as far as vehicle dynamics are concerned lfs´s locked diffs act the way they should
as far as vehicle dynamics are concerned lfs´s locked diffs act the way they should
Still not convinced, according to Hillier's Fundamentals of Motor Vehicle Technology
The locked diff itself reacts nicely. But the tyres make up that scrubbing by just flexing a lot. Just look at them, they seem to be made from chewing gum.
Vain
Vain
All this talk made me wanna race. i'm gonna start a relatively calm server. named something like "gt's peaceful server".
cheers/
cheers/
IMHO the reason most people use a locked diff (with FWD certainly) is the fact that it induces very usefull power-oversterr at corner exit. it's not a new thing, it's been a usefull tool for many years IRL. yes, the tyres take a little more punishment, maybee a couple of laps less than an open diff but thats usually offset by a spinning inside wheel.
the simple fact is, you don't NEED a differential on a race car, it's only on road cars that find themselves turning sharp corners all day long, don't forget that manufacturers are trying to get their cars to last their warranties too, not just a race distance, so having a diff on a road-car makes a lot of sense.
there are a hell of a lot of clubman racers running with welded diffs, it might not be perfect but it doesn't seem to harm the lap times (or the car) one bit.
It'll still be nice to have a full compliment of differentials
the simple fact is, you don't NEED a differential on a race car, it's only on road cars that find themselves turning sharp corners all day long, don't forget that manufacturers are trying to get their cars to last their warranties too, not just a race distance, so having a diff on a road-car makes a lot of sense.
there are a hell of a lot of clubman racers running with welded diffs, it might not be perfect but it doesn't seem to harm the lap times (or the car) one bit.
It'll still be nice to have a full compliment of differentials
well I googled untill my eyes bled and the nascar rulebook is hidden from the public. So I can't find out for sure if they have to uses locked diffs all the time.
Some sites say the detriot locker is the only sanctioned diff but is it just a brand name?
I'd like to know.
Some sites say the detriot locker is the only sanctioned diff but is it just a brand name?
I'd like to know.
1. we have that allready locked diffs understeer like an vectra at corner entry
2. the way you drive your car in lfs means rapid tyre wear anyway ... not like a locked diff is going to make much of a difference ... besides whether the inside wheel scrubs a little or spins wont make all that much difference in wear
Personally i love locked diffs because they give you a big advantage while braking. You can hit the break very hard even over bumps and while cornering and get no flatspot on tires that may loose contact. With standard diff, even with high coast setting, you can never break so late...
Last time I checked, you need friction to make a flatspot.I've never known anyone do this in my years of being around club racing, care to provide some links?
I also think they work the way they should, at least in the way the vehicles behave. I've driven a street/strip Camaro once, had a fully locked rear differential. When you were driving down the road normally, you didnt even notice. The only time it became evident was when you were going VERY slow around a tight turn- ie. 15 mph in a parking lot. Then, and only then would the back end 'hop' a bit and there was obvious drivetrain strain going on. For FWD, I dunno, I've never driven one with a locked diff. But in LFS, locked diffs in FWD cars usually understeer badly and will only turn once you get back on the power, and there is that "heavyness" felt in the Force Feedback, which feels right to me. The only issue is that in real life, I'm sure a FWD car with a locked diff would eat up driveshafts unless they were specially made, heavy duty units.
With Radio Controlled cars, I have locked up the front differential on my Xmod and use a very loose rear differential, as I noticed with the rear locked, the car would become very loose during cornering. We did race on a very slick surface though, and the track did not have any tight turns so this could be random behaviour compared to what everyone else is getting.
And Nascar- I had the oppurtunity to ask one of Dale Earnheardt's crew guys some questions several years ago when they had one of his cars on display at my college- and I asked about differentials. He said that on most long ovals, they used a "detroit locker" style diff, where it was locked under power but open during coasting, and on shorter ovals (a mile or less) and road courses they used a clutch-style lsd, as on short ovals, inner-rear tire wear was a concern. But that was nearly 10 years ago so the rules could have changed.
