Front Downforce

[Eastsoutheast]

I have searched the forums but could not find to help.

My front end goes very light when accelerating beyond around 70/75 mph. It's very noticeable and it's something I would like to improve.

All three plastic trims are in place under the front bumper - one each in front of the wheels and the bigger one in the centre. I have removed the front space saver wheel from the frunk as I am installing an amp in there. It's quite heavy but nowhere near as heavy as the spare wheel.

Tyres are standard staggered FL sizes and good condition Bridgestone RE40's all round. I have experimented with tyre pressures but this has not made any real difference to the lightness at speed.

Suspension is also standard and has never been modified and the alignment is spot on.

Worth mentioning also is that whilst I have reduced the front weight by removing the spare wheel I have had a zero manifold and Janspeed centre exit system fitted which reduced the rear weight by a similar amount.

It feels like it needs a front spoiler but this would look quite strange!!!

Any ides on how to increase front down lift?

Thanks

[dan944]

Front splitter? Combined with a rear diffuser could cause a fair amount of downforce if it was well made.

Then again I'm no pro

[martin_b]

A quick fix might be just to move your battery?  Otherwise This isn't a bad explanation of what each bit of aerodynamic add-ons can do..http://www.rapid-racer.com/aerodynamic-upgrades.php and brush up on your C.F.D.  

Cheers

Martin..

PS: revision notes here. http://en.wikipedia.org/wiki/Computational_fluid_dynamics

[vinp182]

Put the spare wheel back and see what happens

[Jrichards20]

I think you need to find the source of your problem, not try to counter act it. They do go slightly lighter as you pick up speed, but nothing that you should feel dangerous about, I certainly never had any problems on track days with too light at the front, my problem was always oversteer.

[Wabbitkilla]

How old are your front tyres compared to the rears?
How old / mileage is the suspension?
Would be worth having a 4-wheel geo check.

Taking the spare wheel has been known to cause a little loss of stability at the front end ... so worth dropping it back in to compare.

[J03]

A decent uprated ARB will make the car feel much more planted at higher speeds, especially cornering.

[jonty]

I think you need to find the source of your problem, not try to counter act it. They do go slightly lighter as you pick up speed, but nothing that you should feel dangerous about, I certainly never had any problems on track days with too light at the front, my problem was always oversteer.

I agree with this. If you have worn suspension bushes anywhere it will leave the car feeling vague and will kill confidence - you may just be feeling the car moving around more as the tyres aren't being directed as precisely as intended! Mine felt fine being thrown through fast chicanes at 90mph on track, never a hint of lift at the front.

[Eastsoutheast]

Thanks for all the suggestions. Suspension is in great condition with no problems anywhere although appreciate some bushes could be worn none are worn enough to show.

Front and rear tyres have pretty much the same amount of tread.

Can't put the spare wheel back as modified this area in preparation for the amp install.

It does not feel dangerous but I can definately feel it go light up front which is what I would like to fix.

Maybe I need to book a track day and find out how well it reacts at high speed.

It has crossed 60000 so maybe it's time for a suspension update.

[jonty]

Do it! Good thing about fault finding at the track is that the harsh conditions will highlight the problem area soon enough, makes it much easier to diagnose!

[Eastsoutheast]

Would be good to hear from other owners which tracks they have found best suit the MR2's strengths. Thinking one with short straights and lots of sharp turns, preferably in the South East.

[Anonymous]

Would be good to hear from other owners which tracks they have found best suit the MR2's strengths. Thinking one with short straights and lots of sharp turns, preferably in the South East.

I'm a fan of brands hatch. The Indy circuit is well suited to the mr2 - there are plenty of vids in my build thread  s:) s:)  

I've never ran my car on track with a spare wheel or a storage box in; and it's never felt light on the front

[Wabbitkilla]

Likewise, I ran mine for quite some time without a spare and never had instability at speed.
However we have better control with coilover suspension and I ran a 10 degree cant which obviously helps to overcome front end lightness.

