Handeling Thread

[nick47]

Draw the vectors for gravity and cornering force from the C.G. and add them up. If the vector falls outside the tires, the car will roll. Inside, it won't.

 

That's a static example. In real life you could probably do something stupid that would change the dynamics. That's probably more likely with something stiffly sprung. I've rolled go-karts, so I know what can happen when you do something stupid in an unsprung vehicle.

 

Stiffening the suspension alone doesn't make the car that much more likely to roll, except possibly for the reduced camber compensation, which would ordinarily slightly increase the track.

[JohnK]

Physics lesson? :lurk:

And

The fact that a car with a lot of body roll is less likely to flip over than a car that stays flat in a corner is not intuitive to me. By stiffening up the suspension wouldn’t you get less traction on the outside if the weight was not allowed to shift more to the outside front wheel?

I thought that a measured amount of body roll would get you through the corner faster due to the increased traction on the outside front.

 

Well what have I gotten myself into. (HOTTCAR's questions are particularly good) This is gonna take a while but I think/hope I can write something that'll give folks a little comfort here, a little insight, and perhaps a little sense of direction if they want to try something on their cars. This'll be a multipart reply 'cause I'm not smart enough to run it all down coherently and at once, but I'll try to keep things together enough to make sense and be practical.

 

Just to be clear at the outset, my measure of what constitutes a really wonderful car is how it feels in the middle of a corner when both ends of the car are sliding. If you're in that situation and you feel absolutely confident that you can brake or accelerate, turn in or out, steer with the throttle to adjust your line, ... with the sense that you and the car are the same thing, then you've got a really wonderful car. If it goes like a scalded cat, that, of course, is nice, but only if it handles too.

 

First of all, Caterham has spent years improving their cars (finding ways of making them more robust but still really really light while also stiffening the chassis - all to the end of making them handle better and better), and they started out with the basics supplied by the good Mr. Chapman - so the chances of an ordinary guy, or even a remarkably smart guy, going in and twiddling with something and actually making an improvement are really unlikely. As one instance of the kind of work Caterham's invested in their car, spend time appreciating what the link

https://dl.dropboxusercontent.com/u/49212285/oconnell.pdf

is telling you, ... think about what such equipment allows one to adjust/determine/measure/experiment with, not to mention the understandings that are necessary just to tie a car down on that setup and make sense of what all the paraphernalia is capable of telling you about the car and what questions you should figure out how to ask, and ...

I spent well over a year doing engine tuning with two different dynos (all to myself!) and working with a small collection of different engines and ECMs, and ended with what could be called success - and a profound appreciation of the importance of being able to measure things, which included the cost of the time required to develop a protocol for making collections of measurements. I also got yelled at a lot because I found (and said out loud) that it is completely hopeless to try to tune your engine by looking at an Air/Fuel meter and fiddling with the ECM's calibration on a laptop while driving.

A while back Kitcat noted that, in his experience, just making sure that the suspension on his Caterham was in spec as per the Factory seemed to be the best course of action if he wanted the car to work optimally. And possibly fiddling just a bit with tire pressures to see if there was a difference.

Now think back on how well a Caterham handles, that it does so while providing a ride so comfortable that it feels like a family 'saloon', exhibits chassis roll that looks absurd, and then abandon any hope that you're going to be able to fiddle sensibly with anything on the suspension that's likely to improve its handling - or even make sense.

 

What I attempted to do when I got my Se7en was to start with a car that was not highly developed in this regard (which in my humble experience is anything that is not a Caterham) and see if I could use it as an experimental subject to learn about handling and hopefully produce something that worked pretty well. Predictably, as a scientist, I live the Caterham motto, “The journey is as important as the destination.” I have gotten pretty close to my goal. After a couple thousand miles out on local twisties last year, the car does several important things very well and I feel pretty pleased - especially that my newly learned welding skills have stood up without fail. I have two hurdles I've yet to overcome that'll get me in the ballpark of where I'd like to be before I put away the torch and dedicate a big chunk of time to driving the thing, and exploring the way it works. For reference, I have quite a few years spent playing with what were called cafe racers back in the 60's, a collection of wonderfully twisty roads not too far away, and 20,000 miles spent on an early sportbike driving really irresponsibly on these roads.

