Jump to content
HybridZ

Doing mods to cool down engine, need advice


Recommended Posts

Damn Pete, I bet that fan would dim my headlights way down when it came on. 35 amps?

 

I have a 16 in imperial I got from Advance, and it is ok. I really need one on the other side too. As long as I don't run the AC, mine stays cool as a cucumber. Turn on the AC, lookout its time for a new headgasket. Has to be 90 or above though.

 

I really need a better rad that my turbo one. Actually, having it rodded out would probably solve all my problems.

Link to comment
Share on other sites

Originally posted by Lockjaw:

Damn Pete, I bet that fan would dim my headlights way down when it came on. 35 amps?

Yeah, it's enough to pull the idle speed down a 150 or 200 rpm! I need a bunch of carb work though - it's not idling very well (the lumpy solid lifter cam has something to do with that though!)
Link to comment
Share on other sites

Jim, come by again and this time we'll wait for my engine to warm up enough to turn on the Mustang GT electric fan. It may change your mind about electric fans moving air - and only when they need to.

 

Most of the aftermarket fans don't pull much air. Spal may be the exception to this. Consider this: The OE's build cars that hopefully don't have to have later fixes (TSB's, etc.) applied to them if there's a design problem.

Using a fan off of a decent sized engined late model car will most likely mean it can move a decent amount of air. The GT Mustang fan I have has a large permanent magnet motor (read: efficient) and pulls 35 amps on high speed. That's a bit of power.

Link to comment
Share on other sites

I want to add an additional $0.02 to this discussion.

 

Water has the higher specific heat - adding ethylene glycol reduces the specific heat of the engine coolant. I run about 10/90 coolant to water, just to drop the surface tension and inhibit corrosion. Here is a table of specific heat vs. coolant ratio:

 

Specific heat of aqueous propylene glycol

 

Ethylene should be somewhat comparable to propylene.

 

Can I whine about another thing too? I've heard the idea about coolant restriction aiding the engine cooling thing (because of coolant moving too fast in the radiator??), and I don't buy it. The faster you can move the stuff through the faster you can cool it - it is non-linear, and once you get past a certain flow rate, you have diminishing returns, but you can't cut 20% of your flow and dump more heat. Now I'M theorizing, so [flame suit ON].

Link to comment
Share on other sites

Sleeper Z, I agree about the restrictor idea in the radiator making no sense. I drove from Chicago to LA in June one time in my '72 510 and needed to be there by a deadline. It had the original radiator and the core was fairly plugged up by sediment. I had to go through the desert in the middle of the day and the only way I could make it at high speed was with the heater on full blast and removing clothes. Open windows created drag and buffetting so I had them up with the quarter windows cracked. So on the interstate if someone glanced over there I was with it 95 degrees out, 70mph, windows up, sweating like a pig with no shirt on.

I have some questions for you re specific heat because I'm working on another project. I need a liquid media to use in a passive system (container) in which I have a thermister installed. I want a material that will quickly change temperature with change in response to temperature changes of the aluminum vessel it's in. How would water, propylene or ethylene glycol, ammonium or alchohol or mineral oil compare? The temp range is ambient 32F to 100F. DAW

Link to comment
Share on other sites

DAW, if there is no ignition sources, Methanol would be your best bet. I know a guy who ran it in his modified to keep a 400ci chevy cool (has constant problems with the 400 overheating). Worked well...as long as you never crash.

Tim

Link to comment
Share on other sites

Thanks guys, I think you're right about picking the lowest specific heat value material which is practical. I'm going to stay away from flammable liquids and go with ammonia (although alkaline burns aren't good either). Specific heat of water is 4.19 kJ/kg K; oil is 1.67; and ammonia is 0.47. What I'm building is a sensor that can generate a sensitive/responsive signal linked to change in vehicle speed (e.g. acceleration). DAW

Link to comment
Share on other sites

I don't mean to step on anyone’s toes here, just trying to exchange info and get feed back. smile.gif But I still have to agree with JTR when they say how much more air can be moved by a mechanical vs. electric fan.

 

35 amps is a hell of a draw, especially if you only have a 90 amp alternator. But 35 amps at 12 volts has the same power as 3.5 amps at 120 volts. And when have you ever impressed someone with your "three and a half amp" electric drill or circle saw? This works out to only 420 watts which is just a little over half a horsepower. I don't have any numbers on mechanical fans but it seems like they have a lot more HP to draw on. And keep in mind that running an electric motor puts a load on the alternator (hence engine) just the same as the mechanical fan. The only power advantage an electric has is when it is not running.

