would a boot spoiler really help with cornering downforce?

[GuyM]

i am not talking about a boot lip spoiler, but a big mother of a tail (Escort RS/ Sierra Cosworth etc) bolted onto the boot.
i am not too worried about the drag effect it will have on top speed (i don't really go fast enough on most of the UK tracks to worry about losing any top speed )but i would be interested to hear anyone opinions on cornering forces.
i know it will look ugly/chav etc but my car is a real stripped out track slag weighing less than 1000kgs anyway so not at all worried about what it looks like.....just want any opinions really

[maxfield]

The car won't have enough power to create downforce.

[march109]

its not the power that creates the downforce, its the speed the vehicle is going, as downforce is created by the spoiler acting like a wing in reverse as it travels through the air. Unless you are travelling fast enough it won't work.

Depending on the speeds your going though, the porsche electronic wing raises itself at 80mph so they must think this is the speed at which it creates a benefit. Admitedly the porsche is far more aerodynamic than an e30 so this probably lowers the speed at which the wing is effective for that vehicle but I would estomate that if you can maintain speeds of 80-90mph round the bends and the wing didn't weigh too much then on a track with fast corners it would be of benefit.

E30 M3's also ran with spoilers on and they can't realistically be going that much faster round the corners than a stripped out track e30, certainly on the straights they would. But thats not where a wing comes into its own.

The old cossie style isn't great though, try the e30 M3 style spoilers, plenty of different types available some with adjustable wing angles and some in carbon fibre.

[billgatese30]

how loose is the back end in the quicker corners, is it really that sketchy and uncontrolable?

[UweM3]

before fitting my EVO3 rear spoiler I spoke to several other M drivers I know at the Nuerburgring. All believed that the wing adds grip and stability in the high speed bends (and these guy's have a 4digit lapcounter). I haven't done a back to back comparision, guess this is where my datalogger would be very usesful. (if I am ever get round to fitting it again...)
If you add a wing to the rear you need to think about the front as well.

As long as you haven't got any suspension issues causing a loose backend a proper wing/spoiler will always add downforce. But at the cost of drag (I do notice the difference in fuel consumption!) and only in higher speeds.

[oldroydsr4]

I believe downforce can be created at as little as 60mph.

Also a flat bottom would help significantly+ a rake of approx 7 degrees was used at the rear (creating a diffuser)

On of the top dogs (forgot his name) at the ring stated that 8 seconds would be saved over a lap with a flat bottom on the Evo Magazines project 8 minutes M3

[GuyM]

The car won't have enough power to create downforce.

i think this is probably my first problem...my car is no rocketship!
and as has been rightly pointed out most "big" spoilered cars have them to cut in at 60mph+

how loose is the back end in the quicker corners, is it really that sketchy and uncontrolable?

the car is quite tight (polybushes all round, adjustable shocks uprated springs etc) its just i think it is a bit too light in some corners - especially the fast sweeping ones.
didn't really want to chuck weights in the boot (after all the effort of stripping it out - which someone else kindly did!) but wondered if one of the horrible large spoilers on alloys legs you can get on ebay (that you see on the back of the chavved up japcr@p) would help.
i'm really not worried about what the car looks like - and i'd take it off to drive too and from the track (too embarrased to drive around with it on!)

If you add a wing to the rear you need to think about the front as well.

that's always the thing with track cars isn't it.....do something in one area and you end up needing to do something in another to feel the full benefit....

[tomtomtom]

they.re not really about downforce are they big wings? they do make the car more stable at high speed though by stopping the back end from lifting up. anything under 140mph though and it wont make much difference i wouldnt have thought

[march109]

First of all power has nothing to do with how downforce is created, you could have a 1000bhp veyron but while its parked in the car park the spoiler is doing bugger all. Its the speed at which the car travels through the air with a spoiler on that creates downforce.

If you are averaging decent corner speeds a spoiler will be of benefit regardless of both power and weight.

[schuey]

Its very rare that any road car spoilers create any positive downforce,it is generally a reduction in lift more than anything which helps grip but not to the extent where you could drive upside down on the roof of a tunnel like an F1 car could. On an e30 the gains you would get from a decent wind tunnel tested spoiler would barely outweigh the extra drag you would inccur as a result of it hanging off the boot. The old cossie whaletails were quite efficient for their day,they would look sh1t on an E30 though! More mechanical grip through better setup and better tyres are the key in saloon cars.

[GuyM]

More mechanical grip through better setup and better tyres are the key in saloon cars.

i think you are probably right - i guess a £50 spoiler is just a cheap way of not really improving things that much!

oh well - even stiffer springs, adjustable top mounts, slicks, etc etc - better start saving......

[paulg390]

oh well - even stiffer springs, adjustable top mounts, slicks, etc etc - better start saving......

Is the right answer - Watford is saved from a Chav Chariot ...Hurrah !

[UweM3]

More mechanical grip through better setup and better tyres are the key in saloon cars.

i think you are probably right - i guess a £50 spoiler is just a cheap way of not really improving things that much!

oh well - even stiffer springs, adjustable top mounts, slicks, etc etc - better start saving......

The balance needs to be right. Stiffer springs will not improve only because they are stiffer. Get the balance wrong and you may end up with a bigger mess than before. Start with a 200lbs difference front to rear (front less) and don't go flat out in the very first bend
If your springs aren't spot on, you can "correct" that with adjustable ARB's. There was a posting the other day showing how to convert your stock ARB's to adjustable. Saves some money and different thickness stock ARB's are available cheaply from the breaker.

