# Spoiler removal - reasons?



## MattGTR750 (Apr 26, 2012)

Sorry if this is a repost but i'd just like to understand a little here 

I've noticed most of the high powered SVM cars run without the rear spoiler? What is the main reason or advantages of removing the spoiler?

I've just removed mine and it looks AWFUL with the holes in my boot lid so what do you do if you have removed it? New boot lid??

Any help will be great

Thanks


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## Anders_R35 (Jul 20, 2011)

Less drag.


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## Marky_GTSt (Dec 31, 2005)

If it is a real spoiler, then its there to reduce drag, removal of it will increase drag.

If it is a wing then its there for down force, removal will reduce drag.

The GTR 35 looks like it has a spoiler, so removal will increase drag. Nissan didn't fit it for show.


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## Marky_GTSt (Dec 31, 2005)

Don't just take my word for it though...

Spoiler (automotive) - Wikipedia, the free encyclopedia

Wing (automotive) - Wikipedia, the free encyclopedia


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## MattGTR750 (Apr 26, 2012)

So by removing the rear spoiler the car will lose downforce and drag will be increased? Surely running 1/4 mile times more downforce and less drag is better? I'm so confused lol


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## Marky_GTSt (Dec 31, 2005)

If it is a well designed spoiler (And i'm guessing it is) removal of it will increase drag and reduce stability. The reason you might be confused is due to people removing them, The reason they remove them is due to them not understanding what they do.

Read those articles I posted, and put your spoiler back on 

Just waiting now for wind tunnel evidence that a spoiler less GTR has less drag than a spoiled one, I'm guessing it doesn't exist.


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## MattGTR750 (Apr 26, 2012)

I took mine off as the car is being wrapped, it kind of looks like a 599 which I though was pretty cool but with all the holes in the boot lid i'm just going to put a carbon or slightly bigger wing back on. Obviously Nissan spent a lot of money developing the R35 and the spoiler as you said is on there for a reason!! I'd love to hear from the SVM guys as to what differences/gains they've seen...

Thanks for your help Marky...


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## Marky_GTSt (Dec 31, 2005)

I think one of the problems is trying to identify a proper spoiler from a cosmetic one, A lot of spoilers are cosmetic and do sod all or make things worse, But the GTR was so extensively tested and has such a low c/d that I find it hard to believe they would then throw on a cosmetic part that is counter to their goal. Either Nissan are right and it should stay on, or Nissan are wrong and everyone should remove them, Which is most likely ? 

I'm happy for somebody to prove me wrong though


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## Marky_GTSt (Dec 31, 2005)

Found a couple of simulations that demonstrate the basic idea...

Without...

mWgZWFTjbMg 

With..

a8RutPaNChk


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## David.Yu (Jun 28, 2001)

Good point Mark. You'd be hard pushed to improve on a Cd of 0.27 and the GT-R does not produce a great deal of downforce, so not sure what benefit there is to removing the wing.

And as Matt says, the holes left behind look tatty and I think the car looks unbalanced without the wing.

Of course I've probably completely screwed the aero with my carbon raised wing... :chuckle:


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## Impossible (May 11, 2011)

how come the Bugatti drops its spoiler when going for its top speed run? 

i thought a spoiler is designed to create down force but the side effect was drag.


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## Marky_GTSt (Dec 31, 2005)

David.Yu said:


> Of course I've probably completely screwed the aero with my carbon raised wing... :chuckle:


To be honest, I have no problem with folk doing what they like, I just think it's important to know why, and what effect it will have. I don't know if you are right with what you say there or not, but at least you are aware of the situation. Too many people just jump in doing stuff with no real thought.


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## Marky_GTSt (Dec 31, 2005)

Impossible said:


> how come the Bugatti drops its spoiler when going for its top speed run?
> 
> i thought a spoiler is designed to create down force but the side effect was drag.


That's a Wing, not a Spoiler, they are different things. Spoiler reduces drag and improves stability, Wing increases down force at the cost of more drag.

Read those links I put up and it will all become clear 

You will also observe that cars that have a nice long sloped back ends normally don't have/need spoilers, and cars with big flat back ends do.


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## MattGTR750 (Apr 26, 2012)

If I research this anymore i'll get even more confused ha ha (it don't take much)

From what i've looked into there's not a definitive answer, different people have different opinions. 

For a high speed run surely the spoiler would help with downforce? For 1/4 mile surely it would help with drag?

Now to justify spending £1.5k on a big rear wing hmmmm when I don't know if I need it or not ....


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## MattGTR750 (Apr 26, 2012)

Marky thank you for your help with this made me understand drag and downforce a lot better.


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## Marky_GTSt (Dec 31, 2005)

MattGTR750 said:


> If I research this anymore i'll get even more confused ha ha (it don't take much)
> 
> From what i've looked into there's not a definitive answer, different people have different opinions.
> 
> ...


