I'm make more headway on my wiring diagram for my standalone engine computer and have come across an issue. I have ran out of analog temperature inputs but I'd like my engine computer to control a trans cooler pump. I have plenty of additional lowside switching outputs to control a relay to turn a trans cooler pump on and off, but I need an input parameter to go by.
Oddly enough the AEM Tech I'm working with recommended maybe using the coolant temp as my parameter for setting up a 2 dimensional table to control the trans cooler pump.
With that said, is there any type of direct correlation you guys have seen between engine coolant temp versus trans fluid temp?
The only real issue you may have is that the trans pump may find it hard to pump the fluid when it is cold. For this reason I would pick something like 200 degrees engine temp to turn on the trans pump. Even if you don't move the car, hopefully at that engine temp point some temp will find its way into the trans. We have the trans pump manually switched on the race car and turn it on after one warm up lap. The other thing to do would be to have the computer turn the pump circuit on at, say, 150 degrees engine temp, and then put a temp switch in line with the pump so the pump doesn't actually come on until the trans is warmed up. Or just turn on the pump circuit with ignition and let the trans temp switch do the rest?
The only real issue you may have is that the trans pump may find it hard to pump the fluid when it is cold. For this reason I would pick something like 200 degrees engine temp to turn on the trans pump. Even if you don't move the car, hopefully at that engine temp point some temp will find its way into the trans. We have the trans pump manually switched on the race car and turn it on after one warm up lap. The other thing to do would be to have the computer turn the pump circuit on at, say, 150 degrees engine temp, and then put a temp switch in line with the pump so the pump doesn't actually come on until the trans is warmed up. Or just turn on the pump circuit with ignition and let the trans temp switch do the rest?
Hey crash,
That sound like viable option. I can have the computer feed 12V power to relay pin 86 on the coolant pump relay with ignition on or a set engine temp and then install an inline temp thermostat and connect one side of the thermostat to pin 85 on the relay and the other side to ground. I have found several in line fan thermostats that I think would work perfectly. It will turn the circuit on at 180 deg and then turn it off at 165 degrees. See below link.
Do you think this would work and the next question is what would be ideal trans temps for a Mendeola Stage 2? I'd hate to set this up if these temps don't keep me in the ideal operating conditions.
What you want to do is a simple temp controlled switch. There's no need to have it controlled by the ECU. Just use a temp switch like you would for the cooling fan.
I think Bob's got it right. A temp sensor in the trans and/or diff would be the best way to control fluid pump(s).
What does engine temp have to do with diff or trans temp? Simple answer is "nothing". Unless they share a cooling system, unlikely, keep them independent.
Consider running in traffic, hot engine coolant, moderate oil temp and cold trans & diff, you wouldn't want to cool gears. When running on a track coolant is usually good and oil is hot, at least in my experience. I've never checked diff & trans temps but will in the new build and will add coolers and pumps as necessary.
Thanks for the feedback guys. Between what the Mendy guys posted and the additional feedback I think I have all I need to address this now.
I'm guessing the XRP Sump Scavenger Filter will go between the outlet of the trans and the Oberg Filter to catch any large debris first?
With this temps sensor plugged into a port of the transaxle, I can still add an inline temp probe so I can display on my dash the pre-cooler temps. I can also add a post-cooler sensor and connect it directly to my AEM CD-7 dash. Maybe overkill, but I can then keep an eye on pre and post cooler temps for the trans.
Thanks for the feedback guys. Between what the Mendy guys posted and the additional feedback I think I have all I need to address this now.
I'm guessing the XRP Sump Scavenger Filter will go between the outlet of the trans and the Oberg Filter to catch any large debris first? Correct
With this temps sensor plugged into a port of the transaxle, I can still add an inline temp probe so I can display on my dash the pre-cooler temps. I can also add a post-cooler sensor and connect it directly to my AEM CD-7 dash. Maybe overkill, but I can then keep an eye on pre and post cooler temps for the trans.
The pump setup I posted was just an idea.
Build accordingly to your desire.
The SDR5 does come with a 1/8 pipe port for a temp sensor.
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Originally Posted by crash
