WRC 2017 Mechanical Issues and Failures

[jparker]

Portugal 2017 -

Citroen with some poor dampers, Hyundai with electrical & PAS issues (Paddon) & Toyota with fuel pressure issue (Hanninen) ...

but nothing on the M-Sport cars.

Just lucky exception this time I guess. You have to wait for few more events before getting too excited. I guess soon the Fords will be back to "normal".

[adr17]

They sold only two 2017 cars and only run one of them (Bertelli's) and he hasnt competed much anyway.

only 1 bertelli was hiring the 2017 car from msport

[Fast Eddie WRC]

Just lucky exception this time I guess. You have to wait for few more events before getting too excited. I guess soon the Fords will be back to "normal".

Get back under your bridge.

[sonnybobiche]

How hard is it to buy a reliable power steering rack?

[Mirek]

There are usually very high forces in the steering of WRC (S2000, R5) cars. Way higher than of stock cars. The main reason is that the cars have usually much bigger castor mostly due to the angled dampers (those are angled to allow large travel). With big castor steering means not only rotating the wheels but also lifting the car, i.e. the forces grow hugely with every degree of castor angle. I believe the issues with power steering were among the main reason why Škoda came with that strange strut design which is used on Fabia R5 and which was later copied in asphalt spec. C3 WRC and i20 R5 (not the case of WRC though).

[AnttiL]

Latvala tells in a Finnish interview http://www.sportti.com/uutinen.asp?CAT=1-2&ID=343465 about the Poland retirement:

Kaasupolkimen alle oli joutunut väärä esine. Yritin sitä kytkimellä korjata, mutta se sitten suli, koska ei kestänyt moottorin korkeita kierroksia.

Which translates to "a wrong object had gotten its way below the throttle pedal. I tried to fix it with the clutch but it burnt because it couldn't handle the high engine revs"

So after all it was a human error rather than a pure technical failure. Possibly the tool kit under the pedals like Lefebvre on the last day?

[steve.mandzij]

Latvala tells in a Finnish interview http://www.sportti.com/uutinen.asp?CAT=1-2&ID=343465 about the Poland retirement:



Which translates to "a wrong object had gotten its way below the throttle pedal. I tried to fix it with the clutch but it burnt because it couldn't handle the high engine revs"

So after all it was a human error rather than a pure technical failure. Possibly the tool kit under the pedals like Lefebvre on the last day?

Huh. I'm not very informed, so how does the clutch get burned in that situation? In fact, how does a clutch work?

Sent from my Pixel using Tapatalk

[AnttiL]

Huh. I'm not very informed, so how does the clutch get burned in that situation?

By "slipping the clutch", pressing it halfway

[sonnybobiche]

The idea is basically that an engine can't work at 0 RPM. It doesn't provide any torque--it stalls. But most of the time the engine revs is directly related to the rotation of the wheels (via the gear ratio: higher gears = more wheel rotation per engine rotation. Usually in a road car, 4th gear is 1:1 and 5th gear is what used to be called 'overdrive', so you got more than one rotation of the wheels per turn of the crankshaft). Anyway, the fact that an engine can't provide any torque from 0 RPM (unlike an electric motor) means that you need a way of partially connecting the engine to the wheels when the wheels are just starting to turn (at the start of the stage). Hence the clutch. It is made out of the same material as brakes (but thinner, because it doesn't need to do a whole lot after the start of the stage), and it allows 'slip' in the drivetrain so that the engine can rev at high rpm and provide torque to wheels that are not moving. When the clutch pedal is pressed, the clutch slips along the surface of the flywheel (which is connected directly to the engine). When the clutch pedal is released, the clutch itself is pressed hard against the flywheel and does not slip.

Of course the heavier the clutch is, the harder it is to rotate it, so you'd want to make it just heavy enough to last through all the day's stage starts, maybe even just enough to last till the next service. But that generally means it's not strong enough to survive slipping against high revs for a long time. It just gets burned out, like if you were holding down the brakes while driving forward. The friction from the slippage generates too much heat for the material and it breaks down.

[AnttiL]

Updates for this thread? Latvala's ECU broke in Finland, Latvala had a Misfire in Germany, Latvala had no handbrake on the TV Stage in Germany, Meeke's water pump failed in Germany