What do the underbody diffusers look like, and where do they mount. Do they really make a difference?

 

Been a while since I've been under a Z, and that's what I'm referencing...The lip diffuser goes, you guessed it, under the front bumper...I believe, if I recall correctly, the other trays are placed near the rear wheels, filling a gap there...They are meant to keep pockets of air from creating drag and turbulence...I don't recall where on the G they'd go, but those locations are pretty much where I'd guess...I think they make a subtle difference...And of course it depends on what product you use and if that company researched their components correctly, blah blah blah...I'm sure if I felt like it I could look it up and find diagrams, but I'm kinda tired...Hope that helped a little....

"All the Power in the World resides in the Eyes..."

 

They look like flat pieces of plastic panels that are bolted to the underside of the car.

Yes they make a difference, but only really at faster-than-legal speeds. The zero-rear-lift keeps the car from getting squirrely at high speed.

2003.5 G35 Sedan Desert Platinum/Graphite Premium/Sport/Aero/Nav/Winter

 

Bingo...

See? Much easier than me sifting through link after link trying to find a diagram or something...

"All the Power in the World resides in the Eyes..."

 

Boy do they work, my G was smooth as could be last time I was doing 136 on my way to Las Cruces, NM. It was so nice, my mom who was riding in the car for the first time didn't realize we were going THAT fast.

Fasta$$ G...

there goes G35_XTC

 

Hi, Mike. There are two rear underbody diffusers. Their benefit is subtle my sedan was rock solid past 120 MPH. They are triangular in shape approximately 15"x9". They mount on existing studs in front of and just inside of the rear tires. Each diffuser is fastened with two nuts and one bolt. A complete set retails for $89.60. I paid $72.79 for mine. I have them for sale at Parts/Accessories for $50.00 plus shipping.

<font color=blue>Dan</font color=blue><P ID="edit"><FONT class="small"><EM>Edited by dspisak on 11/15/03 04:26 PM.</EM></FONT></P>

 

Were you doing 136 on I-25? I know south of Albuquerque is pretty damned wide open!


Brilliant Silver/Graphite '04 Sedan

 

Thanks for all the replys and info. Dan, I saw yours for sale and was wondering if they were worth it. Also saw they were sold already. Think they help with gas mileage? Congrats on the AMG purchase. Where are the pics of the new ride? Did MB give you a good trade-in value for the G?

 

AB,

I was actually on US 70, going from Alamogordo to LC. It is one straight road.

The best part was when this tricked Civic flew by me (when I was doing 90), I let him get a ahead of me and then I blew by him as I was heading up the mountain. His buddy in some other tricked 4-banger, kicked it in to "catch" me. All I heard was the roar of his engine/exhaust and then poof, he was pulling over to the side of the road...gotta hate when you blow something.

Diffusers work great!

If you see this.....

you must not be driving G




139300-g to LC4.jpg

 

Oh, I've never been on US 70, I didn't know there was anywhere you could go that fast there![img]/w3timages/icons/cool.gif[/img]


Brilliant Silver/Graphite '04 Sedan

 

My take on the aero package from Infiniti's G-35 brochure is that the aero package consists of the rear wing and the diffusers (and maybe some body trim pieces, I don't have a brochure for reference). The package would lower the Cd from .28 to .26 and reduce rear lift to zero.

My reasoning for installing only the diffusers is that while the wing may provide down force it will be at the expense of more parasitic drag. However, the diffusers will reduce lift by keeping the underbody air velocity high, thus underbody pressure low, further to the rear of the car, reducing rear lift with less drag.

The person who was going to buy the Z-tube was iffy on the diffusers. I have not heard back from him so I revised the ad to show that the diffusers are still available. Actually, if I have not heard from him soon I will put the Z-tube back on sale.

<font color=blue>Dan</font color=blue>

 

There are two packages (well, 3, sort of):

Aero Package: Rear spoiler and underbody diffusers. This is the package that reduces drag from 0.27 to 0.26 (in the coupe, from 0.28 to 0.27) and gives you zero rear lift. (Zero front lift is stock, so this gives you zero lift overall.) This package is not too expensive (about $500) -- mainly the rear spoiler.

Aerodynamic Body Kit (5-piece): Rear spoiler, different front bumper, side skirts and rear underspoiler/skirt thing, all body color. This is the expensive package, and does not provide zero rear lift.

Aerodynamic Body Kit (4-piece): 5-piece kit minus rear spoiler, basically so you can have this and the Aero Package together and not pay for the rear spoiler twice. Only available with the Aero Package.

2003.5 G35 Sedan Desert Platinum/Graphite Premium/Sport/Aero/Nav/Winter

 

Are you sure about the zero lift and diffusers? I just went to the website and read the descriptions when you click on the options in the build & price area of the website. The info there is vague and indirect but it seems to point out that the drag coefficient goes down with the 4 peice Areo Body Kit (without spoiler) yet makes no mention of including diffusers. Then it makes mention of the same kit available with the spoiler (5 piece). To make things more confusing, when you select the 4-piece kit it automatically adds the aero package with spoiler. Yet when you click on the full package details it states that you can get it without the spoiler.

So now I'm all confused. I ordered my car with the full package. Does that mean that I won't have the diffusers? Will I need to add them? If so, how much should I pay and how do I know if I have it or not? Are there any pics out there so I know what I'm looking at?

Thanks

On Order:
"04 G35S 6MT Diamond Graphite on Graphite, Full Aero, Navi, Sirius, Premium Coming Mid November (Hopefully)
Till then still driving: '01 AE Maxima SE 5sp

 

As I stated, it makes sense if you think about it. I looked hard at that myself before I purchased.

You get the lower coefficient of drag and zero-lift rear with the Aero Package.

The 4-piece Body Kit requires the Aero Package. It indirectly gives you the aerodynamic benefits.

The Aerodynamic Body Kit is for looks. The Aero Package is for wind benefits.

Although, I'm going off of the marketting that was available for '03. It looks like they've reworded some of it for '04. Maybe you do need both.

2003.5 G35 Sedan Desert Platinum/Graphite Premium/Sport/Aero/Nav/Winter

 

Aha! I found the brochures when cleaning out my desk. One of the footnotes says "Zero-lift front aerodynamics standard; zero-lfit front and rear with available Aero Package." This same sentence is repeated in two different brochures.

2003.5 G35 Sedan Desert Platinum/Graphite Premium/Sport/Aero/Nav/Winter