grille wind deflector

[readytogo!]

I am not sure if this has been discussed before but I was wondering if an insert behind the grill openings would improve mpg like the cruze, also letting less cold air go into the engine bay should help too?

On the other hand, would this have any negative effects?

 

[Swordsmith]

There's at least one person on this forum who has blocked off half his grill for the winter.

The upside of this is that it can decrease drag and cool the engine less (which, in Canada in the winter, is a very good thing)

The downside is that it will cool the engine less.

The Cruze has a more advanced version of this, which opens and closes as needed, so it would be (for example) closed when you start and for the first few miles of driving, then open up to help keep things cool while you drive around town, but close again at highway speeds, when there's plenty of airflow with the smaller opening.

The "plate to put in place for the winter" is clever but the automated louvered device is genius. On the other hand, you can probably do the clever one for under $10, and it would probably cost a couple hundred to DIY an automated one.

I hope you do the latter, and post clear directions on how you did it.

 

[River_Rat]

I can't say that it has improved mpg or substantially reduced engine warm up time, but it doesn't seem to hurt. No negative effects so far.

 

[trollbait]

A grill block is generally the first step for ecomodders. It does improve warm up times and aerodynamics which will help MPG. How much help it provides depends on the specifics of the car and the drive.

It will reduce overall cooling, but the cooling system is oversized for the daily driving most people do. It is designed for the possibility of being needed for hard driving in a desert.

Depending on what and how much is blocked, it can reduce AC output.

I do recommend having a temp gauge of some kind. Also, don't block the intercooler or any transmission coolers. An option to go with the grill block is to wire in an LED to let you know when the fan is kicking on.

PS River Rat, where did you get your grill block?

 

[River_Rat]

Home Depot for a sheet of acrylic: 24x48x.093
Autozone for a roll of door edge molding.

 

[trollbait]

Home Depot for a sheet of acrylic: 24x48x.093
Autozone for a roll of door edge molding.

You did a nice job. Couldn't tell it was DIY from the photos.
How did you mount it to the grill?

 

[River_Rat]

Thanks. A piece of cardboard would probably be equally effective, but I enjoy little DIY projects. I'd say it took me three or four hours to complete. Cutting and shaping acrylic is kind of a PITA, but it makes a pretty nice finished project. Just two little zip ties keep it fastened to the grill, which allows for easy removal should the need arise. There's plenty of air pressure at speed to keep it in place.

 

[trollbait]

Cardboard has worked well for me in the past. That was on vehicles with easy access to behind the grill though.

I found packing tape works well enough for testing.

 

[mitdr774]

I was having an issue with the the car loosing temperature on the highway. Blocking most of the grill has solved that issue. I have not had any issues with running too hot since putting on the grill block.

 

[River_Rat]

I see that you've added a partial lower block. I'm a little concerned about blocking the intercooler (I know that you don't have one), although I have not had any issues with it getting too hot. Mostly I haven't bothered because I haven't really had the time to fight the acrylic to shape a lower block.

It could just be in my head, but I feel that the car is a little squirrelly on the highway since adding the block. I've really not been up past 55 or 60 in about 2 months.

Going to have to get a daylight shot of mine. Maybe I'll remember tomorrow.

 

[mitdr774]

With the current temps I feel that an intercooler would still sufficiently cool things down. The grill block has reduced my warm up time with the current temps, and allows me to stay in a proper temp range on the highway.

 

[readytogo!]

thanks for the replies everyone!!(I have the 1.8l) I was definatly thinking I would devise an upper grille portion air block but for the bottom I was wondering if it would be more efficient to make an air deflector that would not be flat against the grill forcing the air up and over the car but one that I could place behind the grill angled towards the ground .

I had this thought because I figured that if the air wasn't flowing through the grill straight into the radiator like a brick wall and being deflected at a less abrubt angle to force the air under the car, it would be more efficient(in theory)

 

[mitdr774]

Spent some time on the roads today. Mostof the driving was on the highway with speeds in the 45-60 range. Ambient temperature was 16*. Once the car reached the stock tune operating temperature it remained fairly constant. Coolant temps were in the 219-221 range for the drive time after warming up. I do not have a light hooked up to the fan to let me know when it is running, however I had to run the front defrost for most of the time. Assuming it was not cold enough to prevent the A/C compressor from working, I have to assume that the cooling fan was in fact running for most of the drive time.

 

[readytogo!]

related to the air temps going into the engine bay, would switching to the factory air box for the winter yield better mpg?

 

[mitdr774]

I run the Injen intake and going down the highway my intake air temps seem to run higher than ambient. I suspect that a stock air box would result in near ambient temperature.

 

[$ub$onic]

My ddmworks runs 6-8 degrees above ambient

 

[readytogo!]

forgive my ignorance, but wouldn't that the intake is doing the opposite of what it is supposed to do? or am I wrong because they aren't actually" cold air intakes". I was just wondering if running the stock air box(with k&n drop in) would produce better mpg due to the fact that I isn't taking in air from an open filter.

 

[mitdr774]

I am running what is often referred to as a warm air intake. I wanted an intake that would draw in air from the engine bay. This air should be warmer and as a result provide a slight bump in economy.

 

[trollbait]

With the current temps I feel that an intercooler would still sufficiently cool things down. The grill block has reduced my warm up time with the current temps, and allows me to stay in a proper temp range on the highway.

In the winter I wouldn't worry. For summer, I have decided against the lower block because a turbo can go into a positive feedback loop in regards to heat. The exhaust is always going to be hot, and thus the turbine. Some of that heat is conducted to the compressor. Which in turn will further heat up the intake air.

With airflow going to the intercooler restricted, the heat going from turbine to compressor can start building up, and eventually further heat up the engine bay more. This is good for mpgs, but possibly not component materials. I believe the risk of something breaking because of this is small in a non-performance turbo like the Sonic, but the fuel economy gains will be too small, if there, to run the tiny risk.

thanks for the replies everyone!!(I have the 1.8l) I was definatly thinking I would devise an upper grille portion air block but for the bottom I was wondering if it would be more efficient to make an air deflector that would not be flat against the grill forcing the air up and over the car but one that I could place behind the grill angled towards the ground .

I had this thought because I figured that if the air wasn't flowing through the grill straight into the radiator like a brick wall and being deflected at a less abrubt angle to force the air under the car, it would be more efficient(in theory)

Any air that gets into the grill will go through the radiator. You would have to remove an underpanel, or cut a hole in it for your idea to deflect air down to have an effect. In which case, blocking the lower grill and putting an opening in that underpanel so the radiator is sucking air from underneath the bumper will likely have an larger effect.

Getting behind the grill also means taking off the front bumper and grill unit.

related to the air temps going into the engine bay, would switching to the factory air box for the winter yield better mpg?

The factory box is an cold air intake. Warm air intakes are what you want to try for better fuel economy. Even if they don't improve engine efficiency, they will help speed engine warm up. I've heard of older cars actually having diverting flaps to suck in bay air at start up for that reason.

You can experiment by simply removing the snorkel that brings the outside air to the air box. Should be fairly straight forward. Start by removing the air box itself.

 

[Opticon]

The exhaust is always going to be hot, and thus the turbine. Some of that heat is conducted to the compressor. Which in turn will further heat up the intake air.

Heh, that's silly. The heat in the intake charge after the compressor is a direct result of compressing the air. And NOT cooling that intake charge will result in pre-ignition (detonation) and the retarding of ignition timing. Which would be the most "not good" thing for MPGs.