The spoiler isn't really there for down force, it's main job is drag reduction and improved high speed stability. A Wing is generally preferable if you corner at high speeds a lot like in oval racing and a lot of tracks.

Oppinion isn't divided among the people who know about this stuff.


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## Impossible (May 11, 2011)

Thanks Marky.


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## Sidious (Jul 14, 2006)

Marky_GTSt said:


> Oppinion isn't divided among the people who know about this stuff.


Don't let headline results get in the way of science. 

That is not the UK tuning way!


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## MattGTR750 (Apr 26, 2012)

So why would the spoiler drop down on a Veyron in a high speed run if a spoiler would increase high speed stability???


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## Marky_GTSt (Dec 31, 2005)

Sidious said:


> Don't let headline results get in the way of science.
> 
> That is not the UK tuning way!


What do you mean ?


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## Marky_GTSt (Dec 31, 2005)

MattGTR750 said:


> So why would the spoiler drop down on a Veyron in a high speed run if a spoiler would increase high speed stability???


Because its a Wing... So removing it from airflow is good (In fact its used like an airbrake isn't it ?), The Veyron has a nice smooth round back end too so is stable without any spoiler. And besides, there is a lot more to it than just that, the whole car is designed to work in that way.

Also, A car without a spoiler won't be unstable, But a well designed spoiler will improve what stability it has, So its not vital in that role for the most part.


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## MattGTR750 (Apr 26, 2012)

Thank you Mark !

So tuners removing the spoiler know something Nissan don't lol?


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## Sidious (Jul 14, 2006)

Marky_GTSt said:


> What do you mean ?


Well explained posts containing some scientific facts do not bode well in most forums these days if the answer is not what they are looking for.

Basically the answer people look for is "it makes your car faster" even if it is scentifically not true.

Hence headline results.


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## Marky_GTSt (Dec 31, 2005)

MattGTR750 said:


> Thank you Mark !
> 
> So tuners removing the spoiler know something Nissan don't lol?


No, I think they are just taking an intuitive route that seems plausible, That and the years of people confusing Wings with Spoilers and with about 95% of spoilers being cosmetic and doing nothing or making things worse, I just think in the case of the GTR its overwhelmingly more likely that its a good drag reducing spoiler rather than a poor cosmetic addon.

And a good spoiler will give you about 1% better fuel economy too 

I can see why they do it, it does seem to make sense to take things off that look like they cut into the air. I just think intuition is probably wrong in this case.


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## Sidious (Jul 14, 2006)

MattGTR750 said:


> Thank you Mark !
> 
> So tuners removing the spoiler know something Nissan don't lol?


^^ See what I mean Mark?


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## Adamantium (Jun 24, 2002)

funnily enough, for all the great looking add ons you can put on the GTR, the one thing I've done my best to avoid is anything that affects the aero.

I can imagine nissan aerodynamicists crying at the thought of people tinkering.

If you consider that the extra canard on the nose, and the movement of the front naca ducts and revised grille can reduce the cd from 0.27 to 0.26, there is no way on earth I'd consider something like changing the spoiler for anything other than a carbon version of the same thing.

I feel bad enough changing the shape of the components in the engine bay as apparently these were the points where nissan really gained an advantage over the competition.


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## Marky_GTSt (Dec 31, 2005)

Sidious said:


> Well explained posts containing some scientific facts do not bode well in most forums these days if the answer is not what they are looking for.
> 
> Basically the answer people look for is "it makes your car faster" even if it is scentifically not true.
> 
> Hence headline results.


LOL, yea, I know... Red paint, Stripes and stickers chap 

There are plenty of examples, Those switches that cut out the alternator on full throttle for one. Big bore exhausts is another that springs to mind. Oh, and polishing ports...


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## Marky_GTSt (Dec 31, 2005)

Adamantium said:


> funnily enough, for all the great looking add ons you can put on the GTR, the one thing I've done my best to avoid is anything that affects the aero.
> 
> I can imagine nissan aerodynamicists crying at the thought of people tinkering.
> 
> ...


Then you sir, Are one of the best car modifiers on here. in so much as you trust Nissan engineers and millions in development and wind tunnels over some bits that you can buy and bolt on. Any tuning company tells you to change the Aero, Ask for wind tunnel results


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## Adamantium (Jun 24, 2002)

Marky_GTSt said:


> Then you sir, Are one of the best car modifiers on here. in so much as you trust Nissan engineers and millions in development and wind tunnels over some bits that you can buy and bolt on.


I wouldn't agree with that.

Under the skin I've had no quarms about modifying!

It's just the aero that I wouldn't mess with.


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## Marky_GTSt (Dec 31, 2005)

Adamantium said:


> I wouldn't agree with that.
> 
> Under the skin I've had no quarms about modifying!
> 
> It's just the aero that I wouldn't mess with.


