GolfGTIforum.co.uk
Model specific boards => Golf mk4 => Topic started by: tech1889 on 11 September 2010, 15:53
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Been having a look around and am curious to which the best way to create downforce on the mk4..
I no there is various splitters but which one is best i no most people go for looks but i want performance more...
R32 front bumper will this aid in downforce ?? maybe with a custom splitter ??
Are the JOM R32 front bumpers any good and do they require cutting or are they a good OEM fit ??
Spoliers cant be any good as they produce downforce at the back which rasies the front wheels am i correct ??
Any ideas will be much appreciated.. Will hopefully test a few ideas in the near future cost depending..
Many thanks in advance
Dan
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obviously lowering the car on stiffened suspension/coilovers will reduce the amount of air that can get underneath
front splitters are designed to push the lower air around the side of the car or over the car to push down on the car
rear lower splitters are designed for air to wrap around the cross piece, hence holding the back down - any air that does travel under the car
rear spoilers are only of gain at 70mph, so i would hazard a guess and say the splitters are the same
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Yep good answer there.. i wondered if putting an adjustable carbon fibre splitter would help ??
Dan
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i remember reading that a front splitter to work effectively has to be less than 6cm away from the ground! why do you want so much downforce?
and rear downforce wont lift the front, but its a bit pointless on a fwd car.
why are you looking at this kind of thing anyway? golfs not exactly gonna take off at speed, and you get more traction from fitting a rear anti roll bar than a spolier or a splitter
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downforce is so 2009
so as this scooby driver has
fat chicks - instant lowering, road holding and stance
(http://www.thosefunnypictures.com/resize.php?file=pictures/6308/Funny_Pictures_6308.jpg)
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lol @ chuff :laugh:
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Just look to the old 80s and 90s Fords for a few ideas. The gurney flap was used on the RS500s already massive rear wing to increase downforce. Also if you want to know what happens to cars when they take the downforce spoilers off...
(http://img.photobucket.com/albums/0803/WesRS/reylandcrash4.jpg)
(http://img.photobucket.com/albums/0803/WesRS/reylandcrash3.jpg)
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Yep good answer there.. i wondered if putting an adjustable carbon fibre splitter would help ??
Dan
Mate these are not just things that you put on and attach to the front bumper!
There is alot of work involved! The carbon would not just be a splitter, the carbon would be a full pane that runs roughly half way down the length of the car, The only part visibly being the the "splitter".
The reason for this is as you want to gain top speed runs, or higher speed racing, you need the splitter to pull down the car not the actual bumper! So if you just simply attached the splitter to the bumper it would just put strain on your bumper.
these are not for normal daily driver use either, as they need to sit very low to work effectively, and also about 3-4 inches outwards, so they do stick out, So parking would be a b!tch if a curb was infront of you!
Not even taking into consideration a chav standing on it!
For something like this you would be looking at around £300-400.
For road use i would just go for the Cupra R splitter!
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road use all the splitter is for is just looks
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Just look to the old 80s and 90s Fords for a few ideas. The gurney flap was used on the RS500s already massive rear wing to increase downforce. Also if you want to know what happens to cars when they take the downforce spoilers off...
(http://img.photobucket.com/albums/0803/WesRS/reylandcrash4.jpg)
(http://img.photobucket.com/albums/0803/WesRS/reylandcrash3.jpg)
That was not caused by a loss of downforce, from memory the gearbox seized.
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I do understand all them things.. i no what they are used for i was just curious thats all.. Just wondered why my car over like 115 the steering gets all wooley like its lifting just wondered a cure for this as over people have had the same problem..
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Just look to the old 80s and 90s Fords for a few ideas. The gurney flap was used on the RS500s already massive rear wing to increase downforce. Also if you want to know what happens to cars when they take the downforce spoilers off...
(http://img.photobucket.com/albums/0803/WesRS/reylandcrash4.jpg)
(http://img.photobucket.com/albums/0803/WesRS/reylandcrash3.jpg)
That was not caused by a loss of downforce, from memory the gearbox seized.
before my time but talking to my dad he seems to thgink you are correct on the gearbox issue!
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I do understand all them things.. i no what they are used for i was just curious thats all.. Just wondered why my car over like 115 the steering gets all wooley like its lifting just wondered a cure for this as over people have had the same problem..
is your tracking ok?
