Creating downforce without a spoiler

[FireStorm999]

As title really.

how does one go about doing it?

ive started to fit a rear under diffuser thats meant for an R34 GTR,



dont know if this is the kinda thing i should be doing or if it even helps.

dont really wanna put a spoiler on the car though.

[Stavros]

Why do you need to add downforce?

Yeah a properly designed diffuser will add downforce, but just placing a diffuser under a back bumper wont magically make it shithot, it's a big less obvious than using a spoiler to do the same.

[Mr Whippy]

Unless there is a flat floor preceeding the diffuser, its a pointless exercise.

[FireStorm999]

Unless there is a flat floor preceeding the diffuser, its a pointless exercise.

Next job after diffuser. someone is making me a huge ali sheet up.

and i have a big ali sump gaurd that covers quite a bit.

but will this potentially then create lift as apposed to downforce and everything goes whoopy sky high.

re creating downforce - surely downforce is a gd thing in one of these?

ive heard people say its night and day difference in high speed driving with a BGW. i dont want the BGW so wondering if there are other options.

[Mr Whippy]

Getting useable down force without upsetting the overall balance of the car, or creating large chunks of drag, is something that will take a huge amount of effort.

Is it something you wish to undertake correctly, or are you just sticking bits on and measuring results with the "arse dyno"?

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[FireStorm999]

Getting useable down force without upsetting the overall balance of the car, or creating large chunks of drag, is something that will take a huge amount of effort.

Is it something you wish to undertake correctly, or are you just sticking bits on and measuring results with the "arse dyno"?

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at the moment sticking bits on and hoping for the best 2bh

just wanted the back to feel more stable at high speeds.

its not bad i just wanted better.

one is presuming by your comment that drag and downforce are not the same

[Mr Whippy]

They are linked, the trick is efficient downforce. A lot of the issue is deciding how much weight you attribute to gains in downforce, or losses in drag, at specific ride heights/speeds/CoP's etc....

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[FireStorm999]

They are linked, the trick is efficient downforce. A lot of the issue is deciding how much weight you attribute to gains in downforce, or losses in drag, at specific ride heights/speeds/CoP's etc....

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Il either keep adding bits and seeing if there is a difference or spec me up whippy!

my friend had a 600hp evo built by rally art, and he says the angle of his front canyards made a huge difference at high speed. whether or not this was BS i dont know, i wasnt allowed to drive it

[Mr Whippy]

I don't disbelieve, however a "huge" difference can mean many different things as its a subjective term.

Without pressure tapping channels and logging software, amongst other things, doing the job correctly would be very time consuming, expensive and a ball ache!

Additionally, my experience is exclusive to single seat, open wheeled, vehicles.

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[niko]

I hope you've noticed already: it's a very complex issue you're talking about there. If you're serious about all this, then do a bit of homework, i.e. reading, about race car aerodynamics. Go to your local library and have a look what they've got there. There should be plenty of books about it.

I've seen a few guys "optimizing" aerodynamics with home-made diffusers etc. and it was nothing but a huge hassle, loads of extra weight, waste of material (seen both alloy and plywood sheets) and was practically(!) useless. It might make you look like a pro/specialist in aerodynamics for a certain (less informed) group of people, but that's about it...

...UNLESS...

...you do some serious research, measurements and looooads of other things to optimize the car as a whole, which is not done in a few weeks in a backyard garage.

The easiest, most effective and cheapest way is, unfortunately, the spoiler.

[FireStorm999]

I hope you've noticed already: it's a very complex issue you're talking about there. If you're serious about all this, then do a bit of homework, i.e. reading, about race car aerodynamics. Go to your local library and have a look what they've got there. There should be plenty of books about it.

I've seen a few guys "optimizing" aerodynamics with home-made diffusers etc. and it was nothing but a huge hassle, loads of extra weight, waste of material (seen both alloy and plywood sheets) and was practically(!) useless. It might make you look like a pro/specialist in aerodynamics for a certain (less informed) group of people, but that's about it...

...UNLESS...

...you do some serious research, measurements and looooads of other things to optimize the car as a whole, which is not done in a few weeks in a backyard garage.

The easiest, most effective and cheapest way is, unfortunately, the spoiler.

Il add the diffuser for looks then (it was given to me not bought), i barely get to drive the car so going to a what do you call that book place? aint gonna happen. not because im unwilling to learn but its not worth the effort in this case. thanks for your help.

[MrLuke]

First thing to do is a proper flat floor, no complex maths or shite just make the floor flat. Won't gain you much downforce per se but will reduce drag and possibly lift.

Diffuser / splitter is next, these are more complicated to get working at their best but you should be able to get benefits from a simple shallow angled diffuser that's sealed to the floor.

[D12 FTR]

The only way to add down force is with a wings not spoilers, low front and a roof hight rear
The flat floor has to extend a certain distance from the front of the car, and must be low to the ground to limit the amount of air goimg under the floor, the rear of the floor should be higher, the rear diffuser at a certain angle and project a certain distance to match the air over the top of the car. The air under the vehicle should be lower pressure coming out than entering, (work out how to do that), air out of the front wheel arches needs to be chanelled, the frontal area of the car should be as small as possible and the rear smaller still...
Don't mess about with wings/aero, read up at least as if you've got it wrong you can leave the ground

[Ruishy1]

ummm no. smoothing the airflow under the car will make a difference. not a huge difference however but will provde extra grip.
to really see a difference however really needs some VERY complex calculations. you have to take into account LOADS of different factors. and most of the mods will only work at speeds well over what most people will be doing in drifting.
Being a little less negative now you need to make the whole car as smooth as possible, and sharp transitions in airflow need to be reduced. if you can flatten out the entire underside, couple that with a spoiler thats been setup with the correct angle and height and you should be able to feel an increase in grip.
If i was you i would try and copy proffesional race cars, they spend a rediculous amount of money on aerodynamics and should give you a good place to start

[Bolf]

There is a guy on SXOC called Piman2k , who is a designer running a nice s14a with plans for undertray and aero , he works at millbrook for GM , so knows his shit.

Worth an ask , but don't mention your from driftworks , he thinks we are all hicks.

[docwra]

TBH Bolf, anyone who has done TA or similar is a better bet than Piman, I know Jez@Horsham has looked into aero, as has Bren at Apex. Hell, we even have some lads running in Britcar that know what they are talking about.

Heres some to be gettign on with:

Aero
S13 Aerodynamics and Im sure theres more, this below is a very good start:

Browser Warning

[MrLuke]

TBH Bolf, anyone who has done TA or similar is a better bet than Piman, I know Jez@Horsham has looked into aero, as has Bren at Apex. Hell, we even have some lads running in Britcar that know what they are talking about.

Heres some to be gettign on with:

Aero
S13 Aerodynamics and Im sure theres more, this below is a very good start:

Browser Warning

Good links

[Shaarkey]

on topic-ish question but not worth its own thread: Would the spoiler pictured below have any noticeable effect to driving or are they purely for style points???



sorry for thread hijack

[MrLuke]

on topic-ish question but not worth its own thread: Would the spoiler pictured below have any noticeable effect to driving or are they purely for style points???



sorry for thread hijack

I cant really see the purpose of it, its not going to generate downforce per-se and I dont imagine it will aid reattachment of the airflow?

[JFR]

This is the only website you need to go to SM AeRoTechniques - home page
Loads of info, simon has worked on a friends gen 1 RX7, by producing a splitter, underfloor and diffuser.

Lots of practical info and designs.