CCU Removal - alternate controls/functions
01-17-2017, 04:56 PM
#1
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CCU Removal - alternate controls/functions
I know that the CCU has been removed for racing. If done what systems did you have to rewire or add switches to have continued functionality. Has anyone removed the stock CCU once you have removed the AC system and developed an alternate blower control system for the heater and general outside air ducting.
My concern is what alternate system controls run through the CCU and once you take it out how do you control or insure that all alternate systems that pass through the CCU remain functional.
A good example of this is the oil cooler fan. The control of the oil cooler fan runs through the CCU, I have added an alternate switch to allow me to turn on the OC fan when I want. But if I remove the CCU itself will this remain a viable switch.
Has anyone done this and if so what did you do to insure no functions were lost.
I am just looking to simplify the blower/heater system since I have removed the AC system and don't need the complex cross control unit.
My concern is what alternate system controls run through the CCU and once you take it out how do you control or insure that all alternate systems that pass through the CCU remain functional.
A good example of this is the oil cooler fan. The control of the oil cooler fan runs through the CCU, I have added an alternate switch to allow me to turn on the OC fan when I want. But if I remove the CCU itself will this remain a viable switch.
Has anyone done this and if so what did you do to insure no functions were lost.
I am just looking to simplify the blower/heater system since I have removed the AC system and don't need the complex cross control unit.
01-17-2017, 05:15 PM
#2
Racer
Good question. I was thinking about this while driving around the other day.
The older cars and even air-cooled beetles had manual vent controls to allowed hot air into the cabin. My '67 beetle made great heat and didn't need an auxiliary fan to push air in. So it's do-able.
Not much more control needed than a way to open and close the flapper. You could fab up a solution to do the same by either making your own vent controls or finding a way to make the older controls work in our 964's.
Trust me, I'm very tempted to try it for the sole reason that the CCU doesn't do a great job of what it's supposed to do. I'm fine with manually controlling the air into the cabin. So then it's a matter of figuring out how to route the hot air to the windshield for defogging or to the dash vents for cabin heat. Then the last thing to figure out is how to route fresh air into the cabin manually (not by rolling down the windows or opening the sunroof! LOL)
I'm pretty close to trying this out. Just waiting for some free days to work on it in the garage.
The older cars and even air-cooled beetles had manual vent controls to allowed hot air into the cabin. My '67 beetle made great heat and didn't need an auxiliary fan to push air in. So it's do-able.
Not much more control needed than a way to open and close the flapper. You could fab up a solution to do the same by either making your own vent controls or finding a way to make the older controls work in our 964's.
Trust me, I'm very tempted to try it for the sole reason that the CCU doesn't do a great job of what it's supposed to do. I'm fine with manually controlling the air into the cabin. So then it's a matter of figuring out how to route the hot air to the windshield for defogging or to the dash vents for cabin heat. Then the last thing to figure out is how to route fresh air into the cabin manually (not by rolling down the windows or opening the sunroof! LOL)
I'm pretty close to trying this out. Just waiting for some free days to work on it in the garage.
01-18-2017, 02:44 AM
#3
Rennlist Member
Oil cooler fan: you'd have to go directly to the relay if you remove the ccu. Trip the relay, start the fan. You could also do the 911 style and just put a nason temp switch directly to the relay.
Defrost / vents: switch to the fans. Position flaps where you want them and lock into place with servos removed.
Heat... not sure on that one but a manual cable could be rigged up. Servo control maybe possible on or off with a switch but would need to be figured out.
That said based on the stock heat box I think you will lose some functions.
Defrost / vents: switch to the fans. Position flaps where you want them and lock into place with servos removed.
Heat... not sure on that one but a manual cable could be rigged up. Servo control maybe possible on or off with a switch but would need to be figured out.
That said based on the stock heat box I think you will lose some functions.
01-18-2017, 05:17 AM
#4
Rennlist Member
Should be no problem to delete the CCU if you manually take care of the main, oil cooler and rear fans and servos. However, this would require a fair amount of work. The main things would be the following:
Manual control of the two main blowers could be done with a switch. However, a PWM control circuit would maybe better, as you might need something lower than full fan speed.
If you have not deleted the rear fan, you should have a switch for this fan. It shall run when needing heated air to the cabin, as well as in cooling mode when you do not need heat.
You could wire up a switch-based control to manually maneuver the two mixer servos, (heated air) and fresh air inlet servo. A similar arrangement could be done for the defrost/foot well servos. You could also leave the servo flaps in fixed positions if this works for you. Mixer flaps must be fully closed in order for the rear fan to be able to dump the heated air running in cooling mode.
Manually operating all the above would not conform with my idea if simplifying things. Any weight difference between CCU and any switch/relay circuitry would be neglible. Personally, I would get rid of more by avoid delicious desserts.
Cheers,
Tore
Manual control of the two main blowers could be done with a switch. However, a PWM control circuit would maybe better, as you might need something lower than full fan speed.
If you have not deleted the rear fan, you should have a switch for this fan. It shall run when needing heated air to the cabin, as well as in cooling mode when you do not need heat.
You could wire up a switch-based control to manually maneuver the two mixer servos, (heated air) and fresh air inlet servo. A similar arrangement could be done for the defrost/foot well servos. You could also leave the servo flaps in fixed positions if this works for you. Mixer flaps must be fully closed in order for the rear fan to be able to dump the heated air running in cooling mode.
Manually operating all the above would not conform with my idea if simplifying things. Any weight difference between CCU and any switch/relay circuitry would be neglible. Personally, I would get rid of more by avoid delicious desserts.
Cheers,
Tore