I don't understand, isn't a Hypertech a chip? Maybe I'll give that a try, what else does that chip do, will the car need a re-tune? It's my understanding that my 88 is not reprogramable, it's chip or no chip. So, did you change the chip or not? When I'm moving at highway speed I'm at 175/183, when I'm in terrible stop & go traffic I'll go up to 214/17, I don't like that. I understand that the car is designed to run hot, but thats for emmissions reasons only, it has nothing to do with "closed loop" status for the ECM, heat like this will kill any drive-train and it's unnessesary.

 

You cant use "that chip" he has OBDII He used a hypertech reprogrammer.
His PCM has been reprogrammed. This is what you were instructed to do in the first place but opted out of .. remember?

If I were you I would listen to the knowledgeable member's here. On the other hand it looks like you are convinced you idea will work and its reversible right? So try it and let us know how it goes.

 

What I really think I need to know is this; Is running in traffic at around 190 or lower gonna send bad information to the ECM? I understand that the car needs to run certain temps to achieve "closed loop" status, I'm just curious about wether or not running too cool is a bad thing? I realize that hooking up the larger fan to run as the secondary is going to keep the car running within the perameters of the stat/fan-switch in traffic, but is that gonna be a bad thing? I'm very open minded and listening to everything everyone here has been nice enough to say,so if the car running too cool under these conditions is a bad thing I'll be more then happy to redirect my energy to something else, I'm not looking to damage my car.

 

This is what I need to know: What is the lowest temp my car can run at under all conditions that is functional for this machine to operate properly? That temp will then be my goal. Do the temp's and the RPM's work in concert in sending signals to the ECM? In other words, does the car know it's at idle and then requires a higher temp and likewise with lower temps at highway speed?

 

I'm not sure what the "Optimum" would be but considering the stock t stats IIRC are 195 I would assume above 195.

 

I tend to agree with you on that, based on everything I know and have read in everyone's input, it seems that anything above 200 is absurd. The idea of keeping the temps just under 200 all the time might be tricky with an automatic fan configuration, but too low don't seen to be counterproductive either. Someone here suggested a manual under dash switch but I don't like the idea of such a crucial function relying on my memory I have had switches on past high H/P cars and have forgotten to put them on untill the gauge was in the red. For this very reason I have removed all manual/power radio antennas from cars I've owned and thats only an antenna. I hate when they break off in the car wash because I'm a idiot that forgot to lower it, I'm also notorious for leaving my lights on..........I think you get the picture

 

I am sorry but what are you talking about here??? Most of what you posted above is either "alarmist/proffet of doom", or just completely dead, wrong. Where did you come up with your "facts"??

WTF??? Maybe this needs to be re-written in English, but: "Higher loads on the ECM?? That is the whole POINT of the relay! To separate the electrical load in the circuit, from the "driver" of the circuit! The ECM has no "clue" how much load is on the secondary side of the circuit! How could it?? The Relay isolates it.



None of that really makes any sense.
1. you don't need or use shrouding on a pusher fan.
2. Ya say that it doesn't push air against the radiator (but it does), then you go on to say that it's there to provide "some fresh air to be sucked...by the sucker fan". -Which of course draws ALL of it's air across what? The radiator. So which is it. In reality, the pusher fan is there to provide air for the condenser when the A/C is running, car not moving or moving slowly, and it also does move some air across a smallish area of the radiator.



Doing wiring modifications on the secondary side of any relay -ECM would never "know" about it.



Seriously, dude? Really?
1. "Millions"?? I don't think so. I really don't think "millions" were invested in the design of the electrical circuit for the cooling fans. If that is actually true, please cite the source for that data, because I'm going to co ahead and call that a bogus exaggeration.
2. Using your logic above (with actual, real dollar amounts), by our reasoning, no one should ever mod their car period, right? B/c Millions WERE invested in the C4 platform as a whole...so surely there is no possible way to improve on it right? I mean, it's PERFECT as it sits! Millions! Can't improve upon that! In fact, there are 1000's of way's to improve all areas of C4's and many ways ARE cheap because yes, hard as it may be to believe GM did leave a lot of low hanging fruit.