[agreen]

i have an adjustable m3 wing on my car so does northloop and shorty73 and someone else on here i forget now have a look in the motorsport section for northloops car looks good and may help

i got mine because i found a cheap one and who knows it may help even if only on those quicker corners

hth

[shorty73]

I shall be testing the different settings at bedford A!

[schuey]

More mechanical grip through better setup and better tyres are the key in saloon cars.

i think you are probably right - i guess a £50 spoiler is just a cheap way of not really improving things that much!

oh well - even stiffer springs, adjustable top mounts, slicks, etc etc - better start saving......

The adjustable top mounts are good,a couple of chaps on here who I do trackdays with (stoneyV6 and lowpro) have them on their 325i and run loads of camber,the car turns in like no other E30 I have ever seen!

[Black_Potato]

More mechanical grip through better setup and better tyres are the key in saloon cars.

Correctamundo

Or.....

Spend some time & money on instruction and setting your car up at somewhere like Plans Motor Sport or Guggliami Motor sport.... at least that way subsequent mods would be objective rather than interweb hearsay.

[handpaper]

Correctly designed, tested, manufactured, fitted and adjusted, a rear wing can do many useful things, including reducing drag. From PPC's article on the E3 CSL, the addition in 1973 of lots of aero gear including a huge rear spoiler cut drag by 16% as well as giving positive downforce.
In fact, that's what the spoilers on most production cars are for, notably the "Heckspoiler" fitted to many E30s - reducing drag by 'spoiling' the airflow over the bootlid and creating turbulence behind the car.

UweM3 is correct in noting that you'll need to balance it with (ideally) a splitter at the front.

Oh, and the Halfrauds chavtastic spoilers? Well, they look like that because they ape the designs used on racing saloons, so fitted properly they should actually give some downforce - if they stay in one piece and on the car

[shorty73]

This is all I have. Seems to do the trick.

http://www.xlraceparts.com/e30-adjustab ... -223-p.asp

But you could try something like this....

http://www.xlraceparts.com/apr-dtm-wing-1021-p.asp

More tasteful than a cossie whale tail!

[northloop]

The simple fact of the matter is that non of us will really know if the spoiler is doing any good or not as we dont have the means to test it properly. I bought mine because I thought it would finish the look of the car of nicely. Will it be effective? Probably not, but I wont know so I wont care.

As with everything in life there is always someone who will tell you you MUST have one too. The probability is they are simply trying to justify their own spend

Couldnt make my mind up whether to fit it to the beemer or one of these

[oldroydsr4]

^^^

Northloop, personally i think the e30 looks better without the plastic numberplate surround, give it ago see what you think (it also countinues your weightsaving theme)

[shorty73]

The simple fact of the matter is that non of us will really know if the spoiler is doing any good or not as we dont have the means to test it properly.

Agreed. Don't think I could fit a wind tunnel in my garage! But there was a good article in Track and Race car a little while ago that mentioned using drops of oil to see how the air flow acted on spoilers and wings. Worth a read if you can find it.

And the spoiler I have (same as yours) is fitted to a fibreglass bonnet so if it created that much downforce it would distort the bonnet and change angle of the spoiler. oooh Flexi wing.........Will the FIA approve?

[nickso]

In fact, that's what the spoilers on most production cars are for, notably the "Heckspoiler" fitted to many E30s - reducing drag by 'spoiling' the airflow over the bootlid and creating turbulence behind the car.

there is already turbulence behind the car, spoiler or not.

im far from an expert but i though the idea was to move the turbulence further away from the rear of the car to reduce the "stickiness" of the slower tubulent air.

[e21Jason]

Hi

Down force can work at 30mph of you want, buy a decent book like the one by katz, there is a review of the areo on an e36 3 racecar, very subtle changes to the eye but less negative lift (i.e. down force) and less drag. Also some were I have scan of some e30 m3 wind tunnel tests, from the German magazine motor which often done this sort of thing comparing the m3 to the standard e30 and measuring the improvement.

Getting down force at the front no problem with a splitter, again the rear no probs with a spoiler (NASCAR style 20cm vertical plane on the boot) but the drag will eat the power. You need at least an e30m3 spoiler with a proper naca aerofoil section raised at the rear so the aerofoil can work i.e. give good down force with minimum drag. You have got to work out what speed you are losing mech grip to see were you could gain from down force, reduced drag will increase top speed.

Better gains could be had by smoothing the under side and fitting a rear diffuser, also a ducted rad would reduce a lot of high speed negative lift. If you look at some of the e30 track cars with single skin grp bonnets you can see increase in bonnet flex as the cars run down the straight.

Jason

[UweM3]

Hi


Better gains could be had by smoothing the under side and fitting a rear diffuser, also a ducted rad would reduce a lot of high speed negative lift. If you look at some of the e30 track cars with single skin grp bonnets you can see increase in bonnet flex as the cars run down the straight.

Jason

I am going to add a bonnet vent this spring and try to exten my front splitter back to the front subframe. Diffuser will be out of my league and without removing the spare wheel well I might be tricky.

You can see the M3 stock boot spoiler working nicely if you take you car in a carwash and the fan is blowing the water away.

I have a short vid from me driving in Oulton Part in the pouring rain and you can see how the spray behing the car is coming from the wing up high in the air.