As if no one with any significant brainpower and curiousty for truth haven't figured this out years ago. Excellent post anyway, Racer X.

The new world order has just begun.

A flat 6, just like the real Porsche, for its balance (relative lack of vibration) and low COG. Also way easier to package in the confines of a rear engined car than other configuration.

A rotary might be nice, but to be realistic I don't think an owner of such a luxurious supercar covered in the finest leather would want to stain all that with a bottle of Amsoil's/Mobil's/Shell's/Redline's/Royal Purples's finest.

Unless someone comes up with an alternative to the classic F-6 turbo and beats it soundly overall, than we don't have any choices.

Well, at least those FIA monkeys have done ONE thing right...

Quote from Lateralus :

The problem lies with the tire compounds themselves, not the blankets.

Bridgestone is the sole supplier and can do as they please. They should modify their compound so that the rubber works only fairly well in a wide temperature range, including straight off the racks in the garage. The cars would be a little bit slower, but not that much. Now that Michelin isn't forcing them to push everything to the absolute edge, they don't have to make tires that work brilliantly within a 5C range but which fall off hideously anywhere else.

The sometimes dangerous conditions of low pressure/temp during safety car periods would be eliminated, and of course there'd be no need for tire blankets.

While at it, why not just use road compounds that work in wider ranges, like say, Bridgestone Adrenalins or RE-01s?

I don't mind using road compounds as long as the tire is constructed correctly for racing. And it is now apparent that people don't know what they are asking for. Even with today's tire tech, it is still only possible to make a tire perform extremely well over a well defined and somewhat narrow range, not like the silly American notion that one all season tire must perform well with everything (which ultimately fails).

By the way, the infinity quote was from Einstein, I just forgot to mention it that's all. BTW, if Europeans didn't "plagiarize" Chinese agricultural tech a few millennium ago, they won't be too many of them alive today. If the Americans didn't steal German scientist, there is simply no way they could advance THAT much in the short time space of the cold war. Point is, be careful whenever trying to finger point or insult, for the consequences might be more far reaching and dire than one could possibly imagine.

As the Japanese have realized centuries ago, to be creative and innovative, one must first copy. Some things such as basic Newtonian physics and machine physics are universal to all and must be shared. Unshared knowledge is ultimately useless in the long run and can only destroy the discoverer and ultimately humanity or at least one's own race. The Japanese used to copy the west, but now the tables have obviously turned as they are setting the standards. For instance, they did use the 997 turbo as a benchmark for the performance of their new R35 GTR, but the end result is a car as technically different to their benchmark as a 944 is to a 997. And last time I checked, the GTR soundly beats any production 911 turbo. This effectively makes the R35 THE new standard.

Would any of you know how to read, write and speak if not for so many years spent copying from the vast linguistic database that your elders and teachers have accumulated through their own experience and their forebears?

Last edited by Jamexing, Thu 22 May 2008, 17:22.

I thought this thread was supposedly about a turbo rear engined 4WD
version of the FZ50 or equivalent. Please get back on topic?

The sheer stupidity of F-1 regulations popping out these days is both alarming yet expected. It is now clear that F-1 has entered a new age of incomprehensible stupidity.

What's next? Ban hydraulic brakes and mandate the use of dodgy and hopelessly engineered brake cables that could break at any time? Boy, that'll be a great show...

2 things are infinite, the universe and human stupidity, though I'm not so sure about the former.

What's weird with all this is that the XRT was ALWAYS in the demo until patch Y, when it was suddenly pulled off. As for UF1, well, let's be blunt, no one in their right mind is going to judge and buy S2 based on their UF1 experience. I have a hard time imagining demo guys complaining about the loss of UF1 in the demo.

I still remember my demo days so many years ago (S1 era!) and XRT was the only car that was worth testing as it really showed the tire and turbo physics well enough, since it had the performance to do it.

But wait, is this just another ploy to hide how wonderfully neglected and wonderfully bad turbo modeling really is? The plot thickens...

A 4WD FZ50 with rear wheel bias (i.e. front torque will NEVER go beyond 40%, minimum 20% front) would be great fun. I'll rather have it set up with static F/R torque distribution like the RB4 than the real 911 turbos though. The 997 turbos are notorious for oversteering too much on liftoff and understeering too much on throttle, with very little possibility for behavior between those extremes.

If I were to add this car to LFS, I would basically set it up in its own class as the Supercar class, something LFS currently lacks. In reality, this is generating a gaping hole in LFS's car lineup and lots of needlessly wasted opportunities to open up a large but hopelessly undertapped market: Supercar Simulators. Then there is also the gaping lack of REALLY good rally cars, though that's not the focus here.

