Does anyone know the CFM of the stock Fiero radiator fan? I did some searches, and looked at parts on line and maybe I am missing it but I do not see what CFM the stock radiator fan pulls, I have a lot of info compiled on Fieros but this number I do not have, I hope someone does.
My Fiero has a V8 swap, 350HO vortec with iron heads and block with TPI, done in 2009. The A/C has been missing since then. I had the A/C reinstalled with all new components a few weeks ago and it worked great when I tested it, but it was only about 75 degrees at the time. When I drove it with temps around 90 it got too hot sitting in traffic, it did cool back down going down the highway.
When it is cool outside and without the A/C on it runs at 180 consistently, and around 195 when it is in the 90s. It has a 4 core aluminum radiator, Transmission/oil cooler with fan, high flow electric water pump and a stock radiator fan.
I am trying to figure out what it needs so I can use the A/C when I need it, what good is A/C if I can't run it when it's hot. I am in Denver at around 5280' in elevation so the boiling point of water is much lower around 202 degrees so even with coolant it will and has boiled out around 220-230 depending on my elevation at the time, so I need to keep it below 220 preferably 210.
Looking at options to reduce the temp, I am thinking a higher CFM fan would be the easiest thing to try first but I need to know how much CFM the stock fan has to test this.
Thanks
Edit, I do not think there is any thing wrong with the car except it highly customized and the engine generates so much heat the slightest change "like adding the A/C back on it" can make it run hot when idling too long, the the Car normally runs cool at 180-195 and has for years and still does as long as I do NOT turn on the newly re-installed A/C when it is over 90 degrees while sitting in traffic. Here is a link to my Photobucket build album so you can how it is set up to answer most of the question about the cooling system and other added components.
I don't know the answer, but I just want to point out that a singular measurement of maximum CFM in open air might not be very useful. On small fans used in electronics, the more reputable fan manufacturers will publish a graph showing CFM versus static pressure. The rate of relationship between the 2 varies depending on the fan design. I imagine the point on the graph that's relevant to a fan installed behind a car radiator and A/C condenser would be pretty far down the graph away from the peak CFM that's achieved in open air. Still, if one fan is being compared to another that's assumed to be of comparable design, then maybe the peak CFM is better than knowing nothing. But I suspect it would end up being more useful to just compare the electrical power that they draw. Assuming both fans are competently designed for the intended application, it's probably reasonable to assume that the fan with higher power draw is probably the one that pulls more air through the radiator.
I don't know the answer, but I just want to point out that a singular measurement of maximum CFM in open air might not be very useful. On small fans used in electronics, the more reputable fan manufacturers will publish a graph showing CFM versus static pressure. The rate of relationship between the 2 varies depending on the fan design. I imagine the point on the graph that's relevant to a fan installed behind a car radiator and A/C condenser would be pretty far down the graph away from the peak CFM that's achieved in open air. Still, if one fan is being compared to another that's assumed to be of comparable design, then maybe the peak CFM is better than knowing nothing. But I suspect it would end up being more useful to just compare the electrical power that they draw. Assuming both fans are competently designed for the intended application, it's probably reasonable to assume that the fan with higher power draw is probably the one that pulls more air through the radiator.
You make some very good points and give me more things to ponder, I will take this into consideration as I search for a way to have working A/C in my Fiero that will not cause it to overheat and boil when A/C is being used when it is above 90 degrees outside.
...as I search for a way to have working A/C in my Fiero that will not cause it to overheat and boil when A/C is being used when it is above 90 degrees outside.
If you don't already have them... vents in the hood (behind the rad and just ahead of the tub) make a heck of a difference with with helping to keep a Fiero cool.
The fan can be upgraded to a Pro-form 16" very easily. It fits into the stock shroud nicely. You are running a shroud, aren't you? You might also consider going to a higher psi pressure cap on the radiator.
Putting vents or creating an extractor hood is on the list of things I could try but I only want to do that as a last resort, I have nice paint and like the way it looks with a solid hood, I will cut it if all other options fail.
