im thinking about going bare arsed but im woried about down force.
im geting a rear diffuser and plan on flat bellying the rest of the underside.
but without the spoiler has anyone had any issues with reduced down force as i drive my cars on the limit quiet a lot.
thanks
if you fit the diffuser and carnards then u shud be fine lol.. touch wood!
no canards just diffuser and under tray
touch wood or armco lol
o your going to die lol.. iv rad things that removing the wing does have a big effect tho bud.
i can say first hand it doesnt feel safe at high speeds with no spoiler on.
btw you should wash then wipe!
from this post:
http://www.mazdarotaryclub.com/forums/showthread.php?t=48790
DIRECT LINK (http://autospeed.com/cms/A_108677/article.html)
"So the aero attachments certainly increase drag - but do they reduce lift as well? After all, that\'s their supposed function! And front lift is indeed reduced, by a massive 38 per cent in fact. That\'s good going, but what about the fitting of the rear spoiler? Well, according to the Mazda data, it made zero difference to rear lift! Yep, zero. You can see why manufacturers are reluctant to widely disperse this sort of data..."
Yep it\'s true apparantly, the standard spoiler actually makes bugger all difference, so it will feel the same whether it\'s there or not :)
direct link:- http://autospeed.com/cms/A_108677/article.html
I suspect that most of the diffusers for sale are merely cosmetic and will make bugger all difference. Would be good to find a diffuser that is proven to work in a wind tunnel.
I suspect any diffuser would only really work properly if the whole underside fothe car was looked at to control the airflow.
Big GT wings certainly do work and the mazda stock spoilers are mainly to clean up the airflow at the back (detach from the body to improve MPG) and they look good.
Quote from: iaint;495082Would be good to find a diffuser that is proven to work
Watch this space :mmmm:mmmm !!!
Quote from: iaint;495082I suspect that most of the diffusers for sale are merely cosmetic and will make bugger all difference. Would be good to find a diffuser that is proven to work in a wind tunnel.
I suspect any diffuser would only really work properly if the whole underside fothe car was looked at to control the airflow.
Big GT wings certainly do work and the mazda stock spoilers are mainly to clean up the airflow at the back (detach from the body to improve MPG) and they look good.
Yeah, I agree. A diffuser will make little difference in my opinion. If it did, it would have to be bolted onto the car extremely well, as it would be pulled down by the -ve pressure under the car, and would have to \'pull\' the car down to.
I have no rear wing & a RE-A rear diffuser on my 430bhp FD & have never experianced any high speed stability issue\'s (upto 170 on the clock)!
Not sure if the diffuser atually has any affect although it does run quite a long way under the car, rite past the fuel tank.
Can you get gromets to fill the holes left by the spoiler or is it a fill and spray job?
you can get grommet but IMO they look funny. Fill and spray looks much smoother
yeah fil and spray or it will look worse than before.
im not shure i belive that the standerd spoiler makes no more down force seems a bit sus.
and the rex has a massive parachute are in the rear bumper so i think even a home made diffuser would help out a bit.
im planing on fitting a full size undertray fron spliter to diffuser to help.
its just when you find these things out on the road its usualy prety hard to keep it under controll so was after some personal experiences.
lum is that cornering fairly hard at 170 or just on straights?
i think ill have around 400-450 bhp (find out on the 10th may woo hoo) so will be up at those speeds no doubt.
ta
Where are you going to be cornering at 170mph?
not at 170 granted, buy easily 100+ in a lot of places if you use the car on circuits a lot.
Data generated from the links above suggests that the spoiler doesn\'t do anything and is merely a cosmetic part.
I doubt very much the standard spoiler generates enough down force for it to be noticeable around a circuit.
Quote from: T11MNM;495216Where are you going to be cornering at 170mph?
the ring . . . .
Show me a video of you going round any corner at the ring at 170mph and i will buy you the spoiler of your choice :)
Where at the Ring are you cornering at 170mph???
Diffusers do work. The problem with the aftermarket ones is they don\'t! Its that simple. They cause drag so will slow you down, they weigh more so will slow you down, and if you crash because you think you have improved aero then that will slow you down also.
