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HybridZ

GT40 Diffuser


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That would be great, Red Bird is one of my insperations.

Here is the diffuser on Red Bird.

HPIM0579.jpg

This pic came from Hybridz.

One of the things they found in the RCE issue with the Lotus is that it didn't work effectively until the end plates were 40mm or less from the ground. The middle strakes didn't matter, but the end ones had to be close to the ground. Just something that should be considered for another windtunnel test. Mayolives doesn't seem to be real shy about getting the car lower, but that diffuser looks by that picture to be higher than 40mm...

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Just a reminder about the S30 in this video, something is working there for it to outrun the competition spec Viper.

 

I think it's called "superior driving skills" or "hey, you drive behind me and make me look good ok?" Actually, it doesn't take much for a Z to have a better power to weight ratio than the pig of a Viper.

 

On the subject of diffusers, Darius has one on his 240. It's too bad he's out here by me instead of out by the wind-tunnel. It'd be interesting to see what a YZ kit and diffuser can do.

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  • 3 weeks later...

Here is a pic of mine. Of course with a full tube chassis I can have a flat bottom car with a smooth transition to the diffuser. I'm still working on the front air splitter. I have access to one from a Ford GT and Shelby GT Mustang as ideas to work of of. I will probably make my own design from Aluminum stock. Some of my parts could be adapted to a stock S30 platform though. I have a stock body also so I'll look into it. However without windtunnel or track tests it to deternine effectiveness who knows.

diffuser_thumb.jpg

diffuser1_thumb.jpg

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  • 2 weeks later...

I work for a company that modifies Ford GT's into X1's (Genaddi Design Group) and I actually have a slightly damaged GT diffuser. I am in the process of installing an aluminum fuel cell in the Z and will add the diffuser to finish off the back end.

 

Bill

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I work for a company that modifies Ford GT's into X1's (Genaddi Design Group) and I actually have a slightly damaged GT diffuser. I am in the process of installing an aluminum fuel cell in the Z and will add the diffuser to finish off the back end.

 

Bill

 

Just remember to take plenty of pictures...

 

Dragonfly

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  • 4 months later...

 

Says 280zx but I don't see any pictures of it on a 280zx??? It also seems to me as if it is screaming "RICE".

 

Dragonfly

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The hood design was a form follows function thing. I am running a 4bbl with a 1" thermal spacer plus a .5" NOS spraybar spacer so I needed hood clearance. All the after market scoops or hoods put the extra clearance down the middle of the hood. I needed it offset for the carb. By cutting a stock hood I kept the basic Datsun lines intact and you are correct it flows massive amounts of air from under hood. There are some bubbles coming on the front edge so I will remake the hood in fiberglass.

 

Bill

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  • 3 months later...
this made me jump out of my seat. I will def be fabing one of these for my z. Does any one else know any thing else about this car!? Had to share!

 

Search "janspeed". There have been several threads and posts about it, I think the owner hung around for a time, might even still be here.

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  • 1 month later...

Ok, so Ive been looking over diffuser designs and I think I have noticed something. Is a good diffuser just an upside down NACA duct? Correct me if I am wrong but It is using a duct to actually suck accelerate the air out from under the car at a faster rate than it is entering causing a slight vacuum which causes down force.

 

That being said, would it be beneficial to place fins under a smooth bottomed car going at an angle from the center front of the car to the outside rear? The thought behind this is to help pull some air out from underneath the car helping to cause a vacuum. Does anyone know if any of the race cars use this or would it just cause turbulence if the fins do not come in contact with the ground?

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I don't think so. From what I understand a diffuser is in place to clean up the turbulent air under the car, straightening it out so it exits the underside better.

 

that second part is actually what the diffuser does. it cleans and directs the turbulent air under the car, so it gets sucked out of the low pressure wake just behind the car.

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An every day example: Think of the impact of horizontal and vertical stabilizers on any jet fighter aircraft, as well as their air canards, for starters.

 

...Now think of how thrust vectoring works. That is the most dire of examples regarding redirection of turbulent air to create a significant outcome. We may experience it in the 1XXmph range, primarily aimed at downforce, but you'll find that technology is aimed at providing split-second changes at speeds around 500-600mph (sub mach, depending on altitude/barometric pressure,) and even in excess of that.

 

...Having been raised in the aircraft business, and very familiar with these principles, I would suggest looking to those examples for understanding/functionality/application. Not merely for the fact that we don't all have windtunnels in our garage, but that is the most extreme application of air diversion technology and implementation that exists known to man. Not that we can remotely use thrust vectoring directly in any way, but understanding it's core functions and impacts can break down the first components in minute detail. That means it has to be right one way or another, right? ;)

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I don't doubt it for a minute that the straight panels (Strakes) in the diffuser would help smooth out the turbulent air, which is why they are allowed. But if you look at the GT40 diffuser they don't incorporate that, for whatever reason, they only have two expanding chambers.

 

I was looking at the SCCA rulebook the other day and I noticed this:

 

5. Diffusers are allowed at the rear of the car only and shall

have no more than 25-inches front to back of expanding

chamber. Vanes or strakes are allowed inside the diffuser. A

diffuser is defined as an expanding chamber between the

vehicle and the ground for the purpose of accelerating air

ahead of it to develop low pressure.

 

I'm not saying that it won't smooth out turbulence, just that I think that if expanding chambers were built, using the proven NACA duct formula, a much greater improvement would be seen.

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