My specs:

Engine: 3.8L F-6 with VGT Turbo, Aluminum Matrix Composite. Camless.
Power: 410kW @ 6700rpm
Torque: 650Nm @ 3000-5500rpm
Redline: 7000rpm, 7500rpm cutoff
Mass: 1.75 metric tons with 85kg driver and full fuel load (100 liters)
Tires: 265/35/19 F, 335/30/18 R
Turning circle: 12m (reasonable for a monster tired supercar)
Top Speed: 320km/h



Note the relative LACK of mass compared to the real 997 turbos. This is due to use of carbon fiber or carbon fiber aluminum composites for all chassis and paneling components. The entire drivetrain will be made of various Titanium alloys.

Last edited by Jamexing, Thu 15 May 2008, 04:10. Reason : Oops, forgot the turbo!

Quote from March Hare :

@Jamexing

Do you or do you not want a SUV in LfS? And I don't mean a race tuned dakar car but a Chelsea Tracktor = BMW X3/5, Audi Qx, Volvo XCy, H2, H3, Chevrolet Suburban, Cadillac Escalade, Dodge Durango, Mitsubishi Pajero, Toyota Land Cruiser, Porsche Cayenne, VW Touareg etc.

Or are you arguing just for the sake of arguing. In that case you are off the bleeding topic so bugger off.

Please make a short answer as I can't be bothered to read your lengthy and infact very boring drones about cogs and stuff. A simple yes or no will do.

Thank you.

Point 1:

WTH IS YOUR PROBLEM? No one is forcing you to read anything if it bores you. Last time I check there is NO compulsory need to say yes or no to toorak tractors in LFS. WHO THE HELL ARE YOU TO MAKE RULES UP? Unfortunately for the likes or you, like so many things in life, a simple yes/no answer is simply invalid, unless you have the mentality of a spoilt 10 year old brat.

Point 2:

I've seen so much SUV related balderdash and it's about time someone sets things straight. There's popular stereotype, and then there's how things REALLY are. There's one sided bullshitting, and then there's telling things as there are. I prefer to explain and clarify rather than just saying: "ME WANT XX CAR IN LFS!" or worst still "Car type XX SUCKS..." like an individual that is nothing more than the product of pop culture. Got a problem with that boy? Speaking of boring, I find short and meaningless rants on "this car type SUCKS more than anything else" tedious to say the least. And like it or not, to say all SUVs must be excluded from LFS is just too much of a blanket term, since, so many off-road racers are built using production SUV chassis. In Australia, 300+hp Pajeros, Landcruisers, Prados, etc. that race SERIOSULY off road is the norm. In the USA, there are production class off-road racers that use production chassis of anything from the Ford F-150s to 2006 Ford Explorers. Like it or not, those racers are STILL either an SUV or Pickup truck. These cars WILL be a lot of fun with proper tracks, so we should just say "SUVS! BAN THEM ALL!"? What confounds me is how so many are so willing to run simple minded blanket mentalities without considering the consequences.

Point 3:

DO NOT tell me or any one to bugger off a PUBLIC forum open to all LFS demo users and players. It is EXTREMELY RUDE to put it mildly. Enough said.

Quote from Shotglass :

which will drop the cog on a modern suv by lemme see ... 2 metres sounds about right

By stripped out I mean the usual interior stripouts carried out in racing cars of all types (removal of unnecessary seats), sound deadening, A/C, stereo, trim, etc. NOT deliberately trying to remove serious weight off the roof in attempt to lower COG significantly. Of course, lack of roof scondary A/C unit might lower COG a few millimeters max, but than there are those large steel tubes that strengthen the roof and chassis in general, which does weigh a bit. There might be some tiny lowering of COG but don't expect it to magically transforms things significantly. It's a matter of hair splitting, and even if you end up with COG of say 5mm lower than stock, the higher than OEM tires will just about cancel that out. BTW, I happen to be familiar with Pajero roofs and believe me besides some OEM structural bracing, some lightweight sound insulation and maybe a roof A/C system on the more luxurious models, there isn't that much weight that you can strip off up there. Lowering COG by any serious amount would entail either drastic surgery or using a purpose built base chassis (i.e. not publicly available), which in group 8 is absolutely forbidden.

Oh, BTW, to turn ANY vehicle into a rollover hazard, simply load the roof rack to WAY beyond sensible levels (e.g. beyond OEM limits) and drive like a maniac. Works on any car that you can mount a roof rack on. Get an Subaru station wagon, load all the heavy cargo to the top and next thing you know your view of the world turns by 180 degrees on the Y-axis (standard engineering definition for the longitudinal axis), assuming you lived that long. Now who was the moron who came up with the idea to load our 2 100lb dumbbells and 10 gallons of fuel on the roof...

