Cooling options for GEN I ( I already used search button!)

[1994viper]

Hi all,
I have a 94 with AC which always have been running somewhat hot, when pushed. I enjoy going to track events, but the car gets really hot just as I get the tires warm. So I cannot put any good amount of laps in a row. I read all the Cooling threads last year and had reviewed some yesterday. I cannot seem to find the best solution. I remember reading last year, and I cannot find the posts that have suggested certain things. So here I am.
Could someone confirm that the below listed things actually will work:

I read before, that the AC Condenser restricts the flow of air passed through the radiator. If I were to remove the condenser, how much of an improvement am I going to get? Is it worth it? (My AC hasn’t been working for years now, and when recharged the condenser preheated the air passing through the rad so much so that the car would run 5-10 degrees Celsius hotter, so I couldn't use it either way. Therefore pulling some extra weight off is not a problem)

I also seen somewhere here on the board, (can't find it now) that some people have bypassed the heater core to improve the cooling. My understanding the heater core is bypassed already if the switch is turned to "blue" Cold, so I do not see a benefit in doing that. Also, from what seems to be right to me is that when the switch for heat is on in the car with running fan, it should cool the car better as the core acts as a small rad. Could someone confirm that a bypass of heater core will deliver a cooler motor?

And the last but not least. Someone tried to put an extra fan in front of the radiator to push the air through. Anyone have done the mod and got noticeable results? I mean when I am reving the car, I am still traveling at a good rate of speed, shouldn't the rad get enough air flow and perhaps more than the fan could provide?
Does anyone run water only in the rad + water wetter? Would it be sufficient to bring down the temp below and keep it there?

Thank you all.
BTW, I have an improved radiator, I run the fan at high speed at all times, 70/30 water/coolant + water wetter, 180 thermostat, burped.

PS
Oh! I know this was a bit long, so I hope this might be a small video reward to the readers and responders. Enjoy


http://vimeo.com/24450140

 

[RT/ED]

You may still have air in your system even though you burped it. This problem pagued me for years on my 95 until Chuck Tator gave me the following tip. Remove the heaterhose that goes from the heater box to the thermostat and fill the hose with your wather/antireeze mixture and reconnect. I could not believe how much additional fluid this added to what I thought was a full system. Chuck says that this fills the engine to around 95% level (passenger side of block is the culprite). Do this with the car cold!! After the next few runs, allow to cool down completely and top of your overflow tank until it remains full to the top. Hope this helps!

 

[eucharistos]

Hi all,......

just to be sure, you are talking about engine heat vs. cabin heat

......And the last but not least. Someone tried to put an extra fan in front of the radiator to push the air through. Anyone have done the mod and got noticeable results?

i believe dan cragen at dc performance sells the kit

......
Does anyone run water only in the rad + water wetter? Would it be sufficient to bring down the temp below and keep it there?

water +water weter will cool better than w/ coolant, but will not protect from freezing, which is probably an issue up north

 

[eucharistos]

You may still have air in your system even though you burped it. This problem pagued me for years on my 95 until Chuck Tator gave me the following tip. Remove the heaterhose that goes from the heater box to the thermostat and fill the hose with your wather/antireeze mixture and reconnect. I could not believe how much additional fluid this added to what I thought was a full system. Chuck says that this fills the engine to around 95% level (passenger side of block is the culprite). Do this with the car cold!! After the next few runs, allow to cool down completely and top of your overflow tank until it remains full to the top. Hope this helps!

good info, thanks for passing it on

 

[Tom F&L GoR]

I have a '94 - purchased in Montreal - so I have what you had. My original radiator had a poor solder, the dealer offered a replacement. By that time the replacement was a Gen 2 radiator which was the same size, but the studs to mount the fan shroud was different. They gave me a Gen 2 fan also. The Gen 2 fan is much, much, much more efficient and while it seems that at speed it wouldn't matter, during track events it seemed to help more than expected.

Also, search for "Roe duct." This is essentially a hole in the front fascia, on the underside, just ahead of the radiator. It bleeds air pressure that would otherwise go under the car (causing front end lift) and pushes it into the radiator. The hole is ducted to the front of the radiator and not visible unless you are being run over...

Look under the front of modern cars - my Dodge Intrepid had such a "hole". This will also greatly increase air flow through the radiator. You could also "clean up" the radiator entrance by checking the cross in the front fascia. Often the cross will sag and block the entrance - I drilled small holes and used tie wraps to keep the cross pieces from separating.

I didn't remove the AC condenser, in fact, I turn on the AC afterwards because the new fan works so well to cool the engine (and driver.)

 

[TexasPettey]

I do not believe that you need to remove the A/C condenser in order to get good cooling. I ran my ROE S/C '95 in July (95F+ ambient) in TX at HPDE events with no overheating problems. It would run hot, but not hit the red zone. When you say 'improved radiator' what do you mean? A thicker radiator is not always better, given that the increased thickness requires more air pressure to get the same air flow. It looks like you've got some decent straights to catch speed on that track. I'd expect the airflow to be enough to cool it off.

