Andy.F

Regarding the LOOS, I don't think it really effects a standard set up car too bad does it ? You REALLY have to try IMHO Even my track set up car is most reluctant to step out at the rear.

The throttle position mod was done for drag racing really, i think it slowed my track progress by taking away some of the throttle control.

Some pre injection FWD cars had a throttle return damper on the carb ie you could not snap shut the throttle. Not sure if this was to minimise drivetrain shock or help eliminate LOOS ??

PS I am exercising extreme self control to avoid joining in with the slanging

roee

I just *guess* that especially in track set up cars LOOS won't be such a big issue, usually they are equipped with hard suspension settings which minimize the weight transfer such a thing can provoke (and besides they just got s***loads of grip ).

The softer the car is the more unstable it'll be under weight transfers IMHO.

EvilBevel

Andy, you are a better man than I am re: self control

But I agree, trackwise, LOOS is almost a non-issue (in the dry ?). But it's different probably on the road when you overdo it/feel too confident/are not ready to catch things.

I'd imagine it would be more to protect the drivetrain or even the engine BTW (I understand sudden lift off from high revs puts a lot of strain on conrods etc), but a nice side effect could be minimizing LOOS.

How the hell did you find out about the "4 seconds" ? I'm dying to try this out next time on track. (cohones too small to do it on the road )

Andy.F

By using power then backing off I could feel the engine run-on then eventually start braking the car. It was also displayed on my lamda gauge as a normal mixture before going off the scale weak just as the engine braking came in. Could be useful in the rain ?
Beware though, you are likely to toast your brakes !!!

Claudius

Elondan

You sound a little angry. Dont be. Not at people who have no clue about driving. Be angry at the Germans or the Palestinians, or your government, or the USA, or Osama, or what/whoever.

The webmaster of this forum is a "development driver for manfacturers". And look what that "development" has led to: all the cars I've bought from "manufacturers" have been shït and understeer. FWD is the worst, RWD such as my M3 were pretty bad as well, scooby ok. My Evo was best so far.

Chill, enjoy your car, and let talkers talk. Drivers drive

Later, pussies

Claudius

roee

Claudius,

Based on your saying, an Evo VI should be faster around the Neurburgring than an M3, right? (difference in power is neglible).





[Edited by roee - 8/22/2002 1:32:58 AM]

[Edited by roee - 8/22/2002 1:33:49 AM]

EvilBevel

"this post was intentionally left blank"

Claudius

What the "Neurburgring"???

<takes out calculator using his shortcut and enters (343-276)/276*100 = 25.7%

Claudius

Good. At least, for once, you didnt talk shït.


LOL

elondan

I only sound angry at the "Evil" one, none of the things we write is gonna change anyway...
and out of the ones you named the only ones I'm not angry with are the Germans and the U.S.A...

roee

Claudius,

Neuburgring is Nuerburgring with a spelling mistake

www.nuerburgring.de

Sorry for not being clear enough, I meant the power/weight ratio of the EvoVI and the M3 is pretty similar (something like 4.6kg per HP for the Evo compared to 4.5 for the M3). Shouldn't make too much of a difference, especially not if the M3 is the crappy understeering POS you claim it is.

Mr_TonyC

I'm not suprised that the Evo was the best seeing as the rear diff is breaking the rear wheels independantly to REDUCE REAR GRIP and allow the car to regain its balance and the front to grip.
Evo's will understeer as much as any other car given too much welly. Just witness them driving around a trackday.

AWD is great if your a RWD pussie If you get too much understeer you've entered the corner to fast (basically). And its not how fast you enter a corner - its how fast you get out the other side. AWD is great if you are a turkey with no concept of throttle balance, or chassis balance. You can bang it down mid corner and it usually gets up and goes. You don't even really need to lift the throttle to balance any oversteer just steer where you want to go and it'll drag you out. Much like FWD.

On an ordinary, mechanical diff AWD car you normally have to compromise you overal corner speed to allow the nose to bite, so you can get on the power and exit without suffering from power understeer. Or use something like a throttle lift, trail braking, left foot braking, etc.

PS: Worshiping Simon, LOL - that would be like worshiping a kind of sideways Buddha

darkblueturbo

evilbevel said: "Try putting 40 psi and bald tyres at the back. THAT would make you oversteer

And before you think I'm nuts... I've seen this done by oversteer junkies with great success, even on a surface like Elvington's "

This makes perfect sense to me. As I understand it power oversteer is because there's more power through the rear tyres than grip (or traction, I don't know) so the back comes out as the tyres are driven forward more than they can grip (am I right??) hard bald tyres would have less traction / grip (help I'm getting out of my depth) and therefore oversteer.

Although on real-road conditions I find dropping a couple of psi from the rear tyre of my bike helps me to corner that much faster, but it's most likely to induce understeer if I get onthe throttle early due to more grip from more rubber on the road.

krankyd

I don't know what's wrong with everyone.