And for your own sake don't say something as silly as lowering the COG by 2m for a typical SUV. Never can and never will as it defies the laws of physics. BTW, most SUVs are well below 2 meters in height, even if lifted sensibly (e.g. 25-50mm). This nonsense only serves to make yourself appear less intelligent then you might be.

Ford weakening roofs? Oh come on, that's REALLY old news. Must be a slow news day. Yes, I am aware of the Firestone/Explorer debacle. The car was no sports car, though it wasn't THAT bad. Roof weakening is of course just another of Ford's long line of stupid or just insane ways to cut cost, no surprise here. This is what happens when sensible engineers get overridden by bean counters and marketing agents with no respect for the laws of physics. Then there were the manufacturing errors and worst of all, STUPIDLY LOW OEM tire pressure specs. If it wasn't for all those thread separations caused by tires built to less than satisfactory quality and the stresses of high speed running at highways speeds (excessive tire body flex at speed generate TREMENDOUS heat) and all those consistent rollovers of similar nature caused by this, chances are the media won't be getting an easy meal ticket out of this.

What I can't believe is that I actually bothered to check a bunch of articles that accuse a lot and come up with practically nothing concretely scientific. And yes, there is quite a bit of propaganda, half truths and even pure balderdash in those articles. Some of what they say is of course true, but only to a certain extent. Listen to what the media says, but always take things with a grain of salt and try to dig deeper than what is popularly raved about to ascertain the truth.

Of course, SUVs do have higher COG in general, but narrow tracks? How narrow? Last time I checked, most manufacturers are widening track whilst keeping COG constant or even lowering it. Some have actually widened the track, lowered COG whilst maintaining or even increasing off-road usability by keeping the ground clearance constant or greater than previous models. The most high tech have the ability to actively recalibrate their suspension according to user input to suit conditions and actually lower themselves automatically when driven above a predetermined speed. A car that mechanically and aerodynamically re-engineers itself to suit conditions.

If you believe everything the media says, SUVs would be so magically roll-prone they will flip over on anything that resembles a high speed corner or a quick swerve. While some SUVs do drive more like sedans running on their sides instead of the usual way, such vehicles are a TINY group and are in fact very rare in the western world. They're too small for any practical family use so they're not going to proliferate any time soon. I've even slalomed SUVs and find them quite stable in general (aka can't say the same for all) unless you are absolutely devoid of useful g-sense, which seems to be the norm these days (along with absolute lack of common sense).

What troubles me is that none of those articles mention the fact that most rollovers aren't a simple matter of swerve and flip. Most involves going off the side of the road, getting out of control, trying to get back on the road ASAP and actually end up making things worse. This applies to all car classes, SUV, sports cars or sedans. The fact that some drive more recklessly in SUVs since they actually reduce your perception of speed quite a bit (seat height dependent, higher is greater), it's no surprise they end up rolling more. For the worst examples, just take a look at South East Asia and the middle east in general. Remember that video of some guy trying to climb hills sideway or skidding up a vertical concrete curbs?

Last edited by Jamexing, Wed 14 Nov 2007, 18:21.

Quote from Crommi :

I bet those group 8 cars are not using the chassis from street model and are much lighter with lower center of gravity. Neither it is surprising that real offroad car sits higher than SUV that has ground clearance designed to go over speed bumps instead of rocks and ditches.

I agree with you on that suspension tuning depends on where the car is designed to go, however most SUVs are designed to be used as a people carriers in city area. At low speeds soft suspension is more comfortable and target audience is not really that interested in how it drives rather than how it feels like to sit in. For complaining husbands car manufacturer's have come up with "sport SUVs" such as Land Rover Sport which still handles like a pig but 4.2 V8 has more horsepower than neighbour's Honda CR-V.

To be absolutely honest, those group 8 cars I talked about are ALL based on 100% OEM chassis. The current reining champion happens to be a Pajero (independent suspension and reinforced unit chassis aka 3rd generation) driven by Geoff Pickering. If you google around you could find quite a bit about this guy and his car. The only significant structural changes were a roll cage (absolute must since it improves both stiffness and safety besides the fact that it is compulsory under racing rules) and seam welding, nothing more and nothing less. I happen to have seen the car up close and personal so I know.

And I don't care about all the urban myths circulated around about using some special chassis that is not available for sale. The blunt truth is that the car is nothing more than a production chassis seam welded, stripped out and mounted with a roll cage for racing. Try as you can but given group 8 rules that specifically prohibit the use of specially built race chassis that is all blown out of the water. Suspension geometry changes beyond factory specified limits are absolutely verboten. Springs and dampers are almost completely free.