 

Electric fans can obviously get the job done. There are too many guys who make them work. However, if you look back through the postings on this site most of the people with cooling problems are running electric fans.

 

Coincidence?

Link to comment
Share on other sites

Guest Drewz

Some decent points Jim but I am running a pretty peppy small block chev with the datsun rad with an extra core and an electric fan from a supercharged 3.8 and have had no cooling problems. When a car is being reworked in a swap all the hoses, heatercore, rad, and ensureing the coolant is passing through these parts properly is sometimes all that is wrong. One guy locally couldn't get his 96 vette motor to keep cool until he found out about the reverse cooling it used. Sometimes you can't see the forest for the trees in front of you?? I think the electric fan being the MAJOR factor is possible but probably not the major factor, there are probably other issues that were overlooked??? Just tossing some ideas out, IMO :confused:

Link to comment
Share on other sites

DAW, I'm no chemist (I'm a sparky, actually), but I'd think you'd want a fluid with the lowest possible specific heat for the quickest possible temperature change. I'm thinking the less heat energy the fluid can hold, the faster it's temperature will rise.

Link to comment
Share on other sites

Jim, no toes stepped on here.

 

But I just want to point out that alot of the electric fans on the aftermarket are wimpy marginal things. Even the BlackMagic flexlite 150 electric fan that looks very impressive really doesn't pull that much air through the radiator.

 

No doubt that running the fan pulls power from the motor - I see a 150 rpm drop at idle when my fan comes on high - although the idle carb settings are messed up a bit. I had to tighten the alt belt a few times to get it to stop squealing when the fan came on at idle.

 

My point is that electric fans do work, but many people just go to the local parts store or Jeg's, etc. and buy a big fan they think will work, but in actuality is a wimpy fan, compared to the ones the OE's use and the mechanical ones.

Link to comment
Share on other sites

All good points.

 

If something is broken in the cooling system than you can't expect a bigger fan to make it right.

 

I guess all I was trying to say is you need to make sure the electric fan you want to install will get the job done. I'll go further to say that when the set up allows it, a mechanical fan with a shroud has the potential to move a lot more air and should be less prone to overheating than an electric set up.

Link to comment
Share on other sites

I could work the 35 amp rpm drop on my efi motor by rigging something to trigger the ac deal that raises the rpms when the compressor kicks on.

 

Has anybody tried the redline water wetter or some of those other products that are supposed to reduce coolant temps by 40 degree's? I just wonder what that would do.

 

I am not going back to a clutch fan, I don't care how much it costs me to get a radiator that will keep my car cool. I hate the helicopter sound they make when they engage when the engine is warm and it lugs my vehicle way down in comparison to what the alternator does when the electric is running. On my 2000 Silverado, when the clutch fan is engaged, it is a very noticable drain on the engine. Electrics would get rid of that.

 

This kind of stuff is more noticable on the L6's than the V-8's. If you have ever had a fan clutch lock up on an L6, man that is no fun. You talk about drag. Yes it moves some air, but, noisy.

 

Mine does really well with my cheapo electric. As good or better than with the clutch and shroud that came on it.

 

Pete what kind of mustang did your fan come off, and how hard it is to mount to one of the stock radiators?

Link to comment
Share on other sites

Jim, I agree - make sure the cooling system is in order - then start working on more powerful fans.

 

Lock, I put water wetter in my Z's V8 engine, but I also think at the same time I got some air out - I saw 20 degrees lower temp just sitting in that garage, and the fan cycled off and on much slower than before. Hard to tell what did it.

 

The fan I have is off of a 98 GT Mustang. It's about 19" in diameter overall. The pics on my website (top of this page has a link) show the top brackets. The bottom was bolted through some existing tabs on the fan housing down low to the bottom radiator bracket. Pretty easy. But I'd probably due the dual Taurus fan as it has a nice shroud that covers the Z/Camaro radiator.

Link to comment
Share on other sites

Guest fly yellow

i have the electric fans off a '99 sl 500 that na friend of mine gavee me

retail $900

but man these puppys flow air tested them in garage they lifted themselves off the ground

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...