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Old 1st August 2003, 11:45 PM   #281 (permalink)
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Quote:
Originally posted by SDB
Shall we take this in a new direction now? (question, not a demand!! )
Some fun ideas might be ...
Simon, I'm happy to hear about all the above, but with a lower importance on the race-car dry setup in the wet (I don't have a racecar )
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Old 1st August 2003, 11:46 PM   #282 (permalink)
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ROFL @ andy

I did a bit of work with the CLK55 AMG, and even that was a stunning car to punt around.

R500 is a beast. Had very little time in them, but one of the scariest craner curves I've had was in one of them.

Mark

You're more than welcome. In all my years of driver training, development / test driving, and motorsport, I have noticed that the people who are able to understand (or in the case of driver training, learn) the most are the people who underestimate their abilities. You clearly fall in to that category.

You would not believe the some of the ****y, loud mouthed, know it all, losers that turn up thinking they're god and end up making a complete fool of themselves in front of the quiet and consiered thinkers. It's basically the difference between deep seated insecurity (so the poor souls have to "prove it" to everyone) and quiet self respect and confidence (in that you know that not knowing / being able to do something, only means you haven't learnt yet).

The losers will go through life shouting at everyone that they know it all, and the thinkers will end up actually understanding.

It's an interesting (and related) fact also, that the most talented chassis engineers I've worked with (during development testing) are the ones who every now and then say "Do you know what? I just don't know. Let's just try it."

All the best

Simon
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Old 1st August 2003, 11:46 PM   #283 (permalink)
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Mycroft you've been posting since the early hours, are you not a bit tired

* andy passes Iain a beer.
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Old 1st August 2003, 11:48 PM   #284 (permalink)
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Christ everyone's still awake and posting

* andy goes bankrupt handing out rounds.



Meant to say in last post,

I'm happy to hear information on any suspension related topic, because at the end of the day, the pursuit of knowledge is a worthy goal. The more knowledge I have on a subject, the warmer that feeling inside
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Old 1st August 2003, 11:48 PM   #285 (permalink)
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Thumbs up

'3 dayer'
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Old 1st August 2003, 11:55 PM   #286 (permalink)
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LOL @ andy

OK, I'm going to request that we come back to the race car thing later, as it has some really cool stuff in it. but, let's take the next on the list..

How do we make a car lean INTO the corner, rather than away from us.

Well, the loud mouth know-it-alls among us, may say something like "[We've done active, I have an Active car, have worked on them, know more in real terms than you ever will]"

Isn't it interesting how this would have stopped any possible learning or discussion, where as a thinker would have said "do you mean just by active suspension? or something else?"

Well ....

It has nothing to do with Active suspension, and can be achieved by pure geometry (and has been in testing and a few other special vehicles).

What causes roll?

Roll is caused by the c/g being above the roll centre. Think of the roll centre as a pivot point, and the c/g being a ball of weight above it. Push the ball of weight and the thing tips over (roll).

Now... arrange the suspension so that the roll centre is ABOVE the c/g. Now the ball is dangling (bad word, but you get what I mean) BELOW the centre of gravity. Now push the ball and the pivot goes the other way.

Some great testing happened on cars with this arrangement (some really odd looking things) many moons ago, and the idea was that you would always have the tyres cambered in the correct direction for better contact with the ground.

I don't know the full story of where it ended up, but it was obviously pretty crap or we'd be driving round in them today .

Cheers

Simon
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Old 2nd August 2003, 12:01 AM   #287 (permalink)
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Active won the arguement years back.

Why discuss a dead-end?
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Old 2nd August 2003, 12:01 AM   #288 (permalink)
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Ahh now you've started talking about wheels cambering dynamically, and this makes me flashback to the Mercedes ... Carving was it? That funny prototype car that had hydraulic rams to camber the wheels for the ideal traction. Don't suppose you have any more info on that, and whether that kind of technology will make it into road cars ?
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Old 2nd August 2003, 12:03 AM   #289 (permalink)
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Mycroft, you're handy with Toyota's (not supras! ), how come they have not introduced active suspension in any car since the Soarer? Bit of a vague question which I personally haven't seen the answer to so figured you'd be the man to ask
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Old 2nd August 2003, 12:04 AM   #290 (permalink)
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It did to some extent in the 1991 Active Soarer, it uses a fifth link and CDBs to manipulate the cambers and even the RAI in a turn.