That's how I would approach it, Afterall, Any mass produced car is a compromise, and there are parts one can get of greater quality, Performance gains are there to be had, But you have to pick carefully so as not to undo good work.


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## Marky_GTSt (Dec 31, 2005)

Anyways, If anyone has proof that removing the spoiler on the R35 improves airflow I would be really interested in seeing it. But for now i'm off to play Warcraft 

Have fun kids, And don't forget, Intuition != Fact.


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## Adamantium (Jun 24, 2002)

Marky_GTSt said:


> That's how I would approach it, Afterall, Any mass produced car is a compromise, and there are parts one can get of greater quality, Performance gains are there to be had, But you have to pick carefully so as not to undo good work.


Sound advice.

I'm feeling pretty good so far about the bits I've done.


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## MattGTR750 (Apr 26, 2012)

Some very good info !! 

I'd love to hear from one of the respected tuners as to why they do it ?!


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## asiasi (Dec 22, 2007)

Found this a while ago http://www.suzukaracing.com/GTR page/racetoroadgtr.pdf


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## vanos (Mar 8, 2008)

Mr Suzuka wanted it wingless with a elevated gurney instead but Nissan said no to that. There is a vendor who made thé trunk Suzuka wanted. Cant remember their name..

Also i asked Mr Suzuka about removing thé spoiler and he Said "do not remove the rear spoiler, It is dangerous"

There you go.


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## Marky_GTSt (Dec 31, 2005)

asiasi said:


> Found this a while ago http://www.suzukaracing.com/GTR page/racetoroadgtr.pdf


That's a superb document, Here are some bits that stood out for me...



> y. If the ride height of the GTR
> is lowered by 10-30mm, like other exotic cars, one can assume the Cd value will be lower and
> the downforce will increase substantially


Seems like a legitimate way to improve down force if needed, lower the car 25mm. There will be a drag penalty of course.



> , rarely did we see a positive
> gain when switching to a new model part, it was always a step
> backwards. After nearly 2000 runs, and much agony, we achieved Cd=
> 0.27 in drag and combined front and rear downforce.


So at a certain point every change made drag worse.



> we spent nearly a year and half in the windtunnel
> creating the GTR. Good numbers do not come easily!


I think this all backs up my argument quite nicely.


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## Marky_GTSt (Dec 31, 2005)

asiasi said:


> Found this a while ago http://www.suzukaracing.com/GTR page/racetoroadgtr.pdf


I also want to encourage everyone to read this, you don't need to understand it all, just check out the effort involved in making the GTR the car that it is.


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## SamboGrove (Jun 27, 2010)

Marky_GTSt said:


> I think this all backs up my argument quite nicely.


indeed!

An interesting thread....i always thought wings and spoilers were the same thing and just added downforce....every day's a schoolday!


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## Marky_GTSt (Dec 31, 2005)

One thing I didn't consider before, and which now seems obvious, is the way the rear diffuser and spoiler work together.

While thinking about all this I have also been thinking of a way to stop my old GTSt lifting at speed on the front and I suspect I may now have thought of something that will work.

Its been fun


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## andyg (Apr 1, 2012)

asiasi said:


> Found this a while ago http://www.suzukaracing.com/GTR page/racetoroadgtr.pdf


good interestinfg read mate nice find


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## vanos (Mar 8, 2008)

Marky_GTSt said:


> Seems like a legitimate way to improve down force if needed, lower the car 25mm. There will be a drag penalty of course.
> .


False. it Will reduce drag. You need to be as Close to thé ground ås possible to reduce turbulence on thé underside


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## Marky_GTSt (Dec 31, 2005)

vanos said:


> False. it Will reduce drag. You need to be as Close to thé ground ås possible to reduce turbulence on thé underside


Your right, not sure what I was thinking there


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## alloy (Apr 29, 2005)

No doubt the GTR has a spoiler, it's one of my favourite bits of the cars design. The c-pillar has a crease which directs airflow through to the spoiler. If you look at the base plate of the spoiler there is another little canard to channel that directed airflow....it is pure function!


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## Anders_R35 (Jul 20, 2011)

No doubt Nissan will have spent a fortune in wind tunnel tests, but their design criterior and targets may be different than someone who is tuning their car to run faster laps on circuit for example.

I'm sure the Cd value helps their fuel efficiency targets, but they could have created a car with more downforce at the expense of drag if they wanted to.


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## Marky_GTSt (Dec 31, 2005)

Anders_R35 said:


> No doubt Nissan will have spent a fortune in wind tunnel tests, but their design criterior and targets may be different than someone who is tuning their car to run faster laps on circuit for example.
> 
> I'm sure the Cd value helps their fuel efficiency targets, but they could have created a car with more downforce at the expense of drag if they wanted to.


Correct, They actually chose that particular level of down force, If you want to improve it, lower the car.

