Sneak Peak: GM’s ALMS GT Challenger, The Corvette C6.R
A super lightweight Braille lithium ion battery provides power for the car's electronics while weighing less than half of what a conventional battery does.  You can buy this for your own car as well!

Power is delivered from the engine to the Xtrac 6 speed sequential rear mounted transaxle via a Tilton carbon triple disc clutch and an aluminum driveshaft.  The transaxle uses Xtrac’s revolutionary low drag, low loss, limited slip differential.  We were not allowed to photograph any of this so a lot of this is actualy our educated guess.

Sneak Peak: GM’s ALMS GT Challenger, The Corvette C6.R
Pratt and Miller would not let us get too close to the rear of the car but we were able to discern that it has an Xtrac six speed sequential transaxle.  A notable thing is that Xtrac has a low drag, low loss, limited slip differential.
Sneak Peak: GM’s ALMS GT Challenger, The Corvette C6.R
The fact that the car does not use a conventional digital racing dash display tells us that the car probably runs on some bespoke electronics suite probably developed by Delco or another GM supplier as an engineering exercise.  The Grant steering wheel is not one you can buy from JC Whitney.  Look at the configuration buttons and the low tech hand drawn track map!

The car's electronics look like some sort of bespoke stuff probably from Delco as we did not see too many familiar bits in the interior and the crew did not want to talk about any of it.  We did note that the car is air conditioned as per ALMS rules.  We think all race cars should have AC!

Sneak Peak: GM’s ALMS GT Challenger, The Corvette C6.R
Firesafe fire system.
Sneak Peak: GM’s ALMS GT Challenger, The Corvette C6.R
Some of the stock center console seems to be retained.
Sneak Peak: GM’s ALMS GT Challenger, The Corvette C6.R
This centrifugal blower on the carbon duct is part of the super light, low loss, air conditioning system.  The AC system only uses 1.8 hp and is lighter than a cool suit.
Sneak Peak: GM’s ALMS GT Challenger, The Corvette C6.R
Carbon ductwork and filter contain the evaporator and centrifugal blower for the AC system.


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Andrew Brilliant
Andrew Brilliantlink
Wednesday, July 13, 2011 9:11 PM
My first guess would have been strain gauges. Also you should see whats under the covers in the rear, you'd love it ;)
Mike Kojima
Mike Kojimalink
Wednesday, July 13, 2011 10:49 PM
Those are not strain gages on the dampers, they don't even look like them. They would not let us near the back or the underside of the car nor too close to the inside, hence this story isn't as good as our usual.
Wednesday, July 13, 2011 11:56 PM
Thanks for sharing Mike.

I learned the hard way, when taking detailed pictures of super-exotic racecars, the race teams I was dealing with, did not like the fact I was nosy, asked tons of questions, and take a butt-load of pictures.

My nature of being curious and trying to understand how things work, causes those teams to not allowing me to get closer to their cars again. (I burned the bridge if you will), and I expected that to happen eventually.

This might not apply to you , but I bet you, the fact that you were curious to know how those Corvette and other uber expensive racecars are put together (like I was/am).....in the long run (posting publicly and sharing VERY informative details)....people in the biz start hating you. (they know you are not a regular amateur).

The Corvette mentioned above took first place at LeMans, there's a reason why the GM Team is secretive about their stuff, they simply don't want other competitors to copy their stuff.
Eventually all this technology will tricke down to production cars in few years.....but before then, they've done LOTS of R&D (which is worth millions of dollars), then they move forward and try to stay always ahead of the game. I don't blame them.

Anyway, thanks for sharing, hope you don't burn the bridges :)

Dusty Duster
Dusty Dusterlink
Thursday, July 14, 2011 3:45 AM
Cool article. Why do LeMans cars always have yellow headlights? I've always wondered that.
Dave Coleman
Dave Colemanlink
Thursday, July 14, 2011 4:30 AM
Mike, the Le Mans cars have iron rotors too. Only the Prototypes run carbon rotors.
Thursday, July 14, 2011 5:36 AM
Dusty, the headlights are to help distinguish between the GT cars & the prototypes in one's rear view mirror.
Thursday, July 14, 2011 6:22 AM
Wow, this is an amazingly complex car. Impressive.
Thursday, July 14, 2011 7:22 AM
That bulge looks suspiciously like a spool valve or solenoid, I agree. The connector could be for position feedback or control, or both I suppose.

I wonder if those Penske dampers are related to the Penske 3000 Series active dampers... I don't know the ALMS rules well enough to make any assumptions of what type of active systems are allowed.
Mike Kojima
Mike Kojimalink
Thursday, July 14, 2011 7:42 AM
Dave GT1 cars are allowed to have carbon rotors in my research and the GT1 Corvette runs them or at least sued to run them.

