Underbody Diffusers FOR SALE! um... soon.

[jetblackskye]

Hey guys, I'm an Aerospace Engineering student at Embry Riddle in Daytona Beach, FL.

I'm going to be developing some front and rear underbody diffusers for S13 and S14s, (as well as civics, Evos, Skylines, and a few other imports) They will be made from aluminum and should cost somewhere around $300-$450. I would like to know if anyone would seriously consider buying one.

I'll post pics of the prototypes as soon a I get a chance.

[boostdeliquent]

Perhaps. Lemme see some pics once you have them.

[S14DB]

Have you ever been to an SCIC meet?

[exitspeed]

Hey guys, I'm an Aerospace Engineering student at Embry Riddle in Daytona Beach, FL.

I'm going to be developing some front and rear underbody diffusers for S13 and S14s, (as well as civics, Evos, Skylines, and a few other imports) They will be made from aluminum and should cost somewhere around $300-$450. I would like to know if anyone would seriously consider buying one.

I'll post pics of the prototypes as soon a I get a chance.


Probably have better luck selling them to the Civic and Integras of the world. It's no something you see too many 240 owners getting...But that's just my point of view.

[alexchanman]

yeah, your bulk of sales are going to be geared thowards the civics. isnt 350-400 a bit too pricey for an aluminum one?? i dont know this, just a little question.

[MrSkinny]

put some pics up.

[tacotacotaco]

I would be interested

[boosteds13]

Have you ever been to an SCIC meet?
Yeah, you ever come out to SCIC? I run the SCIC website. PM me.

[nismoenthu]

i would definitly be insterested as well....just post some pictures so i know what im going to buy....

[Gnnr]

For that price they better be made of Carbon Fiber! :loco:

[ThatGuy]

Price is a bit too high for the 240sx community, and you won't sell much without pictures. Also how many street cars on your list actually travel fast enough to NEED diffusers. :loco:

[spdfreek0o]

Yeah, but honestly, how many high end street driven cars do you actually see on the track or going fast enough to actually need the functional factory aero they have?

[aznpoopy]

most people buy aero for looks. and a undercar diffuser isn't going to be cool or noticeable enough for people to drop $300-400 on it.

[TheWolf]

I always thought if you wanted cheap aero underneath the car with minimal weight gain. Just cut some cardboard out. Proper shape. Then laminate it with fiberglass. Bolt on. Instant underbody for less than $100.

[SoSideways]

Man, see, that's why there isn't any quality parts made for the 240 community.

Someone offers to make something for us, that will be guaranteed to be functional, and what happens when he asks about the feasibility of said item being sold to us? Someone posts about how to make something similar in a ghetto way for less than $100.

Anyways.

$300-400 is a bit steep, yes, but this is also not a "must have item" like adjustable T/C rods to replace your busted factory T/C rod bushings. Not every 240 owner is required to have this diffuser, just like not every 240 owner is mandated to own coilovers.

Obviously this diffuser would only be beneficial to the guys that actually track their cars, and by track I mean like road racing or auto-x, where downforce is important, and not your internet drifter that must have a piece of everything made for the S-chassis on their cars.

So basically, I'm just wondering. For those of you that said this piece costs too much (and I do agree it's a bit on the high side. $200 seems more reasonable), how many of you are actually going to buy one and use it even if it only costs $50?

[alexchanman]

if it did cost 50 dollars or, maybe even up to 150, i wouldnt mind shelling out the 150 to try it out at least. if it worked great, then it would be smart to jack up the price and quality of it but then again, not alot of people on the streets have underbody diffusers so its hard to ask a friend or whatever if its a good buy.

[krustindumm]

how much will it cover? I need something to protect the underbody of my car from racks, logs, and small animals.

[jetblackskye]

Hey guys Thanks for all the input. I have been to an scic metting in the past but I owned a blue honda accord then, now I have a gold 240 hatch. Thursday nights are not a good time for me.

I'm glad that you guys gave me some good info on what you want about prices and things, I'll see if I can produce them a little cheaper. The front ones will cover most of the engine bay area (I have the same problem with rocks and dirt) and will have an opening to drain the oil or some sort of a quick release system. (thats part of the reason it may cost a bit much)
The rear one will be from the differential back.

I know that drifters won't really be into these but those who do track runs and even highway battles will benefit from it.

I hope to develop a full undercar venturi tunnel too, but just for fun.

I know that a lot of people buy wings and splitters on their car cause they look cool, but have you ever seen an RX7 or something with a real diffuser, to those in the know it is way cooler than a big wing sticking out of the trunk.