 

So, next I'll describe how I approached the problem of understanding handling, what I found useful to inform myself about, the tools I used to gather the information, the procedures/protocols I had to develop to actually accomplish things, and ways of assessing the work. The goal of all of this is to understand the things that contribute to the car's handling and what can be productively adjusted and to what end and at what cost.

Edited January 17, 2014 by JohnK
Making the writing easier to understand!

[bigdog]

A while back Kitcat noted that, in his experience, just making sure that the suspension on his Caterham was in spec as per the Factory seemed to be the best course of action if he wanted the car to work optimally. And possibly fiddling just a bit with tire pressures to see if there was a difference.

Now think back on how well a Caterham handles, that it does so while providing a ride so comfortable that it feels like a family 'saloon', exhibits chassis roll that looks absurd, and then abandon any hope that you're going to be able to fiddle sensibly with anything on the suspension that's likely to improve its handling - or even make sense.

 

 

At a certain level I have come to look at the crazy obsession that a lot of us have for chasing numbers to be as silly as the futility in this old video. We sometimes have a hard time just admitting that we should just stop chasing numbers and enjoy the drive.

The Caterham is one of the best handling cars on earth. Why would one need to sink multiple thousands of dollars in search of that elusive extra .1 G on a skid pad. And would anyone that was unaware of the mods even notice the difference from a stock Caterham?

[yellowss7]

BigDog, as a new Caterham owner, you obviously have not yet been infected with the dreaded, UPGRADEITIS virus. You cannot avoid this disease and will eventually succumb to its power.

 

Chasing Lightness, Handling, and Power are the three main symptons of the disease. You'll know when for some reason you buy carbon fiber "cat whiskers" to put on your nosecone to improve your down force, or buy a carbon fiber cam cover to save weight. :willy_nilly:

 

Assuming your caterham was assembled correctly, and suspension set up to specs, have good rubber and inflate it properly, it will be one heck of a good handling car. I've found that driving style/ skill has as much impact on handling as anything else.

 

You are right that enjoying your car is the key. Some like to Polish, some like to drive, some like to go really fast. Nothing wrong with any of them. Just have fun.

 

Tom

[bigdog]

BigDog, as a new Caterham owner, you obviously have not yet been infected with the dreaded, UPGRADEITIS virus. You cannot avoid this disease and will eventually succumb to its power.

 

Chasing Lightness, Handling, and Power are the three main symptons of the disease. You'll know when for some reason you buy carbon fiber "cat whiskers" to put on your nosecone to improve your down force, or buy a carbon fiber cam cover to save weight. :willy_nilly:

 

Assuming your caterham was assembled correctly, and suspension set up to specs, have good rubber and inflate it properly, it will be one heck of a good handling car. I've found that driving style/ skill has as much impact on handling as anything else.

 

You are right that enjoying your car is the key. Some like to Polish, some like to drive, some like to go really fast. Nothing wrong with any of them. Just have fun.

 

Tom

 

I'm not one that ever had the upgrade bug. With one exception. I have been quite satisfied with just having a nice toy that I don't see someone else driving every time I turn the corner. And I like the social aspect of owning a not often seen car. I enjoy entertaining questions about what I'm driving or riding, more than I enjoy pointing out to everyone the minutia details of having managed to get 20-30HP more or shaved a few grams at a cost of X thousands of dollars. I've owned a "69" Corvette convertible, "69" Mustang 302 convertible, "94" Ducati 888 SPOLTD superbike #9 of 100 made. A Suzuki RG gamma street version of their MotoGp bike. They were all stock and were better off for it.