In case you were wondering why this race Pajero is TALLER than OEM, it's got nothing to do with suspension ride height setup. The rear springs have close to OEM spring rates whilst the fronts are stiffer than stock. Has a lot to do with jumping around and landing front first really often in conditions where dips can swallow an entire car. The bumpstops and bushings are left stock since there is no point changing what works so well. the spring material used is, however better than stock. The dampers are Donner Dieres aka the same manufacturers that make dampers for Dakar T1 rally raiders.

Now, as to WHY it is taller than OEM: Tires. The OEM tires were 265/70/16, swapped with 16 inch forged aluminum alloy rally wheels and 235/85/16 tires which are about 32 inches tall vs. the 30.5 inches of the stock tires, it IS taller, but by millimeters. The chassis donor was from a production Mitsubishi Pajero, 3rd generation GLS 3.5L petrol engined manual model. Interestingly, they left the gearbox and transfer case stock. The latter hasn't had a serious problem to date, though the stock gearbox was swapped for a proper racing sequential box since it blew after few races of merciless abuse. The suspension travel is practically stock, though OEM 3rd generation Pajeros aren't exactly short legged shopping trolleys. For reference, the rear suspension travel is about 260mm long. That is just slightly more than what is allowed in the Dakar T1 class (250mm).

Last edited by Jamexing, Tue 13 Nov 2007, 09:16.

Quote from March Hare :

SUVs bad, m'kay.

Off-road race cars (Dakar, Baja, Outback challenge etc.) good.

Unfortunately we would need tracks to drive them and they would be next to useless on the tracks we have now. So I can't see them coming very soon.

FYI, the T1 racers (Pajero Evolutions, Dakar Touregs) are chrome molybdenum tubed spaced framed race machines, but the T2 class cars are ALL based on production SUVs. The same for group 8 racers in Australia. And no, they're no slouches off road or on it. 200+kph on teh straights (OFF road!) and 120-160kph through the fast corners isn't exactly slow. And if SUVs are as magically super roll-prone as some here claim that simply wouldn't be possible. Note that the group 8 vehicles all have seriously modified springs and dampers and off course tires too, but they're slightly TALLER than OEM. Yet they're actually more stable thanks to superior suspension tuning and spring/damper behavior. BTW, group 8 specifically prohibits ANY major changes to major suspension components (e.g. wishbones) i.e. the actual suspension geometry must NOT differ from OEM.

As I've stated from my own experiences, stability for a given SUV is VERY suspension tune dependent, though much more so than many cars thanks to higher COG. And contrary to popular belief, softer isn't always better off-road. What works best is extremely case dependent.

Last edited by Jamexing, Mon 12 Nov 2007, 07:06.

Quote from Gunn :

Do you honestly think he has only had experience in F1 cars?

We're talking about a guy who demolishes the competition in the wet here, TC or no, go kart or 900+hp monster. Excellent point Gunn.

Quote from mrodgers :

May I just ask why you quoted me, then stated "stop chanting stereotypical SUV bollocks......" I'm not exactly the one who is chanting the SUV easy roll over crap.

No you are not. I just quoted you because you made a good point.

Quote from yoyoML :

http://www.youtube.com/watch?v=nmko3952548

He's really skilled, but it just shows how easily an SUV can flip on its own, on flat tarmac.

edit: more
http://www.youtube.com/watch?v=7_XpObaKeOw

I've seen the 1st one before and that's a Nissan Patrol BTW. Notice the strong, uncontrolled spring rebound on the front suspension in response to suspension unloading.

Let's assume that the Patrol's suspension was absolutely OEM. If it was with those super cheap dampers, such behavior is no surprise. BTW that is NOT a high speed cornering maneuver in the proper sense (say taking a fast corner at 140km/h). Such driving is akin to trying to feign drift the vehicle and the results were no surprise. OEM SUV dampers, unfortunately, are notorious for stupidly stiff compression but little in the way of rebound damping, so it's no surprise the suspension bounces the car up so much as it rebounds uncontrollably. Change that to a carefully selected heavy duty spring set and adjustable dampers tuned for maximum tarmac handling and it's a different story. Take it from a guy who owns and drives an SUV with dampers calibrated by himself. And yes, the ride is quite kidney friendly. The only items I'm missing are stiffened front springs and the vehicle will be perfectly setup. The results before and after the damper upgrade were extremely significant. Since I've pushed both OEM and my current upgraded setup to their limits (on a closed former runway), having done multiple handbrake 180 turns too, I have 1st hand experience of what the vehicle can and can't do. If it gets unstable, there is plenty of margin to recover as the vehicle gives excellent feedback. That was with the hopeless OEM dampers. With the upgraded units, I had to push MUCH harder before the vehicle suffers from mild instability, again, providing plenty of feedback, though there was little danger of overturning. Resistance to feint induced instability also increased significantly with proper rebound damping.

