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Under the hood of an Impreza STi WRC...

Posted: Mon Dec 11, 2006 9:07 am
by sirwilliam
...not sure if this was posted already here but my friend posted these pics on another forum and I thought I would share them with you all.

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Pretty sweet! I haven't seen the pics before today.

Posted: Mon Dec 11, 2006 9:53 am
by cheshirecat
wow, nice....definitely like to ask them a few questions...

Re: Under the hood of an Impreza STi WRC...

Posted: Mon Dec 11, 2006 10:29 am
by Mr Kleen
sirwilliam wrote: Image
looks like somebody has disconnected the hyper-drive, I better tell Chewbacca. :lol:

Posted: Mon Dec 11, 2006 11:02 am
by Sabre
Wow, amazing to see the differences between our cars and theirs... Actually, I shouldn't say differences since there is very little that resembles our cars!

Posted: Mon Dec 11, 2006 11:42 am
by VIPGarage
i love seeing real race cars posted like this because it really helps people see what it really takes to get to that level. As you can see there is little to nothing stock under that hood and more buttons than Homer's power plant. lol

thanks for posting.

Posted: Mon Dec 11, 2006 11:53 am
by Sabre
What I think is most amazing and unexpected is the size of the plenum! That's just crazy!

Posted: Mon Dec 11, 2006 1:51 pm
by avriette
Sabre wrote:What I think is most amazing and unexpected is the size of the plenum! That's just crazy!
Yeah. I noticed that too. It kind of reminds me of the RB26 motors that are doing 700-1000hp (which I suppose makes sense). Are there any public numbers on what those cars make in WRC trim? The intercooler placement is interesting in conjunction with the retained hood scoop. By putting vents above the intercooler, there isn't a low pressure zone on top of the block, so it seems like the hood scoop is just there for looks.

I'm also interested in what those black boxes are. Is it fuel?

Also, it took me weeks to get over the rear spoiler wiggling all the time. Maybe Subaru should make that monstrous wing-with-vertical-struts a factory option. :)

Posted: Mon Dec 11, 2006 3:44 pm
by Cereb Daithi
The hood scoop has always been just for show on the subaru WRC cars really. 04 05 models also had the IC in the same location and the 02 03 models had FMICs. Not 100% sure about before that...

That is one of the reasons i dont feel bad about having a scoop on my RS. If Subaru and Prodrive are allowed to put a hood scoop on simply for looks and ventilation then i should be too damnit! :lol:

Posted: Mon Dec 11, 2006 4:08 pm
by Sabre
avriette wrote:
Sabre wrote:What I think is most amazing and unexpected is the size of the plenum! That's just crazy!
Yeah. I noticed that too. It kind of reminds me of the RB26 motors that are doing 700-1000hp (which I suppose makes sense). Are there any public numbers on what those cars make in WRC trim? The intercooler placement is interesting in conjunction with the retained hood scoop. By putting vents above the intercooler, there isn't a low pressure zone on top of the block, so it seems like the hood scoop is just there for looks.

I'm also interested in what those black boxes are. Is it fuel?

Also, it took me weeks to get over the rear spoiler wiggling all the time. Maybe Subaru should make that monstrous wing-with-vertical-struts a factory option. :)
Subaru stats:
Engine: Flat four-cylinder, 16 valve, turbocharged
Capacity: 1994cc
Bore: 92.0mm
Stroke: 75.0mm
Engine management: Subaru programmable electronic engine management system
Power: 300bhp @ 5500rpm
Torque: 60kg-m @ 4000rpm (433lbs-ft)
Exhaust system Ceramic coated, lagged with fire-proof material and aluminium covered. Fitted with two, three-way catalytic converters
Turbo charger: IHI - with WRC regulation 34mm restrictor
Spark plugs: DENSO
Fuel tank capacity: 80 litres

Weight: 2712 lbs!

Those black boxes I'm guessing are sensors and such. Almost looks like CAN interface.

