[LRG SOUP]

Alright guys, take it easy on me. I am a very amateur fabricator who uses house hold tools to make things for my supra (mostly ghetto things haha). The Diffuser is made of 1/16th thick aluminum, held together with rivets. I went through 3 phases with this diffuser to get it where it is now. I am not totally satisfied with it. I am probably going to buy some support rods to give it more rigidity. For mounting I used 3 long bolts with washers and nuts to hold it up where the stock rear bumper bolts to. And the rear I am still working on since its kinda ghetto fabbed with that steel tape with holes in it. anyways, on to the pictures...


First design...

Second Design. I thought the right side was a bit longer and didn't match the left side so I modified it more.

Third design. I wanted the diffuser to be a little bit noticeable so I extended it a bit more lol. I like the length but I am gonna need some support rods so it will be more structurally stable.

This mod was relatively cheap. Just over $100 to make in supplies. Plus it was fun making it!

P.S. Link to my build page to get a sense of what my build is about.
http://www.supraforums.com/forum/sh...Forums-quot-Blasphemous-Supra-quot&highlight=

 

[Mr Ree NZ]

Nice one for having a go yourself...

Now, to borrow a windtunnel to get some data

 

[LRG SOUP]

Nice one for having a go yourself...

Now, to borrow a windtunnel to get some data

haha, now I am on the hunt... They are probably really really expensive to rent haha.

 

[madmax98]

Good effort Brendan.

I can't tell from the pics, but are the channel plates "vertical" parallel to the ground? How far back do they go?
Also, at what angle does the diffuser sit? I'm still working on my CFD simulation skills, but I had a go at a simple diffuser and found that the optimum angle was about 8*. After that, flow separation occurs Drag/lift takes over the car. Aerodynamic forces are more powerful than most people think lol

 

[LRG SOUP]

Hey max, The channel plates are as parallel as I could get them to the ground. I can always adjust it to go lower from my mounting points. And they go about 2.5 feet back just shy of the differential. Lol i don't know the degrees unfortunately of the diffuser. Hopefully this diffuser helps me, not hurt the performance or my
time.

 

[MKIVHT]

first that looks completely ghetto, but u admitted to that already, second - and Im not being a dick - if I would see u drive in front of me with that hand-rigged shit, I would call the cops on you ... do you have any idea what happens when this crap comes loose on the highway? that that shit off immediately!

 

[LRG SOUP]

first that looks completely ghetto, but u admitted to that already, second - and Im not being a dick - if I would see u drive in front of me with that hand-rigged shit, I would call the cops on you ... do you have any idea what happens when this crap comes loose on the highway? that that shit off immediately!

When you have more than a couple of hundred of posts you might have some room to talk. Until then, keep to the frequently asked question thread.

 

[Nick 95 6sp]

Hey Brenden, I love your approach to your Supra and your alternative path.

It's hard to tell from the pics, but I think I liked it better when it wasn't sticking out quite as far. As far as "does it work"? I recently added a "butt windtunnel" to my "butt dyno" facilities and suggest you do the same.

 

[FLZ_Boy]

I see competition is heating up in So.Cal. I got something brewing also......

 

[njn63]

First one: looks too steep, needs side fences, 1 of the dividers is crooked and the threaded rod is in the way.
Second one: looks slightly improved.
Third one: Hard to really see anything but looks even more improved.

This link has some good info for aero DIY: http://www.specialprojectsms.com/info/technical.html

 

[LRG SOUP]

Hey Brenden, I love your approach to your Supra and your alternative path.

It's hard to tell from the pics, but I think I liked it better when it wasn't sticking out quite as far. As far as "does it work"? I recently added a "butt windtunnel" to my "butt dyno" facilities and suggest you do the same.

Damn I will definitely think about that. Thanks for your input and comment!

thank you, I copied the design from the GT1 Corvette that I had a picture of on my computer. I kinda like it, looks really aggressive but maybe a bit too much...

I see competition is heating up in So.Cal. I got something brewing also......

lol ohhh I can't wait Sheldon to see what you come up with!

