Technical Analysis: WRC Cars 2016

[itix]

This thread is brilliant...! We should have a lot more technical discussions in the forum!

[TyPat107]

There is nothing wrong with the machinery. Maybe they could do with a bit more power and nothing changed in the rest of the car but I doubt that you could make the cars more spectacular with any other comprehensive rules change.

The inwards caster angle (which is not called inwards caster angle but I have forgotten what it is actually called) seem to be virtually nil (or 90 degrees or however you put it) on all the current WRC machinery, am I right?

You are thinking of "camber" I think.

I was searching for pictures of wrc/r5/s2000 engine bays the other day and stumbled upon a Ford Fiesta street car forum. A technician from m-sport was commenting that thinking has changed for current generation cars as far as the intake system goes. He said they are using smaller diameter charge piping, intercoolers, and smaller diameter throttle bodies to improve engine response. He also said doing so didn't have much affect on top end power because they removed the turbo restrictor and the car made nearly 600hp.

[Mirek]

The camber on asphalt is usually between 2 and 3° I think. Less on loose surface. I think that camber reliance in a setup of car with McPherson struts shall be somewhat eliminated to minimum because the camber changes hugely with the damper travel.

[itix]

You are thinking of "camber" I think.

I was searching for pictures of wrc/r5/s2000 engine bays the other day and stumbled upon a Ford Fiesta street car forum. A technician from m-sport was commenting that thinking has changed for current generation cars as far as the intake system goes. He said they are using smaller diameter charge piping, intercoolers, and smaller diameter throttle bodies to improve engine response. He also said doing so didn't have much affect on top end power because they removed the turbo restrictor and the car made nearly 600hp.

Camber is the angle of the wheel to the ground. I was actually thinking about the angle of the damper to chassis (relative to flat ground). You can have backwards or forwards angle (caster) and "outwards" angle which is called something else... maybe damper camber but that sounds weird to me.

Super interesting about the inlet dim. and the restrictor. I guess they optimized the intake to create as ideal flow as possible and make sure the restrictor was still the bottle neck. It still doesn't make 100% sense to me as they would have potential for pressure losses and you'd want to have as little under pressure as possible on the turbine side to optimize air flow through the turbine.

[skarderud]

Just Wonder of some specnumbers.
I find that the polo, officially, has 329hk and 430nm in the engine. How far of is it really? I going for a radiointervju and they going to ask of stuff like that

[Mirek]

Good question. Maybe somebody has real figures for these 1.6T WRC cars.

Afaik Fiesta R5 Evo or Fabia R5 have around 450 Nm of torque and I'm quite sure WRC cars have more. Also the peak power is around 305-310 Hp for these R5 cars and more for PSA ones (I believe). Therefore I think that WRC have more than 330 Hp.

[Toyoda]

Ok, Question to those of more knowledge,
The Hyundai boy's were continuously complaining about poor lateral grip, I also noticed that in videos such as this https://www.youtube.com/watch?v=Q42jT7AsNFE the Hyundai's are bouncing at the rear end after large jumps.
In order to increase lateral grip would they have tried to soften the back suspension (perhaps also lower the car? lower COG less body roll?) and hence the result is it bottoming out over the big jumps?
or if not how would you go about fixing this kind of thing, what have the VW and Citreon guys cooked up that improves their lateral grip?

Many thanks

[Zeakiwi]

Quite complex.
I would suspect the VW/ Citroen have a better 'blade setup?' design between the rear suspension and the antiroll bar.
http://tinyurl.com/hvafxqg (VW sus rear pic)
Probably have different shock absorber valving etc
https://youtu.be/GhUE7LIxAso
Guess that Hyundai went a bit heavy with the antiroll bar or coil springs etc causing weight to reduce on inside wheel - reducing cornering speeds.
http://reigersuspension.com/wordpres...uto/rally/wrc/

https://youtu.be/cVzpoF3S48w (Reiger Rally Shock absorber explained)

[br21]

Hyundai is not using Reigers anymore in their 2016 cars. Same goes for 2017 car and R5.

[Mirek]

By the way has anybody already seen a photo of VW 2017 suspension? I'm curious to see if they keep following the Fabia S2000 scheme or if they decided to switch to what Škoda has been trying with the R5 or something completely different.