So what does all that mean for LFS? Who knows.
I'd personally like to see mechanical failures implemented- as one person said, most road cars arent made to race and therefore have differentials to aid in longevity and drivability of the cars, some racing cars do it for the same reason, as many race teams in all sorts of different motorsports dont have the budget to replace a $1500 rear axle every week. 
Brendan
With Radio Controlled cars, I have locked up the front differential on my Xmod and use a very loose rear differential, as I noticed with the rear locked, the car would become very loose during cornering. We did race on a very slick surface though, and the track did not have any tight turns so this could be random behaviour compared to what everyone else is getting.
And Nascar- I had the oppurtunity to ask one of Dale Earnheardt's crew guys some questions several years ago when they had one of his cars on display at my college- and I asked about differentials. He said that on most long ovals, they used a "detroit locker" style diff, where it was locked under power but open during coasting, and on shorter ovals (a mile or less) and road courses they used a clutch-style lsd, as on short ovals, inner-rear tire wear was a concern. But that was nearly 10 years ago so the rules could have changed.
So what does all that mean for LFS? Who knows.
I'd personally like to see mechanical failures implemented- as one person said, most road cars arent made to race and therefore have differentials to aid in longevity and drivability of the cars, some racing cars do it for the same reason, as many race teams in all sorts of different motorsports dont have the budget to replace a $1500 rear axle every week. Brendan
info-tastic thanks.
Another reason you see people wanting locked diffs is because they don't want "one-wheel drive" like you get with an open diff. So, having a preference, and depending on the car and the track, welding an open diff to be a locked diff would make sense. You will have two wheels driving you off a corner instead of one.
I think another reason an LSD is preferred for racing IRL, is that if your inner driven wheel is spinning faster than it needs to becaue of a locked diff, you are needlessly using up some of your traction budget. Sure, inside wheels are less loaded, but they still contribute to the total traction budget.
LSD's are a compromise, trying to take the best of a locked diff for having two wheel drive coming off of corners, with the best of an open diff for cornering and driveline health. As with most compromises, there are problems but overall it works.
In LFS, LSD's seem a bit quirky, so that may be another reason people are using locked diffs. Under braking, you get that problem where the engine bogs down, which causes the driven wheels to lock once your release the brake because your engine revs are too low. Plus, there is no preload...
I think another reason an LSD is preferred for racing IRL, is that if your inner driven wheel is spinning faster than it needs to becaue of a locked diff, you are needlessly using up some of your traction budget. Sure, inside wheels are less loaded, but they still contribute to the total traction budget.
LSD's are a compromise, trying to take the best of a locked diff for having two wheel drive coming off of corners, with the best of an open diff for cornering and driveline health. As with most compromises, there are problems but overall it works.
In LFS, LSD's seem a bit quirky, so that may be another reason people are using locked diffs. Under braking, you get that problem where the engine bogs down, which causes the driven wheels to lock once your release the brake because your engine revs are too low. Plus, there is no preload...
id say those problems are actually the same
Many of the oval racers over here (not MSA) do it. I personally know a bloke called Bill who welds his diffs. He is very successful in the series he competes in. No links I'm afraid. If you know anything about these series you understand why.
I was thinking of circuit racing but by ovals in the UK I suppose you mean banger racing on a less than ideal surface?
Yes that's the racing I'm on about but it's not always on loose surfaces. They also compete at Lydden Hill for example. Bill's lad Scottie absolutely caned everyone else the last time I went and watched there.
Isn't Lydden rather fast (and lethal) for full contact racing? Is this more the type of semi-contact racing?
Lydden is actually quite tight (and lethal yes). When the oval racers run there they cut across the midfield so they only really use chessons drift and pilgrims. When they run at these types of circuits it's meant to be non contact. Doesn't always work out like that though obviously. Me and a mate were watching and we had to run from the exit of chessons when a big bl00dy hurse thing started to head straight for us! lol
What's up with that Locked Diff again ??
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