I am currently developing my "ion XFE" concept into a real car. part of this effectively cuts off any ram cooling air for the winter, and modifies it for the summer to make it more fuel and cooling efficient. I block the grills with corrugated plastic held on with zip ties, the under side of the car gets a belly pan (held in by existing and 2 additional plastic rivets) that keeps the air going into the radiator better while improving coefficient of drag. you cannot block both grills any time it is above about 40, though, only the top one. this will improve fuel efficiency, reduce packed snow, and should stop the car from not making any heat at long stop lights in really cold weather. it will also decrease warm up time significantly.

in the summer, it's cooler, in the winter, it's warmer, it's all easily removable and held in without drilling into metal. I have a sedan, but with a short amount of time, materials, and a car, I can adopt this concept to any car. my research will apply to american delta platform cars. it will let you go faster (higher top speed), more efficiently.

currently I have "stage 1" done. I have effectively increased coast down from 70 to 40 by 15%, my goal is to get much higher. currently the car looks like an ion with a blacked out grill. next starts "stage 2": advanced under car aerodynamic modifiers. then "stage 3": wheel and tire aerodynamic fairings. after stage 3, I believe the car will be complete, but time will tell. I am also closing up some body gaps, since it is an ion, but do not expect a big drag difference so much as a wind noise difference. speaking of which, the car does seem quieter already.

 

well you've done some tard stuff before but i'd like to see what you come up with

 

pics?

 

I need to take some. then I will post them. right now it's pretty simple stuff, but it's netted some interesting gains for having used $15 of materials. ~5 more seconds 70-40 coast down, and 4MPG at 65. honestly, if you didn't care about the big picture, you could get close to this with just the one mod, but everything so far has made a positive difference in one way or another.

 

here they are, the upper grill block is still in mock up form (it's just "tacked on" for a visual), but will not be much longer. these mods have been on the car total (mock up to present) for almost 400 miles, and have undergone highway stability, noise, and efficiency testing. all of the above has improved, and I am far from done, aerodynamically.

the rear under tray is the most significant drag wise, but I am not done, I need to add a bit to it, still.

 

i like the rear.. with the front.. you should have an opening though... that flap is there to direct air onto the radiator

what about one for the rest of the underbelly? also.. how will this hold up to heat?

 

no, if you actually look at it, the radiator ends right about where the grill starts. I recorded temps (intake and engine) before and after these mods, and it is cooler after because of the front under belly panel I added. it held up to a 90 degree day just fine, with the AC on, no elevated engine or intake temps. on redlines or ss/sc, ss/tc, I would not recommend the grill block in the summer, though, without careful testing. also, in heavy stop and go traffic I would recommend removing it. the rest of the under belly (and even the nose, the front belly pan is for cooling) is aerodynamically fine. it may not be perfect, but it is about as smoothed as a 3rd gen prius by looking at the two.

my next step is wheel/tire aerodynamic deficiencies in relation to under car air flow.

under car drag is ~30% of total drag, the wheels/tires are about another 30%, so these are my areas of focus

 

if you say so

 

I do want to mock up a full under tray if I get like a fridge box, but I would need a lift so I could install it. As far as how much drag what part of the car produces what percent of total drag, I don't say so, some really smart aerodynamicist does.

 

i meant if you say so with the temps.. when my flap got knocked off i immediately started running hotter

 

so u gonna hit me up with the green you're smoking or what

 

did you ride the short bus to school?

 

, Oh, you're talking about the air dam. That isn't supposed to affect cooling, it's primarily aerodynamic in function.. Notice I say primarily. Also, I have yet to test this on a coup. Your bumper cover might be different aerodynamicist to the point where these act differently. I intentionally monitored both temps meticulously, anticipating problems.

And why do I need to be smoking something for aerodynamic fairings used on production cars to make a difference?

 

^ bc you are taping cardboard to your car and being dead serious about it

 

Cardboard is only for mock up and proving how effective it is. I then make a permanent piece out of aluminum or plastic depending on the purpose and location. No cardboard is permanenT.

 

lol you think a random flap underneath is there for aerodynamic reason.. if anything it's going to hurt them.. sigh..

 

Thanks for the post. You made my day.

 

Depending on the car, it can help or hurt. And it's far from random

.air dam: Definition from Answers.com

The only time they should hurt aerodynamics is when you are lowered with a full under pan. But, yes, they are aerodynamic modifiers.

 

Dude...the BEST thing you can do is regear the final drive ratio...and change your tires to something with an insanely high treadwear rating which usually coincides with rolling resistance. And btw, don't block the air dam, it creates a pressure wave at highway speed to direct airflow to the radiator, and actually increases aerodynamic efficiency on your front end by creating a static high pressure area directly in front of your radiator...which is how they were designed. And of course do a tune up, run all synthetic fluids, detune your engine, buy a higher temp thermostat, check and replace any brake component that drags even a little bit, take apart your halfshafts (cv joints) and replace the stock grease with a synthetic grease made by Mobil1 just for cv joints. And of course, change your driving style.

I've gotten more than 40mpg in my SS/TC on factory tires by being creative with driving, messing with tire pressure and drafting large trucks.

 

take the rear window out.

 

That's why at highway speed I get a measurable and repeatable drop in drag. Also, I have done everything else you said, besides the tires. Improving aerodynamics quiets the car down and gives you a higher top speed, and improves track times, but go ahead and call me crazy.

 

I'll be watching this with interest. I doubt I want to go as far as putting on fairings, but if a couple discreet mods help with winter mileage and keeping the car warm, why not?

 

Your factory thermostat and letting the car warm up berfore you drive it, is all you need in the winter

 

The grille cover and the rear underbelly covering are both good ideas that are proven to work. Just be careful with the one covering the bottom of the diffuser.

 

I am intrigued by you interest in getting better fuel economy. A few months back I was reading on gassavers.org and it is silly/unsafe/ "what the hell are you thinking" for some modifications they are making to gain a 1/10 of a MPG. Not mention how hack some of them are or how silly some of the cars look.

However

I am sceptical of the result you are seeing. I agree a splitter, diffuser, and bellypans will give you better mileage. But you are claiming that you are seeing a gain of 4MPG from a rear bellypan and blocking front lower bumper. That kind of gain is HUGE. If it was that easy to gain that kind of mileage I think the OEMs would invest to few bucks to make some bolt on belly pans if that kind of HWY MPG improvements could be made.

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