Every post seems to contain "I'm just a crap driver", and "but I'm just a driving noob"

Speak for yourselves. I'm a fecking brilliant driver. I only crashed cause it was raining

Claudius

Dont worry, happens all the time here. I know what you meant, I was deliberately misunderstanding it

See!? That's what I thought you meant!

The M3 IS an understeering POS. I shall know, I have owned one for 2 years and driven the new one (E46).

That does not mean that is will be slow on a fast track like the ring, in fact I believe it's pretty similar in time to an Evo 6. My point is that you cannot go back on the throttle early enough in relatively slow roads or tracks with tight bends. An M3 would be ridicoulous in a special stage, that's what I mean. I never said it's not a good road car!
Where I live, we have lots of tight bends, hairpins, SS type roads, an M3 is no good there. On the motorway, I'd rather be driving an M3. Thing is, I dont drive on the motorway

ex-webby

oh dear been out of this one for a while (sorry) and in germany now so may not be able to respond quickly...

elondan... an LSD *limits* slip, it doesn't (by definition) change the direction of the slip.

Claudius / elondan

It is always important to remember that vehicle dynamics and driving on the limit are 2 subjects that you don't and CAN'T know everything about.

please just open your mind to the possibility that you don't understand it, then we can all have a good conversation about it and come to some conclusions.

If your appraisal of the dynamics of a car differs from that which is accepted among the entire vehicle dynamics community, it is possible that either you are a complete genius, or you are wrong.

Just because the BMW in a mag test understeered, it does not mean that RWD cars understeer more than AWD cars.

"development driver for manufacturers". I agree that the majority of road cars are set up to understeer as a rule.. but in order to help create a vehicle handling characteristic, you need to know how to create it and how not to.

In addition, you may be surprised to know that most *fast* race cars are set up to understeer in theoretical steady state. This is so there is plenty of available longitudinal scope left in the rear tyres for when you want to get on the gas.

In addition, I did mention that I have tested for a number of motorsport teams and companies, including some of the biggest and most well known in the world. It is an interesting comparrison between the facts that take my testing for manufacturers in isolation to say I know nothing, in the same way as you take the BMW in isolation to say that all RWD cars understeer.

If you have something constructive to add, let's hear it because I would really love to learn something new today. Otherwise, leave the thread to people who actually want to learn / impart knowledge rather than simply want to argue a point (that is blatantly innacurate).

All the best

Simon

elondan

I don't wish to argue with anybody.
If you felt I'm putting you down accept my apologies.
I don't think that if an M3 undesteers all RWD do, like I don't think all AWD cars behave the same,
I know there is more to it, the way the system works (Golf 4motion, EVO, 22B, 911C4 won't behave the same), the setup of the car, weight disturbution....
but I still feel AWD is the better solution, and with a good system you get the best (FWD.RWD and AWD).

ex-webby

apologies accepted, but not necessary, I didn't feel you were putting me down, just wanted you to take a step back.

In terms of "better solution" it depends what application the solution is for.

Which is better? a transit van or a ferrari f40?

well, if you want to kart bricks 200 miles, the van is the better solution.

If you want to traverse bump, low grip, or changeable surfaces easily and quickly (without needing to REALLY drive the thing) AWD is almost certainly the better solution.

If you want to put a highly skilled driver in to a car and set a lap record around a smooth dry circuit, RWD is almost certainly the better solution.

Both of these solutions are of course relating to the best suited versions of each. Why? because you can't make a judgement on an AWD / RWD / FWD being "best" at something unless you take them to their pinnacle (otherwise all sorts of other limiting factors may skew the evidence).

This is exactly the same when it comes to the driver. Unless you can TRULY take a RWD to IT'S limits and TRULY take an AWD car to IT'S limits, with their own individual styles and characteristics, you cannot make a personaly judgement on which is the more performant.. merely which one suits your driving style / limitations most.

All the best

Simon

carl

I'm still not convinced by this. I wonder if anyone's ever done a test of a RWD and AWD version of the same car (with some ballast to account for the drivetrain mass differences) in controlled conditions (same circuit, same driver, etc.)

You'd have to make sure both cars had the same power at the wheels (so the AWD one wasn't disadvantaged by drivetrain losses). Trouble is, I can't think of many cars that come in both RWD and AWD versions. Porsche C2/C4?

elondan

Even if we agree that RWD in the hands of a skilled driver is better for lap times,
I don't see how a FWD will have an adventage over AWD in any case.
and I still think that for road use AWD will be better for any driver, even skilled ones. (I mean a Scoob's AWD don't know about systems like the 4motion)

ex-webby

carl.. the problem is... (like I said) that would still not be a true comparrison of which is better, as one type of body weight distribution might suit RWD more than AWD, one kind of suspension design / setup might suit one more than the other, etc, etc.

The only way to truly prove it in the real world is to make an IDEAL (for performance only) AWD car, and then an ideal RWD car both tuned and perfected for their absolute optimum in the conditions of the test.

This is of course not possible...

So we turn to science and years of accepted norms based on technology and testing. We make a meta model of the entire dynamics package of a car. We make prototypes in motorsport to find the optimum possible.