In Malaysia, SUV drivers are well known for cornering on pothole ridden highways at 120-140+km/h. Yet few have actually flipped from high speed cornering. Most rollovers actually occur on the straights, usually when say trying to dodge stuff, getting off the road (on the side) without much issue, only to flip when trying to get back on tarmac as the car turns into the curb. In such a situation, even a sports car could flip. Unsurprisingly, most rollovers occur early morning (3-6a.m.) with lone drivers, usually under sleep deprivation or alcohol intoxication.

On the 2nd video, one SUV actually skidded and spun without ever getting close to flipping (until some other car hit it). On the other hand, some others simply flipped. Again this was very model and setup specific. The shorty tripped over a a solid ledge, i.e. it was levered. Notice that it survived bouncing up the curb unscathed until one of its wheels caught a solid ledge and subsequently tripped. The 1st SUV flip was no surprise, since a combination he severe feint action pretty much guaranteed that. The same maneuver on the latest double wishbone coilover front 200 series would have a much lower chance of such a flip. Assuming of course it is properly sprung and damped. The worst case I can think of right now is the latest prado. They lowered the ground clearance to a stupidly low 180mm, but also chose to make the springs/dampers 30% SOFTER in the name of "comfort". Can't see how a wallowy spongebag that threatens to leave terra-firma all the time is comfortable and reassuring. In order to cope with this disastrous setup, they installed a stability control system, again software to deal with hardware calibration flaws. No wonder the Australian 4WD aftermarket suspension industry is booming, since they tend to lift the vehicles just a tad whilst actually improving handling, stability and wheel travel.

More feint induced rollovers...

As for the shorty on a race to the hilltop? Well, it hit some REALLY bad bumps at high speed. I won't be surprised if a dune buggy flipped because of that. BTW, shorties THAT short and tall make lousy hillclimbers and descenders.

Another feint induced Nissan Patrol flip. This is getting old. Patrols are notorious for that, with their hopelessly primitive suspension that is good for nothing more than snail paced off-roading.

Crash whilst climbing a sideslope. As if climbing a hill sideways isn't stupid enough. Notice again it flipped because the driver suddenly changed direction and managed to dig into the ground, again leveraging the car to a rollover. This could easily happen to a sedan based rallycar too.

Again another antique SUV with seriously outdated dynamics...

Again, another Landcrusier flip. The poor thing was shunted from behind pretty hard at a high point, so a flip is no surprise.

More feint flips... Landcruisers again.

The poor sedan lost its wheels! That thing might have been rusted through...

And unknown case since we didn't see HOW it flipped...

More of the same feint flips....

Nice driving... Survived the curb pretty well. Notice that there was quite a bit of time to react.

A bunch of head-on crashes...

My real point is to try to analyze each situation carefully before jumping to conclusions. Notice that the vehicles shown are mostly those that are old and already known to be more rollover prone (Landcruisers and Patrols). Patrols are the worse and that's no surprise.


With some of the driving I see here, ANY car could flip. There are plenty of what NOT to dos in this video.

Last edited by Jamexing, Mon 12 Nov 2007, 07:02.

Just to be clear, I'm all for well tuned SUVs such as the Group 8 Pajero (3rd generation model aka fully independent suspension, monocoque body, etc) and of course Dakar Rally Raiders and Baja Racers (aka F-1 cars of the off-road world. 36 inches of travel, 3 stage spring/damper setups, the cutting edge in passive off-road suspension technology). And I have yet see anyone roll these vehicles through a result of nothing more than fast cornering on flat and grippy surfaces.


And of course, no CR-Vs, RAV4s, and all the crossover pile of poo that they're trying so hard to shove down our throats these days. BTW, it's amazing what a latest model 5-door Suzuki Grand Vitara, with well selected suspension, wheel and tire upgrades can do. And I have yet to see anyone roll one over without doing something REALLY stupid.

Speaking of rollovers, it's surprising how rollover prone today's fat, tall and overweight "compacts" are. For instance, those Honda Civics sold in the southeast Asian market have body profiles more tall and narrow than many SUVs. The fact that their center of gravities are quite high AND the fact that they have really narrow tracks doesn't help. The worst vehicle I can think of ATM is the Mercedes A-class. As usual, the manufacturer took the cheapest route and used a software solution to cover up a serious fundamental flaw in the hardware. So much for the theory that SUVs are all a bunch of hopelessly roll-prone vehicles in particular. This of course does not apply to silly individuals with 4-6 inch lifts without widening the track to compensate. Judging by what they'll pump out these days, I won't be surprised that he day comes when your average compact sedan or small town car is much more roll-prone than any decent SUV.