[Jrichards20]

give snetterton a go, its a bit cheaper than brands, but has longer straights, but the is a whopper of a bend on there which would be great to check your problem out, a long long right hander very exciting push the car round that corner and realising how much grip these little cars have  s:) s:)

[Eastsoutheast]

That's a couple of tracks worth trying then. Do members on here get together for any track days?

[mikey P]

Given your location I would do bedford autodrome as a nice circuit that's very local. (I do it fairly often and really enjoy it) the mr2 is a bit slow down the main back straight but I just let people by here and then try and catch them back up through the twisty bits. The front of the car is fairly light (you can even pick the front of the car up) but it shouldnt effect the handling.

[Anonymous]

It couldn't be anything to do with what you said in another thread about hitting something in the road earlier ?? Just worth a thought...  I am not mechanically minded enough to say what damage could cause a floaty front end... unlike some of the experts on here who have all been very helpful in diagnosing my 2s probs, but occasionally my front end does not seem as planted at high speed, but that could just be due to the fact I dont go above 75 very often   s:oops: :oops: s:oops:

[jonty]

Given your location I would do bedford autodrome as a nice circuit that's very local. (I do it fairly often and really enjoy it) the mr2 is a bit slow down the main back straight but I just let people by here and then try and catch them back up through the twisty bits. The front of the car is fairly light (you can even pick the front of the car up) but it shouldnt effect the handling.

My MR2 isn't trackable yet, but my 200sx is... Give a shout when you're heading out, will see if my bro and I can wheel the ol' girl out for a thrash! I agree with this recommendation, Bedford feels like a proper race circuit (quality of surface, has curbs, etc) but in most of the track there's very little to hit which is a nice bonus.

If you've knocked something get your alignment checked, it'll wonder all over if geometry is off!

[Anonymous]

Bedford is on my list too  s:) s:)

[Eastsoutheast]

Bedford autochrome sounds like something worth arranging. When I finally had the nerve to check underneath the only damage I found was a dent in a roll or stabiliser bar approx 30/40% along the car (from the front). I had noticed the lightness at speed before this but that's not to say I will need to get this item replaced at some point.

The car drives absolutely straight and true at all speeds so I am pretty confident my geometry is still OK.

I would need to change my tyres, brake discs and pads as a minimum for a track day but not sure what else would need to be done.

[Anonymous]

Why would you need to change your tyres, discs and pads?!

[Jrichards20]

Why would you need to change your tyres, discs and pads?!

my thoughts exactly! Before you change them is when you want to get on a track day  s:) s:)  then change them after, no point getting brand new tyres just for a track day. Or discs and pads.

[Eastsoutheast]

I have already planned to change tyres and another forum member is waiting for my wheels and tyres, I can't give him badly worn/bald tyres.

My brake pads are all at least 50% worn so I am not 100% they would last a day on the track. I would take the opportunity to fit some decent aftermarket disc and pads. Not sure if I would also need to change the brake fluid for track use, it was changed last year by Toyota so is fresh but standard.

[jonty]

What pads do you have currently? I use EBC Yellow Stuff for about £60 per axle from Camskill - these are plenty good enough for a stock MR2 on track.

With regards to your aligment, plenty of the big franchises do a free check, so it's worth popping along and making sure for certain that nothing is wrong. If there is something off then it'd be a shame to do a trackday with a compromised car, but whilst you are there you could let another owner drive the car (not necessarily on track if you are worried) and tell you how it compares to their car.

[Jrichards20]

The factory discs on the MR2 are more than enough stopping power for a non modified 2. If you want to put ebc pads on start on green, they are enough. I wouldn't make upgrading discs as a priority as they are very good standard. what you need to do is just take some EBC pads with you on the day, if they wear out, only takes 30mins to change them over, especially if you are there with a couple of owners like mark or me there will make changing them over no problem.