I have access to a large shop in Sanford, FL that does lots of aluminum fabrication, they dont do any carbon fiber though. And I can't really use the Composites shop at Riddle for any sort of mass production of diffusers, if I could belive me I would.

I'll be making one for my 240 Hatch this weekend and if everything goes well, I can put up some pics for you guys so you see what I mean.

Oh and this is sort of what it will look like, these are taken from different websites but you get the idea of what I will be making.

http://i24.photobucket.com/albums/c10/jetblackskye/diffuser_kevlar.jpg

http://i24.photobucket.com/albums/c10/jetblackskye/0401.jpg

[Gnnr]

Well, if you can price it at $250 I think they'll sell very well. How will you test the functionality? Like you have access to a wind tunnel or what? I'm curious because I dont really know what goes on in the engineering side of things.

[RightWheelDrive]

Hmm...I don't think the wind tunnel is going to be neccesary since conditions and car configurations will not be constant. As far as functionality goes and granted all the engineering is correct, probably only really low cars could benefit from the diffuser. So my advice to you during design is to take into consideration the affects of steep gradients on lowered cars, such as curbs and speed bumps, because they can easily dent the fins out of shape. Otherwise, you have a good plan and good luck on your project.

[boostdeliquent]

Hmm...I don't think the wind tunnel is going to be neccesary since conditions and car configurations will not be constant. As far as functionality goes and granted all the engineering is correct, probably only really low cars could benefit from the diffuser. So my advice to you during design is to take into consideration the affects of steep gradients on lowered cars, such as curbs and speed bumps, because they can easily dent the fins out of shape. Otherwise, you have a good plan and good luck on your project.
:werd: What he said.

[s14xman]

what kind of aluminum will this be made of? sounds to me like you are doing some serious "fraud waste and abuse" (air force term for steeling). Unless you are ordering the aluminum yourself, which i doubt, you are making 100% profit, nice work! I guess i'll have to see one to see if it's legit or not. Just saying all this because i work at the sheet metal/compostite/paint facility for the air force, and i know it's tempting to do something like this!

[TheWolf]

I'm not trying to ghetto... cardboard is actually a composite. Mixed with resin it's quite a functional piece of aero. throw some glass in there for strength. A full cheap underbody would probably be better for you in terms of aerodynamics than a rear difuser pannel that has a giant turbulent section of air to deal with. If the air is not somewhat smooth aproaching this pannel any gain would be negated and it'd be cosmetic. underbody would yield greater gains.

[turtl631]

I think this is a great idea. I agree about the pricing though, 250ish might be more realistic. I'd love some under aero though, I was actually thinking about trying to make something like this myself later on.

[Angel]

If they can be made functional I would be interested.

[PoorMans180SX]

EDIT: Sorry the pics didn't load the first time, if they look like above and below, I'd buy...
For you other guys:
1. Cardboard laminated with fiberglass is poor, just because
2. Underbody aero is not just functional for really low cars, as they actually have LESS air traveling underneath them.

[Maximamike]

http://www.rakuten.co.jp/laile/img10012466310.jpeg

Something like this would be pretty cheap to make. Its 2 pieces and the rear is on quick releases(dzus fastners I imagine) so you can change oil/filter/etc.

[jetblackskye]

I'll post the pics as soon as I get a chance, I'm glad that alot of you guys are interested.

s14xman: I will actually be ordering my aluminum through InterAmerica Stage (the shop in Sanford). 1/4 inch and I haven't decided on the exact grade yet. InterAmerica builds theaters and play houses, they also do overhead design for the themeparks in the area, Disney is their biggest customer.

RightWheelDrive: I will definately keep in mind speed bumps I'm glad that you reminded me about that.

The design should be functional above about 30mph, though at that speed you wont notice it, but it will be making some downforce, to make anything real though you will have to be traveling at highway speeds and above.

Here is a link to some of the math that goes into it (this is simplified, though) http://www.princeton.edu/~asmits/Bicycle_web/Bernoulli.html

so $250 is a more reasonable price? I think I can do that.

Thanks again for the input!

http://www.rakuten.co.jp/laile/img10012466310.jpeg

Something like this would be pretty cheap to make. Its 2 pieces and the rear is on quick releases(dzus fastners I imagine) so you can change oil/filter/etc.

Thanks for that pic, that design doesn't look like it produces the low pressure area that I was thinking of, but I'm sure that It helps stabilize the airflow.
Plus it is nice and simple.

I like!

[R33GTS-T]

personally, i road race and autox my s13 and would definitely be up for front and rear diffusers :drool:

my only issue is that i swapped an RB25 into my coupe and my engine sits lower than any of the SR/KA engines....i can send you pics if you'd like but i imagine this may be an issue for my application

[REDSH!FT]

Good luck clearing the front sway bar with any ground clearance to spare...here's a story.
When i was driving my car off the trailer and into the garage the other day, i ran over a tennis ball...a second later it rolled out in front of me. The end.

