DIY Diffuzers

[alantjw]

Hi.. as u can see this is my 1st post... and im new to all this car stuff... i am just wondering can we actually DIY own diffuzers...

Reason:
To me is just a thin metal layer that is black in colour...
Cant we just use alluminium plate and black spray to do it???
Of course using the correct tools to Cut the alluminium plate..
and i find no reason spending more then RM300-RM1k to make this small thing for all 4 sides of the car....

Conts:
After DIY perhaps it might fail and falling apart....
Might not be nice during 1st time trail...

Pros:
Save Tons of money...
Make car looks more garang...
Might Improve Airflow.....

 

[rex79gt]

Diffuzers under the car like GTR?
sure can DIY but yr mounting hav to b really tight

in order to make the difusser works
it depends on angle also (aero dynamic)
meaning if u're able to let yr front lower than yr rear
the air from yr front to yr back is small, n when it come out from rear, vaccum power will produce to gain more speed, of coz the car may lift higher
u might need spoiler those stuff in order to stable the car then :P


correct me if i'm wrong
hope this may help what u need
alluminium use for diffusser need large size in order to cover yr chassis which ever is under yr car
i think 1k should b enuf
better don find too thin, else the force cause by the air may bend yr alluminium panels

 

[alantjw]

sure can DIY but yr mounting hav to b really tight
One silly question... can superglue be the mounting/???


-u might need spoiler those stuff in order to stable the car then :P
And my car has full body kit on it with mugen spoiler...


-Diffuzers under the car like GTR?
Yes.. that is what im talking about...


-it depends on angle also (aero dynamic)
My main purpose is to make it garang...
if wan do aero dynamic i need get aerospace engenearing student to help liao loh.. hahaha

-meaning if u're able to let yr front lower than yr rear
will abs help??? cos im changing to adjustable abs soon

 

[SkYwAlKeR]

of coz superglue wont be strong enough... use rivet to secure the aluminium plates together... den use bolts and nuts to secure it to ur car underbody... make sure it is secured strongly... u dont want it to fly off in the middle of the road and chop some motorist head off...

diffusers work best if underside of ur car carridge is covered up nicely.... uneven gaps underneath will create turbulance... turbulance will cause drag and reduce the speed of air flowing underneath.... slow speed at the bottom with high speed at the top will lift ur car up (bernoulli effect)...

diffusers are designed to allow and guide air flowing underneath ur car to exit the end of ur car faster and smoother... accelerated air flow underneath ur car reduces lift and hence making ur car more stable at high speed.... (bernoulli theorem)....

 

[alantjw]

ok.. meaning this diffuzer thing need to cover under whole car??? is that what u mean???

if meaning that the air flow below should be faster then above meaning below should be straight... making no risistance on the lower part of the car... but does it really need to fully covered the bottom of car???..

 

[SkYwAlKeR]

ok.. meaning this diffuzer thing need to cover under whole car??? is that what u mean???

if meaning that the air flow below should be faster then above meaning below should be straight... making no risistance on the lower part of the car... but does it really need to fully covered the bottom of car???..

diffuser is diffuser.... undertray design is to cover the whole undercarridge so u can have better effect for ur rear diffuser....
every part of the car aerodynamic such as diffuser, splitter, gt wing, vortex generator work together to create an ideal aerodynamically balanced car....

u cover the undercarridge of ur car to create a smooth surface for air to flow thru at the bottom... as i said, uneven surface causes turbulance in the air, hence creating drag which slows the air flow....

bernouli principle says that high velocity air has lower pressure compare to low velocity air which has higher pressure.... hence, we need to match the speed of air flowing at the bottom with the top of the car to minimize the lift effect due to pressure difference....

 

[alantjw]

ok.. i get what u mean... but there is 1 problem... what happens when i need to do repair to eksos system??? or even changing muffler... even changing engine oil would be a problem since the whole bottom is covered... well and im making this project at home co i dont think i can able to lift up my whole car and build the whole thing under the car...