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Yer tracking is all good.. :cool:
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Never heard that the gearbox had seized, just that they had only removed the rear wing a few miles down the road. I've seen the footage of it going off the road from the car they were overtaking, thinking about it, could well be the gearbox, it just suddenly lurches right across the road...
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Never heard that the gearbox had seized, just that they had only removed the rear wing a few miles down the road. I've seen the footage of it going off the road from the car they were overtaking, thinking about it, could well be the gearbox, it just suddenly lurches right across the road...
I remember it from a feature in Fast Car, 99% sure the gearbox or transfer box seized, they are rebuilding it into another shell.
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I do understand all them things.. i no what they are used for i was just curious thats all.. Just wondered why my car over like 115 the steering gets all wooley like its lifting just wondered a cure for this as over people have had the same problem..
Get your camber checked out, -ve camber will make the steering light at high speeds.
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Just look to the old 80s and 90s Fords for a few ideas. The gurney flap was used on the RS500s already massive rear wing to increase downforce. Also if you want to know what happens to cars when they take the downforce spoilers off...
(http://img.photobucket.com/albums/0803/WesRS/reylandcrash4.jpg)
(http://img.photobucket.com/albums/0803/WesRS/reylandcrash3.jpg)
That was not caused by a loss of downforce, from memory the gearbox seized.
before my time but talking to my dad he seems to thgink you are correct on the gearbox issue!
Here is the crash
http://www.youtube.com/watch?v=4zdyr9PyILk
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To creat frontal downforce on a mk4 at a guess i would say an R32 bumper with Cupra R splitter would be your best bet, purely judging on the aerodynamic properties of the standard compaied to the R32 bumper. The R32 with larger vents would allow cleaner air flow, the standard bumper also moulds in towards the car at the bottom of the bumper which wouldnt exactly help unless a large front splitter was added which would stick out far to far for every day use(as mentioned). The cupra R splitter if mounted in the right place could help as it would work as a small front splitter, if mounted incorrectly it could create drag as you could be creating a pocket between the bumper and splitter? I would also fix the Bumper and splitter on as tight as possible, also smooth the bumper into the wings and try to seel up any gaps in the body panels.
If your wanting a higher top speed i would work on the untray of the car as there is not alot you will be able to do with the body aerodynamics. The mk4 isnt exactly going to cut through the air very well, in all honesty it was the aerodynamic properties of a 1 tonne brick lol
thats my thoughts on the matter :smiley:
good luck!
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Never heard that the gearbox had seized, just that they had only removed the rear wing a few miles down the road. I've seen the footage of it going off the road from the car they were overtaking, thinking about it, could well be the gearbox, it just suddenly lurches right across the road...
I remember it from a feature in Fast Car, 99% sure the gearbox or transfer box seized, they are rebuilding it into another shell.
I seem to remember he was trying to over take someone and ran a little to wide off a foriegn country road and the rear wheels came into contact with a dusty, sandy sureface next to the road and he lost traction and control of the car. Happened in the gumball rally of europe
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I seem to remember he was trying to over take someone and ran a little to wide off a foriegn country road and the rear wheels came into contact with a dusty, sandy sureface next to the road and he lost traction and control of the car. Happened in the gumball rally of europe
That would be the vid i posted up mate :D
Save you money on all the body kit stuff and get some lowerd saspention mate. It will sort you golf out with this lift off light waight steering problem.
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More to the point... 115mph? Track or Road?
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What you mean track or road ??
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More to the point... 115mph? Track or Road?
:grin: :grin: :grin: :grin: :grin:
someone had to ask - knew it would be you :kiss:
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What you mean track or road ??
Do you do these speeds on the track or on a public road?
Downforce only becomes an issue above 60+ and without a scale and accurate model of the car in a CFD package your gains will be like sticking your finger in the wind.
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Lets say for track purposes running a more aggressive setup more closer to the 300bhp mark, maybe more... I'm finding speeds of 140 make the steering feel light myself and thats with lowering and stiffer setup, my tracking etc is fine, but not sure on camber. I can understand where he is coming from as stock suspension at 120 is scary in the golf as mine actually snaked and spun off in the past, but that aside...
