Rear diffuser in the making
 

Been working the idea for a few weeks now. The abs sheets came in last week and well this is what I got so for. This is the first "working" model I have done. The next will be wider on the drivers side and a filler panel for the passenger side of the muffler. Also I have the perfect piece left over to be placed on the axle. The familiar diffuser slates will be on v2. As for "does it even work?" Yes! the car is more stable at freeway speed and beyond. Its more of a mpg saver mod or suppose to be atleast anyway. Reduce drag yadda yadda you get the idea. But that remains to be seen. Anyway on to the pictures.
http://img.photobucket.com/albums/v2.../DSCF16913.jpg
http://img.photobucket.com/albums/v2...a/DSCF1698.jpg
http://img.photobucket.com/albums/v2...a/DSCF1697.jpg

Nice startin to look like a Ferrari under there

looks nice...ive thought about doing it

wind tunnel proof it works? :wall:

Oh, of couse I got an appointment sheduled for next friday at Delta's windtunnel and umm dyno results.....myea :ugh:

its its visible i think it will look good with your black lip...like a splitter and diffuser

Cool idea!

I like that idea, your maxima looks really cool with the black front lip and now the black diffuser for the rear. Nice look!!

looks amazing, you could definitely get a GB for this.

Where's your RSB? :nono:

+1

+2. Looks good, and if there is a decent price and benefit involved, you'll have buyers man! Keep it up!

wow, looks great...., VERY clean

Thanks for the kind words guys. As for a GB, well I never planned to produce these just trying something new since I havent seen it done yet.

I wonder if you did this to the whole underneath of the car and made channels for the air to flow, would the affect of highway speed driving be beneficial?

Not really a believer... maybe if you have one large sheet that covers the whole undercarriage.

Ive considered that too trust me, but its alittle beyond what I want to do at the moment. This panel came in at 33"x36 or so, with the way the mounting braket turned out the next will be 48"x38" with a cut out for the muffler obviously. I do plan to make one for the front of the car as well to attach to the lip and run a couple feet back to the engine.

nice job....

If you made a DIY, it would be helpful and really cool to work on something like this.

it look to me like it would just create drag and channel air up into your bumper. at least from the pic it does.
the whole problem our cars have is it acts like a big scoop back there especially with the rear lip or any aftermarket bumper.

can we see more pics possibly with better lighting.

i'm not trying to come down on what you are doing i'm just skeptical. also does this get in the way of a RSB?

rsb > air diffuser

The panel does have a decent sized lip on the front of it so it doesnt channel air up into it. Believe me that was a major concern. I wasn't totally satisfied with its placement despite that fact. The front was just too low. It was slightly lower than the leading edge of the axle and I wanted it more inline with it. Well thats what prototypes are for I guess. The next one will be higher in the front and closer to level than the one pictured.
As for the RSB, um i dont see the need for one at the moment. My car had Eibach springs and Tokico Illumina struts, I don't really have much body roll. In any case the panel that I am going to attach to the bottom of the axle will leave no room for one. Im sure it can be mounted lower to allow room, but then it would be lower than the gas tank which I dont want.

thx for the details. i almost filled in the holes in my rear lip but my main concern was airflow. i'll be interested to see how this goes...

will be interested in seeing how it works out, though I share concerns of it scooping air and causing drag rather than reducing drag. With a IRS car you would be able to run the front edge up to the body to eliminate that problem. I'm not sure what the workaround is with that beam axle in the way, though...

I was thinking of doing this....

http://www.nicoclub.com/articles.php?id=189235
:hide:

IBdues but dues did a nice job

From all the aftermarket diffusers I've seen for IRS car their designs could all potentially scoop air. The front of the panels are just narrowed and run to the rear suspenion mounts. You still have air flowing through the arms and axles. Im gonna mount a small panel as I said a few times before on the beam itself. I can get the leading edge pretty close to the gas tank so Im not too worried about it.

http://img.photobucket.com/albums/v2...722082223a.jpg

Looks good, nice job so far.

Any updates on this?

looks great, may try this myself.

that looks great bro..job well done

Havent taken any good pics yet and it still needs minor fitment adjustment

http://img.photobucket.com/albums/v2...a/DSCF1705.jpg

thread added to how-to sticky links....

So, you see any improvements in mpg yet?

Is there a how-to or am I missing it? :confused:

is there any gains proven?

moar pics.

Yes, but only at freeway speed. Using the carputer as a guide i've avg 33-34mpg @ 60mph where I used to avg 30-31. This is on a familar stretch of road. At 70mph I avg about 30-31 vs 28-29. Now we know that the our carputer mpg is usually 2-3mpg higher than realitly so keep that in mind. But as it is at the moment I've seen a 2mpg decrease in fuel consumption, which it about what I figured. I haven't had the chance to make any long highway trips lately, just here and there. The most I got out of a tank before the dte light came on was 405mi, so if I can get 420-430mi I will know for sure it is doing its job.

Now as for handling, oh yes it makes a difference on the hyw the car no longer feels like it has a fat *** switching lanes quickly. Far less tire swirm in the rear that before.

This diffuser is a work in progress, there are some little modification that I want to do to it yet. And I still have yet to finish the panel for the rear axle. This peice will make the car flat from the gas tank to the end of the bumper. As for the front underpanel well the material and the idea are there, but gotta take it one step at a time. Ill try to snap more pics today.

if nissan could improve their mileage by 2 or even 3 mpg with the addition of a $100 part wouldn't they have done this from the factory? nissan knows all about diffusers...

not trying to say you didn't achieve better mpg i'm just curious...

another 2-3 mpg is a HUGE selling factor especially when cross comparing similar cars. i only add this because i'v sold cars and know how much mpg means to people...if you look at the window sticker off all the options etc the 2 biggest numbers in bold in huge font are the mpg city vs highway


glad to see it helps!

it would have cost nissan a bunch to engineer those little things, plus they would need to be more secure than his will be and the materials price would add up. considering that most people dont make much of a deal about 2mpg when buying a car, they figured the extra several million to do it wasnt worth the thousand extra cars they would sell. remember, this was engineered around 2000, when gas was still pretty low

Well you r right, nissan does know about diffusers they are on the some G35-37s and the GT-R, but the little tacked on panel I made if is alot different from and finish factory piece as you know. For the most part companies see rear bumper covers as just that a cover for the rear bumper. Have you seen the Pontiac G6s? They have a diffuser looking plasic peice on the bottom of the bumper and its just there to look like one, the thing literally flaps in the breeze on the expressway.

And like someone just mentioned when the maxima first came out gas was like $1.15.

http://img.photobucket.com/albums/v2...a/DSCF1712.jpg

http://img.photobucket.com/albums/v2...a/DSCF1709.jpg

:sprint:

How many people in 00-03 were really paying close attention to 1-2 mpg difference when they bought new cars? At least I know I wasn't.

How-to:

Look at the pics.
See how he did it.
Do something similar.

See, that wasn't so hard...