2012 BMW M3 GT - Team Rahal Letterman Lanigan

As you stated, the big ducts feeding in the back are probably to help fill in the base area behind the car to reduce drag. If you look at its competitors, even in race trim the M3 has a lot more frontal area than, say, the Corvettes or the 458s. There'd been a lot of talk about how many waivers the Z4 would need because of the V8 and so on, but these days in racing when a manufacturer wants it enough...

Bet they got rid of that berm.

When do we get a similar piece on the Z4?

@Kenku, yeah, it was like the GTR racing in FIA GT1 vs all the low slung cars like Lambos and Ferraris. The GTR was a whole foot taller.

In racing, throw enough money at an organization and they'll give you the waivers. They equalize out performance with the air restrictors anyways. I remember those Caddys racing in World Challenge with the firewall moved back a good amount, engine moved back and lowered, etc.

It's funny looking at the FIA GT classes... early adopters like the Corvettes started with almost no waivers - thus the destroked 5.5L engine. Then the 458 came in with none at all, but OEM a lot in design that made everyone else need waivers to upgrade to keep up. Now the Viper came in with a waiver for its engine capacity, which GM is possibly kicking themselves for, and now the Z4 which doesn't even share the engine of the production version.

I'm not holding anything against the manufacturers here - more I think it's just a little sad that the market is such that nobody can justify making homologation specials anymore.

Porsche and Ferrari could... haha. But not many are going to buy a $250k homogolated BMW or Corvette. And corporations are all about the bottom line now.

On page 2, bottom picture are 2x ¾”-ish lines running to the cowl with red caps.. what are these for? Force feeding water to the cooling system under pressure? If so, that would run to the coolant reservoir… what else needs quick filling besides fuel? Oil…?

What is the brand that make that clotch tape on the wiring page 6 second picture from the top?

Just a small correction. It is likely that the damper position sensors are not LVDT but likely just normal potentiometer spec. While with the BMW's system which is a Pi Research LJB (Lightweight junction box), which can do LVDT with no extra hardware, it is not normally done. The LVDT requires a sinusoidal excitation and 2 inputs. Most competitors just utilize single ended 0-5v sensors. This includes differentials being mated to amplifiers because many systems maximize their flexibility and inputs by offering configurable ones.

If you want differential, then many times you will have to use 2 signals and then they become instead of +sig and + sig you will then have sig + and sig -. Taking 2 x 0-5v single ended inputs and changing them to 1 differential.

the LVDT goes one step further. Our system for example, internally will do an AC excitation, but you then take what was 2 x excitations and convert them into excite + and excite - so to speak.

I just wanted to chime in as it reminded me of the debate on the corvette dampers from last year where everyone stated they were the penske adjustable dampers and the plug was the controller. Not true. I will not talk about what it is, but it is not that.


Also one more note. It is likely that the other plugs around a wheel area would either be for TPMS receivers, upright temps, pad wear displacement sensors (specialized for high temp and usually just for endurance series), brake disc temp sensors, tyre temp sensor arrays. Those are just a handful.

Oh and I think the lines if we are referring to same ones could be for fluid transfer like for a heater.

@Mark, thanks for adding the input!