27 replies to this topic

[Gibbo1974]

Hi Guys,

 

me again!

 

I have some questions on handling.

 

the car rides like it's on rails until the 120mph mark (on track of course) and then she gets a bit jittery and wayward.

 

what should I check or replace first ?

 

steering column is tight and works fine.

 

what tyre pressure are you running ?

 

turbo 2004 standard (original suspension)

 

ta

[Acidpopstar]

That could just be the 'unique' aerodynamic properties of our cars Sent from my iPhone using Tapatalk

[SteveA]

 

Some people have found diffusers and splitters help but nothing to my knowledge had been properly wind tunnel tested.

 

To be honest you'd be hard pushed to see over 120 on most UK tracks without Silverstone straights or enormous power.

Edited by SteveA, 16 June 2017 - 01:54 PM.

[Gibbo1974]

lol good point.

 

I have read that some people have rock solid handling up to max speed and some don't....hmmmmm

 

I will get my MOT mate to have a good look at the steering bits and bobs and report back.

[piwo]

carbon rear wing will fix the case.

 

https://pl.aliexpres...04-f58d6e5ec22a

 

http://www.ebay.com/...CFYt6OP&vxp=mtr

 

http://www.mazdaspee...33214&mode=view

http://www.mazdaspee...33217&mode=view

Edited by piwo, 16 June 2017 - 02:10 PM.

[Gibbo1974]

carbon rear wing will fix the case.

 

 

Lol I can see that making the front wheels completely leave the tarmac at high speed.....lol

[navx]

carbon rear wing will fix the case.  

  Lol I can see that making the front wheels completely leave the tarmac at high speed.....lol

You do need a BGW for it to have an effect. There is more lift at the rear than the front. It becomes a cat and mouse game though. I would say get someone to look at your geo Matt Bentley, Back on Track or Guillemi are usual go to places. Large rear wing will increase drag so unless you have plenty power or use car primarily for the track, I would not bother.

Edited by navx, 16 June 2017 - 03:17 PM.

[fiveoclock]

carbon rear wing will fix the case.

 

https://pl.aliexpres...04-f58d6e5ec22a

 

http://www.ebay.com/...CFYt6OP&vxp=mtr

 

http://www.mazdaspee...33214&mode=view

http://www.mazdaspee...33217&mode=view

Post of the year and its only June

[piwo]

Big rear wing doesn't change front grip to 120km/h where vx220 is understeer. After this velocity vx220 is getting oversteer. And rear wing help then. IT work only in big velocitys. Give Stable rear on braking to corner And traction on leaving the corner. Someone Who use IT on track know how much Stable give IT. Ok the car is slower on long straight (for example i have 180km/h not 185km/h on track i driving) but the car is Stable in 160km/h corners And times are shorter.

[hairy]

For me, a front splitter worked a treat but I have no aerodynamic data it just feels good to me. Different owners have different opinions.

[fiveoclock]

Big rear wing doesn't change front grip to 120km/h where vx220 is understeer. After this velocity vx220 is getting oversteer. And rear wing help then. IT work only in big velocitys. Give Stable rear on braking to corner And traction on leaving the corner. Someone Who use IT on track know how much Stable give IT. Ok the car is slower on long straight (for example i have 180km/h not 185km/h on track i driving) but the car is Stable in 160km/h corners And times are shorter.

Those wings you linked to wont do anything except damage the clam. They're all body mounted and will crack the clam/ The profiles are mostly useless as well. Also you cant just stick a wing on the back on its own.

[Nev]

Jitteryness can be down to geometry, tired bushes, play in the steering rack, tired bearings etc etc.

 

Best to check all of those, in particular any toe out on the front wheels at high speed can contribute to twitchyness.

 

 

 

[pete-r]

I know pretty much nothing about nothing in terms of the technical stuff, but I had similar to you at very high speeds and a leftfield mod seemed to fix it. I ditched the fogs and fitted solid brake vent pipes which seem to not just cool the brakes but release pressure in the front wheel arches. When the car is dirty you can see vortex swirls down the side of it now where the air leaves the arch and flows down the car. 145 is the most I've done in a straight line but it is really stable. Was nudging 120 on the autobahn a few weeks ago with some gentle bends but again with no issues. Not saying it'll work, and i would start with the bigger thinks like geo, tyres and steering rack, but I didn't do anything else to sort it.

Edited by pete-r, 16 June 2017 - 05:50 PM.

[Winstar]

I know pretty much nothing about nothing in terms of the technical stuff, but I had similar to you at very high speeds and a leftfield mod seemed to fix it. I ditched the fogs and fitted solid brake vent pipes which seem to not just cool the brakes but release pressure in the front wheel arches. When the car is dirty you can see vortex swirls down the side of it now where the air leaves the arch and flows down the car. 145 is the most I've done in a straight line but it is really stable. Was nudging 120 on the autobahn a few weeks ago with some gentle bends but again with no issues. Not saying it'll work, and i would start with the bigger thinks like geo, tyres and steering rack, but I didn't do anything else to sort it.

No you will have pressurised the arches, swirls down the body work is the additional turbulence from the flow escaping and no a good thing as it will increase drag.

[harboged]

My Turbo had a quite nervous front end. The steering wheel was vibrating at higher speeds (not due to unbalanced wheels) and the front felt like it was floating on water, ie bad feedback and it didn't feel very stable. I had medium caster angle at that time. During winter I made a complete suspension refresh with Nitron inner bearings, Nitron NTR40 dampers and I increased the caster to its maximum. Afterwards the steering wheel didn't vibrate anymore, the feeling of the front was razor sharp and the front end feels much more stable now. Unfortunately I can't say which mod resultated in what. I believe that the suspension refresh took care of the vibrating steering wheel and maybe more stability in the front. The increased caster must have improved stability because that's what it does. Perhaps the dampers improved stability too due to the front now being a bit lower, but I honestly don't know. Start by increasing caster and see how it behaves, it doesn't cost you anything. Next thing would be balljoints, rod ends and bushings, though I imagine that bushings play a bigger role when cornering. But I'm not an expert so I don't know for sure Cheers PS And check the geo of course. Mine was good though, even when the front end was nervous.

Edited by harboged, 16 June 2017 - 07:41 PM.

[oakmere]

I think the 10mm drop front to back with adjustable suspension helps with high speed stability, or at leat it seemed to with mine.

[pete-r]

No you will have pressurised the arches, swirls down the body work is the additional turbulence from the flow escaping and no a good thing as it will increase drag.

No idea on the physics but it transformed the high speed stability.

[james_ly]

Jitteryness can be down to geometry, tired bushes, play in the steering rack, tired bearings etc etc.

 

Best to check all of those, in particular any toe out on the front wheels at high speed can contribute to twitchyness.

 

 

 

 

 

Probably a bit of bump steer too.

[Andrew aka Stuwy]

my old N/A went light at 110+ never been jittery Splitter fixed that /shrug

[Paddyn123]

Hi all, new here... .mine can feel a little twitchy (it's a standard turbo aside Gaz shocks). Has anyone got any setup advice for the shocks. A friend mentioned taking some advice on his kit car and he said it transformed the car... any advice would be appreciated. I'm a total novice with suspension. Also rear bushes sound knackered, any recommendations? There are a cheaper brand on flea bay called Flo flex? Buy cheap buy twice? Anyone got any experience with these... Paddy