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Author Topic: After Market Cruise Control  (Read 3333 times)
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Pete RTS/Daytona ->'89 TMC 35' 102" 6V92TA 4:10


« Reply #15 on: March 08, 2010, 10:23:39 AM »

I found the OEM Installation instructions for setting the dip switches - VERY CONFUSING

and The original support person at Rostra (difficult to deal with  - especially when I said I was an Engineer)

So after many trails and errors and lots of phone calls - I got one of there engineers to FULLY explain the dip switch settings

I have written my OWN set of instructions - that works VERY well for Buses -

The current support team at Rostra is much inproved - The anti-engineer guy has finally retired

The tricks are:
. Have the correct amount of slack in the cable that pulls the throttle (1/8") - too loose cause lag and lost speed on initial set
. If you have a Unusually hard throttle (over 25 lbs of force is required at the cable pull point) - install an assist spring
  (Throttle pedals that require over 25 lbs at the cable pull - MOST drivers would find EXTREMELY UNCONFORTABLE and Fatiguing during NORMAL driving)
. The Rostra Global differs from earlier versions - switch 1&2 and 7-9  let you adjust the RATE of control response and The timing of the control response)

Yes guys I have a horse in this race (I sell discounted Rostra for Buses)  - but The cost difference is HUGE - The KING IS A GREAT UNIT - but  it is EXPENSIVE

Here's copy of my instruction:s
* Switch settings                                                                                                        *
Switch 1& 2 (gain)
         . This controls the degree of 'surge' the cruise control will                       
            have. If the unit tends to apply too much throttle change for
            small changes in speed - then "lower the gain". If the unit does              
            not apply enough throttle change corrective action - then set         
            the gain "higher"  
                 . Example - (high horsepower/light weight vechicles - set to low)  
                 . Suggested setting- High  (1=on  2=on)

 Switch 3-6 Pulses/Mile
          . Proper setting of these switchs controls minimum speed to set
            cruise and Provides a 1-2 MPH change (up or down) per tap of the
            accel/decel switches
           . To Calculate "PULSES / MILE"  (PULSES/MILE)
            1.  Determine the number of tire revolutions / mile (TIRE-REV/Mile) for your size tires   
                       09R22.5 = 542 revs/mile                12R22.5 = 492 revs/mile    
                       10R22.5 = 520 revs/mile                11R24.5 = 480 revs/mile
                       11R22.5 = 504 revs/mile                12R24.5 = 470 revs/mile
             2.  Determine the number of pulses / tire rev (PULSES/TIRE-REV) P/TIRE REV
                       . RTS & GMC buses have 60 notch front hub w/pulse sensor => 60 P/TIRE REV
                       . Many MCI/Eagles have 4 bolts on the front hub pulse device => 4 P/TIRE REV
                       . Many Speedo Cable Pulsers give 8 pulses/cable rev X axel ratio =>P/TIRE-REV
                       . ATEC tailshaft Vechicle speed sensors produce 12 pulse / tailshaft revolution
                        12 pulses per tailshaft revolution times your axle ratio = PULSES/TIRE-REV
            3. Calculate PULSES/MILE by multipling PULSES/TIRE-REV by TIRE-REV/MILE
            4. Use the chart on page 4 of the Rostra Cruise Control Installation manual to set
                 the switches to the corect PULSES PER MILE range

Switch 7-9  Engine / SetUp Timer
              . If cruise speed drops off 5 miles per hour when initially set to 55 and then recovers
                Slowly - change to higher setting
                Settings are based on 1/8" slack in cable - More slack will cause cruise to surge or
                loss speed on set
   . Suggested setting = (Weight to HoresPower Ration (HIGH - LOW ?)
                       (High Weight to small HP Ratio = HIGH  or    Low Weight to big HP ratio = LOW)

Switch 10 VSS Source
             . Magnet pickups require this switch to be set to OFF
               (sine waves  have a negative and positive component to the wave form).
             . Speed signals processed thru a computer (ATEC / DDEC) require this    
               switch to be Set ON for square wave (only positive wave component)

switch 11 Manual /Automatic
            . Set to "manual' allows longer application of full throttle during       
              heavy loads (hill climbs) before tripping a reset

Switch 12 Control Switch
            . Dash mounted switch (250-3592 or 250-3593) - set to open (switch off)

Plus the wiring IS DOWN TO ONLY 4 WIRES
 Quick & simple wiring for diesels / Rostra Global 250-1223 & Rostra 250-3592 or 250-3593  switch
Ground (-) ->To the following wires  (Note -  Dark Blue  is n/a for diesels & grounded to prevent noise)
                        * (Black & Dark Blue Wire) - From Control Unit 250-1223)
                        * (Black Wire & Blue Wire) - From switch 250-3592 or 3593)
Ignition (+) ->to the following wires
                        *(Brown wire) - From Control Unit 250-1223
                        *(White wire & Gray wire) - From switch 250-3592 or 3593)
                        *(Red wire) - From Control Unit 250-1223
Brake (cold)-> to the following wire (Note - Cold side of brake switch is + only when braking)
                          * (Violet wire) - From Control Unit 250-1223
Speedo ->  to (Gray wire) - From Control Unit 250-1223

Switch Plug ->(4 pin- Thin Red/Brown/Yellow/Green wires) - to plug as shown in instruction sheet
« Last Edit: March 08, 2010, 10:29:42 AM by RTS/Daytona » Logged

If you ain't part of the solution, then you're part of the problem.
Greg Roberts
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Posts: 137


« Reply #16 on: March 08, 2010, 11:50:24 AM »

Thanks Pete. Your write up certainly is more clear than the book from several years back.

Check out my Eagle 20 here: http://photobucket.com/GregRobertsEagle20
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Posts: 278

« Reply #17 on: March 08, 2010, 12:18:34 PM »

I called King Controls in Faribault and they charge $695 for their unit, Pete is around $200.  I may be a touch too thrifty to spend an additional $495.

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