marc_w

I got a weird one:

I've got the DCC unit running my fans in my truck. At what temp should I set the unit to turn the fans on?

It sounds simple enough but...


- The Flex-a-lite temp probe goes near the radiators inlet/hot radiator hose. This is very similar to the engine coolant temp (ECT) that the computer sees.

- The DCC probe goes anywhere against the outlet/cooler hoses side of the radiator. It turns on when the coolant (which supposedly has already been cooled) is ready to go back INTO the motor through the thermostat.

- The stock thermostat starts to open at 195*F.

- The stock ls1 cars turn on the fans at 220*F ECT.

I don't know the optimium temp the engine would like to see incoming coolant at. The thermostat temp of 195? I've got the following temps to choose from: 148 158, 166, 173, 180, 187, 194, 202, 212 *F.

I've currently been switching between 187 and 194*F. Since installing the fans, my tranny temp has not gone below about the 180-ish(?) mark. (a little over the first tick above 150) That's *VERY* unusual for me and I'm honestly a little uneasy about that. (a larger tranny cooler will be comng, and I'm considering one of the e-fan models from B&M)

There is a slight increase of idle/stationary engine temp from 197-199 to 199-201 as shown via HPTuners.

I'm considering moving the temp probe to the inlet radiator hose, and setting the temp to turn on at 202 or 212.

Thanks.............

one03sierra

iTrader: (1)

the temp probe for the vsc needs to go near the inlet side to catch the signal when the hotter coolant comes in the radiator.it is then adjusted accordingly.

the computer on the f bods gets its reading from a sender in the head--coolant temp sensor. it turns on around 195 or near.

on the dc controller they want it to go to the outlet side since the temps are more stable there. i would set it at 187 and leave it for a while. if you have a stock thermostat it is suppose to run it around 195 to 210. if it is running at 199 to 201 then it is working. i have a built tranny and if it is running a tick above 150 then it is doing great.if you are wanting to run it cooler you will need to get a cooler therm. your engine with a 195 thermostat will run from 195 to 210. that is the correct temp.

160 therm will run at 180ish

180 therm will run 192 to 195ish.

195 will run 197 to 210ish.

the fans will not come on more than about 40% to keep the engine cool. if you are keeping the engine at 199 to 201 then it is workinhg great. if you are wanting to keep it at 195 exactly then they will be running hard all the time.

HAZE

yeah, what he said. i have the vsc, i'm sure the difference has been expained but i was'nt paying attention. i have a 16o t-stat and the vsc turned all the way down, runs consistnat 180's. seems to me the controller should be set 10 -20 degrees above t-stat temp to reduce "competition" between them and reduce wear and tear on the componants. i'm sure denali just said that but i'd have to read it a few more times to be sure.

marc_w

Thanks guys.

Yeah, that makes sense... I trying to hash this out all day long and pretty much came to the conclusion anything under the t-stat temp is not necessary.

I've got the fans turning on at 187 now to try to help with the tranny cooling. Surprisingly, even at idle they don't run constantly. They run at quite a low speed, for 10-15, maybe 20 seconds at a time... in 30-60 second intervals.

The hotter tranny temps must be from the lack of cool air CONSTANTLY being pulled in the front of the truck (and through the factory tranny cooler), by the stock fan.

MacADaYear

DAMN! Oh well.... that was the reason I would have switched to the DC control from the VSC to stop that from happening but I guess it happens to us all. There was an interesting thread I read from another board where the theory is that the actual temp probe piece is being cooled from the air of the fans moving aound it, thus cooling the temp probe and giving a false reading and causing the the fans to cycle on and off like that. The fix they used a was piece of foam over the part of the temp prob pertruding tword the engine.

Have you guys found any beneifts of the DCC over the VSC so far?

one03sierra

iTrader: (1)

i think the dcc is better since it doesnt have to turn the fans up all the way to keep the engine cool. thus less amp draw. but if you do want it to run it cooler then just go to the next temp down and it will turn them up a notch.there is a jumper for ud pullies that will turn them constant at 10% as long as the truck is on and then it will turn them up 100% for the a/c.

MacADaYear

Well the VSC has 60% on speed so I think its ok. The DCC might be a little bit smoother but I dont see that it would make a big difference.

Why would you need the fans running if you get a UP pully kit? I just never heard of that

one03sierra

iTrader: (1)

its just an option.the vsc turns them on at 60% or 100% and that is it. the dcc turns them on from 10% to 100%--which they hardley ever reach and then 50% for the a/c. less amps all the way around.especially since they usually only come on at 40% to keep it all cool.

HAZE

ok, what's a dcc ? i thought i had a vsc, at least that's what flexalite called it. mine has low and high speed hence the term variable speed control. so what's the acronym dcc ? i have mine set so i can turn it on with a switch if for some reason the thermo does'nt work. i also hav'nt had any problems with my trans staying cool even when towing. my instructions say the starting point is 60% at your set point then if it does'nt reduce the temp it will rise until 100% supposed to hit full before 10 degrees above set point.

HAZE

you posted that right while i was asking the question. so how much is the dcc, and why did'nt the bastards give me one.