Posted: Mon Dec 11, 2006 4:43 pm
by sirwilliam
I think in one of my subaru drive performance magazines it shows the new engine w/ 300hp but between 500-600ft/lbs :shock: The exhaust is pretty crazy and setup for all that torque...mmm, torque!

Posted: Mon Dec 11, 2006 4:54 pm
by Sabre
^^^ I thought I remembered seeing something like that too! It was in Performance or Drive, I can't remember which :/ The SWRT website gave those performance figures though :/ Who knows...

Posted: Mon Dec 11, 2006 5:00 pm
by sirwilliam
Sabre wrote:^^^ I thought I remembered seeing something like that too! It was in Performance or Drive, I can't remember which :/ The SWRT website gave those performance figures though :/ Who knows...
I think the website info is for the model being/was replaced.

Posted: Mon Dec 11, 2006 7:52 pm
by GeneralGrievous
Sabre wrote:What I think is most amazing and unexpected is the size of the plenum! That's just crazy!
Thats what she said... :lol:

Do the black boxes store the dylithium crystals?

Posted: Mon Dec 11, 2006 11:00 pm
by avriette
Sabre wrote: Power: 300bhp @ 5500rpm
Torque: 60kg-m @ 4000rpm (433lbs-ft)
Exhaust system Ceramic coated, lagged with fire-proof material and aluminium covered. Fitted with two, three-way catalytic converters
Fuel tank capacity: 80 litres

Weight: 2712 lbs!

Those black boxes I'm guessing are sensors and such. Almost looks like CAN interface.
Hm. It's a shame I can't read any of those labels. At least one of them says "water," and it's obviously too small to be conducting water, so it's got to be sensors. Another one seems to say EGT. But good grief, that's a lot of sensors. I mean, consider there have to be sensors elsewhere (such as under the car).

That's really a fascinating tune, with the ratio of torque to horsepower so dramatically off-balance. Generally people talk about having very long rods (stop it) to change the distribution of torque to horsepower. But since they're making 300hp, it makes me think that perhaps they have a very long stroke and small bore. They don't really say what block it is. It's possible it's the 2.2 or the 2.5 (or indeed, it's possible it's just something they pulled out of their asses to go racing), but it's clearly modified to produce that kind of output.

It doesn't seem like it's too dramatic a trim, however. Perhaps it's the restrictor that's keeping it from making better numbers.

Heh, also the e-brake being near vertical... does this mean that they're using the e-brake to bring the back around, rather than using the loud pedal or shift locks?

Posted: Tue Dec 12, 2006 2:29 am
by Cereb Daithi
yep. if you watch any rally vids you can see the teams using the e-brakes

Posted: Tue Dec 12, 2006 3:52 am
by Cereb Daithi
nabbed a shot of the 05 engine bay

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Posted: Tue Dec 12, 2006 10:34 am
by Sabre
avriette wrote: That's really a fascinating tune, with the ratio of torque to horsepower so dramatically off-balance. Generally people talk about having very long rods (stop it) to change the distribution of torque to horsepower. But since they're making 300hp, it makes me think that perhaps they have a very long stroke and small bore. They don't really say what block it is. It's possible it's the 2.2 or the 2.5 (or indeed, it's possible it's just something they pulled out of their asses to go racing), but it's clearly modified to produce that kind of output.

It doesn't seem like it's too dramatic a trim, however. Perhaps it's the restrictor that's keeping it from making better numbers.

Heh, also the e-brake being near vertical... does this mean that they're using the e-brake to bring the back around, rather than using the loud pedal or shift locks?
It's definitely a 2.0l block, as that's what the WRC dictates. Here are the measurements you spoke of on the Subaru car:
Bore: 92.0mm
Stroke: 75.0mm

They (The WRC) put the restrictor in there ?2? years ago to limit the power that these cars were making :(


Cereb Daithi: Awesome find! Interesting that they had flipped the intake manifold before, but then flipped it back to put in the bigger plenum.

Posted: Tue Dec 12, 2006 11:07 am
by Mr Kleen
in addition to the change in the intake plenum, I also found it interesting that they "flipped" the angle that the IC is mounted at.

[wish] now to see them in action... [/wish]