?? To say that you can't get an ECM controlled car to "live" and "run right under 200*"...that is just completely wrong and not true. There are tons of people here with cars running below 200....and somehow...they do! In fact, my box-stock '92 never runs ABOVE 190, unless I sit still with it running. How can that be? B/c they are also "designed" to run under 200, too.

 

Its a range...not an exact temp that the stock tune will tolerate and allow good performance, no excess emissions and everything works well.

185 to 200.

The ECM does not even switch to closed loop and go to full run function until 158+-(5)...
Running without a t-stat and mild ambient temps it tries to run at 168-9. Thats the absolute minimum. Any lower on the stock prom/tune and you get fouling and comtaminated oil

Keep in mind there are several reasons that the car NEEDS to run hot.
IT MUST reach temps hot enough to boil out ANY and ALL moisture in the crankcase otherwise a chemical process starts that corrodes the fragile aluminum engine parts...(heads, intake etc) Been there done that..cost way too much to do again.
For longivity the engine needs to be hot enough and lean enough so the lubrication oil does not get washed off the cylinder walls each stoke and end up like a POS carb that only has a 100K life expectancy on the motor. Excess fuel is why carbed motors wear 3 times faster than EFI motors.
Too cool and the plugs foul, carbon builds up inside the engine. More issues later with ping and sludge formation.

So, get it past 158 and get it stable between 185 to 200(even 210) and it'll be happy and you'll be more comfortable.
Keep in mind these were designed to run hot so there is nothing to fear about idling at a stop lite at 235 degrees. Thats what it was designed to do. Harms nothing. The ONLY problem there is a lack of time to react to an emergency...like a blown hose. 235 turns into 265 in about 5 seconds and THAT is the only good reason to lower the normal operating temp...to get a little more cushion to CYA on the road.

I got my motor stable at the above temps under most conditions, by adding a big double row all aluminum radiator, hi-vol water pump, 185 stat, (160 is pointless) and the tune. My motor is enhanced and generates enough heat to get AL Gore to come out of hiding... but I keep it under control with the listed upgrades. Messing with fans alone is not enough. My fans are managed by the PROM where they are set to come on just before the stat opens. Thats why a 160 is useless...if the stat is open and water is circulating...what good is that if the fans are not cooling the water? 160 is too low for fan and stat opening...so a stable 185 (cruising) is still cool by todays standards and easily achievable. I also upgraded the air dam (big mouth) for maximum fresh air while moving. I wouldn't even need a fan if it were not for stop lite traffic and long delays sitting still.

Good luck

Jesus Christ.....praying of course the Almighty voice of whatever...approves of someone elses opinion...
are other opinions permitted here? Guess not if they disagree with uncle tom.

 

Thank you "Almighty Voice of Reason" for backing me up on this. Some of these responses were beginning to make me doubt what I knew to be true.

 

OK.
If you say so.

Seeing that you want to take the narrow minded view and not see ANY of those statements as being factual even in the figurative sense...
I'll try to clarify in 30 words or less.

You doubt that GM spend more than $50 in the many yrs of C4 developement on that system? The electrical system wasn't developed in a weekend sitting in the garage with a beer...unlike most bubba projects.
ok.

The ECM is not directly in control of fan activation but it is involved in temp mngt which leads to engine mngt, thru many sensors, and other real time data input.
Try on Circuit 935 (the coolant fan control circuit...duh), 992, and 450. (one of which is one of those "mystery" grounds that you do not seem to understand. if you can read the schematic..you'll see them clearly. They ALL go thru the ECM...so the ECM DOES play a roll in the cooling fans. Dude......
BTW..
keeping up with technology will go a long way. 200 degrees is a comfortable number...for YOUR peace of mind. For a contemporary ECM engine..its stone cold. NAME ONE (1) 2013 yr model car that you can find made here that has a normal operating temp of under 200, AND has a warranty of ANY kind...
EFI is why engines now are able to run well past 250,000 miles with even bubba shade tree maint. They are designed to run hot to help maintain that level of performance. Its old school paranoia that keeps people from comprehending the science of todays high-tech control systems. Dude...

I admit that I try to run mine at or just under 200....for MY COMFORT. That is NOT ideal for the engine.
Dude....

 

I do. :Thumbs:
Varies, depending on car and year.


