So ive been saying for a long time that I was going to do some aero mods on my car.
![](./images/smilies/spacer.gif)
Why? Because ive done virtually every mod I wanted to up to doing expensive engine work, and
![](./images/smilies/spacer.gif)
£500 spent on aerodynamics will be far more influential than
![](./images/smilies/spacer.gif)
£500 spent on engine power.
![](./images/smilies/spacer.gif)
In april I got it up on axle stands and started designing how my car would look, sculpting the new air flow paths.
![](./images/smilies/spacer.gif)
The MR2 as standard has some key flaws when it comes to downforce.
![](./images/smilies/spacer.gif)
firstly the turbulent air that passes through the radiator is sent under the car, which generates lift underneath.
![](./images/smilies/spacer.gif)
Secondly the rear window step causes the flow to detach, creates a low pressure zone above the car and generates more lift there.
![](./images/smilies/spacer.gif)
It also doesnt create cooling for the engine so its a bit pointless.
![](./images/smilies/spacer.gif)
The spoiler does nothing for downforce, and the engine being exposed ruins the rear under car airflow.
![](./images/smilies/spacer.gif)
Basically its awful for downforce.
![](./images/smilies/spacer.gif)
So what have I done to change it? I purchased
![](./images/smilies/spacer.gif)
£500 of 1.5mm sheet aluminium to use for the mods.
![](./images/smilies/spacer.gif)
First off i cut a hole in the frunk behind the rad fans.
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/cbevftawl/IMAG0701.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
The i cut a hole in the bonnet and crafted a tunnel to connect the two holes.
![](./images/smilies/spacer.gif)
This was quite challenging because the bonnet swings past 90 degrees with the frunk wall, which created closing issues.
![](./images/smilies/spacer.gif)
I also put a plate beneath the frunk wall to block the previous flow path.
![](./images/smilies/spacer.gif)
My solution isnt pretty, but it works.
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/qvvyan5v9/IMAG0702.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/k9dvv7dkl/IMAG0705.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/3mwbm4kmt/IMAG0706.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/lydsbseid/IMAG0091.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
Then i focused on the floor.
![](./images/smilies/spacer.gif)
A good aero car has a flat floor to reduce drag and give the low pressure a uniform surface to act upon.
![](./images/smilies/spacer.gif)
So.
![](./images/smilies/spacer.gif)
.
![](./images/smilies/spacer.gif)
.flat floor required.
![](./images/smilies/spacer.gif)
Front downforce is generated by a front lip, giving the high pressure stagnant air on the front bumper a surface to act and also by accerating the air under the car lowering the pressure.
![](./images/smilies/spacer.gif)
It only makes sense to have the front lip as an integral part of the floor to make for a smooth transition underneath the car.
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/5h963v7n9/IMAG0708.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/rvquk3aet/IMAG0711.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
The floor panels are bolted into the existing undertray holes, but there are not nearly enough of these holes.
![](./images/smilies/spacer.gif)
Some holes were drilled through the floor pan and tapped, with a nut placed on the cabin floor.
![](./images/smilies/spacer.gif)
Where this was not possible the panel edges are bolted together using overlapping tabs.
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/u1l5eldv9/IMAG0712.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/6bvppwfhx/IMAG0713.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
You can just make out the under engine bay panel in this pic
![](./images/smilies/spacer.gif)
(and the one afterwards).
![](./images/smilies/spacer.gif)
A cut out was made at the front of the panel with the front edge rounded upwards, much like the standard undertray.
![](./images/smilies/spacer.gif)
This allowes air into the engine bay.
![](./images/smilies/spacer.gif)
Other cut outs were made below the gearbox because it protrudes through the floor plane, one under the sump for oil drainage and three under the rear subframe, 2 for axle stands and 1 for a jack face.
![](./images/smilies/spacer.gif)
Whilst this is not ideal its necessary.
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/s9izs7fqt/IMAG0088.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
So nice low pressure uniform airflow travels beneath the car and reaches the rear, where a diffuser is required.
