Festiva Aerodynamics

[jwxr7]

jwxr7 I though you had a SG. Mine comes on at 211 degrees. I run around 200-205 when moving.

No, I wish. My geo is obd 1 anyway. I'm not even sure what temp my fan is supposed to come on .

[VetteOwner]

hmm ive been thinking about installing an Efan on my chevette, buti have no idea what temp to have it come on...i guess i could hold the upper radiator hose and have it kick on once i feel the hot coolant flow thru... an dturn it a bit past that point

[brucepick]

I put an e-fan in my ride, took out the old clutch fan. Put sensor in lower radiator hose. Mine comes on at about 83 or 85 deg. C. I definitely think the e-fan is a winner. Poor little underpowered 115 hp
engine doesn't have to spin the clutch fan all the time any more.

I tried sensors in the upper hose, they came on too late or as soon as I got up to highway speed. That water is supposed to be hot.

I also rigged a relay to trip the fan at low speed off the brake light circuit. This does make it run sometimes when not needed but the coolant rarely heats up past the usual setpoint. That means the temp switch in lower hose really only serves backup duty in case my wife or somebody idles the car with foot off the brake. And the low fan speed is not taxing on the fan motor or the alternator.

[VetteOwner]

LOL 115 is not that underpowered... a chevette 1.6 L engine has 68 HP. a stock 2.2L 4 cyl s-10 has 90 somehting... 115 would be nice to have in either one...

i have an efan in my truck that has helped (maybe 3mpg or so)

but the chevette doesnt even have a clutch fan. its fan is just bolted straight to the water pump shaft...thats why im lookin for a way to do an efan...get a few more hp and torque out of it and a bit more MPG. BUT im not sure if the stock alternator (that is the origional 27 year old one mind you) has enough juce output to run a fan (can draw ALOT of amps)... unless i find a low speed one.. then maybe...

[SL8Brick]

One of my neighbors has a nice, red Festiva with a custom-fit rear spoiler. Its a diffusor-type wing(w/center air dump port) thats mounted to the top of the hatch. I'm not sure what mfgr originally made it.

[XFi]

There was a factory wing available. It was mounted on the top of the hatch, it may be a factory spoiler.

I am holding off on a spoiler and think I am going to put on vortex generators (air tabs) along the rear roof line of the vehicle.

[Silveredwings]

I think you're correct to avoid the spoiler. Most of them are for looks and just add drag. Maybe a small boattail that looks kind of like a visor facing back?

From what I've seen from others who've tried them, I don't think the Festiva's shape will benefit from VGs. Anyone else know differently? They do add a little drag but the idea is to prevent laminar flow separation instead of turbulence. You'd need a trailing surface angled much closer to the slipstream than your rear window is.

That said, it's a relatively cheap and reversible mod. You can tape some yarn tufts onto the rear window and see what they do as you drive.

[XFi]

I was under the impression that the boxier or more harsh the angle of the rear window, the more that the vg's would improve cd. I am by no means knowledgeable on this subject, but I remember reading that somewhere.

[Silveredwings]

Yeah, I don't have any experience with VGs on cars. Most of my knowledge is from their use on airplane wings to decrease the stall speed. Of course they add parasitic drag that increases with speed. They reduce cruise speed/efficiency so that's why you don't see them on most planes.

[Telco]

Originally Posted by VetteOwner

LOL 115 is not that underpowered... a chevette 1.6 L engine has 68 HP. a stock 2.2L 4 cyl s-10 has 90 somehting... 115 would be nice to have in either one...

i have an efan in my truck that has helped (maybe 3mpg or so)

but the chevette doesnt even have a clutch fan. its fan is just bolted straight to the water pump shaft...thats why im lookin for a way to do an efan...get a few more hp and torque out of it and a bit more MPG. BUT im not sure if the stock alternator (that is the origional 27 year old one mind you) has enough juce output to run a fan (can draw ALOT of amps)... unless i find a low speed one.. then maybe...

Wow, a straight fan? You would see a considerable improvement going to electric fans. Any time you have the engine running you are beating the air to death. You want the fans to come on at about the same temp as the thermostat, so if you are running a 195 degree thermostat, you want about a 190-195 degree switch to turn the fans on. You also want the fans to come on at least 50 percent any time the air conditioning is on, as no airflow across the condenser will cause the AC to overpressure when running due to heat buildup, and blow the AC system. You can either do an aux fan just for the AC, or get a good controller to run them. I use DC Controls on mine as it allows you to manage the coolant temps more exactly than the head switches, AND brings the fans in slowly so as to not put a sudden, huge drain on the electrical system. This system has an AC tap, and if you have overdrive with a lockup converter you can install a relay on that to shut the fans off when the AC is on, but the converter is locked as this will only happen at 40MPH or so, plenty fast enough for the AC with no fan. It is pricey at 100 bucks, but well worth the money IMO.

For my 96 Tahoe I had a custom shroud built, for the 87 S15 I just hacked in a single fan into the factory shroud. The custom worked tons better, but the hack job was quick and allowed me to get some other work done that required the fan. Eventually the hack job will go away for another custom job, but it suffices for now. Yes, a larger alternator is required, look into a GM CS-100 alternator. This will provide more than enough power for efans in a Chevette even at idle, and I'd have to wonder if running a higher powered alternator at a lower load puts less drag on an engine than running a lower powered alternator at capacity.