It is the same with the newest Quattro technology. I don't think it is possible in Rally cars without central diff and electronics, but I'm not that familiar anyway. Let the experts tell.Quote:
Originally Posted by Rallyper
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It is the same with the newest Quattro technology. I don't think it is possible in Rally cars without central diff and electronics, but I'm not that familiar anyway. Let the experts tell.Quote:
Originally Posted by Rallyper
I think that no carmaker has yet found a non-permanent 4WD system useful for competitions but that's partly because of the rules. Where rules allow hi-tech stuff it might be different. Just one example. My brother was heavily involved in SAE Formula competition (worldwide university cup for small combustion and electric formula cars). The best electric car of all (from Dutch University of Delft) uses full-active 4WD system with four small but powerful engines mounted in wheel hubs. Each engine has maximum output around 30 kW but weights only 4 kg. Maximum allowed power available from batteries is 85 kW so that there is plenty of space to play with torque distribution. But here we speak about car which weights only 170 kg (its power make it able to do 0-100 km/h in 2,5 secs)...Quote:
Originally Posted by Rallyper
Of course there are differences but I doubt You can see them by eye on the video as was pointed at the start of this discussion. I bet what is possible to see comes much more from suspension, diff setup, geometry etc. while the differences given by bodyshell and it's weigh distribution although sure important for the very best performance must be marginal or impossible to see for outside observer. Currently used cars are too similar to each other...Quote:
Originally Posted by makinen_fan
I have no values, sorry. I'm just writing what comes to my mind ;)
Probably it was. With rules of 2.0 WRC cars it was possible to achieve that. But it's not everything. You know dumbbell has also 50/50 weight distribution but an awful moment of inertia :) That was the case of Audi Quattro. The S1 had perfect 50/50 weight balance but most of the mass was in front of front axle and to compensate it another big mass was at the back. That's what makes the car slow and hard to turn. The 205 T16 had awful weight balance but it was very nimble as most of the weight was concentrated close to the center of gravity between axles. If I remember right with Focus they tried to make also the center of gravity as low as possible and also the ideal balance by putting the spare wheel behind the rear axle under the floor (among other things). That's what goes against the previous point. I remember Pentti Airikkala was a loud critic of the Ford solution here on the forum.Quote:
Originally Posted by TyPat107
It is the most important if it is active one like in Subarus and Mitsubishis or even more sophisticated like in old WRC cars. But when You are limited to simple clutchpacks or other dumb mechanical things it's all different. With the S2000 they first use center diff - for example Abarth had it. Peugeot discovered that it brings very little advantage but serious disadvantages - car was heavier with it (in that time S2000 rules allowed cars to be only 1100 kg heavy and nobody was able to achieve the limit) and it consumed power. Especially the second point was very valid because the S2000 with just naturally aspirated engines were a bit underpowered. The problem of releasing rear axle when using handbrake was solved by a clutch in rear diff body. I am pretty sure Škoda largely tested both variants - with and without center diff and decided to go Peugeot way although with different supplier (X-Trac instead of Sadev). Abarth later switched for X-Trac system without center diff too. Later when rules for 1.6T cars were created they decided to ban the center diff at all.Quote:
Originally Posted by TyPat107
As makinen_fan explained, in chassis I meant the hardware you can't change in a few minutes. If it was suspension and diff preload, VW would have easily done it as they did so many thousands of test kilometers with factory drivers and engineers. Even we fans here saw that problem from short clips some months ago. Maybe this is why VW had been so conservative about their future performance in real competition. Note that masking "chassis" problem with various small setup tweaks conflicts with drivers' driving style and harms their ultimate confidence.Quote:
Originally Posted by dimviii
So I want to repeat the question, when VW is allowed to introduce (homologate) big changes?
also at wrc are sensitive about wd front -rear and left-right.Quote:
Originally Posted by makinen_fan
Slowson maybe driver liked the slight understeer of polo,is not bad thing when driver can pushes with this.Also dont take Latvalas words by rule,he has setup problems for many years.Its better to see Ogier,or he has a different chassis?Quote:
Originally Posted by SlowSon
Yes it is.Quote:
Originally Posted by Mirek
"Old" chain driven 1.2TSI was designed and manufactured by Skoda, new belt driven 1.2TSI is also produced by Skoda but I don't know whether it was developed by them too.
No, it was Capito or some other chief saying that, not Latvala.Quote:
Originally Posted by dimviii
And I dont think Ogier set that understeer on purpose. In Monte it was making him so angry that he was applying the exit-throttle so early. There was a perfect clip (I should have mentioned it back then :( ) showing a tight corner where the two Polos almost stalled versus all the Citroens smooth as trains on rails. Also the flatout clip from Sweden you posted - I know Ogier and JML are not the tidiest drivers but they threw the rear so early while everybody else including Neuville Novikov etc were smooth and clean. But lets better wait for typical dusty events.
The Nissan R32 GTR's ATTESSA system also ran in RWD initially, moving forward based on wheel slip and G forces. This was very effective in Group A touring cars, with the rules being changed in both Japan and Australia to effectively outlaw 4WD as it had such a significant advantage. The idea of it of course was to help on turn in/mid corner, without the front diff causing understeer, then on throttle application the 4WD kicked in, allowing full grip on corner exit.Quote:
Originally Posted by Mirek
As a road car it made for a quite tail happy drive as the sensors were a bit slow to react (this improved considerably in later models). However I don't think it would be much use on loose surfaces.
Active Centre diffs in production cars such as late model Subarus and Mitsubishis and then the ultimate in the WRC 2L formula of course were the evolution of this. But they add a lot of complexity and cost... I believe most modern cars with a performance 4WD setup would have some form of electronic adjustment?