Nah, that's not true either. Are you asserting that NO evaporation of fuel or water occurs below 169*F??


You're going to have to cite your data source again here. I had a carb'ed car that I sold at 200k still running perfect. The buyer sold it at 230k. Going by your statement of "fact", EFI motors last 750k?


sludge and carbon build up are actually cause by EXCESSIVE heat in the oil, or poor oil's inability to deal with heat. Plugs won't foul directly b/c of coolant temp. That is not true.



Nope. That is not the only reason. There are other reasons why someone would choose to have their car operate at lower temperatures.


So youre fans are running virtually all the time?


None if the car is stopped/stationary, but if it's moving down the road, obviously there is a 20* difference. For starters.


Didn't you say you reprogrammed your fans?? So....


The bottom line is that "proper coolant temp" is a personal choice based on criteria, the particular engine combo, and goals. There isn't one number (or even range) that works for everyone.

 

Dude, I was saying the whole time that the ECM has nothing to do with switching the fan designations and there would be no difference in the signals sent. To think that wouldn't make sense, doing anything before the relay would be a different story. I think too many people need to be spoon-fed information instead of using common sense and my common sense told me that there shouldnt've been any problem with rewirering those fans. I was just a little in the dark about wether or not lower temps were good or bad but you just gave me the answer I've been waiting for. Anything above 160 or so is fine, Thank you. I realize that temps around 200 or so burn off impurities in the oil and plan on running no higher that that at idle, in traffic.

 

I am norrow minded?? You're the one stating opinions as "fact" i.e. "only one right way". I am saying proper op temp is a personal choice based on factors/goals/criteria...you're saying "this is it -anything else is wrong". *I* am closed minded??

Right. "Factual...in a figurative sense". What ever THAT means. Sorry I "missed" that you were being figurative, with your "facts". People come here looking for good advice. Facts, where possible. Just state your opinions as opinions, and facts (that you can back up) as facts.


I'm sorry...where did I say they spent $50 or less on the electrical system? You'll have to quote where I said that please. But let's be honest shall we? The FAN CIRCUITS are not rocket science folks. Didn't take "millions" to develop that is for sure, and yes, "bubba" systems work just as well. How do I know? I've built several that worked perfectly. Couple relays, couple coolant switches, some wire, weather pack connectors, loom...NOT rocket science.


OF course it does, in stock form. However, there are many way's to manipulate control of the fans w/o affecting the ECM in ANY NEGATIVE WAY. You make it seem like that is not the case and that is misleading and untrue.


Really? Our '05 Caddy runs at 190. Bone, box stock. How contemporary are we talknig here, b/c the OP's car is an '88. My '06 C6 ran at 186. Maybe cars in 2012/13 run hotter (no, they don't).


Again....wrong. Today's OEM set temps are there for emissions and fuel economy criteria that the OEM's have to meet...that WE DON'T. Our criteria is often different than the OE's.


But it's ideal for you and your engine. Right? Personal choice based on criteria, goals, etc. Just as I stated above.

BTW, My CARB'ed boat runs at 150*F. 160 when it gets "hot". Thing is 20 years old this year. According to you, it's got TWO major strikes against it; cool operating temps and a "POS Carb". Yet it still runs absolutely perfect. What engine life am I "missing out on" here?? Lol. 20 years, and still perfect. How long should an engine last?

 

Well, aside from all the "bickering", I was able to filter-out the useless information and get the answers I needed, so my conclusion is; I'm gonna give my fan idea a go and see what happens. I'll be back with my results, I'm just waiting for my tranny cooler to come. Believe it or not, I can't even find a place to get a tranny cooler local, WHAT THE HELL HAPPENED HERE!!! I went to an AutoZone and they didn't even know what the hell I was talking about. Thank God for E-Bay, and screw everybody who has some kind of dislike for it, if it weren't for E-Bay many of my projects would still be sitting.

 

Did you have the Radiator boiled out yet?

 

No, I'm gonna get that done the day I rip everything apart. It looks pretty clean and new, it's also flowing pretty good too. I'll have it done anyway, makes no sense having it out and not doing that. I bought a large tranny cooler and I'm gonna run it alone, I've never seen the point in running it through the radiator as well, seems to defeat the purpose if you ask me.