No one in their right mind denies SUVs have higher centers of gravity than most cars, but well designed suspension, good wheels/tires and appropriately wide tracks mean they're actually quite hard to roll with nothing more than just cornering in one direction a bit too fast. BTW, the Cayenne did the skidpad at an average of over 0.85g, so the instantaneous maximum g is of course significantly higher than this, which one could make a rough estimate of say 0.95g peak. This cannot be achieved if the car was simply unstable. Of course, it'll never outdo 911 GT2, but then again when was the last time the GT2 went seriously off-road and lived to tell the tale. Despite of the low profile tyres, they still could still keep up with Landcruisers over most tracks that one could reasonably negotiate, at least until the tyres get ripped. It's only a matter of time before tyre manufacturers make off-road tyres for them. It wasn't so long ago when the hopelessly closed door off-road community used to bash 265/65/17 tyres. In reality, this had more to do with tyre manufacturers failing to produce decent all-terrain tyres of that size then anything else. This of course applies to well design and tuned vehicles (aka Suzuki Samurais and their like need not apply).

Last edited by Jamexing, Sat 10 Nov 2007, 05:22.

Quote from mrodgers :

SUVs don't easily roll over. It's the idiot's skills at driving that make them roll over. Drive a car in the way you need to drive an SUV to make it roll over and you will still crash.

Well, lets see... the Land Rover Range Rover Sport has an AVERAGE of 0.78gs based on a road&track instrumented test. BTW, there are LOTs of very grippy SUV tires these days designed for SUVs like the Porsche Cayenne Turbo. Just google this:

Michelin Diamaris

Impressively grippy and VERY road biased pattern. BTW, the 2 tonne plus monster snaked through the slalom at around 58mph, which is impressive by any raod car standard. Porsche Cayennes go significantly over 60mph.

On the other end of the tech scale, Toyota Landcrusier has been safely run through the skidpad on normal (aka all-season tires) at 0.76gs. Those tires, though no summer tire or slick, aren't exactly knobbly. Just go to www.tirerack.com and check out the all-season highway tires and you'll get what I mean.

BTW, Do check the summer performance 4WD tires. They are WAY more technically impressive than the usual performance tires since they have to carry relatively high loads, withstand 200+kph of constant speed, provide excellent steering response and cornering grip wet and dry and still have enough comfort to not jar Mr. and Mrs Chelsea drivers to objectionable levels. And believe me, overprivaledged spoilt brats nitpick even on problems that simply aren't even physically there.

My point? Stop chanting stereotypical SUV b0ll0cks and do some research/testing before jumping to weeping and to be absolutely blunt, STUPID conclusions. SUVs are like humans, too much variation to draw sweeping conclusions.


That said, if LFS magically comes up with a Suzuki Samurai I'll cry foul. Give me a Pajero modified for class 8 racing (aka minimally modified production class) or better a Pajero EVO and that's a different story. Just remember to add LFS equivalents of BFG Baja T/A tires and of course, INCREASE the number and size bumps on the Blackwood Rallycross Track...

Left foot braking with part throttle. An advanced technique though, much better for getting the most of the rear brake bias required to take maximum advantage of rear brake force than catching slide, but its all good nonetheless. LFB whilst on part throttle, done just right (depending on intent), effectively turns your RWD car into a front brakes only machine. The brakes also have a secondary effect of forcing the front wheels to behave as if they are connected via a super tight clutch pack LSD. This alone generates significant stabilization.


BTW, the above explained LFB technique can be extended to DELIBERATELY generate extra rotation on entry, useful when you are say on not so grippy gravel. The front LSD effect moderates the yaw rate whilst extra throttle spins the rears up a bit, generating oversteer if yawing force is applied. Works for both RWDs and some AWDs.

On FWDs, you can achieve a similar effect but via a different route. Just before turn in, slightly release brake pressure or maintain it, depending on exact condition) whilst adding steering and throttle simultaneously. This allows a hand brake turn effect as the car acts as if the hand brakes are on, but can be much more easily and quickly stabilized with just a bit less brake or a bit more throttle. Great for all sorts of conditions but especially on low grip surfaces.

Man, its getting boring these days...

That's why I don't post anything in LFS forums weeks on end these day. I REALLY wish the next patch comes with significant aero and turbo updates. Last thing I want whilst racing against the clock or others is a stupid AI car to mess it up but......