[jetblackskye]

I'm considering making it somewhat adjustable for the installation, I'll show you pics when I get it built so you can see what I mean. I dont think that there will be too much of an issue making it clear the front sway bar, my car is also lowered so I have to compensate for the amount of clearance.

[r-b-x]

sounds like an interesting project. I was wondering how effective it would be, if it can be quantified, let's say as compared to a GT wing (those are all the rage these days...), which are also priced similar to your projections.

[chmercer]

um lol. no undertray will make anywhere close the downforce of a GT wing. unless you build a full venturi tunnel and run your car off a cm off the ground. different parts for different purposes. comparing them is pointless

[90RS13]

this would be a "looks" thing. The gas tank really gets in the way of having a good rear undertray. with the space provided it won't make any significant downforce, and without relocating the exhaust to side exit it would be hard to even straighten out the air flow under the rear. The gas tank position really sucks.

[kandyflip445]

I want a front underbody cover thing. My factory panel ripped off long ago.

[Igor]

go for it, i want some s14 to...

[Sky240PWR]

I'm just getting into all this too. I have a 91 hatch, with the Jacquemond wide body kit, I removed my gas tank and buying a fuel cell. I bought the Ab-flug cf rear diffuser to put in there and building a front diffuser similar to the one already posted. we are going to try to make the underneath as flat as we can get it on my budget. I know alot of people don't like my kit but I do and I'm trying to make it as functional as I can, that way it will be harder for most of you to say it's rice..lol...the side vents we made functional by opening them up so the back brakes are getting enough air(some say too much) here is a pic of the back bumper without the rear diffuser

for some reason, it's not posting my pics!

[JohnC]

I would be interested
Very Interested but..........
as stated, 350-400 is a little high.
250 I will pay now for a proven functional
part. Go ahead and make it.
Thanks

[TurDz]

350-400 is very reasonable if you're talking about a nicely designed underbody.

The thing is, you have a very limited market. Most of the people here can improve performance with simple supension upgrades. This type of mod is for the dedicated race trackers, those who have nothing else to upgrade.

But it does help with the drag coefficient and gas mileage...haha :)

[ThatGuy]

for some reason, it's not posting my pics!

Use www.imageshack.us to host the pics. Then post them here.

[JohnC]

Thought about it some more.
If you sell both the front and rear
for under $500 I would be all over this.

[HyperTek]

just make this universal fit..
http://img195.auctions.yahoo.co.jp/users/8/1/7/7/welcome4457-img512x384-1144714789111111_008.jpg

[EvilRB]

I have an Rb pushing over 550 to the wheels an I understand that not everybody is like me, but i would spend about $500 on anything that would help control and make my car safer, so please make something for an S14, I'll be really interseted in the upgrade for my car

Thanks

[Sky240PWR]

just make this universal fit..
http://img195.auctions.yahoo.co.jp/users/8/1/7/7/welcome4457-img512x384-1144714789111111_008.jpgthats the diffuser I'm using, it's the Ab-flug carbon fiber rear diffuser


EvilRB.......I feel the same way, and soon my RB will be pushing the 550-600whp mark!

ThatGuy.....it still isn't working but thanks anyway

[ThatGuy]

^ That is too low, and looks too skinny to be any real good. I'd rip that off in less then a day on a real road. From what I have sen the diffuser should be up to about mid license plat on that car and extend to, if not beyond, the edges of the bumper. Not saying that the Ab-Flug one is completely useless, just stating that it's not as efficient as it could be. In my mind at least. I'm sure someone with more engineering and hydro-dynamics knowledge can step in here and correct/support me.

[Advan]

I know that a lot of people buy wings and splitters on their car cause they look cool, but have you ever seen an RX7 or something with a real diffuser, to those in the know it is way cooler than a big wing sticking out of the trunk.

Actually, riding around with a rear diffuser on the 7, wouldn't look cool at all going down the street. The only benefit for this is people using it at the track. And if I did see a 7 with it, my question would be......why? As far as the, depending on how the car looks with rims, etc...the wing can actually look damn good, depending on which one they get.

