J richard

Odd, was that for crash protection or weight/balance. With the standard GT3/cup the wheel is already offset to the right, in the box I had the seat moved over to align bit it puts it tight to the tunnel. This has to get it even more off center? Strange thing is if it were for weight the location of the seat would make way more difference than the column. With the column/seat/pedals plus the cage mod there must be some real payback...

GTgears

There's also Pirelli Drivers Cup and Mission Foods that are Cup "spec" series.

IMSA GT3 and ALMS GTC are both sealed gearbox series allowing only stock ratios that must be Porsche factory parts. And new for this year, the gearbox must be resealed every race is what I have been told.

Grand Am and WC are not sealed and allow aftermarket components. Grand Am definitely allows gearing changes. I don't think WC does. Pirelli Drivers Cup and Mission Foods do not allow gearing changes to my knowledge.

mklaskin

My understanding was that it was done for handling purposes.

Charles A. Toupin

Was it done by K-Pax/3R?

mklaskin

That car was built by Kelly Moss. My car was built by 3R, but my seating position is normal.

lordpantsington

According to this WC does not allow gear changes beyond what is listed:
http://www.world-challenge.com/inclu...2231822bfff66c

coryf

To go along with what has been stated before:

GTC:
Shocks/springs are free
Alignment settings are free (limited to -4 camber in imsa challenge)
Endurance brake cooling kit
Battery re-location to passenger foot well
Restrictor (unsure what size, but it was intended to keep the GTC cars from being so close to the GT2 and LMPC cars at the end of the straights so it would be easier to pass for the faster class cars)

Grand-Am
seam welded
Any shock/spring
complete RSR suspension and brake components
floor mounted pedals (much better brake bias linearity with pedal pressure)
carbon body work
carbon dash
3.8l or 4.0l engine
RSR transmission (open ratios)
2in ride height
RSR style rear wing mounting (uprights mounted to the body)
Flaired rear quarters (Not sure what the body width limit is but I think its 64 or 66in)
RSR headers and open exhaust
Stock front splitter
Crawford rear wing (less down force than a 2010 wing)
285/640 320/710 continental tires
Pankl/Metalor axles
Sectioned/enlarged rear wheel tubs to make room for the large diameter rear tires with the low ride height.
Basically teams are building GT3R's on a modified cup tub without the ABS, Traction control or e gas with auto blip.


WC:
ABS
Aftermarket brake calipers (stoptech?)
Front splitter
larger wing end plates
Spec shorter gear ratio set
RSR exhaust (not completely sure its RSR but thought they were allowed headers of some sort)
285/640 325/680 pirelli tires (not sure on the sizes)

mobonic

Question answered dead on!

Also I know PDC (pirelli drivers Cup) allows shocks to be open, but im not sure if GT3 challenge does too, but Id think they would since pds is basically a feeder series.

ZSA Motorsport

cory,
whats the story with that RSR gear box? cost? cost to rebuild?
is it a performance, shifting thing? or just the fact that you can flip it over and reduce ride height down to the 2" min without straining the axles?
can you explain all that a bit more given your expertise in that area of transmissions..

GTgears

The RSR gearbox is about $75k to buy and about another $25k to fit to the vehicle. In addition to the axle angle change, it's also significantly lighter than the Holinger sequential gearbox. That's due in part to the use of the drop gear with a shortened ring and pinion as well as the fact that the gears are significantly narrower than either the 2010 or 2012 Holinger gear specs. They are skinny like the 2008 spec Holinger gears. Expect service life on them to be somewhat short and rebuilds to be frequent. I don't know what the gears are selling for.

One other advantage of the box is that is allows for quick mid-weekend adjustments to tweak the ratios. This is because of the drop gear. One can change out the drop gear ratio while leave the individual ratios static, thereby moving your overall speed up or down several miles an hour in any given gear as needed. It's the equivalent of changing the final drive ratio without altering your existing rpm drops and just adjusting your top speed or moving a particular gear's top speed such that, for example, you aren't making a 3-4 shift mid-corner because you can alter it to fix an issue with a shift point on a key corner without taking the whole gearbox apart.