I do have a fan shroud the stock 87 set up on the big radiator, I am looking a fan upgrades that was the main reason for this post, to find the stock CFM so I will know how much of an upgrade the fan really is. I am looking at some from 2500 CFM to 3700 CFM, it would be really good if knew what the stock fan CFM was. I can go by amps but more power does not always mean more air due to blade design and placement, so I would rather compare CFM if I can.
Originally posted by Christine: You make some very good points and give me more things to ponder, I will take this into consideration as I search for a way to have working A/C in my Fiero that will not cause it to overheat and boil when A/C is being used when it is above 90 degrees outside.
Upgrade fan is BS for most people. When you need a fan when car is moving, Something is way wrong with coolant system and/or missing body panels. Start w/ See my Cave, Crushed Pipe and rest of section.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
You have a good shroud on the rad fan correct? Make sure your 16 lb cap is functioning properly. Any extra vents in back? You could remove the under grilles on your vents. You could wrap some exhaust.
I dealt with this issue when I built a 406 for my trans am. As previously stated, ensure that the rest of your cooling system is in good working order. Boiling points are raised because it's a pressurized system. Water doesn't boil at 212° in a car's cooling system unless there is air in the system, or if there's a leak. As for fans, I opted for LS1 trans am dual fans. Shrouded dual fans with high cfm's actually make the gauge drop visibly fast. I wired mine with an adjustable hypertech fan switch that reads it's own probe inserted into the radiator. You can buy the LS1 fans used for $75 to $100 on average. Cut to fit as needed, secure with heavy duty zip ties. Small blocks like 195 after the engine reaches 220 on the first warm-up. Double check your electric water pump, it may even be too powerful. My built 406 (cam, AFR heads, etc.) Runs on a stock replacement water pump. No issues whatsoever. I chose the LS1 fans for reliability, the high CFM was just an added bonus. My two cents.
Also, the dual fan can be wired to run only one fan with the a/c on. This fan will remain running until you switch the a/c off, and the second fan will kick in thermostatically as needed. The hypertech switch was only about $25 and they sell them on the shelves at advance/AutoZone/pepboys.
I recently added a 2 speed Volvo fan. I am a believer that amp draw is a good relative indicator of CFM. As a comparison, the Fiero fan was pulling about 15 amps. The Volvo fan pulled 13 amps on Low speed, and 21 amps on high. Low speed felt about the same as the Fiero fan. On my 3800 SC engine, with a 2 core radiator, low speed will pull the temp down about 20 degrees in about 2 minutes. I have the high speed set to come on at a higher temperature, and also when the AC pressures are higher. Running the AC on a 100 degree day here, in traffic, I could see the fan switch from low to high occasionally ( due to AC pressure), but temps never got above 200 ( 180 stat). I'm using the PCM for fan control, through a 3-relay setup.
The JY fan I installed had a cracked blade, so I bought a new replacement Volvo fan off ebay (Depo 373-55006-100 ) . Low speed on the replacement is now pulling 9 amps, while high is pulling 23 amps. Still no problem cooling down quickly once the fan kicks on, but haven't driven it yet . I expect no issues. Fan is very quiet, due to blade design?? Why the difference in amps from the JY fan. Maybe it was the age of the JY fan, or it could just be the replacement doesn't run as fast on Low as the stock one did. I'm betting on age. Age could also be a factor in the amp draw of my stock Fiero fan.
For comparison, I previously ran a MARK VIII fan on my El Camino. It is considered the Bad Boy of fans, reportedly pulling 3500 CFM+. It will cool, but it pulls a lot of amps ( 33), and is noisy when running. I'm now running an LS1 2-fan setup on the Elky, and it cools just as well as the MarkVIII, but only pulls about 22 amps on full speed . My experience is that most of the aftermarket fans that report High CFM airflow and low amp draw just don't cut it. Amps = HP = amount of air moved. BTW, a 4 row radiator will be more restrictive to airflow than a 2 row- just not as much room for air to travel between the fins. Probably not an issue, unless the fan is just not able to move enough air to pull through the radiator and condenser.
And X2 on the radiator cap. Get yours tested ( autozone, etc). A stock cap, with a 50/50 antifreeze mix, should keep boiling well below 240- even at altitude.
------------------ '87 GT in process, including GA / Seville brakes, Poly Suspension, '95 3800 Series 1 SC ( 225 hp ) 4t60e.