Whilst on tracking and camber talk, what would be a good figure on both for track purposes, as I read a toe in would be more benfficial on handling but would chew through tires quicker.
I'm not sure how many tracks will let you hit that speed but with an average speed of 90mph being possible I'm sure an improved downforce setup would be benificial? Reason I'm asking is I myself am slowly thiinking of making the mk4 a track toy but not on a high spec as what I am planning already is allot of money and its not high on the priority list due to other comitments.
Also how would different body kits eg R32... etc effect handling, as I imagine a wider bodykit would cause more restriction, also whats with the little slots behind the wheel arches all about in terms of benifits?
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slots behind wheel arches can work as a diffuser, the air from under the car would go through the slots creating rear downforce also giving better traction for the rear wheels. This is on some new Mercades cars.
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focus st has fake slots :)
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Lets say for track purposes running a more aggressive setup more closer to the 300bhp mark, maybe more... I'm finding speeds of 140 make the steering feel light myself and thats with lowering and stiffer setup, my tracking etc is fine, but not sure on camber. I can understand where he is coming from as stock suspension at 120 is scary in the golf as mine actually snaked and spun off in the past, but that aside...
Whilst on tracking and camber talk, what would be a good figure on both for track purposes, as I read a toe in would be more benfficial on handling but would chew through tires quicker.
I'm not sure how many tracks will let you hit that speed but with an average speed of 90mph being possible I'm sure an improved downforce setup would be benificial? Reason I'm asking is I myself am slowly thiinking of making the mk4 a track toy but not on a high spec as what I am planning already is allot of money and its not high on the priority list due to other comitments.
Also how would different body kits eg R32... etc effect handling, as I imagine a wider bodykit would cause more restriction, also whats with the little slots behind the wheel arches all about in terms of benifits?
Wider body more restriction?
Im not fitting a wide arch kit to slow me down :laugh:
The wider the body, the wider the wheels! Which equals alot more performance!
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It's not this kit :grin: :grin:
(http://blog.jkautospares.co.uk/wp-content/uploads/2008/12/golf-4-w12-30-450x337.jpg)
Also what the gains like by spreading the wheel span as I though that would put more strain on the CV joints and shafts as I remember asking you about it sometime ago?
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what kit is that ?? loooks nice :)
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Front splitters on FWD cars tend be designed to aid turn in traction in medium to fast corners.
Couple of the racers over on Clubgti have had some success running plywood splitters and have reported much better front end grip in the twisties.
Nick
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Its a replica wide body kit for the mk4 of the "mk5 gti w12" by Dietrich and its called WIZ or something, love the front of it but I hate the back, but I do prefer this w12 replica on the mk4 over the mk5 :lipsrsealed:
Thanks nick, any chance of some links as if it helps round the bends it still seems like a good idea, they running flat front undertrays as well?
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Oh and whoever said rear downforce isn't needed on a FWD car is wrong, you do need it to keep the car settled in medium and fast corners. Hence why the FWD BTCC cars etc run quite large wings.
Nick
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Cheers nick thats good info there.. I just assumed pushing the back down would raise the front shows what little i know :)
Top gear tried making a plywood splitter and it set alight :) lol
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A wider wheel span would give a lower centre of gravity and obviously the thicker the tyres the better the traction in the corners BUT i wouldnt want the tyres too wide, they would just create drag on the straights and not give enough gain on the corners to compromise, also think about the cost of wide alloys and the tyres :shocked:
as for an aero pack for the car, the slots in the rear arches can also be in the front bumper and front arches which would give better frontal downforce, i would but the slots in if possible, a front splitter and a rear spoiler to push the back end down, i wouldnt put the slots in the back arches as it would create more drag than downforce where a spoiler would do the job better.
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r888's and 10j wheels will make my car handle fantastically!
The toyo tyres are used through out the whole time attack series! And they run on 12J wheels!
So to be honest the wider the wheel base the better!
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they are semi slick road legal tyres used by a lot of big BHP cars..
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Thought wider wheels had nothing to do with grip, I remember reading autospeed that tire width had nothing to do with the grip coefficient. The material/compound is what dictates the grip coefficient, wider wheels just allow the heat to disperse properly from what I remember reading. Anyone care to dwell on this?
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the bigger the wheel, the bigger the tyre needed.
