GPL (yeah.. GPL) has this utility available that shows the tyre surface temnperature. They increase and decrease very very fast indeed. To the point where I'm quite sure that a big powerslide with opposite lock is only sustainable for one or two seconds before tye rears really overheat.

I doubt that is fully realistic but its a VERY big difference to LFS where the temperatures creep up and down very slowly..

From what I know, rubber has poor heat conduction so it would seem to make sense that a short time spinning or locking tyre produces a lot of heat quickly (high friction, low heat conduction) at the surface.

The frex pedals are misleading. Unless they changed something very recently, they CLAIM pressure sensitive but it just turns a pot so it is motion sensitive.. I.e. 'pressure insensitive' as motion gets near 0 when you're pressing the rubber..

I guess we could be definitive if there is telemetry of a race car available showing longitudinal G forces and brake pedal force, when braking in a straight line..

Throttle is interesting and I think some sims are weird. I have been told what the problem might be but I can't comprehend. I think throttle should set the 'target RPM' whereas it seems, in ISI perhaps and NKpro for more sure, to be more directly connected to the power / torque. So when you lift off the throttle when the back steps out, you basically don't apply any power as long as the RPM you 'set' with the gas pedal is lower than what the motor is currently running at.

With the 79 mod, in neutral, giving some gas until the revs start.. then even doing this carefully, makes the revs max out! In NKpro, which I have barely played, I found the gas pedal odd in response. As said though I don't fully know how this should behave but I have some suspicions towards a few sims.

Because since its probably a fairly simple spring/damper thing if you simplify it a little, it would be a lot easier for sims to do this for each car.

Of course 2007 won't be the year that everyone uses force sensitive brake pedals, and there are more important things to improve in sims..

I do wonder though if the attatched crap drawing could be the case, or if there are any other factors going on in 'real' (race) car braking that 'flatten' pedal force fluctuations.

I find it nearly impossible in sims to get smooth braking done while blipping the throttle. And looking at video's online from real cars, I just don't believe that their brake pedal force doesn't go up / down a bit when they heel and toe.

Yo folks!

I wonder in real life, how quickly the force at which the calipers clench the brake disk, varies when the driver changes load on the pedal. Why?

Well now that one can use a 'load cell' to get a true force sensitive brake pedal I wonder if in real life, slight brake pedal force variations, when blipping with your braking foot for instance, have an immediate influence on the actual braking done.

If there would be an ever so slight brake caliper displacement when braking harder and harder, that would mean things like the viscousity of the fluid, the tube diameter, return spring strength, tube expansion etc ALL have some damping effect. Even when the pads don't move, even the brake fluid 'tubes' will expand a VERY VERY tiny bit, which will act as a 'spring' ever so slightly disconnecting the pedal pressure from the caliper pressure..

Could it be however, when I'm braking, heel & toe-ing and have quick, slight, fluctuations of pedal pressure, that the actual braking would react slightly damped and thus show less fluctuation?

illepall

Edit: Bah seems more at home in 'general racing talk'

Last edited by Niels Heusinkveld, Sun, 14 Jan 2007 00:52.

A new system? Whats wrong with your current one!

The problem (ish) with processors is that there is always the budget chip capable of nearly the same speed as an *overclocked!!* faster and multiple times more expensive chip. If money is tight, I wouldn't feel good knowing that I'm getting a E6600 will probably run as fast as a half price E4300.

He might be Borat!

looks nice...
Then you see a video..

Then you don't know if you should laugh or cry..

There is horrible, there is very very horrible, and there is F1 on the P(o)S :/

This doesn't deal with the heating / cooling but this is the table from another sim, for sport road tyres. See pic. I don't know if that is correct but at least the difference between this and LFS is big!

It shows temp versus grip multiplier

I found out the RAM "heatsink" on my 6800GT was made out of plastic.. It seems that for ddr3 you don't really need them! I know some 6800 Ultra cards have shipped without ram sinks and I believe I saw 7600GT cards that did without as well..

http://www.silentpcreview.com/forums/viewtopic.php?t=19147 That should be a fun read for possible harddisk sollutions. Suspending them works great, although of course you're best off with as few HD's as you can, especially avoiding old ones..

Yeah they basically have no value.. I hope you got it for a symbolic sum of one beer or similar...

Riced! http://www.silentpcreview.com/ ... 717&highlight=finally ... functionally.. for silence

That should be 'ok' if its a Sempron socket A, and pretty good if its a 754 / 939 / am2 socket type! Definitely worth getting a 9600 / 9700 / 9800 pro type card. I would not get the Geforce 5xxx range as they are inferior in newer directx 8 / 9 games.