One big problem with the Fiero cooling system is that the fan switch kicks the fan on at 237*.....In stop & go, my gauge would go up and down as the temp rose above and dropped below that temp....Sometime I would have to pull over. You can get a lower-temp fan switch- Not a huge drop because then it will run continuously....I bought mine at Oreilly's and it turns on at 230* and shuts off at 220*. My fan comes on in stop & go on hot days, and my needle basically never moves now.
]Upgrade fan is BS for most people. When you need a fan when car is moving, Something is way wrong with coolant system and/or missing body panels. Start w/ See my Cave, Crushed Pipe and rest of section.
I did check out your cave articles and they are very useful I am glad you made them, Thank you.
I said I was driving the car I did not say moving the whole time I just said I was driving it, I live in Denver and the traffic is so bad here now there is never a time you can drive around and not sit idling for a good amount of your drive time, I guess I should have mentioned bad traffic all the time here, maybe if the car was actually moving more than 30 MPH and not stopped in traffic 10 out of every 15 minutes of driving it might not get as hot? Probably still would, the car runs cool at 180-195 without the new A/C on even on hot days. On a 60 degree day I can drive 10-20 miles before it even gets to 180, the only thing that changed on the car was I added A/C back in the mix otherwise everything is still the same.
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Originally posted by 2.5:
You have a good shroud on the rad fan correct? Make sure your 16 lb cap is functioning properly. Any extra vents in back? You could remove the under grilles on your vents. You could wrap some exhaust.
I do not think there is anything actually wrong with the car except it is highly customized and the engine generates a lot of heat, the slightest change "like adding the A/C back on it" can make it run hot when idling too long. The Car normally runs cool at 180-195 and has for years and still does as long as I do NOT turn on the newly re-installed A/C when it is over 90 degrees while sitting in traffic.
Here is a link to my Photobucket build album so you can how it is set up to answer most of the question about the cooling system and other added components. http://s920.photobucket.com...0Build?sort=3&page=1
T-stat 180, Trans/oil cooler fan gets cool air from the driver side scoop and comes on around 160 the radiator fan is set to come on at 180, coolant tubes are good, no coolant leaks, no air in the system (runs cool without the new A/C turned on) headers are wrapped, water pump working good. I might look into this http://www.evanscoolant.com...performance-coolant/ The last time I looked at this kind of thing it was not anti-freeze so it had to be drained in the winter so I passed on it and forgot about this type of stuff.
[This message has been edited by Christine (edited 06-22-2016).]
Just some other ideas on your problem- Make sure(Everyone!) that you NEVER install a waterpump with a plastic impeller- The plastic is more thermally active so it will expand off of the shaft and not pump water- The symptom is as the car is heating up you get on it a bit and a few minutes later it rapidly overheats- Pull the thermostat which removes drag from the system so the impeller will turn and it stops overheating.
You have a custom system, so my suggestion about the radiator fan switch is still viable, but for a different temperature; You want it so that the fan comes on before there is a big change in your temp gauge- it should go up just a small amount and then the fan should catch it. You have more stuff that can go wrong with the Fiero (Mid-engine) cooling system; T-stat, rad cap, T-stat cap, 12 hoses, waterpump, pipes...inspect them all and when you take your car to a shop, tires, wheels, alignment, exhaust- Anything where they may jack or lift the car, WATCH them to make sure they don't crush the pipes. Also, if you go to a junk yard, snap up a couple of those plugs for the fore-aft stainless coolant pipes- They can easily be stripped.
So the fan is already on this whole time. I'm not sure why an AC compressor would work an engine in suich a way that is gets so hot the cooling system cant keep up. AC is something I don't know a lot about. With a 180 stat and a 180 fan switch you are already for sure set up to catch everything before it gets hot as long as it all works. I know timing can make an engine hot, fuel choice can affect it as well, but you don't have an issue until that compressor kicks on....
[This message has been edited by 2.5 (edited 06-23-2016).]
It has a 4 core aluminum radiator ... and a stock radiator fan.