I would start with the following:

- Make sure the radiator, condenser, etc are clean of debris. I collect crap between the A/C condenser and radiator for some reason.
- Burp the coolant well several times. I do this with the car severely elevated at the front.
- Get a later Gen2 'center' fan assembly.
- Consider replacing the water pump if you haven't already
- Get the ROE duct kit or equivalent, if you are willing to cut into the lower fascia.
- Get a vented cowl or make one

I don't know if the '94's have an oil cooler. If not, you'll want one. My '95 has one.

Another slightly off topic cooling element you'll want is a Power Steering cooler. It's cheap and can be mounted anywhere behind the radiator fan. I have mine mounted on the upper cross member in front of the engine.

BTW, nicely done catching the GTS on the first turn in. He was pulling on that straight hard, but you were right there at the turn.

 

[95Viper]

This has zero freeze protection but Zerex Super Racing Coolant is corrosion only protection and allows you to run 95% pure water. Again, you might want to label something that explains that you have no freeze protection. Drain and add regular coolant if freeze is a possibility. Will drop the temp though. Also, search a lot about burping and what everyone has already said.

 

[got one]

Try the lower rated thermostat...like the 170. I did and it made a world of difference.

 

[1994viper]

Thanks all
So, I pulled the AC condenser, and replaced the rad cap (it was holding only 13 PSI) Car runs a bit cooler, and it seems that the temp drops slightly faster after getting off from stop and go traffic. Next step I might want to get a different, high volume fan. I'll try to replace the original fan and shroud in hopes to get more airflow through it. I noticed that the stock fan has a good airflow through the 2/3 of the radiator ( right where the fan is located on the left side. ) I tested the airflow with a piece of paper, and the paper wouldn't even stay put and sutck to the rad from the suction on the left side. It probably has to do with a bad shroud design.
How much more efficient the GENII fan compared to GEN I in CFMs?
What would be the best and moderately priced fan/fan+shroud?

 

[Tom F&L GoR]

Try the lower rated thermostat...like the 170. I did and it made a world of difference.

Sorry, it can't. Once the thermostat opens at 170, it cannot help cool the engine if the temperature is 190. A lower thermostat begins to try to cool the engine sooner, but by itself is not efficient in doing so. The only thing that helps cooling at 190 is a better heat exchange (radiator and/or fan and/o air flow).

 

[95Viper]

Sorry, it can't. Once the thermostat opens at 170, it cannot help cool the engine if the temperature is 190. A lower thermostat begins to try to cool the engine sooner, but by itself is not efficient in doing so. The only thing that helps cooling at 190 is a better heat exchange (radiator and/or fan and/o air flow).

Exactly what Tom said. I cannot believe how many posts I read where suggestions of a lower thermostat are made to keep a car cool. I mean, really, whether the tsat opens at 170 or 185 doesn't mean anything if the car is running at 190+.

 

[TexasPettey]

Sorry, it can't. Once the thermostat opens at 170, it cannot help cool the engine if the temperature is 190. A lower thermostat begins to try to cool the engine sooner, but by itself is not efficient in doing so. The only thing that helps cooling at 190 is a better heat exchange (radiator and/or fan and/o air flow).

Keep in mind that it is driving situation dependent. If you are in traffic, but get to some highway speeds, the lower Tstat may help keep the temp from getting as high because it is cooled to a lower point when you get up to speed. A lot of us TX guys get that in the Summer heat. When continually above temp, like on the track for 20min straight, it's of no value. The real fix is a good fan setup with proper airflow across the rad and good flow in the coolant system.

 

[Tom F&L GoR]

Keep in mind that it is driving situation dependent. If you are in traffic, but get to some highway speeds, the lower Tstat may help keep the temp from getting as high because it is cooled to a lower point when you get up to speed. A lot of us TX guys get that in the Summer heat. When continually above temp, like on the track for 20min straight, it's of no value. The real fix is a good fan setup with proper airflow across the rad and good flow in the coolant system.

Agreed, but it means the coolant temperature is cycling over a larger range from minimum to maximum. Gaskets don't like this. Stepping up on the soapbox, I'll say that lower coolant temperatures were a significant benefit when carburetors sat on water cooled intake manifolds. A lower coolant temperature would keep the intake charge cooler, more dense, give more power, and help prevent knock. Fuel injected engines do not rely on heat to vaporize the fuel, the cylinder-to-cylinder fuel distribution is fine, there is no coolant in the manifold to heat the air, so the only effect lower coolant temperatures can have is what happens in the intake port of the head, and combustion chamber.

If we were all wealthy high-tech racing engine builders, we would actually keep the cylinder wall rather warm because otherwise the combustion energy would be sucked out as heat, not making power. (Think of all those fancy piston top plasma coatings to keep heat in the combustion chamber.) Thermodynamics would say to keep coolant temperatures high and intake air temperatures low - rather than messing with a lower thermostat, there seems a bigger gain with ensuring lower intake air temperatures (Roe duct.) OK, jumping off soapbox, no harm no foul, just relaying what I've done and what school books say, but I know not to argue with the real world.