08 Impreza WRC rear suspension: struts or wishbone?

[superg]

Just curious for intelligence or guesses on the nature of the rear suspension on the next gen Impreza WRC.

Will Prodrive replace the new rear double wishbone with Mac struts due to their longer travel and easy service?

Or work with the double wishbone and try to extract improved competitiveness on tarmac?

My guess is struts, which will leave the new street STI with a suspension different from the rally car.

Anyone?

Superg

[jonkka]

Do WRCar regs allow such change in suspension?

[superg]

Someone please jump in if I am out of date, but WRC regs allow changing the rear suspension to another type.

E.g. from Mitsubishi's change from trailing arm rear to Mac struts when they made the transition from Group A to WRc in 2001.

Superg

[Daniel]

Yes. The suspension can be changed.

[ST205GT4]

More importantly can they make a competitive car. My money is on "no".

[Daniel]

More importantly can they make a competitive car. My money is on "no".
I hear they've got improvements in the pipeline *cough* :p

[FrankenSchwinn]

Just curious for intelligence or guesses on the nature of the rear suspension on the next gen Impreza WRC.

Will Prodrive replace the new rear double wishbone with Mac struts due to their longer travel and easy service?

Or work with the double wishbone and try to extract improved competitiveness on tarmac?

My guess is struts, which will leave the new street STI with a suspension different from the rally car.

Anyone?

Superg

wow! finally an intelligent thread on this website, thank you!

i'd rather see them change it to struts. like you said, it'll be easier to service and i believe easier to adjust. they'll have a lot of work ahead of them with this new car, so i'd like to see them use struts. but then again, look at who's building the car, they might just do the complex stuff just because they can. in the end though, does GrN have to have the same as the WRC suspension? if not then the street STI could inherit some of that.

[smolvar]

Now that Prodrive is done with this Formula 1 distraction, they might be able to build a competitive rally car again.

[cougarrange]

To my knowledge, every current WRC car has rear strut suspension for reasons of suspension travel, robustness, and ease of service. I will be surprised if Prodrive chooses to work with the OEM double wishbone rear suspension, even though it might have theoretical handling advantages on asphalt. I can't see Prodrive/Subaru giving up its past gravel dominance and marketing consistency for an asphalt-optimized car.

If Prodrive switches to rear struts, the supposed advantages of the new hatchback car become even less clear. I will be very surprised if Prodrive can make the new car a winner as quickly as Citroen did, sad to say.

The Group N car will have to use the double wishbone, as they are not allowed to change suspension type. Since almost all the PWRC rounds are on gravel, this could be a distinct disadvantage versus the old car. Nonetheless, the Mistubishi EVOs have done well in PWRC without strut rear suspension.

[cougarrange]

As expected, it appears that the 08 WRC car under testing in Sardinia retains the inverted Mac strut suspension instead of the double-wishbone. The evidence is fuzzy (literally), but note the position of the rear strut in the test car-- inclined slightly forward from the wheel center. The production double-wishbone has the strut behind the wheel center. For comparison, the WRC05 Mexico setup with a clear view of the struts.

For fellow pre-08 WRX/STi owners, no need for "rear suspension envy!"

http://i101.photobucket.com/albums/m76/cfvisser/08imprezawrcstrut.png
http://i101.photobucket.com/albums/m76/cfvisser/wrc2005Mexico.jpg

[leno]

What are difference about struts and wishbone? i dont know much about suspension so what are good and bad points of this models?

[Mirek]

Struts are simpler and lighter and are able of bigger lifting. Wishbones are a bit better in wheel guiding when up or down lifting and when braking hard on bumps I think.

[TKM]

What are difference about struts and wishbone? i dont know much about suspension so what are good and bad points of this models?

http://en.wikipedia.org/wiki/MacPherson_strut
http://en.wikipedia.org/wiki/Double_wishbone

Pretty good explanations of both.

[leno]

Thank you TKM :D :D

[dimviii]

@Mirek Fric +10000
thats why subarus are often faster on gravel and Mitsu at asphalt
double wishbones can ''control'' way better the wheel than struts
it is difficult to change the camber or toe in-out as the suspension works up and down with double wishbones
on the other side the suspension travel of struts is unbeatable specially on gravel where you need big travel from suspension.

wrc subaru 08 definetely is going to be with struts imo