I am not sure why the added load of a compressor would increase the engine heat THAT MUCH… You also have a lot more coolant to try to cool with the stock fan, so yup - you need more air through it. Fan and Vents: http://fierosound.com/moreM...rket%20Cooling%20Fan
Years ago I had a V8 Chev Monza that ran a little hot (small engine bay in that car too). When the original 2 core radiator leaked I replaced it with a 3 core and made it worse. I just increased the amount of water that needed to be cooled with the same amount of air going through it.
What would have worked better for me in that case was a 2 core radiator with MORE FINS to dissipate the heat.
One more thing is the airflow(As you were first addressing).....I had a 1973 mach 1 that I installed a 5.0 in......I would drive at anything over 60 in a cross-wind and the car would feel like it was on tip-toes- ALL the air that hits the 71-73 Mustang front ends is rammed under the hood and then has nowhere to go....The hood was 3000 square inches! 1/10 psi of pressure would create 300 lbs of lift. I made an airdam that pushed all the air (Except the radiator in the 2 foot center) off to the sides....and then I BLOCKED off the actual grill. The car never even suggested overheating and I had it up to 90 and it felt like it was on rails. VACUUM behind is as good as air pressure in front for air flow thru a radiator.
What I am saying here is airflow management- Give the air coming thru the radiator somewhere to go (Vents in the hood, or thru the headlight buckets) and also, possibly cut back on how much air is coming in.....The Fiero is nowhere near as bad as that Mustang I had for ramming air in, but just keep in mind that air can do funny things and use all of the different possible solutions to cool your car. The only down side to hood vents is that the hot rad' air then goes straight into your vent system- Pre-heated air for your A/C system- Yay! I always thought it would make more sense to put vents on the headlight lids- the air would go over the sides of the fender and not go in your ventilation system...
[This message has been edited by cvxjet (edited 06-23-2016).]
So the fan is already on this whole time. I'm not sure why an AC compressor would work an engine in suich a way that is gets so hot the cooling system cant keep up. AC is something I don't know a lot about. With a 180 stat and a 180 fan switch you are already for sure set up to catch everything before it gets hot as long as it all works. I know timing can make an engine hot, fuel choice can affect it as well, but you don't have an issue until that compressor kicks on....
It's not the "load" of the compressor, it's the heat from the condenser that the cooling system has to compensate for. Joe
When the original 2 core radiator leaked I replaced it with a 3 core and made it worse. I just increased the amount of water that needed to be cooled with the same amount of air going through it.
What would have worked better for me in that case was a 2 core radiator with MORE FINS to dissipate the heat.
I know V8 Archie uses a 3 core, a 4 core seems too many, but depends on the size of the tubing and fins I guess.
The other problem we have up here at altitude, (we're not called the Mile High city for nothing) the thin air is less effective at drawing off heat. Cars that cool fine down at sea level often have issues here, my old Dakota r/t would do fine at sea level with the ac on and run on the hot side up here, never boiled over but would make me turn off the ac once in a while.
As someone has already pointed out, the condenser gets hot, that's an understatement, it gets very hot, especially if the cooling fan is not running which at some point will send the high pressure shut off switch into action. That heat passes through your radiator. First recognize that you have twice the engine capacity than what the coolant system was designed for with the exception of the upgrades you have particularly the 4 row radiator. Also recognize that 240 deg is not too hot for a post 1984, SBC 350 as they were setup to run safely at that temp from the factory at which point ECM programming makes changes to accommodate it. The high heat benefits fuel efficiency and is therefore permitted.
Higher cooling fan CFM will help but I believe the most effective CFM increase and benefit would be located in front of the condenser via a pusher fan and a good one at that liking to what's found on some of the imports, BMW etc, that use them. The blades on the stock fan are not as efficient as the modern tech designs so an upgrade there wouldn't hurt. The addition of a pusher fan will help you avoid cutting holes in the hood and should be a relatively easy upgrade as there should be room up front for a 12" fan with no more than ~3" depth.
I've been pondering this myself over purchasing a 1" tube, 2 row radiator as I've found through datalogging the 3 row champion (i've had two) is only marginally better (maybe) than the OE 1.25" radiator the V6 comes with. I'm seeing roughly the same temp averages in 90 deg heat with the most significant influence being the cooling effect at idle when the engine rpm is raised to about 1200 rpm which I thought of when you stated you have an electric pump. If it moves more water at idle than the stock pump it's definitely a plus for you.