I think the down force generating wings would benefit cars that are tracked often where grip and handling comes before economy. But the original question was about removal of the spoiler for drag racing, And I suspect we have put forward a strong case for leaving it on for more or less all purposes.


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## Anders_R35 (Jul 20, 2011)

Marky_GTSt said:


> Correct, They actually chose that particular level of down force, If you want to improve it, lower the car.
> 
> I think the down force generating wings would benefit cars that are tracked often where grip and handling comes before economy. But the original question was about removal of the spoiler for drag racing, And I suspect we have put forward a strong case for leaving it on for more or less all purposes.


Agreed, now John Hanton and SVM team need to do a run with spoiler on to see how it effects their record :thumbsup:


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## Marky_GTSt (Dec 31, 2005)

Anders_R35 said:


> Agreed, now John Hanton and SVM team need to do a run with spoiler on to see how it effects their record :thumbsup:


Honestly, all things considered, I doubt it will change anything that can be measured on a strip. Flying mile or top speed runs possibly, but I can't imagine a way to accurately measure it.


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## [email protected] (Nov 16, 2010)

Hi, we have tried back to back many times !
Spoiler off = 2-3mph higher in top speed. (on a qrt) myth busted ,sorry lads

Can't say to much tonight, but i can confirm we have just taken a spoiler off today,
just to gain such an improvement,car will be racing this weekend  i will let you all know how he gets on !

However for stablity on top speed runs we intend to keep it on, as above 200mph car moves around to much *we just will increase power *, asking both f.man and JH both did the fastest times @totb they agree
We are taking Hulk to a wind tunnel to see what happens above say 160mph as our target speed is now 240mph what is best and what height to set ?
Most guys set their car high, so the air goes under,this unsettle's the car,but you can fudge a higher top speed with balls of steel lol
kk


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## Marky_GTSt (Dec 31, 2005)

[email protected] said:


> We are taking Hulk to a wind tunnel to see what happens above say 160mph as our target speed is now 240mph what is best and what height to set ?
> Most guys set their car high, so the air goes under,this unsettle's the car,but you can fudge a higher top speed with balls of steel lol
> kk


I would be very interested to see the results of this...

As for the small increase in speed without the spoiler, I have to wonder what might be happening there, An interesting observation indeed but I don't think you can quite call it busted yet. When you saw the extra2 to 3 mph, what speed where you going ? I wonder if the spoiler becomes detrimental above a certain speed ? what other mods did you make ?

I think you need to do it with a stock car to really tell tbh.


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## [email protected] (Nov 16, 2010)

ok will try more on?off tests
Maybe the cars will go even faster Lol for now we will keep chipping away at going faster and faster,We will keep testing all ideas, thanks for all views, we will maybe come back to this . i must agree car looks better with it on, as Nissan intended
kk


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## Marky_GTSt (Dec 31, 2005)

[email protected] said:


> ok will try more on?off tests
> Maybe the cars will go even faster Lol for now we will keep chipping away at going faster and faster,We will keep testing all ideas, thanks for all views, we will maybe come back to this . i must agree car looks better with it on, as Nissan intended
> kk


It sure doesn't hurt to gather more data, I'm forced to wonder why it still works as a stabiliser at high speed but apparently has detrimental effect on the quarter, My suspicion is there is more at work here than just the spoiler.

Im beginning to suspect that it may be tuned to work in a certain speed range of the stock car and may indeed be less than perfect at higher speeds, but the stabilising effect at those same speeds has me puzzled???? Maybe they really did sacrafice a tiny bit of drag for greater stability, but it sure doesn't look like they did in that document.

Either way, fascinating stuff.


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## Tigerruss (Sep 5, 2008)

Not sure Kev's talking of the stock spoiler?


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## Marky_GTSt (Dec 31, 2005)

Tigerruss said:


> Not sure Kev's talking of the stock spoiler?


Ah, that might explain things if true, We where discussing stock ones only, Any other kind will most likely produce more drag and give the results Kev provided. It also raises an interesting question, will said car go faster with a stock spoiler back on ???


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## MattGTR750 (Apr 26, 2012)

Amazing stuff thank you so much everyone - I've learnt a lot today!

Kev, what do you do about the boot lid when you remove the rear spoiler as it looks terrible?!?

So for 1/4 mile stuff and 30-130 days I will not be running a spoiler


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## Marky_GTSt (Dec 31, 2005)

MattGTR750 said:


> Amazing stuff thank you so much everyone - I've learnt a lot today!
> 
> Kev, what do you do about the boot lid when you remove the rear spoiler as it looks terrible?!?
> 
> So for 1/4 mile stuff and 30-130 days I will not be running a spoiler


Just hang on before making a conclusion, as it's possible Kev was running an aftermarket wing, So his results may not help in deciding how well the stock spoiler works.


