You're right. That's my issue. I've a mind to disconnect the AUX fan relay for tomorrow and see what happens. If the motor nevers gets above 210 w/o the AUX fan running, I'll know the main fan is enough to cool the motor. (Really, I already think I know that.) If the condenser gets enough air w/o the AUX fan running, that may solve my issue.

The AUX fan is awfully small in comparison to the size of the condensor. So, I'm wondering if it hurts my setup vs helping it. With the MAM AUX sensor, my AUX fan turns on below 200-deg. Because I'm not controlling temps -- to keep them in the 180-190 range, the AUX fan always runs. So, anytime I switch the A/C on, it's blowing a furnace into the radiator.

If I get better results by unplugging the AUX fan relay, I might be better off going back to the stock fan switch. That way it would never come on unless it got really hot. I could wire it so a trigger of the AUX fan turned off the A/C. Maybe hook into the high pressure switch or something.

Whaddya think?

 

I took the aux fan out because it seemed to be an obstruction when it was not running...and when it did run, it was already way hot and too late. At the time I did not understand (or have the a/c retrofit) that all it needed to do was pull a small amount of air in the nose for the condensor to share with the radiator..

end result, my temps under certain conditions seemed a hair better. BUT, right now I need to keep that damn condensor cooled equal to 20 mph driving...thats about what it takes to get the a/c to cool again.

I have been toying with the idea of going back to r-12 these last 3 months in this hellish summer we've had. But yesterday I had a 95* ambient and was doing some city driving and my a/c cooled just fine. its at the extremes where it overheats and then screws my eng temps as well.

I spoke to my brother (a/c tech) and he says the condensor needs fresh air across the whole thing. Thats not possible as far as I can see, so I'll see what 2 or 3 small fans will do when placed right, even use smaller fans if thats what it takes to get air blowing thru most of the condensor coils.
I'll keep you posted on that experiment! Since the 100s are pretty much over...I might be motivated to actually do some car work again. I was on strike until the weather got civilized again.

Bottom line,,IMO the aux fan blocks air and can cause a flow problem when its not running, Thats why I want something running with dedicated airflow on the condensor.

I do know that aux fan was an after thought at the factory so its not a truely GM blessed & engineered part of the whole system.
Its kinda just there,

No worries....we;ll finger it out one season or another...

 

I'm still running R-12. Never added any freon in 22 years (knock on wood). If I understand you correctly, everything might work fine and dandy if I unplug the aux fan and let the OEM R-12 setup do its job?

If the R12 "system" gets too hot, it sounds like the high pressure switch will take car of any overheating issues. And, the A/C would return to operation when the car was moving fast enough to cool the condensor.

I'm guessing this issue is why an earlier poster said an ewp kept his A/C super cold. Maybe he could run his AUX fan constantly...which would keep the condensor cool...and allow the radiator to manage the extra heat load?

 

Nice find & great info Greg, sure beats these $500-$600 rads.

This winter, I'll still upgrade my stock main fan to the Dewitt's fan this winter

 

i'm keeping an eye on that DeWitts fan too , not meant to hijack the thread but is the aux fan the one in front
of the radiator ???? i've never ever seen that one spinning, i was thinking on getting rid of it, i don't have
cooling issues at all and i might need the extra room for the giant transmission cooler i will be installing soon.

 

Thats basically what I did....Laid C-channel in the lower shroud and mounted the cooler in the channel with clamps around the end tubing to hold it down. Solid as a rock. Mine takes about 2/3 of the left/right open space so I moved it to one side to keep the hoses from having to make a radical bend.

So far I cannot see that it has caused anymore heat than was already up there but it must be cooling the fluid more since it is the first thing to get fresh air.

problem is, that now I need the aux fan back and theres no room....so the little fans that stick to the condensor might have to do the job..several of them.

* weather lady is giggling over the regions 1st cool front this monday.....
sure as hell this will be the start of the next ice age if I engineer these fans and find a way to mount them !

Got to admit, I;m kinda goofy over the thought of being able to walk outside without being soaked in sweat....damn a/c has'nt shut off since June...The lite bill comes in a box......yeah, It's been brutal. This is my official promise NOT to whine when its 20* and wet this winter..!

 

Exactly.

When the a/c gets too hot in the system, the pressure goes up and the hi press switch cuts out so it don;t explode. As soon as the pressure drops (cools) it lets the compressor run again. The way the air box is designed the condensor gets air first when moving and little air when the fan is doing all the work. There are ducts on the side of the condensor that allow the trash to get inbetween, that also allow the fan to pull air around the condensor to cool the radiator. So when you're sitting still, the fans pulling air in but its easier for the air to go around the condensor to get to the radiator. The other side of the coin is that when fresh air moves thru the condensor that heat it removes goes straight to the radiator where it makes the temp differential smaller so there is less cooling of the engine. It sends hot air to cool a hot radiator, so the amount of cooling is reduced and the eng temps show this by slowly going up.

All it takes is a very little air on the condensor because its so big, but in the extremes that little bit of air is hard to come by until the car is moving again.

I think the r-12 systems generate less heat for exchange as they are more efficient than 134a. If you have r-12 and it still works....leave it. Heck, the street price for r12 has dropped to $35 to $50...down from $75/lb when I converted. You can still buy 30 lb cyl for around $1000....or you can try to smuggle in some 1 lb cans from Mexico....(big trouble if caught)

 

Id think lowering the idle will also lower coolant flow keeping it in the hot block longer. Try the upgraded fan. 500+cfm should make a difference, 1000 should be night and day

 

I don't understand why you think the block is cooler than the radiator/condenser -- as a heat source. As such, slowing the coolant doesn't sound like a great plan. Also, lower the idle temp with a performance cam can end up with a more pronounced Lumpity-Lump.