Unique in the car world.
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Old 2nd August 2003, 12:06 AM   #291 (permalink)
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Andy, it was simply cost, in 1991 the Active soarer cost £56,000!!!
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Old 2nd August 2003, 12:09 AM   #292 (permalink)
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Hmmm...

Simon did not answer my previous posts.

Let me try and ask about the bumpsteer then, maybe he will answer that, since it's his own suggestion?

Here you go:
- can you explain quickly what bumpsteer is exactly? I read on your forum that it has to do with toe change when cornering. Anything more specific you could tell me about that?
- is bumpsteer Subaru-specific like Iain says or is it simply more pronounced on Subarus?
- is bumpsteer as we call it entirely undesirable if all you care about is to go fast or is a little bit of it needed?
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Old 2nd August 2003, 12:10 AM   #293 (permalink)
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Now that's a good reason

It is strange though, that in 2003 you have a HUGE number of supercars to choose from if you have an excess amount of money in your pocket. I imagine if Toyota (Lexus) were to make a very high-end car, they might look into fitting Active again ?

SC600 with active?
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Old 2nd August 2003, 12:11 AM   #294 (permalink)
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Quote:
Originally posted by Claudius
- is bumpsteer Subaru-specific like Iain says or is it simply more pronounced on Subarus?

I think you will find my work-commute car, an H-reg Nissan Sunny, has more negative suspension characteristics than any Subaru, GTR, Mitsub etc etc

I get used to falling into the passenger seat on fast ( > 15 mph) right handers


<font size="1">sorry, bit off-topic </font>
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Old 2nd August 2003, 12:21 AM   #295 (permalink)
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The next 'Supra' which is likely to be badged as the 'Soarer Supra' or 'SC Supra' will indeed have a top model with Active.

Although a rather different novel version, my friend Nick [who posts/lurks on here since also getting banned from the MKIV site] works for the development arm of Toyota.

I have now seen 'end use' photos of the car... looks rather nice, I think the Japanese are learning to design shapes that stand the test of time. [at last].
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Old 2nd August 2003, 12:22 AM   #296 (permalink)
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Hang on .. you mentioned the word "supra" without hissing, spitting, etc Are you feeling ok??
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Old 2nd August 2003, 12:26 AM   #297 (permalink)
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Hi Claudius

Great questions...

Bump steer is the term used to describe the *change* in toe as the suspension travels through it's range. "bump" I think comes from the fact that it happens when the suspesnion goes in to bump.

The majority of road cars (that I know of) create negative toe (toe out) through bump. Meaning, the wheels splay out during compression of the suspension.

This is notoriously pronounced on the majority of the subaru range, but more so because it is noticeable on that chassis, and is (due to the internet) talked about a lot more.

Is it entirely a bad thing?

Well no. Firstly it can be used to tone down the effects of lift-off-oversteer, but also it can create a lot more driver feedback through the steering wheel.

It's never going to be ideal for pure performance, and certainly one of the first things you tend to do with a competition car is tune out the bump steer. But it's there for a reason, and is designed in purposefully. Not an accidental draw back of something else.

Cheers

Simon
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Old 2nd August 2003, 12:28 AM   #298 (permalink)
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2 of my friends have Supras... Nick and Ellis, both now run them as true twins, Nick always has, and i converted Ellis' car last winter.

There is nothing wrong with the car, it just attracts too many idiots, thats all.

Well, when say there is nothing wrong with the car you have to ditch that dreadful sequential rubbish and sort the rear suspension/dynamics so that it has some traction worth calling the name.

With those two things done the car can be fun, Nicks is a pukka Jun true-twin an astonishingly good car...
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Old 2nd August 2003, 12:29 AM   #299 (permalink)
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Simon, can you enlighten us with some information about tramlining?

I imagine that if it is a 'feature' of cars with bigger wheel and tyre sizes, that it is a compromise which cannot be engineered out.

e.g. EVO's review of the Skyline R34 (Mspec?) mentioned the 18" wheel/tyre combination is good but results in some tramlining on certain surfaces. I take it that the tramlining is a disadvantage to the larger size which is evened out to a greater extent by the "grip" and aesthetic advantages.
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Old 2nd August 2003, 12:37 AM   #300 (permalink)
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Yes a thread on tramlining would be good... deja vu?

there is a distinct move toward this idea Simon.
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