Adam@Autometrics

^^This is absolutely correct.

The improved axle angle is also significant. It takes a fair amount of energy to turn CV joints at the angle created by ultra-low ride height.

ZSA Motorsport

great info.
so what happens to those who dont run the RSR gearbox? are they just out of contention, non-competitive midpack cars? i konw its premier racing, but you'd think rolex would try to avoid the arms spending race that it brings about. a 100k gear box. whats the rebuild cost? 25k, 30k for 25 hours or so. so now you've got another grnad or two per hour, if not more, in running costs.

mobonic

i know of 2 teams that open, inspect and replace parts on their rsr trans, EVERY time its used.

any level of racing is an arms race... even in a spec class like GTC or Gt3 challenge there's always a way to get a slight advantage over your competitors while staying within the rules when you have the benjamins!

James-GMG

Sorry for the late response........been a busy year racing, just catching up.

Cory did a nice job responding, I will add to his list below:

To go along with what has been stated before:

GTC:
Shocks/springs are free
Alignment settings are free (limited to -4 camber in imsa challenge)
Endurance brake cooling kit
Battery re-location to passenger foot well
Restrictor (unsure what size, but it was intended to keep the GTC cars from being so close to the GT2 and LMPC cars at the end of the straights so it would be easier to pass for the faster class cars)
Brake pads and rotors are free
Stock Calipers are allowed modified Ti pistons
SPOT ON!!!


Grand-Am
seam welded
Any shock/spring
complete RSR suspension and brake components
floor mounted pedals (much better brake bias linearity with pedal pressure)
carbon body work
carbon dash
3.8l or 4.0l engine
RSR transmission (open ratios)
2in ride height
RSR style rear wing mounting (uprights mounted to the body)
Flaired rear quarters (Not sure what the body width limit is but I think its 64 or 66in)
RSR headers and open exhaust
Stock front splitter
Crawford rear wing (less down force than a 2010 wing)
285/640 320/710 continental tires
Pankl/Metalor axles
Sectioned/enlarged rear wheel tubs to make room for the large diameter rear tires with the low ride height.
Basically teams are building GT3R's on a modified cup tub without the ABS, Traction control or e gas with auto blip.
Bummer about the GA cars is that they run the stock splitter and the very ineffective rear Crawford wing......plus those Conti tires aren't the best. But the GA cars are big $ with the RSR gearbox so it becomes difficult to run a few races in GA and try to be competitive without it. Plus the 4.0 motor added another element to it.



WC:
ABS
Aftermarket brake calipers (stoptech?)
Front splitter (NICE PIECE and really helps front end grip)
larger wing end plates
Spec shorter gear ratio set
RSR exhaust (not completely sure its RSR but thought they were allowed headers of some sort) We run the GMG headers and rear muffler.....both are open.
Tires are 275/645/18 fronts and 315/675/18 rears and we are allowed the Monobloc BBS wheels vs the 3 piece BBS. They are 10.25 x 18 and 12 x 18.
Open Shocks, Open Suspension either PMNA or GMG components

Skypalace

In the former Pirelli Drivers Cup, now the easy to remember Pirelli GT3 Cup Trophy USA West, with the easy-to-remember PGCTUW abbreviation :-)

Cars as delivered, except a few allowed mods. Sealed engines & gearboxes, ECU must be stock (blipper-equipped cars must have PMNA stock blipper ECU update). Some minor gearing changes allowed (Gold class can run 2007 or 2008-2009 gear ratios, Platinum may use 2010 or 2011-2012 ratios).

Shocks are free in Platinum, but must use stock pickup points and mounts. Gold can use any two-way adjustable shocks.

Silver (996) cars can use aftermarket non-floating rotors, otherwise brakes must be bone-stock, including pads.

A few additional data sensors are allowed, but pretty restricted (no shock pots, no wireless transmission, no GPS).

Ride height is controlled., otherwise adjustments within stock range only. Sway bars may be disconnected but not removed.

That's about it, not a lot. No crashbars. Very similar rules to IMSA GT3.