(I don't know if your comment is directed at me or Leesvet, or both.)

If I went to a 2500cfm main fan, would that be any different than the stock fan plus auxilary? Do you think it will really pull more around the condenser vs through it?

Do fans combine in cooling? Can the aux fan impede cooling for an increase 2500cfm fan -- if left in operation?

Maybe an EWP is the best way?

 

I'm hoping that fans on both sides working in tandom will help. I know that it don;t take all that much air to keep the condensor happy and reasonably cool. The question is, while doing that, we know that hot air is going to the radiator, so more fresh air there is now a must. Fresh air thats not been heated by the a/c system...

Looks like the emergency is over for the next 8 months...the curse has been broken and for now at least, temps have gone down to the tolerable levels...

This research and experimenting will continue and likely be a great winter project.

I don;t think the system is capable of doing what we need (a/c and idle in extremes for long periods) without making air move from both sides. Its just a matter of heat exchange...we know that the condensor contributes to engine temps, so we are forced to address both issues at the same time in order to solve one.....

 

It's been awhile from my last posting about my 3 core Champion radiator.

Just to get thing up to speed I have a 383 with 10.7 to 1 compression that ran on the warm side with the OEM radiator after installng the 3 core the temp did drop but still seemed kinda warm other told me they was more to it why I was running warm.

I took the Vett for a drive down to LA in rush hour traffic it ran ok water temps 215 oil temp 240 it was 100 Degrees that day, On the way home still in stop and go traffic water 230 oil 245, climbing the long up hill grade up HWY 14 temp climb FAST water temps 240 oil temp 270 thats at 70 MPH not good.

After the up hills the oil and water temps started to drop to normal but it took a whle getting there.

After getting home I started to do more looking what I found the fan relay plug was loose some times the fan woud work other times not I think as I hit bumbs in the road it would make the fan turn it self off and on.

I had a up grade fan relay sitting In my tool box so I installed it.

I also installed a 8 row oil cooler.

9.7 Qts of new oil and filter.

We took for a good drive today water temp 235 in the city in traffic oil temp 220, Up on the HWY 210 oil temp 224 I can live with this.

But when I save some more extra cash up I going to get a 2500 CFM radtator aftermarket fan that should keep the temps where I like them to be in traffic.

Up on the freeway at 70 MPH the water temp stayed low due to the air flow oil temps stayed great in the city with of the 70 MPH air run thought it the temps would start to climb it took a while for the temps to start dropping this comming off at hwy speeds in to stop light to stop light traffic.

Just driving around town at normal speeds the temps will stay 190 to 210 for water oil 200 this with out doing and hwy speeds runs.

 

Just thinking back to my last project. It was suggested to me not to go 3 or 4 core due to reduced air flow thru the fins, and that a 2 core would do the job. I'm thinking an air/oil cooler and trans cooler will do well with a 2 core. I'm just getting ready to do the whole shabang in about a week. Hoses, belt, pump, therm, switch kit, and rad. And a place to get great oil coolers like the 5" Earls type is the junk yard. Years ago I had a Volvo 240 turbo. Well the yards are full of them and they use that very cooler. I think there around 20 bucks or less.

 

Greg,

How is the budget radiator holding up? I am thinking about using the Champion in my race car and wanted some more feedback since you have driving it for a while now. Build quality looks pretty good. No leaks or bad welds?

 

I installed mine about 1.5 to 2 yrs ago and it is still the exact same radiator that I took out of the box. The welds were identicle to the "name brand"...looking at them both side by side. No difference. My 'budget' radiator was just slightly fatter at the tanks...where the 1/8" of rubber on the block has to be trimmed away. To some folks thats a big F'n deal. To me it was a 3-$400 savings...

The radiator has no issues and actually NO bent fins or outside damage at all after nearly 2 yrs of service.
Without seeing or asking I am positive that Gregs is doing just as well.

My ONLY regret is that I did not polish the damn thing before installing...in too much of a hurry..

 

This is good to know. I will be leaning mine forward and making my own mounts anyway so the issues of fitting in the stock shroud are of zero importance. Also, it is going in a race car so polishing is not a requirement. Both very small concerns that wont stop me from buying one. They are on sale for $150 right now so I think I will pick one up.

 

If I could afford the Dewitts I would buy from him, its an excellent product and he's done quite a lot of research. Tom Dewitts has posted some excellent tech. (that I'm very grateful for) info on making sure your fan switch/s and t-stat temp spreads are adequate, among quite a few other tips. All of them have worked for me, he should write a book.

 

If I had more of the stock system in I would agree with you. My system is kind of special now and the fan will only be running when stopped in the pits and off while on track. For street driving where the temps change more frequently the spreads between the switch and t stat are more important.

 

Very happy with my Champion radiator (and you can probably tell I'm a stickler for the details). I don't consider it cheap either. The construction is solid, the welds look great, and it cools WAY better than the OEM units.

For anyone doubting the viability, maybe a poll should be in order -- to see if any have failed? Or, consider a search for "Champion radiator". You'll see the growing number of owners who've installed them.

Mine has performed superbly but any radiator can have a bad apple. I remember seeing this thread when I was researching all-alum models. Two or three strong reviews (before I even bought mine) sold me on my Champion purchase (and the need for a solution in this price range). Leesvet was one of them. Thanks!

If they keep this thread open (like I think they should), I'll report back each year to let you know how it's doing. Other Champion owners should do the same.




(BTW...This thread was good in a second way...it brought my attention to Alaskaman's solutions to upgraded cooling fans. I'll be following in his footsteps for an upgraded main cooling fan. Thanks OAM!)

 

anytime greg, anytime.

 

Thanks guys! I ordered one this morning. I will be sure to post back about how it holds up on track.