![](./images/smilies/spacer.gif)
Diffuser angles should not exceed 7 degrees or should feature a smooth gradual curve to allow the airflow to stay attached.
![](./images/smilies/spacer.gif)
Having separating fences helps restrict turbulent motions and improves diffuser efficiency.
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/gzzgoqph1/IMAG0716.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/z5h0gjed1/IMAG0718.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/q3ooxpcad/IMAG0087.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
Focusing above the car now, The above engine bay area needs sorting.
![](./images/smilies/spacer.gif)
This is primarily because i intended to have a rear wing and the area in front is it is vital.
![](./images/smilies/spacer.gif)
Instead of having the recirculating air that detaches off the roof, a better way is to have a saloon style back.
![](./images/smilies/spacer.gif)
I made an attempt at copying the GT style engine cover.
![](./images/smilies/spacer.gif)
Its hinged on the roof edge for engine bay access and bolts to the actual engine bay cover.
![](./images/smilies/spacer.gif)
The engine bay cover was replaced with one fitted with fans.
![](./images/smilies/spacer.gif)
These were wired in with a switch to the cabin so that i can use them when i want and have them running even when the engine isnt, for post track session cool down.
![](./images/smilies/spacer.gif)
It also provides more cooling than standard.
![](./images/smilies/spacer.gif)
Quite awesomely
![](./images/smilies/spacer.gif)
(and by design) the engine lid directs the cooling airflow down along its
![](./images/smilies/spacer.gif)
exterior surface, which will energise the over roof airflow and keep it attached.
![](./images/smilies/spacer.gif)
It also provides uniform flow to the wing, which is vital.
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/m01iafkhh/IMAG0717.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/mdtnijpth/IMAG0093.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/5v5wpq2d1/IMAG0097.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
And lastly the rear wing.
![](./images/smilies/spacer.gif)
Most carbon fibre wings cost
![](./images/smilies/spacer.gif)
£500-£1000 and frankly have no aerodynamic testing.
![](./images/smilies/spacer.gif)
It wasnt feasable for me to do that, and i couldnt be bothered to CFD model my own one.
![](./images/smilies/spacer.gif)
I did have the fortune of being next to a radical SR3, which is an aero car and has clearly been tested in a tunnel.
![](./images/smilies/spacer.gif)
So i basically copied the chord dimensions and wing design from that.
![](./images/smilies/spacer.gif)
an SR3 rear wing costs
![](./images/smilies/spacer.gif)
£1500, mine cost
![](./images/smilies/spacer.gif)
£80.
![](./images/smilies/spacer.gif)
All made of sheet aluminium, purchased steel brackets and some steel cable to reinforce the drag component force.
![](./images/smilies/spacer.gif)
The sheet aluminium was bent using my knees, wood, a black and decker work mate and a ratched strap and was a pain in the ar$e.
![](./images/smilies/spacer.gif)
I think the finished product looks awesome though.
![](./images/smilies/spacer.gif)
Its mounted above roof level for best airflow.
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/aynzmfyph/IMAG0077.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/hqj031d2t/IMAG0078.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/4c5x706et/IMAG0080.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/wdjykpbp1/IMAG0081.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/8lf8mwz1x/IMAG0094.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
I was going to add side skirts but i cant be bothered and they are highly impractical.
![](./images/smilies/spacer.gif)
But because not doing this canards are vital
![](./images/smilies/spacer.gif)
.
![](./images/smilies/spacer.gif)
Canards generate vortices along the side of the car which restrict freestream air being sucked into the low pressure region under the car.
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/d9qn4cyut/IMAG0082.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/l1bygnsdx/IMAG0095.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
So there you have it, my finished race car.
![](./images/smilies/spacer.gif)
Now heres hoping it passes an MOT.
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
![Image](http://s8.postimage.org/xu02gl3zp/IMAG0096.jpg)
![](./images/smilies/spacer.gif)
![](./images/smilies/spacer.gif)
All comments and questions welcome