I could run LFS at 1600x1200, vscync stuck at easy 60fps (offline that was) with a 9700pro and my Sempron 3000+ (although it runs at 2.4Ghz which is 600 more than out of the box )

Firstly you need a reasonable CPU to play LFS properly. So a great graphics card with a 1Ghz cpu won't do wonders.

Secondly, both Ati and Nvidia have had their issues but that averages out pretty well. You can find 100 guys who will say Ati sucks, and you will find 100 who say Nvidia sucks. Reality? Mostly both brands are fine..

The PDF from 3Dmark shows the graphics card to be a 9600 series with *256* MB ram. 3Dmark sees your graphics card as a 256 MB 400mhz type where a 'normal' 9600pro (aiw) sould be 128 MB 600mhz. That was what I was on about

I have found 3Dmark to be wrong when it comes to the speed of the gfx cards but I find it odd that it thinks you have 256MB on the 9600 card.. Especially since the combination (9600 pro, 256MB, 400mhz ram) gives me some hits on google.

The 3dmark PDF you attatched earlier says its a 256MB card with 400mhz RAM.. Of course this could be wrong but that is what I've based my conclusions on!

Oh and Gigabyte DID make socket 478 SIS based SDRAM pc133 boards so I wasn't totally talking out of my bottom!

http://www.gigabyte.com.tw/Pro ... _Spec.aspx?ProductID=1404

Your powersupply is actually good, its a Fortron 250W which will easily deliver the power that 'cheap' 350 .. 400W rated powersupplies do..

for cpu / ram speed tests, and comparing them to 'other systems'

http://www.sisoftware.co.uk/

'sandra' is some free software allowing you to test.

I still find the RAM a bit weird. If it is DDR then it is DDR266 (which actually runs at 133 of course). What does it look like?

|____|____|__| (sdr)

|______|_____| (ddr)

Anyway I guess the SIS chipset and DDR266 (which is what you have, going by CPUz) is not too quick.

I didn't know that 256MB 9600Pro aiw cards existed. If tomshardware is right, the normal 9600 pro has its core at 400mhz and the ram at 600 (DDR)

Going by your 3dmark output, your ram is clocked at what the marketing department would call 400 (its actually half of course) so you have a 9600 pro with ram that is 1/3rd slower than 'normal' cards would! They often did that; put 256meg in but compensate for the extra cost by making it slow memory

Quote :

Even if SDRAM is slower I think 1.5gb should be enough to cope with games that specify 512mb.

If (race) games specify 512mb, you won't or shouldn't notice any difference with 1.5, but as you said, photoshop and stuff can certainly improve as that software can easily use more than 512..

So your 9600pro is a bit crippled and a SIS chipset P4 isn't flying.. With some bad luck your case might have a non standard powersupply (dimensions).. Thats not a nice diagnose but alas..

For graphic bottlenecked games, which rFactor is FAR more than LFS, yes, a cheap graphics upgrade (even if its just a 'real' 9800pro / xt 128MB) would help considerably at probably very little cost. Since you won't be able to put a new 3D card for your current machine in a future one, I wouldn't go for a new AGP card (like the 6800GS) as that might not be the optimal price/performance ratio, plus that will put the bottleneck straight back at the CPU..

Anyhow you should've seen enough opinions now..

Its an easy mistake to make but with race sims you either have 'enough' RAM or you don't. I don't think LFS uses a lot of ram so with 512 it has 'enough' and adding RAM won't help.

Some games do benifit from more RAM as they load game content while playing but LFS and afaik all racing sims load it all at once because loading game content while playing causes a stutter.

I'm not 100% sure it has SDRAM but the chipset does support SDRAM and the FSB that you mentioned (or rather cpuZ mentioned) is 133mhz which might indicate SDRAM.. The system being a Packard Bell could also be an indication. Nothing wrong with them but they tend to pick a 'fast' processor (like the 2.8 was at the time) and skimp on other things..

I am still firmly against 'upgrading' this machine because keeping ANY of the current parts will become a bottleneck when hooked up with new stuff.. LFS is processor hungry so getting a better gfx card will probably not help

Really, I would live with it, reduce some detail, and then in a 6 months or a year, spend like 4...500 quid on a solid new 'self configured' pc!

Last edited by Niels Heusinkveld, Fri, 5 Jan 2007 00:03.

If your current system is an SDRAM equiped P4 then even the 2.8ghz cpu is held back by that.. Pentium 4 systems where good ages ago with RDRAM and later they where good with DDR...

