The chassis is one obvious differentiator between other mid-engine kit cars and the SL-C. Made entirely of aluminum, it is obviously very light (at under 300 lbs, it is just 20 lbs heavier than the all-carbon fiber tub in the latest McLaren MP12C), but it also the stiffest chassis on the market, at over 25,000 lbs/degree.
A stiff chassis is a sort of a Holy Grail for chassis designers, for both racing and street use, as it allows the suspension to do it's job as designed for more consistent handling, and for street use, generally offers a better ride as well. Only in recent times have even some production cars achieved the kind of stiffness built-in to the SL-C.
You can leave the chassis uncoated, or use one of many possible coating options.
- An inexpensive one is to just rub Ballistoil on the chassis as needed to keep things clean and non-oxidized. Originally created for guns, it is a general metal treatment that works well for our cars.
- Another is to use adhesive foil that is reflective. This has the McLaren F1 gold leaf look which some people crave, but has the disadvantage of hiding any damage on the tubes. This is a delicate coating, and hard to keep clean around the edges.
- You could have the entire chassis powdercoated, as many do with their GT40s (from RCR, also with a similar aluminum chassis design) but that is expensive and hard to repair chips as they occur.
- Some specialty paints like POR-15 and similar ones from Eastwood are occasionally used. They are durable, but like all coatings, require some maintenance.
The default is to leave it alone, and just occasionally wipe it clean. That's probably what most people do!
Lots of discussion on this topic. Discussion thread here.
Fortunately, very few SL-Cs end up damaged. But because of the extreme speed potential of the SL-C, it is even more important to check the chassis and suspension very carefully after any kind of an off-road incident or accident. There is at least one case where damage to an SL-C in an on-track accident may have been exacerbated because damage from a previous accident (thought to be just minor body damage) was missed.
As with any race car, it's a good idea to do a thorough chassis and suspension check before the start of a driving season, or before any competitive activity on the track.
The chassis is fabricated from 6061 T6 aluminum sheet, along with some billet. In the event of an accident, the chassis needs to be evaluated and repaired by a competent shop. That means they need a GTAW or TIG welder, experience with aluminum and the techniques used in building race cars with the material, and familarity with welding techniques on the car. They will also likely need to build a jig to ensure that any repairs leave the chassis as straight as it was when it came from the factory.
The best solution may be to send the chassis back to Superlite, where it can be repaired using the original jigs on which the chassis was first made. The factory uses only weldors certified to military standards, and you can be assured that the repairs will be performed to a high standard.
Really seriously bent chassis may have to be replaced, but so far, we know of only one car that was crashed badly enough to need repair, and none that have been so comprehensively crashed that a new chassis was needed. Don't be the first! :)
The SL-C follows contemporary race car design in that the suspension is attached with what some people call "mechanical fuses". The idea is that the brackets will allow the suspension to be torn off in an accident, which has the following advantages:
1. The tearing off activity dissipates a large amount of energy that would otherwise be transmitted to the chassis, where it could have an occupant safety issue.
2. The suspension parts can often be reused instead of breaking after such an accident. making repairs less expensive. Be sure to inspect anything and everything on a damaged car to be sure there are no hidden cracks, etc.
3. By allowing the suspension to tear off in an accident, chassis damage is minimized so repair is simpler and less expensive. It's always cheaper to replace brackets than part of the chassis itself.
This is standard racing car construction design.