[Taniguchi_Is_#1]

http://www.re-amemiya.co.jp/commodity/image/01_fd_aero/bow_tech_side.jpg

the only real reason to have these is for high speed stability. also, they don't work well without some sort of rear spoiler, because the stability comes from smoothed undercar airflow, not increased downforce. so with only a diffuser, you aren't necessarily "safer" at high speeds and alone, it won't keep your rear end on the ground. in any case, $300 is a fair price, especially when the RE amemiya part i posted is ~$600. just don't make this thing some half-assed universal crap, though, because a piece of sheet metal can roughly give you the same effects. make one for my future R32, so i won't have to pay for the top secret one. :naughty: :bigok:

[DJPimpFlex]

http://www.rakuten.co.jp/laile/img10012466310.jpeg

If you could make one similar to this I would be all over if as long as it was arround $400 or less. DO IT!!!!

[Andrew Bohan]

damn that shit is hot as hell. i'm really considering using my car for more than drift...like hpde and other real racing situations. might have to whip something up like that. cuz you know i'll be doin 160+ down the main straights

[Gnnr]

http://www.rakuten.co.jp/laile/img10012466310.jpeg

If you could make one similar to this I would be all over if as long as it was arround $400 or less. DO IT!!!!


Now thats a diffuser! :eek3:

[jetblackskye]

Thanks for all the comments and interest in the product, I'm still doing R&D and I'm not quite ready to reveal the finished design. the price will most likely be about $200 for the front and $230 for the rear, do you guys feel that that is reasonable?
Dont worry, I'm not going to be making a universal one, do to mounting issues, but all of my designs will be simmilar.
I'm upgrading my 240 with a GT2871R soon and will be making about 370whp so I will be testing my product on my car at about 120mph+

I've been doing alot of research into the design and the one that seems the most resonable is the one pictured on the RX-7 above. (Plus I think it looks cool. :-D )
And I do really like the front diffuser posted by Maximamike.

So far these models are in the works, S13, S14, RPS13, R32, R33, Sentra, 350Z, Eclipse 1st and 2nd generations and 4th (hopefully), Integra, Civic, Del Sol, CRX, Evo XIII, and WRX.

What other cars should I include on this list?
Thanks!

[ThatGuy]

You have S-chassis and Z-chassis. Nothing else matters to Zilvia. :D

[MrSkinny]

prices sound fair. mayb eu can do a combo deal. 400 shipepd if we buy both?!

[Andrew Bohan]

how about some RX-7's??

[alexchanman]

mmmmmm, it would be very great. remember to make a removable part from the front diffuser so we can change the oil without taking the whole thing off.

[BOROSUN]

im up for a rear diffuser

[Tenchuu]

mmmmmm, it would be very great. remember to make a removable part from the front diffuser so we can change the oil without taking the whole thing off.


second that, the stock S14 one i had to undo to reach the filter. that got old after the secondt time i did it.

[boosteds13]

Thanks for all the comments and interest in the product, I'm still doing R&D and I'm not quite ready to reveal the finished design. the price will most likely be about $200 for the front and $230 for the rear, do you guys feel that that is reasonable?
Dont worry, I'm not going to be making a universal one, do to mounting issues, but all of my designs will be simmilar.
I'm upgrading my 240 with a GT2871R soon and will be making about 370whp so I will be testing my product on my car at about 120mph+

I've been doing alot of research into the design and the one that seems the most resonable is the one pictured on the RX-7 above. (Plus I think it looks cool. :-D )
And I do really like the front diffuser posted by Maximamike.

So far these models are in the works, S13, S14, RPS13, R32, R33, Sentra, 350Z, Eclipse 1st and 2nd generations and 4th (hopefully), Integra, Civic, Del Sol, CRX, Evo XIII, and WRX.

What other cars should I include on this list?
Thanks!
OT, but did you have your car at Projekt 7 the other day? They didn't know the base fuel pressure for an SR, so I had to help them out, lol.

[S14DB]

My stock KA could do 120+ easily...

[GamblerZ]

If it is going to look THAT nice, I'll be first in line. In fact, if you could make it for the Z32 or Z33, I am sure you would find a number of takers on those as well...including me.

[wangan_cruiser]

how much will it cover? I need something to protect the underbody of my car from racks, logs, and small animals.



true...i agree with it

[Gnnr]

^^Uhh, its not supposed to be used as a protective shield. :ugh:

[alexchanman]

if you wanted something to protect your underbody, then you can just cut out sheetmetal and bolt it on and not have to pay 250-300 for it. this is for aerodynamics and downforce for racing applications.

[RBbugBITme]

another guy not following through with a promised product?

[CaoBoY]

who are you to post that, and bump a thread that died 3 months ago? you come out with any promising/promised products? didnt think so.

[big_schaf]

Sorry to bump again but might as well while the newb did, riceonusa just came out with a rear fiberglass diffusers, there just for looks but thought it might be useful to someone.

[chmercer]

that thing is bogus they want like a G for it, thats like as much as the actual one they copied