For those who may have heat issues in traffic I might have found a solution. After much thought and finally coming up with a game plan, I installed a 12" pusher fan at the front of the condenser to help bring in more air while at idle in standing traffic.

What I found is that with the pusher fan on my temp would not rise above 200*. This was at engine idle with both primary and secondary fans activated. Temp remained constant for a duration of 10mins. When I turned the auxiliary fan off the temp then crept up towards 210* and climbing. Slowly.... I do have a 4 core aluminum radiator, 165* therm and ECM controlled fan activation at 205*.

I know not everyone has problems with this but still have a creep in temp while in city traffic. This so far has seemed to solve my issue and may for others.

I am piggy back off of the fans ground signal from the ECM to activate the pusher fan when the secondary fan kicks in. This is done through an additional relay. This is so I do not have to hook up a additional toggle switch.

I have also added side curtains and lip to help draw more air in at low speed. 12" Fan is the largest you can fit. Two 12" Fans side by side will fit if desired.


This seems to help as I noticed a quicker cool down and lower temp when driving.

 

Is that just a strip of alum you used too reinforce your air dam?

 

Yes, I got the idea from Tommy Morrison's 24hr 175mph run. I lowered my 90 and cut down the spoiler.

1/8" x 1/2" aluminum strip from Lowes.

 

How thick?

edit: Must have miss the numbers in above post.

 

I ran my prior '88 at 165 deg F with fan on at that temp; it might creap up into 170s on a hot day in traffic.

 

Very cool. I just bought a B4P pusher fan on ebay for my '84 that was used on the early Z51 cars. I bought the mounting kit from Mid-America and also a Hayden cooling fan temp switch with relay on ebay. I'll be installing it soon.

 

Hi
It may seem a silly question but have you made sure the gap between the a/c condenser and radiator is clean?
We C4 drivers should be getting reduced registration renewals with the road cleaning service all C4's do, any leaves, twigs,birds roadkill etc all gets stuck there. You can fit screens to keep this area clean, i have slid a screen past the air filter and between the frame fully down to the air dam. See image below, and see link to another item on ebay.

http://www.ebay.com.au/itm/360251155...84.m1438.l2649

http://www.ebay.com.au/itm/84-91-COR...item439d49a472

 

I found this mesh on ebay that I plan on using $17, with free shipping.

http://www.ebay.com/itm/161291276210...84.m1423.l2661

 

Thing for some members to remember is that this "pusher fan" can cause as much trouble as it can solve....IF the a/c is being used.

Because....
the a/c condenser can get very hot. That hot air has no place to go but TO the radiator. So....add hot air to hot air, what do ya get?

over heated radiators.

The BIG benefit to a pusher fan for most street cars is a/c cooling. It WILL simulate 35mph driving to take away condenser heat. BUT, the flow MUST be sufficient to feed fresh air thru the radiators SIDE ducts (look at your rad & condenser from above)so the radiator can get some ambient air for its cooling, otherwise it gets the heated air off the condenser and THAT causes over heating.

As mentioned, that "gap" where road kill lives is critical. That MUST be clean or it blocks all the flow to the radiator... Annual shroud removal to collect paper bags, Styrofoam cups, BAGS of leaves and a few feathers....is highly recommended.

 

I've had the debate (above) about A/C condenser versus ambient air. IIRC, the A/C air isn't the big problem you'd think. Basically, it's still "colder" air than the radiator. Anything colder will drop/cool temps in the radiator (though I'd have to concede a broader temperature difference should cool "faster"). The question is whether the radiator has time to drop temps to thermostat temp.

Put another way, air flows much harder/faster through your condenser at speed (like 45mph and higher). So, if pushing a LOT of air through condenser was bad, it would REALLY overheat on the highway.

I did a search one time and found proximity of the condenser to the radiator should be considered. Even then, you only had to space them something like 1/4" or greater.

It's unclear to me if this option would outperform a higher cfm puller fan. Or dual puller fans in a shroud -- as used on LT1 cars.

 

Yessir....// BUT,
a fact is still a fact even when in dispute...

The reason that I say what I say is because of this fact:

cruising without a/c in 90* ambient temps my engine will sit in rush hr traffic and idle all day at 190-200. Drop to <190 if I get to move a few blocks at 30+mph for a few minutes.

SAME EXACT conditions WITH a/c running.....add 20 to 25 * to ALL THE ABOVE !

idle suddenly becomes 225 or more....cruise temps stabilize at 200-210 at best, and will NOT drop down until hiway speeds have been reached and maintained for a few minutes, THEN it will get under 190 again with a/c.

A/C adds heat to the engine cooling issues. Simple as that. NOT in every circumstance, BUT, in hot to severe climates, the a/c is the culprit behind over-heating. Now, I can't wait for someone that's living in San Diego to chime in and argue that it does not....it probably DOES NOT....in THIER environment. But in the extreme humidity and high ambient temps of the gulf coast....you betcha it DOES.
I see this every day. When I've had all the stress I can take
(about 235*)while stuck in traffic...I simply turn OFF the a/c and watch the temps slowly fall...
My cars temps with all the enhanced cooling 'stuff' works GREAT on the hottest days of the year. Until, I use the a/c. Then it struggles and its proven that AIR-FLOW is the solution, BUT its hiway speed type of airflow...much more than a pusher fan can deliver to maintain control.
the pusher CAN be helpful, unless its "feeding" excessive condenser heat TO the radiator... AGAIN, that is totally dependent on the environment, the situation and the car. Heat + heat = HOT. The only way to negate that is thru increased heat exchange, which amounts to lots of air flowing thru the system.

