Handling defined

[Sam Strano]

n a discussion on another forum, a customer of mine posted this video:

http://www.youtube.com/watch?v=shwgNV36xFA


It's quite good at explain why outright grip is different from handling. I've been trying to explain that for years. So many people only car "how many G will it pull" when that's not really indicative of how the car actually behaves. Handling is a mix of lots of things, and the term for me is very broad. How a car handles incorporates not only grip, but also stability, predictability and balance as well.

The presenter of the video (who is a world-class Sports car racer in things like Porsche 962's) is dead on when he describes "handling" and how it can be subjective.

Also some other notes from the video. You'll notice in the slalom test (which is something us autocrossers are always doing) the car that gets all sorts of stupid is just flopping about like a dying fish. The cars that do better are much better damped and the roll rate is very much controlled. That's one reason I'm always going on and on about shocks being so important.

You can see in these video's how hard I can drive cars setup to be flogged:
http://www.youtube.com/watch?v=i0LkxvH2gn0


That is a car that handles. And on a skidpad the car can pull even more grip than what you see for values in the video. As was pointed out a skidpad is not exactly real-world driving, we do not drive in big smooth 200-300' circles, we have to turn, accelerate, stop.... and blend those things together.

I just thought you guys might like to see the video, and frankly it is a great way to show/explain my personal thinking when setting up a car.

 

[LAllison20]

wow, you ripped that course a new one....Ive been looking at the handling package 1 for my 05 DD on your website. when the moneys right, ill be calling you.

 

[ShadowWulf]

I definately agree. "Grip" and "handling" are two different things.

For example, turn-in response is a part of handling, but has nothing to do with grip.

 

[ArizonaGT]

Tiff Needell is THE MAN. I love watching his old Top Gear reviews on cars like the McLaren F1 and Porsche 996 Turbo.

 

[Cookiemonster]

I always simplified it to

Handling: how the car feels.

grip: speed at which handling comes into play.

 

[Random Asshole]

I think this photo is "handling defined"...

 

[Cookiemonster]

ok... how the fuck do you even do that... the outside tire is not under load..

 

[Random Asshole]

hydros, mayn. I see 64 impalas turn corners like that all the time at the autocross meets.

Sorry, I'm not trying to shit on this thread..but it was too hard to resist.

 

[Sam Strano]

That's where the owner of that car and I disagree. He ran a bigger front bar, I run a stock front bar. I didn't want even more lateral load transfer in a car that already is understeer prone.

You'll notice the real reason is the rear is falling over due to a lack of rear roll stiffness relative the front. Making the front stiffer isn't the answer as the above is the result. That car is/was an FS car so changing the rear to make it stiffer was out, but then again making the front stiffer had a similar effect as making the rear bar softer which is why on a GT in FS trim I do not recommend a front bar, or only a front bar increase in general on any GT.

FWIW, that picture is also the reason why I felt it was important to increase there rear bar rate a good bit more than the front, but also allow the ability to play with the level of roll stiffness by making the bar adjustable vs. just getting what a non-adjustable gives.

The picture certainly looks cool though.

 

[Vapour Trails]

I think this photo is "handling defined"...

Ha, where did you find that photo? He's a member of my local auto x club and was the 2006 Champion. He'd beat AS cars in FS trim. I rode with him and he's a phenomenal driver. He has moved on to a BMW now though and I believe the car is sold. At one point he was trying to sell it to me.

I don't understand why he changed the front bar either. He told me it helped decrease understeer, and I was like, ummmmm OK. That's assbackwards but whatever. I'm not sure a lot of the guys understand vehicle dynamics, but they make up for it with raw talent.

 

[Sam Strano]

In fact.... If I were to try seriously to build 2005-2009 GT to compete with the Shelby in FS trim on sweeper courses I'd actually try the 31.7mm V-6 bar and make it adjustable and deal with more roll and use a lot more shock.

That's all moot because the 2011 will be a faster GT, and there just aren't many trying to make a GT or Bullitt work in FS. Those that are and are my customers I've discussed this with. This is only applicable in that one scenario. If you have no rules to work around, then there is no reason you can't get balance and better roll stiffness both.

 

[Cookiemonster]

Sam i know your big on bars.

Iv always been curious about the springs VS bars debate. high spring rate with small bars vs big bars and lower spring rates. whats the advantage and disadvantage of going one vs the other.

Discuss?

 

[SoundGuyDave]

Well, I'm not Sam, but I did stay in a Holiday Inn Express last night...