 

Now when I owned a Vintage speedsters replica 1957 Porsche 356 Speedster. The original bug engine blew up. I went crazy and had Chico performance racing in LA build a 2.3 Ltr 170HP 173Ftlb Air cooled type 1 monster for it. It was bloody fast, But was a nightmare to drive. The engine ran hot, the weber IDF's were always going out of sync because of the Rube Goldberg linkage. I always regretted haven fallen for the numbers game with that engine build. I also know for a fact that even though a subby WRX will blow past my Caterham on the straits, I take solace in knowing when we get to our local German version of the cafe at the top of the twisties called Johanniskreuz http://goo.gl/maps/sjHab I live not more than a couple of miles from there in Molschbach. Guess who's car everyone gathers around? I don't need big HP numbers nor record low weight numbers to enjoy my self. The chasing of numbers in a seven is mostly an American affliction. Just look at pistonheads and the sevens for sale in the UK.

 

I'm kinda like the kid in the Honda bike adverts. "I just wanna ride" or drive in my case. In fact most folks who know about sevens in Europe/UK like the fact that mine is the same as when it was built by the Caterham factory in 1983. So yes it was screwed together correctly.

 

As you say & I agree. Each to their own. I just think that as I've grown older and a little wiser I see the futility & huge cost that will never be regained from chasing numbers.

Edited January 16, 2014 by bigdog

[DeanG]

The biggest changes to handling on a Se7en seem to be the tiers and how much lard is in the cockpit. If I could drop 50lbs my car would be much quicker.

 

I read about the guys who restore a low cc Italian sport bike then find it isn't as nice as they remember. 30 years of rose colored glasses and middle age spread kills their dream.

[Kitcat]

I will just observe that uber horsepower is not incompatible with great handling. What's wrong with both? And isn't it human nature to improve things (even when they are not broke-Tom, where can a get a set of those "cat whiskers" man???).

 

If we were really all that grown up we wouldn't be driving se7ens in the first place, would we?

 

I don't disagree with BD, just saying I am still waiting for that maturity he associates with getting older to set in(Youth is fleeting but immaturity can last a lifetime, etc).

Edited January 16, 2014 by Kitcat

[bigdog]

(Youth is fleeting but immaturity can last a lifetime, etc).

 

And my wife will whole heartedly :iagree: with that statement.

 

Just because I'm older and what I might think is wiser. Doesn't mean I don't want to have fun. It just means that it no-longer requires that I have to light my hair on fire, And then drive off a cliff to have it.

[AndyB]

It's funny if I analyze my desire to have my Seven go faster it really comes from within the Seven fraternity. The fact that some club members have BDA or Cosworth lumps and I have my 50 year old twin cam.

I too really enjoy the social aspect of owning and driving a Seven, the attention it always draws and the neat people I meet through that attention.

But I digress, as to the handling the truth is the car's capability can probably still out perform me:o

[yellowss7]

Here you go Kitcat. these should make you much faster and maybe even keep you on the track. :jester: http://www.caterhamparts.co.uk/product.php?id_product=3272

 

 

As for any of us maturing, from the guys that show up at our NJMP trackday, I can honestly say that, that statement does not apply to any of us. :jester: Maybe it's the fun that comes with driving a great little car that almost always puts a smile on our faces everytime we take it out. If that doesn't keep you young at heart, then you are probably :svengo:

 

As long as we can keep climbing in and out of our cars I think we will never grow up. And if we can't climb in and out, we can always ask Skip to build us one of those neat Butt chair winches. :cooldude:

 

Tom

[JohnK]

--It's hard to find a place to start if you want to do something to change, or even just learn about the handling of your car. This is particularly true if there's nothing that you know of that is actually wrong and you don't have a framework of some sort for reference purposes as to what's better or what's worse, not to mention a target of what you'd like to accomplish.

--When you sit down and think it through, the actuality is that the suspension at any one corner of your car is pretty complicated all by itself, and when the car is being driven there are an awful lot of pieces that are contributing as systems and subsystems to deliver what one experiences at the wheel. If you buy a new or recent Caterham, all the work related to the suspension being dialed in properly certainly with respect to the hardware, and the car's handling set-up should have, or can be done for you by a competent shop (not to be assumed here, lots of schlock operations out there) – so there's really no reason to touch anything unless there's something broken, or the car is doing something that can be objectively identified as 'wrong'.

