Rear diffuser?

[J13UTM]

Does not have to be shaped like that.

It would be possible to produce a plastic mold to bond to a bumper and painted

[Rob Bell]

To a road car, perhaps not. To a competition car like the Shed, then yes...

[Mark L]

To a road car, perhaps not. To a competition car like the Shed, then yes...

The VX is already a track focused lightweight performance car and it's still debatable if the 'Fuzzer gives any benefit, so to a much slower and heavier MGF/TF I would think it'll be next to useless. Worth noting as well that the VX already has a headstart as it's underbody is enclosed as standard (see my old VX below) so you'd have to look at this before you even start on the Diffuser.

I'd think one psi either way on your tyres would have more effect than fitting one of these to a F/TF..... even on track.

[ErikB]

I quite believe in the diffuser and it's effect: the rear of the F is like a dust magnet, the diffuser could help resolving this. Regarding performance, I doubt it..... but it is nice spielerij.

@mgf.be we 'had' someone who did some computer modelling. If interested, I could try to contact him again

[Jon Norris]

I've posted this on .Org a few times but other mods have sort of over taken this one

This is how far I got and roughly what I was aiming at, a little imagination is needed on these pics though

[Rob Bell]

Mark, I know exactly what you're saying. In fact, the MGF usually has very little in the way of rear end lift under most conditions - unlike, it seems, the VX220. That said, the Shed will soon gain a bonnet vent and enclosed radiator, which should reduce front end lift, and the 'idea' is to balance the front and rear once this is done. VHS's solution is a Gurney flap on the boot lid - but IMO that will only work with a roof in place. If driving without, any boot-lid spoiler is likely to be rendered close to useless (unless mounted up high, as Gerry did on Golden Wheels a few pictures up).

For a road car, well you're likely to be right, but that shouldn't stop us playing with our cars should it? But if/when it doesn't work, we'll know that we've proven you right!

Erik, that vector model looks fantastic! Incredibly detailed. Would the author be willing to share?

Jon, I actually really like what you've done to that bumper - very Ferrari-esque! From my limited reading so far, the optimal angle for a diffuser is around 7 degrees. What you've done so far looks rather more aggressively angled than that? I suspect that the exhaust back box is responsible for this isn't it? What do you have planned for the front bumper that I see with a 'minor' modification in it?

[Jon Norris]

The back section thats slapped with fibre glass is basically the reg plate area, from there it starts curling in, I dont have anything but "Paint" in the way of software so its still all in my head, this is about as good as it gets in paint

The front already has a modified bumper that I had made, it does look very similar to one Mike Satur made but has a much larger splitter built on it, and one I've finished the active rear spoiler properly (just done the wiring today) I'll start on the active front splitter

O yeah on the alternative Front thing, I do have some bits from Golden Wheels, the doors with blanked handles and I have the front bumper too

[J13UTM]

Eric - those files look fantastic!! would it be possible to contact the designer?

I mean it may not be possible to use them with solidworks but it would be good reference material for me.

[Rob Bell]

I like the idea of active aerodynamics - I guess they'll help clear speed bumps too?

When I get to the stage of fitting aerodynamics to Project Shed, they'll all be fixed for simplicity and reduced weight - plus I am wondering whether to vent the wheel arches too to reduce these high pressure spots?

[Jon Norris]

I know its been a while since the last post on this but thought I'd add a little vid of 3 parade laps a few of us did yesterday at Goodwood

It doubled as a bit of a test for my rear active spoiler, I was adjusting the g-force switch to set how sensative right/left corners affected it and it went quite well

I know the facts and figures say that if you have the roof down you shouldn't be able to feel the effect .....BUT the fact is you can and it works well, it doesn't come up on slow corners only when your moving fast enough to create side G-force or braking, or braking to a corner then the G-force switch keeps it up till you on the straight

http://www.youtube.com/watch?v=FibFkb2qymQ



Sorry its 12mins long I dont have any editing software

O yeah also tested my home made 280mm rear brake conversion, great fun

[J13UTM]

Wow, great vid Jon.