Anyway, high nosed (and winged) cars have 2 obvious advantages.

1. Lack of ride pitch and ride height sensitivity

In both CFD simulation and RL aero tests, its has been proven time and time again that the LOWER you run a front wing, the better the aero for all parameters that matter to a race car (L/D ratio, etc). This is true only up to a point, however, just before viscous effects come to play and the airflow under the front wing drops to Zero....

Note that modern regulations force quite reasonable front wing ground clearances to vastly attenuate chassis attitude sensitivity issues, mostly out of safety concerns.


2. High nose reduces nose to wing interactions

Ideally, the wing will act as a wing on itself. In practice, that's impossible as they're meant to be there to make downforce. So to let the wing act as efficiently as possible and ensure maximum control of airflow, you want it to be as decoupled from nose airflow as possible. This is achievable by using really high noses and setting a reasonable distance between the wings mount and the nose.




Of course , the above are quite general explanations and aero is still very much a black art of sorts, since real life aero behavior is both notoriously complicated and in most cases impossible to model in a completely analytical manner. That's why there's CFD that relies heavily on the use of basic equations of aero, heavy numerical calculations and approximations and of course shear computational brute force. That's why teams like BMW Sauber invest millions in Supercomputers such as Albert (or was it Albert 2? I think hey have 2 but can't quite remember ATM...). Aerodynamics of an F-1 car are complex and full of complicated interactions that should either be eliminated or exploited, so all I said should be taken as a general guide, not absolute gospel.

As I said, QUITE CLOSE, not SAME. Of course strengthened parts might be used where production parts don't suffice.

And yes I am fully aware that WRC cars are nothing more than dedicated rally cars with production car like skin. I'm too clear on that, with inconol turbos, etc.

And of course I was never trying to say that its the body shell that provides all the strength. As I've said you start off from a stock body, THEN add a roll cage and the attached suspension and other structural mounts which in itself would be most of the cars ULTIMATE strength and rigidity. Seam welding, strut braces, etc. BTW, extra bracing is actually quite common in well tuned performance street cars too. It's a steel cage reinforced monocoque, not tube frame chassis or space frame.

Of course, I meant that BUILDING the car is quite "cheap". And with brutal features as ALS, turbos and exhaust have tough (and short) lives. And of course those bumps, jumps, etc are expensive...

As is well known in engineering, development cost >>> Conceptual and research cost.Testing is EXPENSIVE. And with very tight rules, testing is the ONLY way to guarantee top level performance.

The gearbox casing in the Group N EVOs are actually quite stock. Of course, the internals are a different story. I'm not denying that at all. BTW, it is quite easy to do sequential shifting with a conventional dog box, which is standard group N practice. I remembered checking out a 5-speed race gear-set for the EVO XI only a few months ago. A straight cut gear-set, well built, but nothing like a WRC system.

Some references for your won interest:

http://www.hewland.com/svga/ralliart.htm

http://www.ralliart.com/05topics/05news/rai-05dogtme.html

http://www.umsrally.com/E7groupnkit.html

Not exactly WRC style space tech.

Quote from ajp71 :

Sorry that post shows you don't really have a clue what your talking about. The Group N cars have no real relation apart from the engine and some of the drivetrain to the production cars. Any 4WD road car could equally easily be converted for similar costs. What makes the Subaru/Mitsubishi different are that they have had factory backing meaning there is a wide range of racing components made especially for them.

That is part of my point actually. When you get say an EVO XI, there are already factory backed homologation parts (i.e. you can't just get whatever tiny increments in ratios you want) available for racing use, so the stock car forms the basis. The car is based on a completely stock chassis that is mounted with a roll cage and strengthened to an extent for racing. The drivetrain systems are still mostly stock and there are severe limits to what you can do to suspension geometry, etc. Of course, dampers and springs are pretty free, but there are limits to what you can do when stuck with close to stock geometry.

This is NOTHING like say a Citroen Xsara, which does NOT have a production 4WD version currently on sale. And when was the last time they sell Xsaras with the same engine blocks as they race? Back in the final years of Mitsubishi's winning streak (EVO 6.5 at the time), Mitsubishi was the last manufacturer that held more closely to group A rules that didn't allow the same level of modification from stock than WRC rules.

Just a bit of history. What I'm saying is that with a "reasonable" budget say U$100,000, you can build yourself a Group N contender with an EVO without doing things such as trying to transform FWD to 4WD, using an engine absolutely unrelated to any production block, etc. The drivetrain is actually remarkably close to stock. Of course, things such as oil coolers would be upgraded, but that's actually quite common with quite a lot of street EVOs that have been properly modified. Not as if you've just banged in a transfer case and a gearbox case that's completely alien. Oh, the Group N cars are still run off the stock gear casings BTW, with homologated (aka STANDARDIZED) gears as previously mentioned.