--So I had a bit of an advantage in that what showed up on my driveway wasn't what you would call “finished” in any sense, and the most prudent approach to be taken was to very carefully verify the operation of every part of the car. That meant I had to really UNDERSTAND how each bit worked within its environment. A lot of the fundamental things that were done are described at

http://usa7s.com/vb/showthread.php?t=7421

but all of this work provided me a good mindset when it came time to tackle the suspension. And it gave me time to consider - - - while I was really enjoying getting the car together, the thing that was at the back of my mind was: “Y'know, If I don't get this (whatever part of the car I happened to be working on) RIGHT, it could very well fail and fail like all of a sudden, and if it does so at just the right time, it may well toss the car off the road and KILL ME.” (Think about Kitcat's Datsun driver – hanging by his seatbelt with his roll bar keeping his car from landing on his head.) So I had a built-in motivator to do a damn good job of UNDERSTANDING what I was doing as well as making sure it was done correctly. I'll leave it to each reader to develop this attitude on his/her own when working with their car.

--With respect to the each corner of the car, the very general rule (Costin & Phipps) is that an outside, or laden, wheel wants to be perpendicular to the road surface, regardless of what posture the chassis is in. This is just not achievable (Staniforth, Smith) so one must try to find a good compromise, and there is no measure of what a 'good compromise' is– I'm not being flippant here, there are lots of pictures of cars going fast around corners where the only wheel that's where it's supposed to be is the front outside, with its mate on the other side looking like it's been disconnected from the car, and this only happens with the outside wheel under a narrow range of ride-roll combinations . Look at the head-on pictures of a Caterham mid-corner. The outside/laden front wheel is straight up. The inside wheel is ….. well, I wound up spending an awful lot of time reading – the benefits of which I really can't convey without putting everyone to sleep, so I'll offer some pictures and a description of a problem/situation that illustrates what's going on.

--My current struggle is getting rid of oversteer – i. e. the rear isn't as firmly planted as the front, so you're always fighting a car that wants to come around on you. This is not good. I improved it a lot by playing with the anti-roll bars (ARBs) but SOMETHING was clearly wrong. Smith and Mitchell provided the solution. Smith, in Tune..., compares the different arrangements of the links that rear suspensions have with a large collection of drawings and comparative values and explanations, and Mitchell gave me a means of visualizing how those arrangements behaved over a range of small increments and of testing their behavior. Since I busted my butt getting pretty accurate measurements of the chassis and the suspension when it was aligned properly, what those pictures showed actually represented the reality that I experienced when driving the car. Take a look at https://www.dropbox.com/s/6cesllwg4xmm6qq/Original_Ride0Roll0.jpg?dl=0

which is the rear suspension viewed from the back of the car. The springs, shocks and uprights should be obvious, the horizontal gray bar and its arms are the rear's ARB system. At the top, in green, are displacements showing Ride (negative is Bump, Positive Droop), Roll (negative means the car is being turned to the RIGHT, positive when the car is turning to the LEFT), on either side of the of the wheels and below ground level are all the sorts of parameters you want to know when the car's being turned and the suspension is assuming any configuration. What's especially useful (and very cool!) is that you can step this thing through increments in Ride, Roll, Steer, ...and watch what's happening to the camber, and how much load is gained or lost on each wheel – so you have a MEASURE of what each spring has to do and how far the shock is being displaced – and you can seen the contribution of the ARB, ….

 

next, the roll center.

Edited December 28, 2016 by JohnK
changes mandated by DropBox, Making explanations better and resizing.

[xcarguy]

BigDog . . . . . you obviously have not yet been infected with the dreaded, UPGRADEITIS virus. You cannot avoid this disease and will eventually succumb to its power. . . . . . Chasing Lightness, Handling, and Power are the three main symptons of the disease.

