X1/9 style/design custom modifications

We've discussed rear wings for the X. Including some modern "blade" styles, the F40 style, and similar others. There has been mixed opinions on them. I happened to see a pic of how NOT to do it, in this case on a restored Miura:



restored-lamborghini-miura-svr.jpg


I could live with the front "splitter", but not the wing on top of the roof. o_O
 
Dr.Jeff said:
We've discussed rear wings for the X. Including some modern "blade" styles, the F40 style, and similar others. There has been mixed opinions on them. I happened to see a pic of how NOT to do it, in this case on a restored Miura:



View attachment 74009

I could live with the front "splitter", but not the wing on top of the roof. o_O
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It’s like someone tried to apply the Stratos roof wing, but the Miura doesn’t need it (at least not aesthetically).
 
I'm in the process of fabricating a one-piece aluminium rear-end cover to replace the heavier engine cover and rear trunk cover. I could include a duck tail at the rear edge. The car is both for street and vintage racing and I am wondering if there any real benefit for a duck tail, à-la-Abarth Prototipo, or is it just a visual add-on?
 
Alain - The Red Scorpion said:
I'm in the process of fabricating a one-piece aluminium rear-end cover to replace the heavier engine cover and rear trunk cover. I could include a duck tail at the rear edge. The car is both for street and vintage racing and I am wondering if there any real benefit for a duck tail, à-la-Abarth Prototipo, or is it just a visual add-on?
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I made a duck tail spoiler and aluminium engine cover that's a replica of the steel original for my track X. I did some air flow testing on a mock up of the spoiler with bits of string attached to it, it didn't seem to do very much at all, but I like the look. There was no noticeable difference to lap times, any slight benefit was probably balanced out by the slight weight increase of the duck tail. If you made a much taller one like Steve Hoelscher's autocross cars it probably adds down force, but also drag increase.
spoiler -side.jpg
 
I doubt it would add any downforce at all, ducktails and gurney strips are not designed for adding downforce per se, they are more to lessen drag / lift caused by the (often spinning) wake at the rear of the car.

To see any real benefit I think you'd also need to add some sort of deflector at the roof rear edge like a Strato's or a 131 Abarth.

SteveC
 
Regarding the "ducktail" style spoiler, my understanding is the same as others have stated; unless it is a HUGE one, the function is not to add downforce as much as it is to reduce drag (smooth out the airflow behind the car). And a huge one will increase drag, possibly offsetting the downforce increase as far as lap times are concerned. So it will depend on your specific application. If you autocross (low speed but need lots of traction) then you want maximal downforce but are not really concerned about drag. However if you race on very long, fast, flowing road courses then you want to reduce drag and are not too concerned with downforce. Therefore the style and size of spoiler differs accordingly; with a small ducktail being best for reducing drag. Also I've read that the size of a rear ducktail spoiler needed to reduce drag is actually very small - basically a tiny lip similar to a "Gurney flap". Again, the smaller it is, the less drag it creates. So a ducktail can either reduce or increase drag depending on its size. But all of this is only what I've read and I'm certainly not a aerodynamics engineer.
 
By the way Alain, I really like the idea of your proposed one-piece aluminum rear hatch. Both of the stock lids (engine and trunk) are very heavy. And on a track car aren't necessary for the same functions as on a street car. This also allows for design improvements, like lots of hot air ventilation from the engine bay, the rear spoiler as you described, and others. :)

Regarding rear spoilers and my earlier comments, I believe the whole 'drag vs downforce' concept is why modern spoilers have gone to the "blade" wing style. Apparently they offer increased downforce with less drag. But in my opinion they just don't fit a vintage car's styling.
 
The big wing on the rear works OK if you happen to have a certain white vintage Can AM car with a Chevy engine in it.

The rain tray on the X engine cover is surprisingly heavy and not hard to remove from the engine cover.
 
carl said:
The big wing on the rear works OK if you happen to have a certain white vintage Can AM car with a Chevy engine in it.

The rain tray on the X engine cover is surprisingly heavy and not hard to remove from the engine cover.
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My rain tray was only 3 pounds. The cover without the tray was 13 pounds. I suppose that the 1500 covers may weigh more due to their size.
 
3 pounds is not an insubstantial amount and you could remove even more but removing some of the internal baffles and reinforcements. 3 pounds here 4 pounds there and before you know it you have whacked off another 100 pounds. I'm always amazed at how sprightly my Fatrat feels even though the motor isn't really that modified (IDFs and a header/turbo muffler. Then I remember I've removed about 400 pounds. Add hp or remove weight.
 
GregS said:
I made a duck tail spoiler and aluminium engine cover that's a replica of the steel original for my track X. I did some air flow testing on a mock up of the spoiler with bits of string attached to it, it didn't seem to do very much at all, but I like the look. There was no noticeable difference to lap times, any slight benefit was probably balanced out by the slight weight increase of the duck tail. If you made a much taller one like Steve Hoelscher's autocross cars it probably adds down force, but also drag increase. View attachment 75194
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Thank you for the informative response. Beautiful work, by the way.
 
fiatfactory said:
I doubt it would add any downforce at all, ducktails and gurney strips are not designed for adding downforce per se, they are more to lessen drag / lift caused by the (often spinning) wake at the rear of the car.

To see any real benefit I think you'd also need to add some sort of deflector at the roof rear edge like a Strato's or a 131 Abarth.

SteveC
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My exact thoughts. Merci Steeve!
 
carl said:
3 pounds is not an insubstantial amount and you could remove even more but removing some of the internal baffles and reinforcements. 3 pounds here 4 pounds there and before you know it you have whacked off another 100 pounds. I'm always amazed at how sprightly my Fatrat feels even though the motor isn't really that modified (IDFs and a header/turbo muffler. Then I remember I've removed about 400 pounds. Add hp or remove weight.
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I left the rain tray off, but more for cooling than weight. A great target for weight reduction would be the spare tire. Mine weighs close to 30 pounds (10 rain trays). I'm sure there must be a compact spare that would save several rain trays worth of weight.
 
I agree with the purpose of the ducktail not being for downforce. Mythbusters actually (apparently anyhow, seems reasonable to me) showed that pickup trucks get better milage with the tailgate up over the tailgate removed. They showed some fluid dynamics showing a bubble behind the cab and the water flowing over it. I used to regualrily ride in the back of a pickup and would shove my helmet to towards the tailgate and it would slide back to me. It would make sense that this would be the same but on a smaller scale with the X. Over time I think it would save on fuel. How much may completely depend on your driving habits but if the point is simply that you like the looks of it then COOL! I like the looks of it, do I care about the downforce, not really. Do I care about the fuel savings... meh, maybe but I don't think it would be enough to really notice. Do most people who run wings or spoilers etc actually benefit from them?
 
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