We always ask what we can shoot before we do, don't ask too many questions and know enough to infer a lot of stuff and sometime have the teams PR guy with us while we shoot. We always have the proper credentials to be where we are as well, that probably helps. If a team tells us specifically not to write about something or show a picture of something we honor that as well.

Notice we know enough to sometimes have more details that magazines like Race Car Engineering as they seem like they have to go off regular PR material.

The drawback is that sometimes we may not always be correct but we can give insight that a regular person might not see.
Mark F
Mark Flink
Thursday, July 14, 2011 9:57 AM
Mike, they could be hiding their electronics where you just cannot see them. You might be surprised to know that OLED is the new screen of choice. If your iPhone looks great in full sunlight, well why wouldn't a dash for a racing car?....
Der Bruce
Der Brucelink
Thursday, July 14, 2011 10:43 AM
Gorgeous example of a race car! Any idea why the collectors go in a 2-1 and then finish in a 2-1configuration? Weight maybe?
Umai Kakudo
Umai Kakudolink
Thursday, July 14, 2011 10:54 AM
That AP caliper design was created 4 years ago and used extensive FEA analysis.

Racecar Engineering Magazine had a very in depth article on them in the December 07 edition.

Digital back copy available here: http://gb.zinio.com/browse/issues/index.jsp?skuId=232124274
Thursday, July 14, 2011 11:00 AM
Der Bruce, the 4-2-1 exhaust design is for better scavenging and resonant tuning. The cylinder combination order is dependent on the firing order and crank design (flat plane or cross plane).
Umai Kakudo
Umai Kakudolink
Thursday, July 14, 2011 11:02 AM
The dash is an off the shelf unit from Gems.

Der Bruce
Der Brucelink
Thursday, July 14, 2011 12:21 PM
Fabrik8 - This 4-2-1 has one of the longest 2-1 gaps I've seen on a V8 which kept tripping me up visually but better questioned, are they wanting more low end out of this design, rather than the high end out of a 4-1 design?
Thursday, July 14, 2011 12:27 PM
We just went to the GT1/GT3 race in Navarra Spain.


I asked what I was allowed to take pictures of, and what I wasn't allowed to take pictures of.

The GT1 cars all run carbon/carbon brakes. Perhaps LeMans has its own set of rules for GT1? Maybe the irons are better for the 24 hour race?

The calipers are the AP Rad-i-cal's. We have one of them here at the office. Its one of those uber cool, uber exclusive types of parts. There are off the shelf kits for the RSR Porsches but not much else.
Thursday, July 14, 2011 1:06 PM
@Der, as the engine has intake restrictors, there's not a lot of top end to speak of. So might as well beef up the low end. I had the same impression that those were long headers.

Those AP calipers are look to be a few generations more evolved than the first Radi-Cal calipers that came out. Only to be expected of course.
Andrew Saw
Andrew Sawlink
Thursday, July 14, 2011 2:22 PM

The word "ikan" on the dash means fish in Malay language :)
Thursday, July 14, 2011 3:29 PM
Active suspension is not allowed in GT2, so those devices aren't part of an MRF or dynamic damping system. Carbon brakes were allowed, and used, when the Corvettes ran GT1.

Tuning restricted engines is a bugger. Since, by definition, you can't have much of a top end, you usually aim for a torque peak lower than usual for a race engine. Wicked-high compression, extra valve overlap, long, narrow intake runners, and long, narrow headers are the usual tricks. Some of these features compromise an engine's ability to rev, thus sacrificing high-end power. But you're restricted, so as long as these modifications do not choke the engine more than the restrictor(s), they'll give you more area under the power curve.
Mike Kojima
Mike Kojimalink
Thursday, July 14, 2011 5:48 PM
ALMS GT is not GT2. I didn't look at the rules that carefully but this is probably just active control of the damping, not active suspension in the old F1 sense.
Mike Kojima
Mike Kojimalink
Thursday, July 14, 2011 8:50 PM
From my friend Dave Lee

Mark F
Mark Flink
Friday, July 15, 2011 2:23 AM
And I was not trying to take a ribbing about the electronics, i just do not have your email Mike.
Saturday, July 16, 2011 7:52 AM
Those are not active dampers and active damping is not allowed in ALMS GT or GT2 (they are the same). Magneride only requires two wires as all you are doing is energizing a coil. The location does not make any sense for damper control anyway. If you place a valve in between the shaft and the displacement adjusters on the remote canister then you defeat the purpose of those adjusters.
The crew members telling you that "I have to check with the boss" is standard practice.
Temp monitoring or a load cell or both in more likely the the answer.
Andrew Brilliant
Andrew Brilliantlink
Saturday, July 16, 2011 2:02 PM
They would have been noticed in tech for sure and protested FOR SURE. It really does have to be just a sensor of some kind.
Mike Kojima
Mike Kojimalink
Saturday, July 16, 2011 2:11 PM
The Penskes are used for NASCAR and Daytona Prototypes so far in testing and practice to quickly get the correct set up and are not used in active mode for racing. The location and size of the bulge on the shock body does make perfect sense especially for compression control, it is about the only place it would easily fit besides the top of the cannister and it is about the same size as the newer moog motorsports valves. If you have PWM flow control before the passive valves it makes perfect sense if you want to alter the base curve.