 

If we were really all that grown up we wouldn't be driving se7ens in the first place, would we? . . . . . . I am still waiting for that maturity . . . . . . with getting older to set in(Youth is fleeting but immaturity can last a lifetime, etc).

 

As long as we can keep climbing in and out of our cars I think we will never grow up. And if we can't climb in and out, we can always ask Skip to build us one of those neat Butt chair winches.

 

Yep. :iagree: :iagree: :iagree:

Edited January 17, 2014 by xcarguy

[coffee break]

John,

I find it interesting to watch dirt track cars. Their inside front fender is miles above the tire, but they are flying thru the corner.

Keep it coming.

Thanks,

Carl

[Guest Terry]

As an ARDS Instructor I have always maintained that unless we are able to do consistance lap times in our cars and our instructor can't improve on those times then any tyoe of mod only works against us improving our skills. Most cars I have driven at the Track are over powered for the driver, making it whole excerise way more difficult. If you have upgradeitis then spend the money on Driver Training.

 

End of sermon

[nick47]

I would only think you'd need suspension mods if you're competing. The handling and sheer cornering power of these things is already way beyond anything else on the road, except another 7. You can corner so much faster than anyone expects, it can sometimes get you into trouble. Power, same deal, although that's at least something other drivers can relate to.

[HOTTTCAR]

As an ARDS Instructor I have always maintained that unless we are able to do consistance lap times in our cars and our instructor can't improve on those times then any tyoe of mod only works against us improving our skills. Most cars I have driven at the Track are over powered for the driver, making it whole excerise way more difficult. If you have upgradeitis then spend the money on Driver Training.

 

End of sermon

 

I am too old and tired to go out to the track and work that hard. I am not a racer..just there for a good time. I like the feel of a fully controllable 4 wheel drift and exiting with so much power that you can hold it on the edge of traction until fully down the straight. Always been that way …..don’t know why……..just a 70 year old teenager but sure like driving sevens.

 

Tom your car sounds like a it would be a great ride.

 

Gale

Edited January 17, 2014 by HOTTTCAR

[Guest Terry]

I would only think you'd need suspension mods if you're competing. The handling and sheer cornering power of these things is already way beyond anything else on the road, except another 7. You can corner so much faster than anyone expects, it can sometimes get you into trouble. Power, same deal, although that's at least something other drivers can relate to.

 

YES, I love a good dose of common sense. :party:

[Guest Terry]

I am too old and tired to go out to the track and work that hard. I am not a racer..just there for a good time. I like the feel of a fully controllable 4 wheel drift and exiting with so much power that you can hold it on the edge of traction until fully down the straight. Always been that way …..don’t know why……..just a 70 year old teenager but sure like driving sevens.

 

Tom your car sounds like a it would be a great ride.

 

Gale

 

Regardless of whether or not your competing, getting the best out of yourself is way more fun than getting the best out of the car. Like so many have already said, the 7 is far more capable than most people who ever sit behind the wheel, that's scary.

 

At a recent Caterham Dealers meeting at Sneterton, by far the most fun to drive was the 1.6 Supersport, way more fun than the CSR, yet obviously not as quick. :banghead:

[Guest Terry]

One of the things that does concern me with the Upgradeits Cult, is that most of the cars that are modified are only driven on the street and not at the Track, which in my opinion is the ONLY place for spirited driving.

[lancylad]

As has been said many times. The handling abilities of these wonderful machines far out guns the driving abilities of the majority of us, regardless of what our youthful minds tell us. What we do have, are toys that allow us to indulge ourselves in an elite world every time we strap ourselves into the silly seat. Whether you propel yourself along in the humble 1.6 or a fully blown twin cam, lets all do it with respect for the machine underneath us, and, the trouble it can get us into when we overstep our capabilities. The sheer joy of piloting my seven and the response of the general public is buzz enough for me. Nothing wrong with upgraditis, we all do some of that, lets all be mindful of where the road ends and the track begins.

Happy blatting guys...