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## [email protected] (Nov 16, 2010)

MattGTR750 said:


> Amazing stuff thank you so much everyone - I've learnt a lot today!
> 
> Kev, what do you do about the boot lid when you remove the rear spoiler as it looks terrible?!?
> 
> So for 1/4 mile stuff and 30-130 days I will not be running a spoiler


Unfortunately, a new carbon, boot lid , or repair and paint, You have to be very keen though as to such a small gain,

Regarding, what* type *we have swapped?, Both! oem and modified "All" seem to have had gains *on removal in a straight line pull*, and Yes the larger fin types even more gain 

As said though there are theories for both, so a trip to Mira (wind tunnel) will give us factual data,instead the "we won "so its right approach
Maybe,making a U turn , Refitting and will give us a little extra pace?:squintdan

I will let you guys know, ON or OFF result kk


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## [email protected] (Nov 16, 2010)

EG of Results,,

Marham 2012,,,Hulk No spoiler 218mph
Stevie G...Spoiler 204mph
chubbie....big spoiler..187 mph
All top speeds were calculated on a 1.1 mile Run...Ok mine was the most powerful,lol but 
stevie g and chubbie were approx the same power !

Another example, 
Two 650Rs...Taken to Crail, with spoiler on, dropped 5mph (same cars)

Everything is worth a shot in competition imo , that extra, maybe all it takes 

As said though, I *will* listen to all views, and have another Go 
Back soon!*
kk*


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## Marky_GTSt (Dec 31, 2005)

To really compare you need to use the same car each time, Ideally under the exact same conditions, The Wind tunnel will be the best approach and if possible compare the Hulk to a stock GTR and see if there are other factors involved, Its possible the modifications made both externally and in the engine bay may play a part in this...

Look forward to some results.


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## Anders_R35 (Jul 20, 2011)

The slight probem with Mira is maximum wind speed of circa 80mph, I suppose most manufacturers are happy with that with national speed limits in most countries not exceeding this. They make calculations for results above this speed, but who knows what vortices and additional turbulance happens at 180mph?

I had planned a trip to Mira post fitting Litchfields front lip and the ARP rear spoiler to see what additional downforce was created / lost and how it effected the balance of the car. I'll need to invite another MY11 in stock Aero trim as a comparison, was going to invite Adam.


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## rasored (Apr 5, 2009)

David.Yu said:


> Good point Mark. You'd be hard pushed to improve on a Cd of 0.27 and the GT-R does not produce a great deal of downforce, so not sure what benefit there is to removing the wing.
> 
> And as Matt says, the holes left behind look tatty and I think the car looks unbalanced without the wing.
> 
> Of course I've probably completely screwed the aero with my carbon raised wing... :chuckle:


Nissan claims the GT-R generates more than 176 pounds of downforce at 186 mph. FRONT AND REAR . According to wind-tunnel tests by the German magazine Sport Auto, few production cars are better, and those few—the Bugatti Veyron, the Mercedes SLR McLaren, and the Porsche Carrera GT - downforce will start at about 45mph

Remove the rear spoiler - and over 60mph you will notice the difference !

Took the spoiler of my old BNR32 and all it did was go sideways .........


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## [email protected] (Nov 16, 2010)

This does back up, our real life tests 
also agree the cars are certainly more lively on the rear when removed,

ON?OFF? i still think off imo 
kk


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## Anders_R35 (Jul 20, 2011)

rasored said:


> Nissan claims the GT-R generates more than 176 pounds of downforce at 186 mph. FRONT AND REAR . According to wind-tunnel tests by the German magazine Sport Auto, few production cars are better, and those few—the Bugatti Veyron, the Mercedes SLR McLaren, and the Porsche Carrera GT - downforce will start at about 45mph
> 
> Remove the rear spoiler - and over 60mph you will notice the difference !
> 
> Took the spoiler of my old BNR32 and all it did was go sideways .........


Where did you read that, the article below shows 24KG downforace at 245Km/h, granted that will be better for the DBA? 

http://www.suzukaracing.com/GTR page/racetoroadgtr.pdf


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## [email protected] (Nov 16, 2010)

thats 52iibs at 153mph,,, maybe does rise to 176llbs at 186mph ?

anyway its still slowing you down  if you ever get to 200mph even more LOl
kk


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## Sidious (Jul 14, 2006)

Funny thread. 

I shall remove my spoiler and gain xxx mph on the end of the next traffic light GP - because internetz says so.


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## [email protected] (Nov 16, 2010)

Sidious said:


> Funny thread.
> 
> I shall remove my spoiler and gain xxx mph on the end of the next traffic light GP - because internetz says so.


Goooooo on then Lol :wavey:
kk


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## MattGTR750 (Apr 26, 2012)

Looks like I'll take a carbon boot lid then 

Next time I'm at pod I'll run a comparison ... Stock boot lid and rear spoiler vs carbon boot lid and no spoiler ! 

What's a fair test 2 or 3 runs with each set up??

I've only got a 650R so will have less variables compared to the higher powered cars but maybe I won't see the gains like the 850/900R ?!


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## [email protected] (Nov 16, 2010)

true, imo, the faster you go the more gain

pls let us all know..3x runs on each sounds ok, but im sure some wont agree lol
rather than going to expense of a carbon boot, just remove your spoiler after 3 runs and run again kk


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## Marky_GTSt (Dec 31, 2005)

MattGTR750 said:


> Looks like I'll take a carbon boot lid then
> 
> Next time I'm at pod I'll run a comparison ... Stock boot lid and rear spoiler vs carbon boot lid and no spoiler !
> 
> ...


The problem with this kind of testing is that the margin for error may be greater than the gains/losses of the spoiler, But by all means do the experiment and report your findings, It will be interesting if it is actually counter to what it technically should be. 

Obviously more runs is better, but maybe you will see something in 3 runs, but it would be hard to rule out other things based on that number. Unless of course the difference is significant.

Something else to consider, When you remove the spoiler, put it inside the car (on the rear seat or something) so you have like for like mass. This way you are changing only the aerodynamics and nothing else as far as possible.


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## [email protected] (Nov 16, 2010)

Make sure you also do not have anything to eat, or go for a dump btw runs LOL 
Im sure it wont come down to splitting hairs 
kk


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## Sidious (Jul 14, 2006)

Marky_GTSt said:


> The problem with this kind of testing is that the margin for error may be greater than the gains/losses of the spoiler, But by all means do the experiment and report your findings, It will be interesting if it is actually counter to what it technically should be.
> 
> Obviously more runs is better, but maybe you will see something in 3 runs, but it would be hard to rule out other things based on that number. Unless of course the difference is significant.
> 
> Something else to consider, When you remove the spoiler, put it inside the car (on the rear seat or something) so you have like for like mass. This way you are changing only the aerodynamics and nothing else as far as possible.


If the stock spoiler is a drag reducing part, then SVM has effectively claimed to have defied physics. Although most UK tuners tend to behave this way.

Just like how Dynamo can 'walk on water' - it's all an illusion or a big fib.


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## Marky_GTSt (Dec 31, 2005)

[email protected] said:


> Make sure you also do not have anything to eat, or go for a dump btw runs LOL
> Im sure it wont come down to splitting hairs
> kk


It was just a thought  

At what speed did you find the 2 - 3 mph difference ?

I think just making sure fuel load is similar at the start of both tests should be enough. There is only so much can be done in real world tests afterall...

As a computer programmer I get the luxury of being able to test things millions of times in exactly identical conditions, So making code run fast is rather easier than cars


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## rasored (Apr 5, 2009)

Anders_R35 said:


> Where did you read that, the article below shows 24KG downforace at 245Km/h, granted that will be better for the DBA?
> 
> http://www.suzukaracing.com/GTR page/racetoroadgtr.pdf



2009 Nissan GT-R - First Drive Review - Car Reviews - Car and Driver


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## mags993tt (Feb 3, 2011)

Marky_GTSt said:


> The problem with this kind of testing is that the margin for error may be greater than the gains/losses of the spoiler, But by all means do the experiment and report your findings, It will be interesting if it is actually counter to what it technically should be.
> 
> Obviously more runs is better, but maybe you will see something in 3 runs, but it would be hard to rule out other things based on that number. Unless of course the difference is significant.
> 
> Something else to consider, When you remove the spoiler, put it inside the car (on the rear seat or something) so you have like for like mass. This way you are changing only the aerodynamics and nothing else as far as possible.


Thanks, found this thread a really interesting read. I don't know the first thing about aero but something I noticed a year ago while driving through thick fog on the motorway (quite sad I know but I did find it intriguing) was that I didn't have to use the windscreen wipers once. Not a drop of water in a 1hr plus foggy motorway ride. What's this I thought to myself..completely dry fog? Then I looked at the wing mirrors and they were streaming water like they had built in taps... So the air flow seems to completely miss the windscreen and possibly some gets directed to the sides and across the mirrors.

Anyway like I said I don't know the first thing about aero but it may mean that any change to the front end aero or mirrors (not to mention bonnet, ride height, wheels, arch extensions etc) may have an affect on the rear spoilers performance. So would say I agree everything needs to be stock for any rear spoiler on/off experiment to work. Sorry if I am talking b*ll*cks (certainly don't mind being educated if I am) but thought in the current absence of data that the fog thing was interesting enough to mention as I have never driven a car that didn't need it's winsdcreen clearing in those conditions and I think it may show that there is something quite peculiar to the GTR going on with the airflow over the car to the rear spoiler that starts off somewhere in the design of the front...so the front/sides/mirrors/ride hight etc may need to be completely stock to check the real effect of the stock rear spoiler removal.


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## Adamantium (Jun 24, 2002)

Do AMS run spoilerless too?

Might be worth checking since they are the gtr quarter mile and top speed experts.


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## Anders_R35 (Jul 20, 2011)

rasored said:


> 2009 Nissan GT-R - First Drive Review - Car Reviews - Car and Driver


Nice one, now I need to upgrade ball size to take on Stowe corner at 186mph


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## johnhanton57 (May 2, 2009)

Marky_GTSt said:


> Honestly, all things considered, I doubt it will change anything that can be measured on a strip. Flying mile or top speed runs possibly, but I can't imagine a way to accurately measure it.


Proffessor Matt ran TOTB last year and when he took the wing off he got 6 mph more over the Kilometer than before. But i agree it does affect stability and you pay a price for the reduction in drag. But it's the choice you make:thumbsup:


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## NISFAN (Oct 11, 2003)

There is little doubt in my mind that the spoiler adds drag......very few examples (if any?) where a tea tray bolted to a boot doesn't. 

It will no doubt be a smallest amount of drag to achieve x down force scenario. Same issue that affected Elise mk1 and audi tt mk1. Both of those cars were designed to have a clean boot line, but had to add a spoiler to reduce the rear end lift.


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## Marky_GTSt (Dec 31, 2005)

NISFAN said:


> There is little doubt in my mind that the spoiler adds drag......very few examples (if any?) where a tea tray bolted to a boot doesn't.
> 
> It will no doubt be a smallest amount of drag to achieve x down force scenario. Same issue that affected Elise mk1 and audi tt mk1. Both of those cars were designed to have a clean boot line, but had to add a spoiler to reduce the rear end lift.


Another example of a person confusing a wing for a spoiler... 

Might be worth you having a read back and finding the links which describe the difference


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## Marky_GTSt (Dec 31, 2005)

johnhanton57 said:


> Proffessor Matt ran TOTB last year and when he took the wing off he got 6 mph more over the Kilometer than before. But i agree it does affect stability and you pay a price for the reduction in drag. But it's the choice you make:thumbsup:


Wing ? or spoiler ? was it a stock spoiler on an R35 ?


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## [email protected] (Nov 16, 2010)

i dont want to be a* thread spoiler *remove this thingy and you will increase speed!!
trust me  
kk


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## Marky_GTSt (Dec 31, 2005)

[email protected] said:


> i dont want to be a* thread spoiler *remove this thingy and you will increase speed!!
> trust me
> kk


Have you got that wind tunnel booked yet ??


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## [email protected] (Nov 16, 2010)

We don't need a wind tunnel to establish that one ,,,only a stop watch   
kk


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## Marky_GTSt (Dec 31, 2005)

[email protected] said:


> We don't need a wind tunnel to establish that one ,,,only a stop watch
> kk


Since you're not running a standard spoiler your results don't help anyways, removing a downforce creating wing will allways up your speed as has been established numerous times in this thread alone.

Until somebody does some testing with the stock spoiler and comes up with some actual, measurable facts, ill stick by what I said originally.


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## [email protected] (Nov 16, 2010)

Marky_GTSt said:


> Since you're not running a standard spoiler your results don't help anyways, removing a downforce creating wing will allways up your speed as has been established numerous times in this thread alone.
> 
> Until somebody does some testing with the stock spoiler and comes up with some actual, measurable facts, ill stick by what I said originally.


Nooooooooooooo you have the wrong end of the stick,,,we have tried many many times, in Portugal,Romania,Spain,England and Scotland Removing stock OEM spoilers On/Off
(some call them wings) Guys want to win :bowdown1: I'snt that enough testing ?

Also much data is shared across the globe,,enough said now imo...
Remove if you want to take a few tenths off..:flame:


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## NISFAN (Oct 11, 2003)

Marky_GTSt said:


> Another example of a person confusing a wing for a spoiler...
> 
> Might be worth you having a read back and finding the links which describe the difference


Marky, Don't be a numpty, I know what the difference is. In a nutshell, a wing creates downforce, a spoiler reduces natural lift (in the context of a boot lid mounted device ). And that's what I'm talking about, both result in more aerodynamic weight on the wheels.....and the thing you seem to have a problem with is, both add drag.


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## NISFAN (Oct 11, 2003)

Double post


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## Adamantium (Jun 24, 2002)

Nisfan,

I think you are being the numpty,

Adding downforce and removing lift are the same thing if they change the effective weight of the car. Both of those things are accomplished with a wing.

A spoiler is there to spoil the airflow around the rear end of the car to reduce drag. From what I've read in this thread and the links posted, it has nothing to do with lift/downforce, only cD rating.


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## NISFAN (Oct 11, 2003)

Adamantium said:


> Nisfan,
> 
> I think you are being the numpty,
> 
> ...


lol, the clue is in the name

_4. spoiler - an airfoil mounted on the rear of a car to reduce lift at high speeds
aerofoil, airfoil, control surface, surface - a device that provides reactive force when in motion relative to the surrounding air; can lift or control a plane in flight 
5. spoiler - a hinged airfoil on the upper surface of an aircraft wing that is raised to reduce lift and increase drag
aerofoil, airfoil, control surface, surface - a device that provides reactive force when in motion relative to the surrounding air; can lift or control a plane in flight _

Perhaps the thing on the back of a GTR is not a spoiler either then right? Maybe it is a strake? :chuckle:


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## Adamantium (Jun 24, 2002)

Where are these definitions from?


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## Adamantium (Jun 24, 2002)

http://en.wikipedia.org/wiki/Spoiler_(automotive)

Note the reference to spoilers reducing lift is when they reduce airflow under the car. This will not be the case when mounted on top of the bootlid!!!


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## dtox (Sep 21, 2009)

I know this is a daft question and please forgive me if i'm wrong,

as 6 pages of Spoiler Related,

Is it possible I know a Long shot, to have 2 Boot lids,

1 - With A or OEM Spoiler what ever you prefer, i.e track days and all
2 - Other i.e Carbon spoiler-less i.e drag times

Yes I know it will be a pain removing the boot lid everytime but it will save trouble  and a Win Win situation


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## NISFAN (Oct 11, 2003)

Adamantium said:


> http://en.wikipedia.org/wiki/Spoiler_(automotive)
> 
> Note the reference to spoilers reducing lift is when they reduce airflow under the car. This will not be the case when mounted on top of the bootlid!!!


Sorry I take wikipedia answers with a pinch of salt as they are written by general members of the public in lots of cases. Many wiki threads are completely wrong, or skewed to a particular view point.

The definitions I got are from dictionary sites.

The general concept is that a slippery modern car in itself becomes a great wing, and wants to go airborne at speed. Not a great feeling for the driver. 

Some clever engineers adapted aircraft devices, called 'spoilers' to spoil the lift characteristics of this car shaped wing phenomenon. Spoilers don't produce downforce...they merely disturb the cars own shape from producing lift. The nett effect might seem like it produces down force, but it not designed to.

This is different from a wing that generates down force on it's own. 

What is the 'thing' on the back of a GTR? I don't know it could be a spoiler, or a wing, or a useless ornament.....(it's soft edges lead me to belive it is more the latter :chuckle


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## [email protected] (Nov 16, 2010)

Guy's is all this getting too much now ? Take it from me, in the case of an R35 remove the rear Wing/spoiler and it will go a little faster, Not worth all the effort at the lights
though , lol
does it really matter, what it does to the areo? Just , try it out
kk


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## NISFAN (Oct 11, 2003)

Nope you are right Kev.....take it off if you like it that way, or leave in on.....your car......your choice


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## johnhanton57 (May 2, 2009)

Marky_GTSt said:


> Wing ? or spoiler ? was it a stock spoiler on an R35 ?


YESopcorn:


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## Adamantium (Jun 24, 2002)

NISFAN said:


> What is the 'thing' on the back of a GTR? I don't know it could be a spoiler, or a wing, or a useless ornament.....(it's soft edges lead me to belive it is more the latter :chuckle


Fair enough re Wikipedia. Whatever happens I think there have been enough examples that removing the thing does increase velocity across the line in the quarter.

Not sure I'm convinced Nissan did anything on the aero of this car for show. They made far too big a deal out of it for that to be true.


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## FLYNN (Oct 6, 2006)

Below is a pic of a GTR developed by Nissan. Someone should tell them to put the standard spoiler back on. Hopefully they will read this thread and see the error of there ways :chuckle:


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## FLYNN (Oct 6, 2006)

Adamantium said:


> ....................
> 
> Not sure I'm convinced Nissan did anything on the aero of this car for show. They made far too big a deal out of it for that to be true.


I have read somewhere that the wing mirrors channel the wind onto the spoiler. If I can find the article Ill post it up


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## [email protected] (Nov 16, 2010)

FLYNN said:


> Below is a pic of a GTR developed by Nissan. Someone should tell them to put the standard spoiler back on. Hopefully they will read this thread and see the error of there ways :chuckle:


Completely different scenario, I have been reporting our findings, on *does the **removal of the rear spoiler/wing help the car go faster*, all my comments are
in the context We are assuming straight line,either *1/4 mile or top end Runs*.

Your picture dipicks a track car, a different story entirely , take a look At the SVM powerd Time Attack car..Wing On! 
kk


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## FLYNN (Oct 6, 2006)

[email protected] said:


> Completely different scenario, I have been reporting our findings, on *does the **removal of the rear spoiler/wing help the car go faster*, all my comments are
> in the context We are assuming straight line,either *1/4 mile or top end Runs*.
> 
> Your picture dipicks a track car, a different story entirely , take a look At the SVM powerd Time Attack car..Wing On!
> kk


Wasn't directed at you to be honest. I was suggesting that although Nissan spent millions developing the car, there is more than one way to skin a cat


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