So Areodynamics?
 

What are the most effective areo mods that people do to their cars?

I have access to a lot of goodyear conveyor belt. I am planning of making a air dam extender out of it. It is pretty heavy but I think it could work good and be basically indestructible.

What are your thoughts?

adjust the driver.

Driver mod is the absolute most effective thing you can do. It's not just a single thing that can be explained in response to a new user's introduction post, either; each person has to read about all the different things we do and decide what will work best for him.

There are some vehicle modifications that can be done. Most of them are small and have little effect. A few are small and have a decent effect, and most of the large ones can't pay for themselves even when gas is $4/gallon.

The first vehicle modification I always recommend is to find the highest comfortable tire pressure you can use (without exceeding the tire's maximum, stamped on its sidewall). This can have quite a large effect for some people.

What engine is in your Grand Prix? The 3800 is known for being a great engine all around -- great efficiency, great power, great longevity.

Yeah unfortunately i have the 3.1 I have been planning on putting the tires around 40 for a while but I am not at my house and dont have a compressor.

I have seen good reports about the 3.1's fuel economy. I had the 3.1 in my '97 Grand Am and it died prematurely, but I think that was due to my abuse. I have no idea what kind of fuel economy it got, that was the furthest thing from my mind at that time...

This tank I am trying to be a more efficient driver. I am just starting with not jumping off from stop lights and trying to time getting to the light when it is green and coasting as much as possible. I also am using the cruise control more.

My motor has been through hell. I am very surprised that I am getting as close to epa as I am. I am the 3rd owner of this car but I know both of the previous owners and, just to show maintenance, Im about 90 percent sure that when I got the car with 135,xxx miles that it had the original brake rotors. And that it has never had a tranny service until I did it. While I have owned it the water pump went out and overheated, blew an intake gasket and ran with a coolant oil mix for lubrication for a good 10 min while I limped it back to my house, I had to it was in the middle of no where with no way to tow for at least a few days.

All fixed up now and I might have 700 in the car including parts and such.

Here's a good thread on aero mods. Also check out the threads in CO ZX2's signature. He's seen some fantastic results. www.gassavers.org/showthread.php?t=2173

I'm gonna guess that if the belt material flexes under the force of the wind at speed then it may not be that effective. I spose if ya brace it really well it won't flex much though. How much of it extending down are you planning?

Its half inch thick reinforced rubber. It might flex a little bit but I think that if it had any curve at all it would stay rigid.

Thanks everyone Ill look into some other stuff on this site there seems to be a lot of info.

My goal for this tank is 300 miles.

300 miles? In town type driving? that should be easy, in the winter I can get 350 miles on my GP, '02 with the 3.1L. Granted you have quite a few things stacked against you, but I have faith. Tis a shame that GP was so abused, they are quite nice cars when taken car of.

The 3.1 is not a bad motor. I have it in a 99 Cutlass with 150xxx miles on it and it is peppy and comfortable to drive and very economical on fuel for it's size. It will get an easy 28-30 highway during the summer. Right now with all the cold weather and winter gas it isn't as good.

No mostly highway. I achieved 331 this tank but Im going to say that 300 of those were on the highway at 65 with the cruise on. I really wish this car would have been taken care of a little better but then I probably wouldn't have it. Maybe o2 sensors could help but they are so expensive it would take a while for the mileage to pay for them.

Where does your temp gauge sit? I always think mine runs cold. it sits at the mark between 160 and 210. In my Camaro it always says right at 210.

Yeah, that sounds right. If I get up to 210 its because the thermo is sticking or its 110*+ outside. Mostly when running open its around 175-185. I put some cardboard in the grill openings and raised it slightly for in town driving, but I still can't get past 200 for normal driving in the winter. Summer was the same without the grill blockings. I've got a replacement for the thermostat since I don't like it sticking. Last time it stuck it raised to 240 before kicking open, way too hot in my opinion. After opening it usually drops to 170 or so, so I know the cooling ability is very high.

That motor has potential, if you can get it back to good standings. I've logged a few 510 mile highway tanks, one was with 5 people and cargo, so I know 35mpg loaded is possible.

If you can, swap all the fluids to synthetic. I've found that synthetics from intake to wheel has improved my FE a little bit, enough to offset the higher cost.

Hey, I would assume that gm or someone did some aerodynamic testing on a car very similar to mine. Does anyone know where to get pictures that would show how air flows around this body style?

Im looking into making vortex generators before the rear window. But I dont know exactly where I should put them or how tall they should be.

I also think I have rethought my initial thought about just extending the existing air dam down. I am now thinking about making some kind of underpan that would go the entire width of the car and include some kind of tire deflector into the design.

I had another idea about using a model of my car and doing some low budget air flow testing with a few fans and some punks for lighting fireworks to see how the air attaches the the deck lid. And then maybe doing scale modifications to the model and testing them before investing in the larger materials to do the real car.

Also just changed the fuel filter hopefully that will free up some mpg.

Okay, so I think I found another large aerodynamic problem on this car. When Im going down the highway the hood kinda flaps then when I inspected the front of the car I realized that the hood sticks over the bumper a little bit and there are huge gaps between the headlights and the hood.

When I tried to move the hood it barely budged. I think that on the highway there is air getting under the hood and actually pushing the hood skin up in the middle.

Is there anything I can do about this? I already tried to adjust the hood back and it was already all the way back.

I was thinking that some weatherstripping on top of the headlights and the bumper could keep air from getting in there.

Yes, use weatherstripping along the front of the hood. Hardware stores will have a self adhesive weatherstrip that can be cut and shaped to fit.