The new MK4 Challenge Chassis

[fireballferkey]

So other than the new front MK4 suspension and tubular X member what else has changed? Do they run a back bone in it now?I kinda hope so as it adds a lot of rigidity to the frame at least in most unibody cars Ive seen fully caged and Is the body still two piece (cut in half) or is it one now?

[johngeorge]

fireballferkey,

The Challenge chassis is 15% stiffer then the street MK4 version. As for the body, its up to you to cut it in half if you want to (most racers have already done this for serviceability)

Have you looked here? http://www.factoryfive.com/challenge/design/frame/frame.html

[Jim Schenck]

There isn't a backbone in the challenge cars still because we didn't want to give the newer cars an advantage, but it also makes servicing the car easier in rushed situations. (like between session transmission changes). The front end on the MKIV can still be configured to either the new geometry or the old (to run in FFR2) and the front tubes being changed from square to round was cosmetic and provides no performance advantage.

We mount the bodies as one piece but it is legal to split them below the door, just check the rules as there are guidlines there for where the split can be.

[fireballferkey]

Jim thanks for the info is it possible to order it with the back bone for a non spec build? I have a background in drag racing and would really like that the extra rigidity it gives a chassis.