BTW, Group N turbo casings are still made from cast iron, not inconol or any exotic and ridiculously expensive materials.

Quote from Sudo :

"The only thing I don't like is that it seems to be a Suby and Mitsubishi only race. I watched the New Zealand event and the top ten were either Suby or Mitsubishi."

That's how it's supposed to be! Mitsubishi and Subaru are the only manufacturers that still make production cars that can be prepared for rally use with relative ease and cost effectiveness. The currently domineering European WRC cars are just non-representations of their manufacturers.

Power to those produce cars easily adaptable for racing. Race what you build, not build to race. The fact that you can easily turn your Mitsubishi Lancer Evolution XI MR to a serious PWRC contender with less than millionaire level funding proves it. Do the same to a production Citroen/Toyota Corolla/Peugeot 307 and nothing will be left stock, not even the basic drivetrain layout or even the engine block.

Quote from Forbin :

I think Todd is talking about the wheel's camber. In order to get equal load across the tire, the wheel's camber has to stay negative as explained by post above with LFS used as an example. If the wheel is flat (0 camber) under high cornering stress, the contact patch flexes inward. This effectively puts more load on the outside of the tire. To counteract that, you need more camber, which effectively makes the contact patch's camber more even (closer to 0 instead of highly positive)

By having your wheel camber more negative then the road, this compensates for tread deflection, so the actual thread contact area is greater and the vertical and lateral loads more evenly spread. Thus, more even pressure distribution.

It is not just area that affects load sensitivity. Pressure distribution is the real factor here, though it is related to area on the ground too. and no I have no intention of being condescending. People seem to be misunderstanding me a lot these days. I am just helping you to visualize tire behavior better by encouraging the use of imagination.

Remember, we are trying to get the tread to 0 degree camber relative to the road, not the wheel. To understand this better, just play around with a wide racing style, low profile, soft and hollow (non-pressurized air filled) remote control car tire tire that you can easily load with your hand. As you vertically and laterally load the tire simultaneously, note that zero wheel camber actually forces the inside edges of the tread block(s) to lift off the ground as they flex under the lateral load. In real cars, this easily shows up as more temperature on the outside tread block(s) then the inside since the inside is actually experiencing less pressure. This condition is easily remedied by adding just a few extra degrees of negative camber relative to the ground, so we end up with the individual tread blocks square to the road for ultimate pressure distribution.

And yes, Forbin's explanation is actually quite good and straightforward, though it misses out a bit on the subtleties of what really happens. Just try my suggested experiment and you can easily see that Forbin and I are absolutely right on this.

Hope this helps. If not just say so politely and I am OK with trying to explain this better.

Last edited by Jamexing, Sat 22 Sep 2007, 17:31.

Quote from Ball Bearing Turbo :

Do you know why this would be? That's unintuitive. (but then what part of tire physics IS intuitive! :razz

It is intuitive BTW. Whilst the outside tire is cornering, it is subjected to both severe vertical and lateral loads. Since tires aren't exactly stiff wooden blocks, the tread block(s) (depending on whether tit's a slick or treaded tire) are deflected to the inside of the corner. The final result is that the pressure distribution over the contact patch becomes uneven when cornering at the limit with 0 relative camber to the road because the tread blocks actually deflect, causing uneven pressure over. The extra negative camber compensates for this tread block deflection, allowing more even pressure loading across the contact patch.

Just read my explanation and with a bit of imagination one can easily figure this out.

Quote from xaotik :

Not so much related but... it's interesting...

Prologue (feel free to skip):
Some time ago with a pal we pondered over the availability of software to properly simulate fluid dynamics, initially in a sort of musing-over-beer about ideas for a speargun body he was making out of carbon fibre and specifically about the best hydrodynamic shape for maximum lateral speed vs maximum horizontal stability. After busting our heads over some of the opensource stuff, Xfoil, OpenFOAM and some others - we gave a shot to Xplane's modelling deal which was close, but not easy/comprehensive enough to get it to actually do high viscosity fluids. So in the long run we ended up "acquiring" this:

http://www.fluent.com/solutions/sports/sports8.htm

(yes, the specific page was selected to get your attention)

Simply put, it's great. Design your 3d model - or have someone design it for you - toss it in there and begin the fun. Last time I checked the latest version it was still available in the land of the torrents.

That is far from irrelevant if winning is concerned. Even "schoolboys" (Uni students) need aero speciallists on their team if winning is a top priority.