Could be useful in the pits, after working out a setup, put the car on a dyno so you can work out optimum change points etc? Or thinking about it, engine won't change will it, so just a picture of the torque/power curves for each car.
Dyno / Rolling Road?
(18 posts, started )
Dyno / Rolling Road?
+1 for torque curve display and a manually set shift light (either for all gears, or for each gear, depending on the car).
+1
That's actually a great idea as it gives us the true driving force on the wheels, allowing MUCH better gear tuning.
+infinity
I don't really care if the shift points are manually or automatically set if there's a chassis dyno that churns out wheel torque graphs, since it won't make any difference.
we dont need a dyno or rolling road but the torque curve would be handy.
+1 for it would give an idea to the perfect ger changes at what points through the power band, but -1 thats only as the crow fly's and every track has its different gear changing points so its noot going to able to substatute good ol' trial and error when setting your car up, so a bit pointless I'd say because Bob's "Gear Ration Spankulator" does just that!
The only thing that'll help here is the torque curve. The dyno bit is an irrelevance.
+1 from me too, a proper shift light system would be good too, adjustable even better, heck, my bike can do it, surely LFS can
Dan,
As far as I know Bob's program uses estimates of the torque curves, so the results aren't that accurate. I've done some work on calculating the torque curves based on straightline acceleration tests but it's very difficult to work back to the engine torque and get it to agree with the published data on LFS cars. I really wish the devs would post some torque curves, ideally in a spreadsheet so we have the raw numbers as well as the pretty curves.
Edit: I have got some nice curves for the XF GTi but it took a lot of work and I still can't get both the peak power and peak torque to line up. The curve I got looks quite different to the ones in Bob's program.
Yes , I agree we need some data on torque, I have little/ no knowledge on this topic but if the dev's where to publish a "torque data sheet" would that reading not be only for that gearbox setting?...I mean any data produced would only be relevent to that .set ie: what gear ratios where used in the testing.
So what I can imagine to be more useful would be a data sheet with the info on each car's engine on the most efficient settings eg: ratio 1.258 @ 6.5k to 8k so on...
Maybe if Bob could clear some of this up for us we're a bit lost(I am) it seems.
The real idea is to have the dyno generate torque curves of each gear throughout usable rpms, overlay the torque vs speed graphs of each gear onto one graph and get the whole drive torque vs speed graph in one go.
+1 I can now see how usefull a dino would be...So whos the man for the job?
Coder?...whos good at writing apps? Forget about improvement suggestions!
Who can make one?
I mean all we need is resistance added to the wheels while in the final drive screen???
Hmm, what is you want coded? How are those graphs different compared to what is in GRC?
You can get the torque curves (ish) from RAF outputs, the last time I tried do that properly was 0.3 days so no doubt things have changed a bit. Also we have more car data available now than we used to which means guessing less things. Perhaps I'll have a go over the weekend.
Btw my torque curves in GRC work differently, they will never match up exactly with the LFS torque curves but are adaptable to any engine (within some awkward limitations).
You can get the torque curves (ish) from RAF outputs, the last time I tried do that properly was 0.3 days so no doubt things have changed a bit. Also we have more car data available now than we used to which means guessing less things. Perhaps I'll have a go over the weekend.
Btw my torque curves in GRC work differently, they will never match up exactly with the LFS torque curves but are adaptable to any engine (within some awkward limitations).
Meh!, I didn't mean "coded" I'm a noobcake at this stuff Bob
Thanks for your time tho'
No, what I would like the devs to provide is the torque developed by the engine (at wide-open-throttle) through a range of engine speeds. Have a look at this example from a Google search:
http://www.netcar.co.il/img2/m ... _torque%20curve%2016V.jpg
The blue curve shows the torque produced by the engine over a range of speeds. To obtain the torque output at the wheels you just scale the speed/torque using the drive ratios and account for drivetrain losses.
The torque curves in LFS seem to be calculated by some high-order polynomial. I got a very good fit to my experimental data using quartic regression but the curves couldn't quite match the LFS data.
I've also tried solving various orders of polynomials using data from the LFS engines but without any real success. The problem I had was that we can only get 4 pieces of information from the max torque and max power figures, so the highest order polynomial that can be fitted is a cubic. I've tried assuming various other boundary conditions to allow a higher order polynomial but that didn't work either.
What data variables are you missing from the LFS engine, world variables or somthin?
There are more pieces of information if you think about it.
Peak power and peak torque is only really 2 points of the torque curve, but you know some other properties from which you can generate other points and make a more precise torque curve.
i.e. torque curve gradient must be 0 at peak torque, must be positive up until peak torque, must be negative after peak torque, must be negative enough around peak power so that power does indeed drop off after peak power rpm and must be flat enough before hand so that power isn't higher before peak power rpm.
That's the basis for how torque curves in GRC work anyway, though I'm currently only using linear+cubic dual equation thingy, will up to quadratic+quartic when I feel like hurting my brain.
Peak power and peak torque is only really 2 points of the torque curve, but you know some other properties from which you can generate other points and make a more precise torque curve.
i.e. torque curve gradient must be 0 at peak torque, must be positive up until peak torque, must be negative after peak torque, must be negative enough around peak power so that power does indeed drop off after peak power rpm and must be flat enough before hand so that power isn't higher before peak power rpm.
That's the basis for how torque curves in GRC work anyway, though I'm currently only using linear+cubic dual equation thingy, will up to quadratic+quartic when I feel like hurting my brain.
Yeah, that's exactly how I got my 4 pieces of information. You have torque values at two engine speeds (once you've worked backwards from peak power) and you can also differentiate torque with respect to revs and set those to zero (zero gradient at the peak). That only gives you four boundary conditions, hence the limit for an exact polynomial solution is a cubic.
But how are you going to gain any extra information about the torque curve? Saying that "the gradient must be positive before the peak" doesn't fix a boundary condition, it just limits the possible solutions to a narrower 'corridor'.
Dyno / Rolling Road?
(18 posts, started )
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