names you'd recognize to the effect that the driver with the higher entry sector speed was slower out of the corner than the driver with the slower entry sector speed...now to be really fair, you can't just go slower and slower on the way in and come out faster and faster...

Xian

Not sure if the first part was aimed at me or one of the other posts... but I think (thought) we were on the same (or similar) setup wavelength in that a whole lotta lift isn't ideal.

Regarding the Data: yeah, that's the trick with it, right? Looking not just at entry, not just at exit, but at sector and overall lap times. Don't even get me started on theoretical laps. They're are hardly worth their ones and zeroes unless there are a **** ton of sectors so you have the highest possible resolution. Otherwise, you'll get bogus info... A theoretical that contains a "fast entry" from one lap with the "fast exit" from another... Where achieving one means the exclusion of the other. GIGO.

RR98ITR

Not "aiming" Christian...and as far as we know we're on the same wavelength in not wanting to superstitiously believe in some easy wrong dogma.

Scott, who hates imperfect laps...therefore I hate all laps...which are still better than no laps...how I long to hate again as I love to...

Xian

I've been wearing my aluminum foil hat quite a bit recently... It seems to have cut way down on my ability to accurately perceive what wavelength I'm on. So, to mediate any wavelength related gaps, I decided to follow a 12 step program for the path to driver enlightenment. The first step is realizing that you're powerless over your chassis' weight transfer. Given a static (or roughly static-ish) amount of grip at each contact patch, all you can do is try to maximize the amount of grip at your "weakest" end of the car. In our mutual case, that's the rear... Increase it back there as much as you can and then balance it with all that front grip you can create (since you're never going to be lifting the inside front). And *this* is why you end up adding front roll stiffness. Because you need it to balance the rear and keep the tires (and grip, y0) in their happy place. Don't let the inside rear hike way up and create extra front roll with the corresponding drop in adhesion...

As far as Evolving Driver Style... Yes, it sounds a bit dogmatic but there's some truth there (or at least it feels like it to me). When I look back at the me that's the driver (and not the setup guy turning wrenches or noodling while he watches everyone else go in circles), I see that my approach to going fast and my confidence in going faster multiplied by my ability to fool myself into believing that I'm too good to crash isn't the same as it was 12 years ago. Or 8 years ago. Or 4 years ago. Or even 2 years ago. I'm not saying that I've gone off the deep end and think I'm a driving god but I'm in place where there's no (or nearly no) nervousness on track. I get out there and wheel the car. And what, you may say, does this have to do with the inside rear? Well, my driving style helps keep it on the ground. Trail braking just isn't something I really do... Because the car is setup to where you don't have to and the only way you *could* do it is if you were just poking around the center of the traction circle. You turn in and then it's maintenance throttle or more all the way to the apex. The combined spring/bar rates are sufficient to keep the car pretty flat and all the tires more or less on the ground. Compare this to a more tentative me who trail braked more and had a different setup because of it... In that combination you could feel the car tripod as you headed toward the apex. See, evolving driver style. Driving methodology is interlinked with setup. Chicken and the egg. Now could you toss a n00b into a well setup car and have them hike the inside rear? I dunno? Maybe. Maybe they'd stand the car on its nose and try to trail brake it into the corner. And maybe they'd make it... Maybe they'd end up backwards. I'll have to see if driving slower and the "wrong" way can get the inside rear up there...

It's interesting (well, at least it is to me) that the older I get, the more often I catch myself thinking "if I'd have known *that* back then"... I guess that means that at least I've fooled myself into believing that I'm still learning new things.

RR98ITR

Christian,

I'm gonna take that winkie at the end of that whole thing as indicating that it's all a joke, else I'm gonna be up late writing some more.

In an effort to keep it short, if you don't do any trail braking, and immediately go to maintainence throttle on turn in, then you're overbraking and not taking full advantage of the available physics in that sector and you could be going faster and still coming out faster.

We NEED the rear end to want to come around so we can take steering lock off and put More power down. That rear tire "height" is nothing more than a tell tale for a less or more unloaded inside rear and hence more or less loaded inside front. We simply want to maximize the load on the inside front, short of diminishing returns of course, in virtually ALL sectors of the turn.

Scott, who has posted the following graphic before - those areas between those curves are weight on or off the inside front or rear respectively...when you choose a negative value for lift you are choosing to carry less load on the inside front thru a significant portion of the whole corner. When you take into consideration how little grip capacity is left for tractive work on the inside front, the limiting factor with the most commonly used diffs, you cannot generally want less weight on the inside front...

* Note to Gringotegra: We have been having these threads for Years...they're always the same and they always recur...it's alot like arguing about torque and horsepower...

Black R

Can't you just add more droop to prevent tire lift?

My autox car sometimes lifts - but it doesn't have much droop:

RR98ITR

I've made so many jokes about "droop travel" over the years. What is droop travel? Within the ultimate bound of the free length of the shock, droop travel is Less with a stiff spring and More with a soft spring...and more with a soft bar and less with a stiff bar.

Some of this is looking at the same thing in a different way and calling it something different and thinking erroneously that it actually is different. But it's not.

To answer the question literally, yes you can add more droop travel to prevent lift - just put on softer springs and bar on the rear and there you go! OR, if you really want to get tricky, put stiffer springs and bar on the FRONT to do it. This will also reduce the tendency toward the front wheel drive oversteer problem that some drivers report struggling with...

Scott, who finds droop travel to be a concept almost entirely un-useful except for making jokes...

FlewByU352

I only get rear inside lift on trail braking. If I do all my braking before the turn it seems pretty solid and planted but I never put a camera on the rear to see if it's still lifting.