ABS Delete - Technical Information

[Viper_Race_HQ]

VIPER COMPETITION COUPE

TECHNICAL SERVICE BULLETIN

07 - 6

Date: January 29, 2007

Subject: ABS Delete

Technical Bulletin –

Viper Competition Coupe Teams,

There has been quite a lot of concern and negotiation in the off-season regarding Viper Competition Coupe brakes in the SCCA World Challenge GT Series. The intention of this bulletin is to clear up what Dodge expects the configuration of the Viper to be for the 2007 season and to suggest a non-ABS brake package for competitors.

Optimally, the brake system would have remained the same as it had been for the 2003-2006 seasons. Dodge still believes the standard ABS brake system to be the best compromise between cost and effectiveness. Unfortunately, the SCCA views ABS as an unfair advantage, believing Viper drivers are able to take more risks under braking without fear of flat spotting tires or missing corners. Regardless of how Dodge’s ABS advantage stacks up against the advantages of other vehicles, the SCCA feels they must take steps to eliminate it. After a lengthy process involving negotiations and clarifications there will be two specifications of Viper Competition Coupe in the World Challenge GT series for 2007. Those specs are as follows:

ABS Equipped – Essentially the 2006 car with base weight provisions
- Stock Viper Calipers Front and Rear
- 355mm (14”) Front Rotors
- 355mm (14”) or 328mm (13”) Rear Rotors
- 275/35R18 Front Tires
- Drivers with “non-professional” status who choose to run 5 races or less will race at the base Viper Competition Coupe weight as listed in Appendix A of the SCCA Pro Racing Regulations (PRR). Professional drivers or any driver wishing to run more than 5 races in 2007 must practice, qualify, and race with an additional 100 pounds added to base weight.

Non-ABS Equipped
- Any Caliper allowed in PRR Section 2.12.3
- Up to 380mm (15”) Front Rotors
- Up to 355mm (14”) Rear Rotors
- 305/35R18 Front Tires

For competitors looking to make the change, Dodge has put together a Non-ABS brake system for the Viper Competition Coupe. This system will replace the stock brake/clutch pedal assembly, brake booster, master cylinder assembly, front calipers, and front rotors. The new brake and clutch pedal assembly has two pedals, three master cylinders, integrated balance bar, and firewall mount design that places the master cylinders in the engine area for improved serviceability. The master cylinders are a full floating design which minimize friction/binding and provide consistent line pressure. These pieces mount to a front of dash panel that closes out the previous component holes in the firewall and stiffens the front structure of the vehicle to reduce unwanted master cylinder motion. New 6-piston front calipers are lighter and house larger brake pads than the previous calipers. These calipers mount using an existing knuckle adapter that has been proven in FIA GT3 competition. 380mm x 32mm front rotors also use FIA specification hats to effectively slow down the larger diameter 305 front tire. All of these components will mount to 2006 World Challenge spec suspension components utilizing 355mm (14”) front, and 328mm (13”) rear brake packages.

Teams utilizing the stock wheel speed sensors for ground speed through the ECU or traction control will be obliged to retain the electronic portion of the ABS module. The electronics can be separated from the hydraulic portion of the ABS module by removing four retaining bolts and disconnecting the power feed lines between the electronics and the pump motor (see Appendix A). The ABS electronic module should then be fastened solidly to the chassis to avoid unwanted vibration. As run in this configuration the ABS module will log a hydraulic circuit failure code. The fault will not affect wheel speeds or the vehicle electronics. It will trigger the ABS warning light in the dash. Since the vehicle is not running ABS, this light can be turned off in Motec Dash Manager by going to the Functions Menu, selecting Alarms, and clearing the ABS Warning message.

If attempting to reuse the production brake lines, some steps can be taken to eliminate extra plumbing. Dodge recommends splicing into the rear circuit at the tube nut located directly below the production booster (see Appendix B). By connecting there, the lines from the original master cylinder to the ABS module and the lines back to the splice can be eliminated. The front circuit can reuse part of the original plumbing down to the ABS module. It will require new plumbing to a point where a union can be made to the existing front circuits. While modifying this brake line plumbing, the customer can add a brake pressure switch to activate the brake lamps. The Tilton pedal assembly has no provisions for the production brake lamp switch, either a new bracket must be fabricated for the Tilton assembly or the switching can be completed by a brake pressure switch in the lines. Pressure switches are available from most racing industry suppliers. In order for the brake lights and brake switch signal in Motec to function properly, care must be taken in wiring in the new switch. Please refer to Appendix E for wiring instructions.

While the majority of these pieces are available directly from Dodge Motorsports, some components will need to be ordered from other racing industry suppliers. Pieces supplied by Dodge will be available for order on February 19th. Please see the attached Bill of Materials (Appendix C) for component details and ordering information. Pictures showing the new pedal mount package are also attached (Appendix D). If you have any technical questions regarding either brake package, you may contact me via the e-mail address below.

Thank you,

Jeff Roselli
Development Engineer – Road Racing
Dodge Motorsports
DaimlerChrysler Corporation
jmr29@dcx.com

SEE IMPORTANT LINKS BELOW:

http://compcoupe.viperclub.org/brake...Appendix A.pdf

http://compcoupe.viperclub.org/brake...Appendix B.pdf

http://compcoupe.viperclub.org/brake...dix C Rev2.pdf

http://compcoupe.viperclub.org/brake...Appendix D.pdf

http://compcoupe.viperclub.org/brake...Appendix E.pdf

http://compcoupe.viperclub.org/brake...stallation.pdf