On the other hand I have never looked at a Penske 3000 series shock and have zero experience with them but it is feasible. If you do have actual expertise with what this car is running, can you tell us what the wires, extra hydraulic line, controllers and the mysterious bulges are? Is it some sort of pitch control device? I have seen pictures of experimental Penskes with a central accumulator which all 4 shocks fed into which was supposedly for this.
Mike Kojima
Mike Kojimalink
Saturday, July 16, 2011 2:14 PM
On the other hand this sort of race car isn't that pitch sensitive.

Saturday, July 16, 2011 4:39 PM
While I do not have experiance with this car I do know that the dampers are Penske 8770.
@Mike can you explain how you would alter the "base curve" by limiting the the oil pressure on the canister/displacement valving. The way I see it if you do this then you decrease their effectiveness of the second set of valves as they will see less pressure and flow. The valving on the canister is low speed compression (parabolic needle) and high speed compression (blow-off spring bypass and low inertial poppet valve). they work by incressing the pressure acting on the cross section area of the piston shaft. I think that to work at there best they need direct unrestricted oil flow.

What are your thoughts mike?
Andrew Brilliant
Andrew Brilliantlink
Sunday, July 17, 2011 4:20 AM
I think pitch control would be a big deal on that car. It's aero is not going to be pitch sensitive like F1 or LMP, but it is. I did a study on that car once in particular as well as familiarity with other cars in that field. I worked on two different cars that compete directly. A tenth is a big deal there. Quite a lot of development time probably went to pitch sensitivity. This teams stuff in particular was less pitch sensitive than others, I'm sure they have a lot into it. If you are talking about 5% your talking about win or lose potentially.
Mike Kojima
Mike Kojimalink
Sunday, July 17, 2011 6:03 AM
If you are using the valve to control fluid flow into the cannister then you can electronically control low and high speed compression. You can probably slightly influence rebound as well.

We looked at the cars on a Friday practice. One of the cars had conventional Penske 8000 series 3-ways but the other had the mystery shocks. This would be in line with what I have heard how the shocks are used on NASCAR and DP cars. In testing and practice the team uses the active shocks to quickly find the optimal shock settings via DOE, which is valid as many iterations can be tried before the variables like tires change.

Then the optimal settings can be applied to the conventional shocks that are installed for the race.

Andrew, I didn't think a GT car would need so much attention to pitch control considering the limited splitter size, ride height and the almost not a diffuser diffuser.

I had better hire you when I do serious things. Do you think I should pay more attention to pitch control at the expensise of lower speed mechnical grip on something simple like my MPTCC car? It has a bigger splitter and diffuser than the GT cars have. I was thing that since the ride height rules keeps the splitter 3.5" off the ground it would hardly matter at all.

I need to talk to you about drift car aero. We are experimenting a lot for this Formula D round.
Andrew Brilliant
Andrew Brilliantlink
Monday, July 18, 2011 12:22 PM
You've got mail!
Monday, July 25, 2011 7:25 AM
There hasn't been GT1 class at LeMans for a couple of years now.
GT1 was ditched and only GT2 remained. This year the only GT class was called GTE and is probably over 90% the rule set of GT2.
That LeMans Corvette above is a GT2 machine and not GT1.
Turbo Shangbanger
Turbo Shangbangerlink
Sunday, December 25, 2011 10:33 PM
I learned how antsy the WTCC teams get when you start poking your camera into spots that aren't painted. ;)
However I must say that once you have a bit of trust (or a working relationship, as I did) they are very open and friendly. They will typically explain a lot of things and reasons for certain engineering and set-up decisions, and short of handing over blueprints, they'll tell you anything you want to know.
SunRed (Pro SEAT Team) and Bamboo Engineering (privateer Chevy Cruze team) really showed me all I wanted to see, and the Polestar Volvo Team were also quite amicable.
Eric Hsu
Eric Hsulink
Monday, December 26, 2011 8:23 AM
I'm not 100% sure, but I think the pro racing Corvettes world wide run Cosworth Pectel ECUs. Or at least they did at one point in time. That GEMS display is pretty cool too though. You see it in a lot of the Group N rally cars owned by ballers.
Friday, December 30, 2011 8:09 AM
So what's the chance of a write-up for just the air conditioning system?? In the old sense that's one of the first things to be thrown into the scrap pile, and I'm curious as to the type of low drag compressors and evaporators they're using.
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