First one: looks too steep, needs side fences, 1 of the dividers is crooked and the threaded rod is in the way.
Second one: looks slightly improved.
Third one: Hard to really see anything but looks even more improved.

This link has some good info for aero DIY: http://www.specialprojectsms.com/info/technical.html

Thanks for the compliment. I will definitely check out the link to make improvements.

 

[MKIVHT]

When you have more than a couple of hundred of posts you might have some room to talk. Until then, keep to the frequently asked question thread.

As long as YOU don't have a legit MKIV, and Im talking about a TURBO of course, maybe you should keep to the NA section ... by the way your shit is ghetto-rigged, maybe you should even hop in the MKIII section.
Anyways - take that shit off - By the way ur car looks I doubt u can afford the lawsuit that hits u, when that thing comes apart!

 

[CasperMK2]

Ok, ok, chill out guys. No reason to bash each other.

@LRG Soup: Great job making those diffusers. I think your first design look pretty well, especially wingless.
As others already suggested, get it tested in a windtunnel. Do you plan using it on the streets, or only at the track?

Make sure the diffuser is attached properly as MKIVHT said. If it falls of...

Take care,

Casper

 

[quick_dry]

the angle on the last one looks a lot better - though it really needs a full underbody to be effective, and side fences. (How does it go near driveways/changes in gradient with the extended version?)

madmax98: between 7 and 8 degrees is what Racecar ENgineering also came out with as optimum in simulation article they did a few years back. (11 degrees on the throat IIRC if anyone is interested in the full underbody route)

Anyone know what happened to that project on here where the guy was going to do a full sculpted underbody tray, with option for sliding skirts ala the old Lotus F1 ground effects cars?

(enough of this BS 'legit' car crap, this thread is about rear diffusers)

 

[NITECRUISER]

MKIVHT, I think it doesn't matter turbo or not, it is still MKIV.

 

[FLZ_Boy]

Duplicate Post.

 

[FLZ_Boy]

As long as YOU don't have a legit MKIV, and Im talking about a TURBO of course, maybe you should keep to the NA section ... by the way your shit is ghetto-rigged, maybe you should even hop in the MKIII section.
Anyways - take that shit off - By the way ur car looks I doubt u can afford the lawsuit that hits u, when that thing comes apart!

This the road racing section. What other sections think about NA versus Turbo does not apply here. This section prides itself in helping others to be fast on the road course/autox/time trials. Many members here have driven much faster cars to the slowest cars in their racing careers (NA Supra, Miata, Corvette, GTR, Porsche, etc.). This section isn't about how fast you are on the street, it's more about pushing your personal driving goals and setups to make you competitive in any type of sanctioned racing.

There is a handful of people in the road racing section that do road race the NA Supra and have poured in big budgets to be competitive at a cost of a nice single turbo (TT). Goals, budgets, classes, sanctions, modifications has to be strategized to mature as a driver and setting up your car to win.

Road racing isn't for everyone, if you like highways and thinking NA are Toyota is a mistake, than that's fine. Don't expect everyone here in this section to read your post seriously. I do encourage you to attend a real sanction racing venue (NASA, SCCA, POC, whatever floats your boat), to see the different types of motorsports that exist.

 

[LRG SOUP]

As long as YOU don't have a legit MKIV, and Im talking about a TURBO of course, maybe you should keep to the NA section ... by the way your shit is ghetto-rigged, maybe you should even hop in the MKIII section.
Anyways - take that shit off - By the way ur car looks I doubt u can afford the lawsuit that hits u, when that thing comes apart!

Lol I got the response I was looking for out of you. I am satisfied...

 

[njn63]

1 other tip I didn't mention above: make a template out of cardboard first when designing parts like this. Way way cheaper and much easier to work with.

 

[LRG SOUP]

1 other tip I didn't mention above: make a template out of cardboard first when designing parts like this. Way way cheaper and much easier to work with.

Yup! This is what i did in the beginning to avoid interference with my exhaust.