Sure, the condenser IS definitely "cooler" (relative term) than a hot radiator, BUT when the differential is reduced, the exchange is as well.
Ex: only 20 degree cooler air available to cool the engine off? its gonna take awhile ! poor temp differential.

Got some air that's 100 degrees cooler? takes only seconds to carry away excess heat. A HIGHER/GREATER differential.

Look at it this way....

You can have a heat exchanger that's the size of a barn with a 5 mph breeze and get wonderful cooling effects.

OR

you can have a heat exchanger the size of a C4 radiator/condenser combo and you will NOT get an equivalent exchange UNLESS you INCREASE the flow....from 5 mph to 55. Then it becomes equal to the larger exchanger.

its ALL about heat exchange and adding, or removing heat. Condenser adds....sort of. Its not exactly ADDING heat, BUT its slowing the heat exchange because of the **** poor differential. That's harder to comprehend so its just easier to say it adds heat. Same end result...

Speed ( thru increased air flow) takes it away. I've always had the 'hots' (bad pun) for a super sucker fan that would solve ALL these debates....but it just don't exist for a 12v system...yet. Not one that's gonna flow as well as 65 to 75mph with an air-dam. Most good fans are equivalent to approx. 35...maybe 40 mph in speed. That's flirting with sufficient air flow for all conditions...but not quite enough.. Speed still works better. Forces more air thru the exchangers than a fan can...

To have adequate cooling ability, if you can't have a BIG temp differential, then you MUST have a higher air flow. ---- >Speed.



Think I'll try that one in court next time...
.."the engine was getting hot, your honor, so I HAD to go fast to cool it off..."

Then again...maybe not.

Like the time I tried to tell the judge that I had actually let off the gas and the car accelerated going down a long hill...so I was NOT purposely speeding or trying to increase my speed...

so he changed my charge to "failure to control speed".
Guilty.
great.

 

One of the issues is the fans cirulate the airflow, you can get a ton of air thru the radiator however the air will recirculate.
The hot air from the radiator will find the easiest path back, under the air dam and back to the condenser/radiator while stopped at traffic lights. Only a little fresh air getting in that is why the temperature goes up.

When you are on the highway, you get cool air thru the a/c condenser and through the radiator. The heat is drawn out the engine bay, It cannot reirculate that is why it seems to cool better on the highway.

With a/c on and sitting at traffic lights you are relying on the spare capacity of your cooling system, any cool air that goes around and over the condenser to your radiator.

So if you could duct all the hot air further back to the rear of the car, you can have a better cooling system.
The a/c condenser is designed to be big enough but also small enough to allow some cool air to reach the radiator.

Now i have a supercharger blowing very hot air to the intercooler, i can keep the engine cool with a/c on to around 90F. Intercooler heat, condenser heat and then barely any cool air to the radiator.
I can keep the coolant temp below 240 on the highway and stop start traffic up to 90F ambient, that is using all the spare capacity from the standard single row GM radiator.

I have to turn of my a/c when it is 90F+ ambient.
I now run with the supercharger bypassed in summer and can maintain 220-240f with a/c on even in heavy traffic and lots of traffic lights.
(Yes we get 110F+ days in summer her in Australia.)
Thank god we do not get 138F days like i saw in the United States in Bartown on the way to Vegas during my holidays
Even when my vette was standard she had no problem in the hottest days with a/c on and never go over 240F but my vette has the optional booster fan.

 

I have the pusher fan wired so that it comes on with the secondary fan. It will turn off once at speed by the ECM. It works pretty well.

Tony

 

I too have a super charger and intercooler. I get way too hot in 90+F. I have a 11" two puller shrouded fan with the fans hooked together. My fan doesn't come on with the a/c so I think I'm going to add a 12" pusher to the condenser to turn on when the a/c is used. Can you tell me the reasonable operating range for the L98? Seems nobody knows for sure around me.

 

There are so many C4 owners that get freaked out if their temp hits 210. It's NORMAL!
If you have a clean radiator, you usually won't have heat problems under normal conditions.
If you are regularly 220 and more, your system is dirty and the radiator needs to come out to clean thoroughly
240 and more is when this needs to be done now
normal I'd say is 190 to 210

 

The pictures have been blurred. How can I get to them in Photobucket?

 

I'm constantly over 220 around 230-237 with all cooling fins clean in the heat with the double puller fans running. They are Derale fans with the automatic speed controller. I'm hoping that the additional 12" fan will keep the temperature in a more normal temperature range. It never got hot until I reinstalled the a/c after the supercharger installation.

 

Is the license plate grill a home Modification or can it be purchased?

 

did you take the radiator out to clean the fins? If you didn't they are still plugged up!

 

Do what ya got to do. Installing a pusher fan is a reasonable idea.

Back in 05 or so I installed a manual switch to run my auxiliary fan to help with the cooling. It worked pretty good but I knew I was at maximum efficiency the radiator could do.

This summer I installed a aluminum 2 row radiator (1" tubes). No major modifications had to be done as things look the same under the hood. This was the solution and it worked great. In traffic or moving I'm under 200 deg and this is in 90 to 100 heat. I no longer need to use the aux fan.

For a stock LT1 a 3 row radiator is not necessary. And it also requires high power fans and I did not want to change the fans or go to that level of mod. I lowered the temperature 20 degrees

If you live in a cool climate you can get by with the stock radiator. But if you live in the south or a hot climate 10 months a year then you need a better radiator which I think the car should have come with it from the beginning.