After reading threads and posts here on Pennock's along with other site and doing as much research as I could stand, I have decided to start with a higher flow fan with the factory shroud or a custom one to fit the new fan and see how much improvement I get, I will also change the coolant and make it a 65% / 35% mix as discussed in the article in the link below. Things you should know about coolant, http://hellafunctional.com/?p=629
If it is not enough to cool it down I may try a radiator with fewer cores so there is less restriction of air flow through the radiator and/or add a pusher fan to the condenser to help the dissipate the heat from that quicker. The article thread in the link below was very informative regarding radiator design and size in relation to cooling abilities. http://www.pirate4x4.com/fo...m-vs-brass-tech.html
Both links above have a lot of good information so if you have similar questions or just want to know more about coolant and radiator design and function check them out.
[This message has been edited by Christine (edited 06-25-2016).]
From what I've seen import cars come from the factory with the best radiator cores around with thinner tubes and more fins per inch than domestic radiators. The difference on domestic cars can be seen in the condenser on our cars. although it has round tubes, the fin arrangement is dense in the same manner as what I've observed on import radiators which are thinner than domestics but still do an outstanding job.
The 3 row radiator many have purchased for their Fieros has slightly more tube volume than the stock radiator for the V6. The big selling point is 3 rows of tubes, but if you do the math and find that 3 x ~3/8" comes out to less than 1.25" in width, it's not that much of an improvement by total cooling surface comparison. I recently pointed out to an ebay vendor that the two row radiator they were pushing for V8 swaps was actually thinner than the stock V6 radiator. If the tubes in your 4 row radiator are only 1/4-5/16" wide, you have roughly the equivalent of a stock V6 radiator and that would likely explain why it's being taxed with the A/C on.
I looked at some of your photos and noticed something you did that is going to hurt your A/C output, you removed and did not replace the firewall insulation with something more appealing to your paint and assembly work. That is going to cost you and I'm speaking from experience as there's a lot of heat from the engine put into that wall. The next time you go for a good drive put your hand next to the center console vent next to the seat back and on the firewall to get a feel for it. I believe this is a major source of some of the complaints I've read where the A/C is working properly but barely cutting it performance wise.
The car looks great, don't even think about cutting a hole in that hood.
[This message has been edited by Joseph Upson (edited 06-25-2016).]
The reason the insulation is not in the engine bay is not really for looks it is because it left even even less room to access items in the engine bay and it was falling apart, so we did insulation on the inside of the car. It is not hotter in my Fiero than our stock Formula if neither on have the A/C on it is to hot form me without it in any car I am driving I just cannot take the heat. I Will post the results of my experiments with the cooling issue. If you have not read the articles in the links above they are pretty good and informative.
Originally posted by Christine: The reason the insulation is not in the engine bay is not really for looks it is because it left even even less room to access items in the engine bay and it was falling apart, so we did insulation on the inside of the car. It is not hotter in my Fiero than our stock Formula if neither on have the A/C on it is to hot form me without it in any car I am driving I just cannot take the heat. I Will post the results of my experiments with the cooling issue. If you have not read the articles in the links above they are pretty good and informative.
As long as you've accounted for the missing insulation then yes it should be fine. Didn't see anything relatively new in the links having done a good bit of reading on this challenge over the years already. The pre 80s V8s tended to be more sensitive to heat but better metallurgy pretty much solved those problems although old habits and tales die hard.
I ran my TPI 350 Fiero over 100 miles straight at 240 deg on the interstate which was as cool as I could keep it at the time. I believe a pusher fan will definitely be an improvement for you providing a considerable boost in air flow over both cores. Make sure your alternator is up to the task as you'll have two additional significant amp loads normally not seen by the charging system, the additional fan and the water pump combined might up your amp load by as much as a combined 20 Amps or more, plus what the blower motor and compressor clutch add on top of that with A/C on 10 Amps +/-.
It may sound like over thinking but the alternator will generate a lot of heat with a full load and as the temp goes up the regulator will start to turn the current down in an effort to keep it from cooking. If you already have a high output alternator disregard. Let us know what you come up with.