 

[eyong]

Don't bother trying to get it 100% right. If you can DIY and get 50% efficiency, or if not disruptive, then consider yourself a pro ...

Yes, you need to hoist your car up and really see where you wanted to maximize you downforce ...

 

[alantjw]

ok 1 question what if i didnt cover whole car... will there be any problem??? like i make it on the front and back only.. center are empty.. of course the design will be for downforce....

 

[SkYwAlKeR]

u mean underbody tray or the rear diffuser itself??...

underbody tray, u diy some sort of opening for easy access to oil sump and oil filter lor...

as for exhaust pipe... dont weld dead ur underbody tray lah... use bolts to secure it in place... when u wanna change exhaust piping, jz remove the bolts to remove the undertray can adi...

as for ur rear diffuser, best is to cut the shape according to ur muffler.... something like this...

jz make sure u aint planning to change ur muffler in a vr long time... or else u might have to diy another rear diffuser and cut it into shape again... haha...

as for ur 2nd question... if u dont cover up the whole undercarridge also can la... less effective lor... jz cover those huge gaps such as are between ur front bumper and under ur radiator.... and the exit jz before ur rear bumper (where ur rear diffuser will be)....

do more research on how car underbody aerodynamic stability works... good luck...

 

[alantjw]

okok.. be working on it when i have time

 

[DLegend]

okok.. be working on it when i have time

Please share photos of the work done

Here are some sites to get you going:

Front undertray:
http://forums.evolutionm.net/showthread.php?t=338176


Rear diffusers:
http://www.honda-tech.com/zerothread?id=1637246&page=4

 

[DLegend]

Some more links:

Some examples:
http://www.pennon.com/products/diffusers/diffusers.html

Brief explanation of underbody aerodynamics:
http://www.tuningmag.net/?name=tuning-car-aerodynamics

Another DIY on an Integra:
http://www.team-integra.net/forum/d...92892&ReturnPage=&PagePosition=0&ThreadPage=9

There are more out there...

 

[SkYwAlKeR]

thanks for the infos DLegend...

 

[alantjw]

yeah.. tnx dude... Ur Going to be a legend...

im still thinking on how to fix it to my DAMD bumper... :hmmmm:
cos DAMD bumper alredy looks like a diffuzer :hmmmm:
need to think of a way to design it....

 

[DLegend]

'looks-like' and 'works-like' a diffuser are different things :proud:

Anyway, try looking for those picture of the underbody of the Ferrari 599/430/360 and the McLaren SLR... notice that their rear diffusers are actually part of the whole underbody package.

Anyway, for us 'normal' ppl, the rear diffusers have to at least start from the rear lower arms area... and curve slightly upwards at the rear. (dunno what angle to curve, have to do calculations... malas... )

I actually wanted to make front undertray and rear diffusers also... but got no time to experiment

Try with simple ways first, use aluminium/stainless steel sheet first, then after perfect, ask the fiber shop to make for you....

Go google : Aerodynamics, Tech

 

[DLegend]

Here's my fav article:

Modifying Under-Car Airflow, Part 1

Modifying Under-Car Airflow, Part 2

 

[alantjw]

use box and do... hahahahaa...then see if cun.. then only use aluminium.... Like me im more to fancy the looks... Works like dont really bothers me.. but of course i would be glad if it works...

Well maybe i get mine done i try posting pic of it... maybe project starts next month..

 

[nitrus]

use box and do... hahahahaa...then see if cun.. then only use aluminium.... Like me im more to fancy the looks... Works like dont really bothers me.. but of course i would be glad if it works...

Well maybe i get mine done i try posting pic of it... maybe project starts next month..

How are you going to get the looks, if u're gonna be sticking aluminium pieces to your car body?

Careful ur car don't end up in the "post the pimp rides thread"..

 

[alantjw]

hmmm... im planning to do a small layer only at the bottom... im gonna spray it black to make it have the diffuzer look...:hmmmm:

:stupid:then i try shaping it according to other diffuzers our there in the market....