The more surface area of tyre on the floor = more grip?
Jake
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Thought wider wheels had nothing to do with grip, I remember reading autospeed that tire width had nothing to do with the grip coefficient. The material/compound is what dictates the grip coefficient, wider wheels just allow the heat to disperse properly from what I remember reading. Anyone care to dwell on this?
Well wider wheels will definitely improve grip, the bigger the surface area contact between the road and the tyre the greater the grip from the tyres. Slick tyres will give great benifits but again when up to temperature will create drag in a straight line. The weight of the car will also be better balanced with wider tyres.
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Also on the serious side, what people think of that wide arch w12 replica body-kit?
Another thing for food for thought is, my spare tire/wheel is really light in comparison to my alloys, same size in rim and width, would 4 of them be better for the track over the alloys, also give reasone why :smiley: In short steelies vs alloys?
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http://www.autospeed.com/A_108915/cms/article.html
and
http://www.autospeed.com/cms/A_110774/article.html
What actually influences the size of the tyre's contact patch? Is it the width of the tyre, or the profile? The simple answer that it is neither of these; the size of the tyre's contact patch is related to:
* the weight on the wheel
* the tyre pressure.
Okay, most people will come to the conclusion that if you have "more rubber on the road" you will have increased grip. Sorry to say this folks, but to very close to 100% accuracy, the size of the contact patch is irrelevant.
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So if i run a 7.5j wheel on my track car, it's the same as me running a 12j wheel on my track car????????
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So if i run a 7.5j wheel on my track car, it's the same as me running a 12j wheel on my track car????????
According to autospeed and physics is appears so :huh: But since your gonna be a rwd ferrari from what the article says you could use with wider wheels to disperse the heat?
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hmmm interesting lol
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hmmm interesting lol
I love reading autospeed, some intresting stuff they do do on there, just not enough off it, the car aero side is what's intresting me at the moment to see how things can go together with to my idea of what I want from the golf. It's all adding up very quickly and I'm not even thinking of serious power!
Do track cars with the arch diffusers have the arch lining or not as I imagine that would aid in air flow around the wheel?
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hmmm interesting lol
I love reading autospeed, some intresting stuff they do do on there, just not enough off it, the car aero side is what's intresting me at the moment to see how things can go together with to my idea of what I want from the golf. It's all adding up very quickly and I'm not even thinking of serious power!
Do track cars with the arch diffusers have the arch lining or not as I imagine that would aid in air flow around the wheel?
adapted arch liners, but yes.
And about the width of the tyres, yes that makes sence, but! the width will definitely have some importance, imagine going round a track on Ford Model T wheels, the grip wouldnt be there and the car would constantly want to roll or buckle the wheels! The width with the tyres will disperse the weight better and the correct pressure will give better traction so really the width does play a crusial part as the weight through the corners would be despersed better and give better road handeling as the car wont want to roll as it would on smaller wheels, the castor and camber angels will be crusial aswel as mentioned
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Too much rubber and you go slower as you have more resistance.
Nick
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Too much rubber and you go slower as you have more resistance.
Nick
as said, inceases drag :smiley:
lots of maths would work this out :grin:
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Read away ... http://www.eng-tips.com/viewthread.cfm?qid=102250&page=1
But I'll stick with my original answer, geo is out or the OP's foot is too heavy, too early coming out the corners.
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You want downforce?
Nothing beats this :grin:
(http://i885.photobucket.com/albums/ac53/mawkbw/ugly-car-pictures-53w.jpg)
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You want downforce?
Nothing beats this :grin:
(http://i885.photobucket.com/albums/ac53/mawkbw/ugly-car-pictures-53w.jpg)
:laugh: :laugh: :laugh: :laugh: :laugh: :laugh: :laugh: :laugh: :laugh:
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I see that a couple of years back how funny.. must of spend a bomb on that car tho..
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You want downforce?
Nothing beats this :grin:
(http://i885.photobucket.com/albums/ac53/mawkbw/ugly-car-pictures-53w.jpg)
:laugh: :laugh: :laugh: :laugh: :laugh: :laugh: :laugh: :laugh: :laugh:
What the hell is it?! a volvo? haha :laugh: :laugh: :laugh:
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Its in Japan i believe so christ noes what it is.. :laugh: