Mazda Rotary Club

General => General Technical => Anything Engine/Performance/Tuning related => Topic started by: Andyp on February 29, 2004, 01:14:58 AM

Title: Downforce question
Post by: Andyp on February 29, 2004, 01:14:58 AM
Hello!

I\'m running at the top speed challange thing at the end of March, got thinking today about my downforce.

(http://homepage.ntlworld.com/robert.pogmore/spoiler.jpg)

Anyone know anything about my spolier (i.e. what\'s the best way to position it for top speed) as there are 5 settings that do change the angle a heck of a lot
Title: Downforce question
Post by: Martin on February 29, 2004, 02:29:32 AM
If your doing a straight run then it shouldn\'t matter that much I don\'t think, also the GTwing doesn\'t provide any real downforce until you reach over 100mph anyway, I\'d put it on the middle setting:)

I\'m thinking about putting a GT wing on mine Andy, did yours fit perfectly on the stock mounting holes?
Title: Downforce question
Post by: Gman on February 29, 2004, 08:47:17 AM
I may run at this event - I have no spoiler, am I gonna take off?
Title: Downforce question
Post by: Carl on February 29, 2004, 08:57:18 AM
If you both want top speed then take the spoilers off.
You should get a few MPH more that way due to less drag.
If you don\'t believe me try it both ways.
Kind regards
Carl
Title: Downforce question
Post by: Andyp on February 29, 2004, 10:27:45 AM
think I might do both just to see the difference. I get unlimited runs :)

I know last time I was doing 155 / 160ish (kms of course) the car felt like someone had a big foot on it, really gluded... being the size of a picnic bench does have it\'s affect I think

Gman yay! be glad to finally meet ya there. You probably will take off over the two miles, people will say "is it a bird? is it a banana? no it\'s GMAN" :rollin :rollin :rollin
Title: Downforce question
Post by: rextreme on February 29, 2004, 10:43:39 AM
The Re-Amemiya Gt wing you have should be set as flat as possible if you want Speed.

But youll still be paying a small penalty.
If its absolute top speed your after then just take it off completely.  If you dont think you\'ll be the fastest then dont worry, Just use the flat position.

If you leave it in attack mode its not speed thats the issue.
Even in the middle position.
The front of the car will become extremely light. and at around 200+kph, I wouldnt like to be behind the wheel of a car that doesnt respond so well.

As I have found with mine. Unless you can balance the front of the car as well, A big GT wing will upset the handling.
Title: Downforce question
Post by: Andyp on February 29, 2004, 10:50:56 AM
cheers matey!

looking at that pic, would you say that\'s in the flat position as I havn\'t changed it really...

I think I will take it off as its real easy to take off anyway being so light, infact I may just do it when I get there :)
Title: Downforce question
Post by: rextreme on February 29, 2004, 10:56:57 AM
Definately not flat position.

You should be able to adjust to the hightest bolt hole.

this is the difference in mine.

I think you can tell the flat position.

:p
Title: Downforce question
Post by: Andyp on February 29, 2004, 11:15:26 AM
righty ho.. i\'ll go and have a play with that then & move the bolt to the other end :)
Title: Downforce question
Post by: mids on February 29, 2004, 11:59:25 AM
With the power required to overcome drag being proportional to the cube of the speed it means that to increase top speed it is often more effective to work on reducing your drag.

You can spend several hundred quid on an induction kit and exhaust system and find that it has less effect on top speed than simply tweaking your rear wing.

In Best Motoring Volume 8, they experiment a little with the adjustable rear wings on a GTR, EVO and RX-7 and this had a pretty big effect on the speed measured at the end of the main straight (i.e. not even Vmax).

Here\'s a screen shot of the results....

(http://homepage.ntlworld.com/andy.middleton1/wing.jpg)

So, an extra 3 kph at the end of the straight for the RX-7 between the 1° and 14.5° settings.

If you are really serious, I\'d take the rear element off for the day and fold in the wing mirrors whilst you\'re at it :D
Title: Downforce question
Post by: Andyp on February 29, 2004, 12:03:45 PM
ahh i\'m not totally going for it or anything, just wanna see what she can do, but didn\'t want to be floating along loosing loads of speed due to the wing. Think i\'ll try both see the difference it makes @:)
Title: Downforce question
Post by: Fish on February 29, 2004, 05:52:20 PM
When I removed my Cusco GT wing last month I really noticed the difference. Above 60(ish) mph the rear end was nowhere near as planted to the road as with it on, even in flat mode.

Fish
Title: Downforce question
Post by: Gman on February 29, 2004, 06:42:03 PM
Fly like a butterfly sting like a bee! :D

If i do take off i will be the yellow stain at the end of the runway.
Title: Downforce question
Post by: Iwan on March 01, 2004, 10:30:48 AM
I wouldn\'t recommend to drive high speed without a spoiler.

Your rex will get unstable in rear without a spoiler  on wet roads above 250 km/h, that\'s my experience I have made on German Autobahn.

REgards
Iwan
Title: Downforce question
Post by: maximtaylor on March 01, 2004, 11:39:03 AM
:eek

I would imagine most things are unstable on a wet road at those kinds of speeds, thats 155 mph !

Regards

Max
Title: Downforce question
Post by: Andyp on March 01, 2004, 12:16:41 PM
ok now I\'m leaving it on.. 155 isn\'t where I\'ll be stopping hopefully :)
Title: Downforce question
Post by: g11ary on March 01, 2004, 12:35:34 PM
Ive been off the clock more times than I can remember with the small stock spoiler, car was light but no problems, cant see anyone going that fast that your be near take off speeds.
Title: Downforce question
Post by: andyrose on March 01, 2004, 04:46:25 PM
Fold your wing mirrors in (if possible) or even better remove them
gives at least an extra 5mph (on my fireblade anyway) no joke.
Andy
Title: Downforce question
Post by: mids on March 01, 2004, 04:57:08 PM
I have a friend who went flat out on a Dutch motorway at night in his 928 and he decided to see how much extra speed could be gained by turning off the pop-up headlights.....:evillaugh
Title: Downforce question
Post by: Iwan on March 01, 2004, 05:09:45 PM
lol @ Mids :)

Max,

with a stock spoiler mounted, no problems on wet road til redline (above 280 km/h)

REgards
Iwan

QuoteOriginally posted by maximtaylor
:eek

I would imagine most things are unstable on a wet road at those kinds of speeds, thats 155 mph !

Regards

Max
Title: Downforce question
Post by: Andyp on March 01, 2004, 06:45:04 PM
Quoteto see how much extra speed could be gained by turning off the pop-up headlights

no chance of me testing that one.. ;)
Title: Downforce question
Post by: maximtaylor on March 01, 2004, 11:09:48 PM
Brave man Iwan!

I\'m not on road tyres, so the rain keeps me down to normal speeds................... most of the time ;)

Max

QuoteOriginally posted by Iwan
lol @ Mids :)

Max,

with a stock spoiler mounted, no problems on wet road til redline (above 280 km/h)

REgards
Iwan