Rostra Cruise Control in a Plus 2

[stugilmour]

Installed a Rostra cruise control in my LHD Federal Plus 2. Searching the archives I didn’t see any posts on the topic. I was familiar with the Rostra kit from an installation in my Esprit V8. Rostra parts are available on eBay or through a few online stores.

Parts required are:

• Rostra universal cruise control kit, part 250-2334. The kit includes all the required hardware, cable, and wiring loom.
• Control switch. I used the universal cutoff style, part number 250-3032. Some suppliers bundle the switch with the main kit.
• Universal speed signal generator, part number 250-4165. This is typically sold separately.
• I did not use a clutch cutoff switch; rather I set the unit to Automatic Transmission which senses engine rpm and turns the unit off if revs go up about 500 rpm in neutral or with the clutch disengaged.

The instructions are all available online, and very complete. In addition each separate component has detailed instructions. Following are just a few tips from my installation.

• No vacuum connection is required.
• The module is tuned to the car’s power to weight and throttle response using several dip switches.
• I was able to detect engine rpm directly the tach wire from my MSD electronic ignition, not sure of the details with points or Pertronix. If you are using a clutch cutout switch you may not need an rpm signal.
• The loom is pretty ungainly. I opted to modify it to get it through the driver’s side firewall cleanly. In hindsight it may have been easier to use the included connectors and go through a new firewall hole on the passenger side where the control box is mounted. Most of the required connections are located on the driver’s side under the dash though.
• I had to install an isolation relay to the brake light switch and run the Rostra connection through the relay. This is caused by having LED lights installed. The LED’s would stay glowing without isolating the Rostra.
• My low rise Weber throttle linkage already has provision for two throttle cables, which made connecting the cruise cable relatively easy. The hardware kit provides different connection methods.
• Although my drive shaft is non-stock, I think a stock setup will be similar. The speed generator just requires attaching two small magnets to the driveshaft and mounting the barrel shaped pickup about 1/4” from the magnets. I was able to use a couple of included steel strips to attach to my Spyder frame through the big inspection bung on the right side of the tunnel. The magnets are glued with JB Weld and topped with an included nylon zip tie. I used two magnets and set the pulses per mile to suit.
• There are a number of options for control switches. I used the cutoff style 250-2032 on the high/low light stalk. I tried it on the turn signal stalk but the unit was too heavy, interfering with the self cancellation of the turn signal. Note my stalks are moved side to side, so the light stalk is on the right, so I had to install the cruise control switch upside down. If you want to try the turn signal installation, I would suggest taping the cruise wand to the turn signal to see if it works OK. Another option might be adding flat switches to the console area.
• I added a small green LED (purchased separately on eBay) that lights up when cruise is engaged. Rather than drill the dash I attached it discreetly to the driver’s side edge of the dash board. Works well.

The system works pretty well. It will easily hold the car at it’s set speed above about 40 mph in fourth. Like any cruise control, hitting the brake disengages things but allows speed to be resumed. Accelerating or decelerating using the buttons is too slow to be much use, but setting things to be more responsive can bring on some unwanted surging. I just use the pedal to get to speed and reset the speed. The system can be turned totally off with the slide switch, or left on and then speed directly set with the button. My car has somewhat more power than stock, and speed stays reasonably steady in my Plus 2, even in fifth going over hill and dale.

Overall happy with the feature. Going to be great for long four lane transit sections.