In RWD, it has become the likes of F1 and indycar, in AWD is has become the world rally cars.

The big difference is that the AWD development is the refinement of active diffs. If AWD was just better, why would they need to move the torque reaward in order to improve the handling?

elondan

agreed, as I said in my very first post on this topic. The discussion that ensued was whether AWD was more performant as a package than RWD.

All the best

Simon

darkblueturbo

at the risk of repeating something that's already been said for a driver such as myself, 22 driving 5 years, and most other people who drive on the roads of average ability the best solution, to use Simon's phrase, is AWD. It certainly is for me after test driving Honda Civic Type-R, BMW325 and Impreza Turbo (and Evo 6, even though I can't afford it!).
AWD alows bigger margin for error than RWD and more power through and drive out of corners than FWD (this is my experience of these cars)
As simon has said though, it's no just the drive that wil affect this. The Impreza and Evo are (must be) better handling cars than the BM3series and Type-R, so they will have had a lot to do with it too.

Basically, I bloody love my Impreza and wouldn't change it for anything. It's the best car for ME on English roads. Apart from that one argument with the wet road, but we live and learn don't we. Drive through them, don't snap your foot of the throttle

carl

I can see how active diffs would be the ultimate. I assume you want RWD up until the apex, then AWD when powering out? If so, I can't see the point of the first bit. Surely when braking into a bend it doesn't matter which end is being driven?

Why did Williams F1 bother to develop an AWD F1 car (which was promptly banned), if it's obvious that on a smooth circuit RWD will always be better? (When Colin Chapman tried it the technology was in its infancy, so his poor results with it are not so relevant).

[Edited by carl - 8/22/2002 4:09:09 PM]

EvilBevel

carl, one point though... traction has always been a problem with the high powered F1 cars, especially in the turbo era.

They solved this now with allowing traction control (and you can hear that work actually)

Not arguing, just a statement why possibly they wanted AWD back then.

carl

Good point. I'm not trying to be argumentative, I'm just trying to understand

Mr_TonyC

F1 and other circuit races have tried AWD with one advantage in mind. Traction. Very handy when trying to get 800bhp+ down. Its the only real beneift it has on a smooth surface (on a loose surface you get a lot of scope for different corner entry and exit with AWD then 'owt else)

The teams that tried it all gave up becuase of the disadvantages it had. Weight was one, understeer problems in earlier versions, and later ones tried using all sorts of active diffs and active suspension to try and basically make it handle like RWD but with AWD traction.
In the end Elecy traction control to the RWD is a darn sight cheaper, lighter and simpler to deal with.

Most other AWD track cars have been kak. The Quaife in the british GT championship for example. The skylines in the JGTC probablt don't count as they are the ultimate AWD designed to drive like a bleeding RWD.
The Audi's in the BTCC only really did well in the Wet races and most races in Britain are in the wet. Yraction you see.

I'm not sure why there is the current fixation for AWD performace cars, maybe its a kind of dumbing down

ex-webby

the 4wd f1 car thing will not be known (probably ever), but the differences were that grip levels were MUCH lower due to tyre technology, tarmac technology, etc, etc.

But.. just because it was banned, doesn't mean it was better.

It *may* have been that they were incompatible in that they would have been much quicker out of the slower bends, but much slower in the faster / medium bends and on entry.

The active diffs at current state of the art are WAY more complex than that...

the logic is built on a nueral network of parameters including innertia pack data, suspension movement, all control inputs, speed, etc, etc.. and any combination of all of them can produce a different agressive or progressive (meaning an extension of one of the agressive) programs.

For instance.. some drivers like to fully open the centre and front diffs (remember that engine braking also goes through the diffs) and fully lock te rear diff momentarily if they lift agresively and steer after a full throttle period, etc, etc. This specific program enables a shaper turn-in on gravel.

AWD and RWD *does* make a big difference on turn-in / before the apex. even if you are riding the clutch (which you wouldn't be in a true performance test) the diffs still operate between the wheels. If that torque being applied back through the oposite side of the diff causes an undesired lack of grip, they want the diff open (or partially).

On tarmac it's more clear cut. The power goes to the rear for the majority of the time and moves forward under unsettled moments / low speed high throttle, lots of steering whilst sideways, etc, etc.

The logic is truly mind blowing.

All the best

Simon

carl

Originally posted by Tony_C:JGTC is an interesting case. The fastest cars are Supras (front-engined, RWD), then Skylines (front-engined, AWD) then NSXs (mid-engined, RWD). Theoretically the NSXs should be fastest

carl

Originally posted by webmaster:I guess we won't know until someone competes with one in the TGP
The banned Lotus 88B (IIRC -- the twin-chassis one anyway) which never competed in a GP has wiped the floor with the opposition in TGP
PS: Isn't using a neural net akin to guessing -- essentially you do it because you don't know the parameters?

EvilBevel

Tony, I'll get you for this

Simon, I know you hate Drivetrain , but there's an interesting thread there about an affordable mappable centre diff for the Impreza. I think JF is already on top of it Could be really interesting I think.