what about this rear diffuser idea

[J__]

^^^ wow thats a sweet car

[bjhines]

The rear diffuser was not tested in the wind tunnel. There was not time for that kind of testing.

 

Mayolives should chime in on his experience with that device on his car. I know that there were some teething issues that required it's removal.

 

We tested only one version of a front splitter. It was tested with a host of other modifications on the SDI car.

 

As far as underbody modifications go. The Z-car has top-side problems that would need to be addressed first. Stability in traffic and under braking are possible issues with aggressive underbody modifications.

[Flexicoker]

Mayo..

 

I will go back and re-read the data..

 

I just recall a thread that determined it was not very effective..

 

thank you

 

Thats not saying it won't work, its just saying that several people don't think it will work. It will only be proven to work or not work when somebody builds and tests one. I think it will work, maybe just a little, maybe alot. But as long as the increase in rear downforce is balanced with an increase if front downforce I don't think it can hurt.

 

Also, riveting through carbon fiber is not a good idea, CF doesn't handle point loads well... you want as much surface area as possible, ie. epoxy

[260DET]

From memory diffusers were 'discovered' when Jaguar had problems with the back of their race car dragging on and off the trailer. They modified the rear underside to improve clearance and promptly went faster on the track.

 

So, give it a go, I'm going to on the 280ZX.

[boodlefoof]

Here is the plan for mine... when I ever find time to get working on it again...

 

http://www.geocities.com/boodlefoof/Project_Racer-Zaerodynamics.html

[tube80z]

From memory diffusers were 'discovered' when Jaguar had problems with the back of their race car dragging on and off the trailer. They modified the rear underside to improve clearance and promptly went faster on the track.

 

Maybe rediscovered but if you go back in history you can find these on some of the old landspeed cars. I seem to recall seeing a mercedes or auto union in one of my books. Just like a really old pic of a car with a wing.

 

Cary

[tube80z]

Here is the plan for mine... when I ever find time to get working on it again...

 

http://www.geocities.com/boodlefoof/Project_Racer-Zaerodynamics.html

 

You need more of a throat section. Think of a carb venturi sliced in half. The diffuser acts to speed the underbody flow, which results in lower air pressure.

 

Cary

[JMortensen]

Thats not saying it won't work, its just saying that several people don't think it will work. It will only be proven to work or not work when somebody builds and tests one. I think it will work, maybe just a little, maybe alot. But as long as the increase in rear downforce is balanced with an increase if front downforce I don't think it can hurt.

Anyone else see the latest issue of Race Car Engineering? They're playing with a new Lotus Exige and its rear wing and diffuser setup, last month they worked on the wing height, this month its the diffuser's turn.

 

They moved the exhaust which was hanging right in the diffuser area first. Then they did some mods to the diffuser (specifically lengthening the outer strakes and bringing them about 1.75" off the ground) and got 18.3 percent more total downforce and 10.6 percent less drag! FRONT downforce increased 8% (!!!), and rear 23.7%. They had also played with some side skirts that didn't have much affect before lengthening the outer fences on the diffuser. The article didn't say whether those were left in place for the last test or not. Pretty damn interesting though! Definitely makes me want to at see some testing of a diffuser on a Z before assuming that it won't work.

[marcg]

He is competing in the Grassroots Motorsports/CarDomain contest to see who has the best track car in America. Results are to be in the Nov issue.

 

whos car is this?

k.. found it.. http://forums.hybridz.org/showthread.php?t=114152&highlight=stunning