The purpose of a diffuser is to slow the air down having been first sped up at the front of the car. So rather than considering just the rear you need to consider the front...to speed up the air, the flat floor....to keep the air smooth and at the same speed, the side skirts to avoid air from spilling out, and the diffuser to slow the air down to avoid pressure drops thus creating drag. The problem with the show diffusers is they have to work around the exhaust and the other problem is the fuel tank doesn\'t allow a deep enough tunnel to increase the volume to bring the air back to the correct speed.
Get round these problems....and you will have an aero package that works. As Sam says...."Watch this space"
I think the other problem with most spoilers is their positioning.
Get hold of your spoiler firmly in both hands....and wiggle it. If the spoiler moves back and forth then its about as much use as a chocolate fireguard...nice to look at but will produce drag....granted the chocolate fireguard wont produce any drag...maybe a sticky mess, but it will taste a lot better!!!
Most of the spoilers are attached to the rear boot which is made of very thin metal...not much rigidity
We ran a wing last year, same as TonyC, modelled from a Formula 3000 car and this was attached via Carbon stays to the rear quarters. You can stand on the wing...even jump up and down on it...bring your mates over and have a party on it....and it will be fine!
This year we\'re running a bespoke double element wing, but still mounted on the rear quarters. However because we are running a diffuser we don\'t need to run such an acute angle of attack on the wing, so our drag will be a lot less.
this looks like a good wing, looks like the fitting AtomicRex
http://www.youtube.com/watch?v=xbKtHL06xmQ
This is the one we made for Tony
(http://www.justgofaster.com/gallery/gallery/tonys_mg/justgofaster.jpg)
If you are being purist...and this discussion is about getting the best. The stays need to be solid otherwise they disturb the airflow around them.
The ones featured in this picture are a two piece stay....and we have now made some new ones that are connected, we put on Tony\'s car for the Race. These use a Wing profile on them too.
Quote from: Bobfish;495317Show me a video of you going round any corner at the ring at 170mph and i will buy you the spoiler of your choice :)
the whole point is i dont want a spoiler lol
i havent even ever been to the ring .
i but i have had a 300bhp astra "skip" at an indicated 175 it wasnt as funny as i thought it was aperently.
well im split decisions now.
i see the point about aftermarket diffusers.
but then if my spoiler isint doing jack anyway mayby ill just be in the same position as i am now anyway,.
i thought the idea was to get air traveling as fast as possible under the car to reduce presure didnt know you had to slow it down again. why is that?
what time scale are you thinking for your proper diffuser then?
just do a simple test bud, do a corner at 170mph without the wing, when u crash buy a new car, then do the same corner with a wing at 170mph, when u crash buy another car and make your decision :D
One of the points that is missed is suspension set up.
Bumps in the track, as I assume you were on a track whilst doing a 175, can often affect the car dramatically. The wrong springs and damping will exacerbate the issue even further!
Your speedo in the Astra should start working on Jackanory with stories like that!
Quote from: weejimmy;495450what time scale are you thinking for your proper diffuser then?
To answer your question, They are pretty much complete however it really isn\'t a simple bolt in job as you wont be able to keep standard fuel tank, or exhaust, rear bumper would need modifying, as would some of the boot floor. Ow and the rear sub frame would need a little bit of work.
And to make it effective you will need to run a proper aero front splitter and flat floor.
(unfortunately they wont be available for sale or any pictures shown until our cars are launched, *Not too long now*)
So basically to sum up.
Our defuser wont suit too many people, but it looks the dogs danglys and will actually work. The Re-A and simular defusers do look cool for sure but please dont be under the impression that they are in any way helping with downforce as the only way they are doing that is by adding weight to the rear.
mmm not too shure on cuting up my boot floor.
would be nice to see it thoe.
would a tamed down version not be viable? just a bit less effective?
Quote from: weejimmy;495797would a tamed down version not be viable? just a bit less effective?
perhaps we could look into it, but to be honest as i said before without a flat floor it would be practically useless anyway.
And also if you wanted to keep standard exhaust it would be useless as it would have to interrupt one of the channels.
What we sell is not for show it is for performance as that it our target area. As said, it wont be everyones cup of tea unfortunately :Tongue1.
flat floor as in a flat under tray from front to diffuser?
, well look forward to seeing the proper one anyway