i have been waiting to long for any shop to come up with full under tray without any luck. so, i decided to build full under tray , front diffuser , mid section , rear diffuser for 350z. i have the time , money and my friend body-shop garage that is willing to do this kind of job for me.

i need my350z forum members to help me prototype a design for our platform.

my time line start form now until march of 2012. the work should not take more than a week the body-shop says all work would be done in my country KUWAIT. so that give us a good amount of time to figure a prototype under-tray.

my inspiration came from AMS evo 7 227mph run plus other cars that i came across from different platform

i was thing king of the following aspect that should be covered

note,
-materials must be or some thing similar to it : aluminum
-design must be for stock body 350z.. no after market front bumper ..etc
-racing oriented design
-can be easily installed and taken off the car if needed
-where should i place vents?
i know that i need it for differential (LSD), maybe cut rear bumper for air flow ...etc
-heat issue if any ? exhaust , turbo (since my car is turbo charged ...etc)
-fins where should they be placed ?
-washing car ( water escape route )


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any input would be appreciated , if i forgot any point your welcome to add any

 

If you have the money then I see this as an easy task! Think of it this way, a flat piece of aluminum covering the bottom of your car. Have a shop form it over the tranny. Cut it into two even four sectional pieces that interconnect. Then for function cutting scoops that would grab air for vital areas, and vents to let air/heat escape.

It's not rocket science.

 

the problem is the body-shop have done it only once and it was full closed under tray mean no vents no curves.

where i'm looking to do diffusers and use some vents. where should be the vent placed to minimize any heat sock.

with a picture of 350z using 2D design that would help alot and make it easier to follow up and edit on the design as we go along

the following pictures of different cars from different platform to give an idea of functional under tray

 

Roger well your on the right track compiling those pics!

I'm sure someone else has more to post on this topic. We did have a company look for interest maybe you can fund a protype from them.

 

This really isn't that complicated. There's plenty of designs out there to model your's after. Unless you have a full blown race car, you don't need a "perfectly designed" undertray.

 

My diffuser starts just before the pumpkin out to the bumper and there's a little gap between the bumper and the diffuser.







As far as I know the 1st Moulding and Voltex are the only true functional diffuers available. Take a look at those to better orient how the rear diffuser may work better for you.

 

iPhone grammar owns me at the moment... Don't judge me.

 

dzus fasteners to make removal easy.



OP.... you'd really need to think about air flow design.. you cant just seal up the bottom of the car... you are going to create LIFT.. ever see a drag racing boat lift off the water and flip in the air? Cars do it too... Youll see flat bottoms on F1 cars, but the wings they use front and rear combat that at any medium to hig speed.

Ferrari 360s etc w the full bottom still has channels going THRU the car over top of the tray and out the back, and creates actual pressure downforce...and this is the issue w making one for the 350z.. theres very little room to get air moving over top of the plane, let alone to create a pressure differential to create downforce..

other than that.. its best to create an undertray up front and use a diffuser/splitter to create fdown force, and then to simply open the back bumper up ( holes, bumper tuck, etc like you see on NASCAR vehicles.. vertical stanchion diffusers help keep the turbulence in check and helps rear end stability side to side at speed.

there are other threads on this, and the last one was FULL of fluid dynamics calcs, aerodynamic theories, and all sorts of stuff...

search for a term called "ground effect".. ie, not the body part but the actual aerodynamic principle.. its different for cars, planes, or helicopters..

its a cool idea, but IMHO.. very impractical and can easily adversly affect the cars handling and even its safety.

UNless you build some wild stuff..

 

I thought Ground affect only worked for things with an X Y Z axis? Meaning they have up/down and forward/back. Helicopters for instance... The initial lift off is the blades pushing air off the ground to get the helo up. Then after a point they need to pitch the prop angle(creating an airfoil) because ground affect no longer applies. Airplanes rely on the the airfoil principle... Air goes over the wing thus creating lift on the bottom. Those things I mentioned are simplified and are very complicated. I totally agree with air flowing out the back of the bumper and keep in mind the vortex a wing creates has a lot to do with the function of diffuser.

 

yeah thats prob what makes it diff for each thing, airplane ge verus heli ge vs car ge.. dunno.. if i did, i sure wouldnt work at this dumb bank.

I just know there is a factor to flat undertrays that can be sneaky in a bad way.. not 100% sure what it is, so i throw stuff out there so they can google terms on their own haha.

 

Yup I believe it's air going over and creating vacuum under the car at speed... When you decelerate at that high of a speed the forward momentum stops and the nose pitches up. Air gets trapped under and with air moving over the car caused it to launch. The famous CLK racecar that went airborne on a peak in the racetrack... Caught air and landed on the canopy killing the driver.

 

Instead of watching youtube and google images, I would suggest trying to learn aerodynamics.

Cars take flight (CLK) becuase they are giant wings. Take a look at the side profile of a prototype, then look at the side profile of an airplane wing.


http://www.amazon.com/s/ref=nb_sb_ss...+a%2Caps%2C367

 

you sonsofb3tches make me spend more gddamnd money.. i swear..

after reading and posting in this, I bought a Z Speed front alum undetrtray yesterday.

I hate you all.

haha.

 

damn, thats sexy. one day....

 

late to the game man...

 

you can combat alot of the lift a flat body makes by raking the car (nose lower than rear), making effective use of vanes and ducts (seal off the sides making sure only air coming in is from the front and going one direction toward the rear), and (obviously) having adequate front splitter and a rear wing.. the underbody will only do so much, there are alot of other factors that will attribute to the amount of downforce you're gonna get. in theory, you should try to make the entire tray at a certain level. no ups and downs (as far as height) until you get toward the rear axle, and that is when you want to create your diffuser and go upwards.

as for heating issues with your turbos. not much you can really do about that. you will get alot of air pressure at the back of the engine bay, which will naturally go down toward the firewall/transmission area, so you could probably put a naca duct by your downpipe/cat area.. also i'd probably put one near the rear pumpin and run a fan'd differential cooler since the Z pumpkin gets seriously hot.

i dont think you should worry about the water for when you wash a car, there will be areas where the panels come together that it'll probably seep out and once you move the again, it'll make its way out. unless you're making a giant molded one piece flat panel, you should be ok.

i never liked the stock z rear bumper. +1 on getting a vented rear such as the nismo v3 or just cutting the crap out of it. anything behind the rear wheels really isn't going to help you much except to make the car look nice.
good luck

 

Update ...

To day I dropped my car at garage to start building diffuser. First , I told them to build it fully by box cardboard as prototype to see where is the mount points , vents , cuts ... Etc

After that build full diffuser from " carbon aluminum " as their tech recommended to me rather than regular aluminum. Tech sayed carbon aluminum as he claim lose heat faster yet thin and strong

Tomorrow going to post picture of the project

 

One more thing ... My greddy tic ti exhaust hang very low in the mid section " y pipe " area toke a picture of it going to post it later to day sine I can't uploade it from my iPad

 

Alright man good luck sounds like it should be success!

 

Thanks hope so ... Nonetheless I need heavily my350z support to make it work. What I mean by support is giving ideas , inputs and designe reconfiguration. Since to be honest all my experience before taking this step is from reading article on diffusers and other fourms build ideas