Soft springs, hard bars: Generally, a softer, more compliant ride over rough surfaces, bars do the heavy lifting for roll resistance. Downside is that if you hit a diagonal bump, or other single-wheel event, the bar will try to whipsaw the car back and forth, as you've reduced the compliance between the two corners. You may run out of suspension travel quickly over really rough stuff, which may mean you need to raise the static ride height.

Hard springs, soft bars: The springs do more work in roll resistance, also help with nose dive/lift to some extent. Much less unsettled feeling when one wheel hits a pothole or seam, or whatever. You can run a lower ride height without bottoming. Downside is that on a rough track, the car may tend to "skip" over the bumps rather than ride over them. Forward bite may be reduced, from reduction in rearward weight transfer under accel.

Generally speaking, you want the softest rear rate you can get away with running which still keeps the car off the ground on the bumps you hit, and then balance it with the front rates until you go neutral. Then you slap on the bars, and adjust for roll resistance and re-balance the car.

Please note that this presupposes you adjust the dampers to control the spring, and aren't artificially hiking the effective rate with them.

 

[Cookiemonster]

Well, I'm not Sam, but I did stay in a Holiday Inn Express last night...

hahahahahahha best response ever. The question wasn't directed at Sam, it wasn't intended to be anyway.

 

[Random Asshole]

Ha, where did you find that photo?

I was looking around for pictures of s197s with mesh wheels and that came up in a thread on other forum. Can't remember where, I had a million pages open at a time.

I'm not sure a lot of the guys understand vehicle dynamics, but they make up for it with raw talent.

yahuh.

Sam i know your big on bars.

Don't say that, he might go off. j/k
I said the same thing once, we both mean that you are big on the importance of bars, not their size.

While we are describing suspension dynamics via photo:

It's a bit blurry..but I think it will serve it's purpose. I wanna say I JUST got off the brakes at this point

Setup in this photo is a front eibach prokit springs/shocks with the front bar set to medium/middle and a stock rear bar. (No room left for more mods due to points, otherwise I'd have both in) I never noticed while driving that the rear is hiking up so much. Is the stock bar the major culprit. I would think adjusting rebound could help, but no such luck with these shocks. Stiffer Springs are a cheap option, but I'm not sure how much it would help. Either way, I'm running a stiffer rear bar this season since I plan on moving to a different class.

Here's one on the same corner after 1 second later.

I realize an inside corner shot would be better, but from what I can tell, the car looks at the apex. (The is a hairpin turn.) And please excuse the goofy looking number job. My had my lady did those cause we showed up a little late and I had to hurry and unload the car so I could make it to tech before the drivers meeting.

 

[Cookiemonster]

Don't say that, he might go off. j/k
I said the same thing once, we both mean that you are big on the importance of bars, not their size.

While we are describing suspension dynamics via photo:

It's a bit blurry..but I think it will serve it's purpose. I wanna say I JUST got off the brakes at this point

yes importance of bars. thats what I ment hahaha. thanks for the save

and that picture. whoaa holy articulation batman.

 

[Cookiemonster]

heres some vids from a couple months ago at an auto cross school. mines the blue one.

http://www.vimeo.com/7741134
sweet cone hits..

http://www.vimeo.com/7736191 still squerly one cone hit.

http://www.vimeo.com/7715709 watch my turn in where I lift for breaks and the roll in my tire.

http://www.vimeo.com/7715419 shit just makes me laugh.

http://www.vimeo.com/7713709 watch the gas cap

http://www.vimeo.com/7712421 sweet camio. more roll

http://www.vimeo.com/7709685 gas cap. drift and hit cone.

everything suspension wise is stock. tires are nt555s. the down hill slalom was a huge hurtle for me. I'm pretty confident in slaloms now though!

I appreciate any criticism you guys have.

 

[Sleeper_08]

Random did you catch the Z?

 

[Random Asshole]

Random did you catch the Z?

God damn right I did.

That was a weird event. Called a "scat rally". Weird name, I know. It was autocross guys and wheel to wheel guys running at the same time. The name of the game was to match a guestimated overall timed goal for the session with passing zones marked with green cones on certain sections of the track. It was 40 minutes of madness on the 3.5 mile autobahn circuit. The only guy I let by was driving in an open wheel formula car of some sort. My dumbass lost the video somewhere, but I'm doing another one this year.

 

[pieperz06]

The only guy I let by was driving in an open wheel formula car of some sort.

i cant stand the random assholes that dont let ppl pass

on an added note what kind of camera are you using that has a g force censor on it is kinda cool