Lower Grill block that can open and close

[Weather Spotter]

From my trip today, I need to allow more air to flow through. at 50-55 it was floating at 202F (fan on at 206). At 55-60 the fan would come on every few miles.

I am thinking I need to leave say 8" open all the time and just close the rest when needed.

Ideas?

[Patrick]

I know this goes against the conventional wisdom on this site, but I think you may be right in the sweet spot. If your fan comes on briefly each time you know that you are getting maximum cooling drag reduction. If the fan never comes on, you don't know if you are at optimum - you may be accepting additional cooling drag unnecesarily and you have no way of knowing. Yes, you are going to lose a little bit of power with the fan, but you know you are right on the edge of optimum performance. Just make sure the vehicle doesn't overheat at any time. So, bottom line is I'd leave it the way it is. JMHO.

[cfg83]

Patrick -

Interesting. My fan has a 30 Amp fuse, but I *guess* it uses less amps than that.

Question: What is an acceptable *average* amperage draw from the cooling fan over time? Let's say that my 30 Amp volt fan is on for 2 minutes of a 30 minute drive. That's :

(30 Amps * 2 Minutes) / 30 minutes total = 60 / 30 = 2 Amps average.

CarloSW2

[NeilBlanchard]

Have you blocked off the "chin" panel on the plenum just ahead of the radiator? This forces more air through the radiator, and lets you run with a smaller opening. A louver cut into the hood just behind the front crest of the hood and behind the radiator would also help the air flow, according to Hucho.

[Patrick]

Originally Posted by cfg83

Patrick -

Interesting. My fan has a 30 Amp fuse, but I *guess* it uses less amps than that.

Question: What is an acceptable *average* amperage draw from the cooling fan over time? Let's say that my 30 Amp volt fan is on for 2 minutes of a 30 minute drive. That's :

(30 Amps * 2 Minutes) / 30 minutes total = 60 / 30 = 2 Amps average.

CarloSW2

Well, ideally you would have just enough block that the fan was just on the edge of coming on, but never did. I'm not sure how you would set that up; maybe if you had a good enough temp gauge you could monitor that and set the block so that you were 1 degree below the fan switch temp. On some aircraft they have manually adjustable "cowl flaps" and the pilot opens or closes them to keep the engine temp within an acceptable range. The flaps are infinitely adjustable within their operating range.

WRT the fan power consumption, 2 amps times 12 volts = 24 watts on average.

24 watts divided by 746 watts/horsepower = .032 horsepower used by the fan on average. I don't know if you would lose more than that by having the block open too far, but I think it's a possibility.

[robertwb70]

Two things come to mind, since you have a more restrictive inlet now you can either reduce some of the new restriction or improve the airflow out of the engine compartment like Neil suggested, but I don't think you want to cut holes in the car so we'll skip that part.

Those vents actually have 2 sets of louvers at 90 degrees to each other, the movable ones and the fixed ones, it looks like the fixed ones block about 50% of the opening when the others are fully open so I'd reduce that by removing some of the fixed obstructions. Might think about removing them in blocks of 2 or more or maybe every other one since they are probably needed to support the other parts but certainly not all of them are necessary.

(I was thinking about the original vents, not the current setup)

[Piwoslaw]

Originally Posted by Weather Spotter

From my trip today, I need to allow more air to flow through. at 50-55 it was floating at 202F (fan on at 206). At 55-60 the fan would come on every few miles.

I am thinking I need to leave say 8" open all the time and just close the rest when needed.

Ideas?

If I recall correctly, you have two power lock motors, right? Well then make two smaller vents instead of one big one. Both should be closed when you start the car, then open one vent if the fan keeps turning on too often. Open the second vent only when the first isn't enough. Ideally, the vent that stays open longer should be in the middle, but where you put it depends on space limitations and on how your radiator is situated.

[Weather Spotter]

Good ideas, I will have to think about them.

As for being in a sweet spot for temps, I would disagree. My dad works with car electonics for work, he said that the underhood temps can greatly shorten the life of the electonics. I think that allowing a little extra air is a good thing.

[3-Wheeler]

Originally Posted by Weather Spotter

....I think that allowing a little extra air is a good thing.....

I have a Honda Insight, and as you know this little engine doesn't make allot of heat, summer or winter.

However, a trip to LaCross Wisconsin earlier this summer taxed the cooling system to the max.

I usually run the car with the lower grill block completely closed off except for a small patch in the middle. When getting ready for the trip to LaCross, I removed about 1/2 of the lower grill block in anticipation of the large hills in the area.

Over the last 20 miles or so, the terrain gets real steep and the ScanGauge indicated that the coolant got to 213°F on several of the larger hills, and this was after removing the other 1/2 of the grill block.

When I get a chance to make an adjustable grill block, I will ensure to allow fully closed to fully open capability for instances as above.

Jim.

[Weather Spotter]

On my trip back home today the fan did not come on at all. Outside temps were between 50-65F and the coolant temps were between 184- 198F. I think that I may only need a slightly larger open area.

I also found that the air pressure has bent the colorplast in enough that it will not slide. I would need to add some more bolts to hold the sliding piece to the stationary one but I will likely try to remake the grill block instead.

I am thinking that I might make it with the grates again, but make it default to the open for half of it. the other half will need to be counterbalanced or have a spring to keep it in whatever place I put it. I think that for short trips (into town) I will keep this side closed (and most of the winter, since I only had a 4"x3.5" opening last winter). On longer trips I will need to be able to open both sides.

I think I know how to make the one side be open unless I keep the actuator powered. I am not sure how I want to do the other side.
Ideas?