I'd like to add a kit to the car.
Help with part numbers/vendors.
Thanks in advance.
RP
Help with part numbers/vendors.
Thanks in advance.
RP
Aftermarket Cruise Control: Suggestions and Experiences
- Thread starter Patton
- Start date
M88 engine, cable throttle control, mega squirt fuel injection.
Looking for something as simple as vacuum cruise control and accepting a +/- of 5 mph.
They don‘t make simple vacuum units any longer (at least that I can find).
What success has the audience has in retrofitting?
Thanks!
RP
Looking for something as simple as vacuum cruise control and accepting a +/- of 5 mph.
They don‘t make simple vacuum units any longer (at least that I can find).
What success has the audience has in retrofitting?
Thanks!
RP
I would probably go with BMW OE throttle regulator. It is not vacuum-based but widely available and tested over years of usage
It might be taken with original regulator etc as it is independent from the ECU and so on.
A set consist on:
- cruise control ECU with mounting bracket
- stalk switch (electrically simple to be exchange or modified according to the needs)
- clutch/brake switch (to turn off the CC while braking or cluch depressing)
- regulator with the bowden cable
- wiring
All the components can be taken from E23/E30/E28/E24/E34 (early models).
OE BMW cruise control is taking speed signal from the rear differential over speedo. It is "digital" form of pulses so it can also be handled by programmable ECUs.
In my humble opinion it is the best solution as it is basically ready to go with spare parts widely available and it has been made in a professional way with all tests and certifications required where aftermarket solutions might only have CE (China Export) conformance letter.
It might be taken with original regulator etc as it is independent from the ECU and so on.
A set consist on:
- cruise control ECU with mounting bracket
- stalk switch (electrically simple to be exchange or modified according to the needs)
- clutch/brake switch (to turn off the CC while braking or cluch depressing)
- regulator with the bowden cable
- wiring
All the components can be taken from E23/E30/E28/E24/E34 (early models).
OE BMW cruise control is taking speed signal from the rear differential over speedo. It is "digital" form of pulses so it can also be handled by programmable ECUs.
In my humble opinion it is the best solution as it is basically ready to go with spare parts widely available and it has been made in a professional way with all tests and certifications required where aftermarket solutions might only have CE (China Export) conformance letter.
The E24 OEM, per Krzysztof's input, seems natural. Yes the cruise control ECU is stand alone, so you can focus on that system in isolation. The bad part is that it does not have self diagnosis, if you get an ECU from a junkyard you have no way of knowing if it works. If you buy a new one to compare, you cannot return it after plugging it in. Not sure if it is still available new.
So you need a friend with a known good ECU to compare.
Most of the pins of the ECU can be measured and confirmed with a voltmeter, except for the speed input (pin 2 I think), which is indeed a pulse, and you have to observe with an oscilloscope, but the rear wheels have to be moving...
The cable mechanism is, as usual, dual cables connecting in parallel to the throttle, so that part is easy to sort out visually. I recall I was able to test the cruise control actuator without the ECU and determined it worked. I forgot how.
I have no idea if the wiring uses its own harness, but there aren't that many cables involved.
So you need a friend with a known good ECU to compare.
Most of the pins of the ECU can be measured and confirmed with a voltmeter, except for the speed input (pin 2 I think), which is indeed a pulse, and you have to observe with an oscilloscope, but the rear wheels have to be moving...
The cable mechanism is, as usual, dual cables connecting in parallel to the throttle, so that part is easy to sort out visually. I recall I was able to test the cruise control actuator without the ECU and determined it worked. I forgot how.
I have no idea if the wiring uses its own harness, but there aren't that many cables involved.
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This old girl ( the 1974 3.0CS) doesn't have a differential speed pickup location.
Cable drive off of the gearbox is how this car rolls down the highway.
Could I make a BMW system from an older car work? Likely, yes. The car is an orphan of BMW parts from an e30 and e24 already..
Do I want to use BMW parts? Not necessarily.
Any aftermarket cruise control suggestions or experiences?
Thanks all.
RP
Cable drive off of the gearbox is how this car rolls down the highway.
Could I make a BMW system from an older car work? Likely, yes. The car is an orphan of BMW parts from an e30 and e24 already..
Do I want to use BMW parts? Not necessarily.
Any aftermarket cruise control suggestions or experiences?
Thanks all.
RP
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Take a peek.
I would think the only cruise control for that engine is the pedal to the metal 
Back in the 80's I put an aftermarket unit in my e9, it didn't work very well, but then I was young and clueless. I saw an NOS one on eBay a while ago, you might try setting up a search there.
Back in the 80's I put an aftermarket unit in my e9, it didn't work very well, but then I was young and clueless. I saw an NOS one on eBay a while ago, you might try setting up a search there.
Seems like the top aftermarket vendor is Rostra, but still need to solve the speed sensor. Replacing the differential seems overkill just for this, and I would not use GPS for such a close loop control system... The Russians are known to jam GPS services just to mess up with whoever they are messing up on a given week.
In any case speed of the car needs to be translated into any signal any kind of cruise control is compatible with. For BMW OE it is pulse from the rear differential. Some may apply the sensor in the gearbox or inside the differential. Others can use new differential from E24.
There are also boxes available (look on the forum) to transfer bowden cable rotation into pulses. Basically it is very simple but tested products/solution have to be considered.
Pulses does not need an oscilloscope if all is correct. Frequency meter implemented in most of modern middle-class multimeters is enough. There are also cheap frequency meters available here and there.
For independent cruise control it is not so important if it is pulling for the bowden of Motronic or Carb system as long they are correctly tuned and fully operable.
Please do remember that improperly installed cruise control can damage your car or even kill you and others! This is not a joke. That is why OE systems are the best solution as they need to pass very demanding requirements (OEMs but also Government and International). Please beware of that. Car is not a toy and can be lethal.
I do not want to push for BMW OE system but I know how it was difficult for my friend to install vacuum-based system which in the end forced him to create its own electronic unit and to program it.
Good luck!
Side note:
GPS/GNSS or any other system should not be used. There are still many places you will not be able to have it running and is some specific cases it can be switched off or fooled in case but this is rather for country critical cases you would not rather your cruise control in your E9.
There are also boxes available (look on the forum) to transfer bowden cable rotation into pulses. Basically it is very simple but tested products/solution have to be considered.
Pulses does not need an oscilloscope if all is correct. Frequency meter implemented in most of modern middle-class multimeters is enough. There are also cheap frequency meters available here and there.
For independent cruise control it is not so important if it is pulling for the bowden of Motronic or Carb system as long they are correctly tuned and fully operable.
Please do remember that improperly installed cruise control can damage your car or even kill you and others! This is not a joke. That is why OE systems are the best solution as they need to pass very demanding requirements (OEMs but also Government and International). Please beware of that. Car is not a toy and can be lethal.
I do not want to push for BMW OE system but I know how it was difficult for my friend to install vacuum-based system which in the end forced him to create its own electronic unit and to program it.
Good luck!
Side note:
GPS/GNSS or any other system should not be used. There are still many places you will not be able to have it running and is some specific cases it can be switched off or fooled in case but this is rather for country critical cases you would not rather your cruise control in your E9.
The Rostra aftermarket unit uses a magnetic pickup with a metal "ping" fastened to the drive shaft.
Any aftermarket ` suggestions/experiences and/or recommendations?
RP
Any aftermarket ` suggestions/experiences and/or recommendations?
RP
That's cool. Should be pretty universal then.