I got the year out with study project greenlight from Uni this week, and now the cars of road. Im going to start some heavy work on my own car. New wing for a start.

As for the CAD excercise I have the bumper for the F modelled already. Ill post some pics next time im on campus.

[Rob Bell]

Love the active rear spoiler Jon How did you do it? Love to see how this was done

I wonder whether the way that the spoiler is activated can be modified? Unfortunately, looking at the video, the spoiler wasn't really deployed until at least half way through a corner, or indeed until you were through it (dependening on the corner and speed) - perhaps an algorhythm that employs steering angle and road speed might react faster than the G-force sensor?

Very interesting that you say that you can feel the spoiler working with the roof down - which is very useful to know. Perhaps James can tell us more when his aerodynamic model is complete in terms of airflow over the rear bootlid with the roof up/roof down, but your observations are very interesting. Do you think that the spoiler was better for braking or cornering?

Jim - really looking forward to hearing more on your project - and delighted that it's been green-lighted by the college.

[Jon Norris]

Its built using an old escort cab power hood pump, 4 toyota corolla gear cables, 10 relays in total control it all

Its a nightmare to build though, if you look at the legs/stands of the spoiler on the f/tf they angle outwards, so if you imagine pushing cables through the legs, the cables get wider apart the higher it goes and with them being fixed to the spoiler which stops them parting its impossible to get 100% without some serious cash, the front is easier to sort as it doesn't lift as high, on that note you have to lift all points of the spoiler or the edges catch on the rear wing

Yeah I can control when the spoiler kicks in already, I have independant control over the sensetivity of both left and right corners, the main reason on the video why it wasn't coming up quicker is because they were parade laps I wasn't going fast enough, so I was putting my boot down through the corner to make it come up

On the plus side it really seems better on corners and braking

[Rob Bell]

That's cool - I guess if an air brake works on a Veyron, it'll work on an MGF

The problem with using G-force to activate the spoiler is that you're already well into a corner before you are generating G-force. However, if you use speed and steering angle, you could potentially activate the spoiler before serious G-force is generated... just a thought!

Awesome bit of engineering though jon - nice work!

How do you see the active splitter working?

[Jon Norris]

The G-force switch well I say G-force because its shorter than liquid mercury tilt switch, I can set it so fine that bumps on the edge of the road set it off....lol

If you think about it corners where you either don't brake or generate the slightest tilt you shouldn't need the spoiler up, if you brake for a corner then the spoiler will be up for the corner and stay there with the tilt

The front splitter will be a lot easier and more of a gimick than of any use, I can't see any auto feature just a manual raise and lower if needed, I'm thinking of a round poly bush type hinge at each side with two rams again, an position them about a third the way in from either side

Think I'd have to use another pump too or it gets costly with electric switched hydrolic valves

[Rob Bell]

Not sure if you've got any further forward with this project Jon? Project Shed is now back on the road, so I am now thinking about that flat-floor idea...

[nismo]

I am glad this was bumped fascinating stuff, aerodynamics is a true "dark art" and a very costly one at that, I quite fancy a rear spoiler.....purely cosmetic

[Rob Bell]

A one inch lip spoiler at a rake of around 27degrees is what you need from memory (MG Rover aerodynamic test data)

This might also do the job: http://www.ebay.co.uk/itm/JDL-MG-TF-REA ... 23139f15ec (thanks to Allan for the link!)

[nismo]

A one inch lip spoiler at a rake of around 27degrees is what you need from memory (MG Rover aerodynamic test data)

I quick search on ebay should do the trick..........

[British Steel]

Hi there, i have this Spoiler on my TF, you have not much downforce, not as much you must have to feel it.
I thinking about to create one with a friend in spain, a little bit wider and longer, this one is too small.
Klaus