A p4 2.8ghz with SDRAM and a 9600pro is a nice 'match' although of course a bit of a 'mediocre' system at best

I would save up until you can indeed get a core duo and a nice 7900 type graphics card.. That will be money wiser spent than trying to upgrade your current pc imo!

My first car should be a volvo 740 now..

http://www.youtube.com/watch?v=W3h-iIIR8yw

Dave, yep, your 2 point sum it up mostly. The hard bit is to find out why it happens and what is causing it. I used to have some confidence in assessing the problem but really nowadays I must confess I'm just guessing..

I also find that braking is difficult as locked tyres (infinite slip ratio!) don't make braking that much worse, although I would mostly like to HEAR that better. I guess much of the curves dropping at higher slip ratios might be due to the effect of quickly heating rubber.. When you bench the tyre it will heat up of course.

I saw the LFS tyre grip vs temp curves that I think AndroidXP made? It seemed that even road tyres have a 'peak' optimum temperature whereas I heard (I don't know, I just heard) that most tyres have a pretty 'flat' grip vs temp curve, until you're really really heating them. I don't know how LFS does tyre heat. Obviously braking a long distance with locked tyres produces a 'hot spot', and if tyre outer surface temperature changes quickly, the moment that slip occurs, the effects of a temperature/grip curve that is peaky, would make the tyre have less grip almost from the moment it starts slipping and thus heating. GPL had this program that made tyre temperatures visible and the rubber temperature changed pretty quickly. If a similar thing happens in LFS, then a more realistic (again, if what I heard is correct!) 'flat' grip vs temperature curve would probably improve handling.

What I don't quite understand is how LFS, when sliding, is so often oversteer. Over the limit of grip is fine, but why does that tend to be oversteer? I'm clueless as to why this happens. I'm setting up the cars with at least the springs based on weight distribution; but often a slightly stiffer front. Rollbars on the front are at least 2x more than at the rear and I don't think I'm doing extreme things with dampers. I often set them based on the springs so I get nice and even damping when dropping the car. I tend to run LSDs in LFS with about 20..40% power lock and often more than that (50+) coast lock. Springs are fairly soft and ride height is not very low. I can't blame the car setup for the easy oversteer as weight transfer is on the slow side and the parameters are between understeer and neutral.

What is also weird, although probably just a 'threshold' setting, is that at speed x, you take a turn, and at speed x + tiny bit, you leave skidmarks yet the supposed increase of friction doesn't really seem to show up; the car tends to keep its speed. I really do not understand the complexities of a physics model. But a tyre leaving skidmarks, i.e. operating at too high slip, would indicate to me that it has a relatively large amount of force NOT in the rolling direction. In LFS it seems that, even beyond optimal slip, the cars cary too much speed instead of loosing speed due to a lot of force NOT being in the driving direction.. I might be talking out of my bottom but its tricky to put it into words!

ahh thanks for that..

Curves are probably important but if you look at Racer, LFS and ISI.. With Racer and ISI you can change curves.. with LFS they are 'given'.. But even if you sort of make the curves similar, the handling of each sim is not just slightly different; the differences are HUGE! This indicates that the curves are a relatively small part of the physics model. It is nice to see that LFS is 'closer' to reality than most sims but it doesn't mean the physics are 'close' to reality per se. LFS always has me torn... Its very good in some ways but not so good in other ways..

Interesting

But how did you get the LFS curves? Are they exact?

Furthermore, curves are one thing.. In general LFS is a lot better than most sims when it comes to behaviour over the limit. But the slightest dab of throttle or feathering of the steeringwheel can induce oversteer with normal road car type car setups. I'm convinced that there is something fairly major still not quite right, even if the curves are 'good'.

Edit: if you try 'realish' curves in ISI games you still find that it doesn't really work very well

Last edited by Niels Heusinkveld, Mon, 1 Jan 2007 14:52.

With a 40:1 gear transmission you don't have to steer fast before the motor is going bananas and the cogs scream with the drag / inertia of it all

Using 200 degrees mode might help as you don't have to steer so fast then..

13 posts? Age 13? Iq of 13?

Firstly, you're better off naming forum topics properly so instead of 'heeelp', 'FF problems with Logitech vibration wheel' makes a lot more sense.

Secondly, when people do their best to help, and there is even a good chance that they (me in this case ) is right, telling them to 'shut up' is a bit rude.

Vibration is NOT force feedback and I think it is NOT supported in LFS! You'd need a wheel that doesn't say 'vibration' or 'ramble' on the box basically!