Scooby Understeer ...
Discussion
Hi everyone,
I have a 2005 STi with Tein coilovers. How can I reduce understeer? The only thing I have done handling wise is the coilovers, yet I have been meaning to change the roll bars and drop links for ages. The car is a track and weekend toy, so ride comfort is really not a factor...
Thanks...
I have a 2005 STi with Tein coilovers. How can I reduce understeer? The only thing I have done handling wise is the coilovers, yet I have been meaning to change the roll bars and drop links for ages. The car is a track and weekend toy, so ride comfort is really not a factor...
Thanks...
Before you spend any money are you sure it's not your driving style?
The reason I ask is that I went from a RWD BEC westy to my Evo and was discussing under-steer with the lad who looks after it. He's an ex works Mitsi rally driver driver and he mentioned that you do need to drive them very differently to a RWD car. They respond to slow in fast out, with either trail braking or big power application, whereas I was used to maintaining a high entry and corner speed and adjusting the yaw via the throttle. This approach didn't work with the Evo.
Mine has coil-overs and an oversteery geo set-up by Arneside and is fitted with a group N ACD ECU and it still takes some provocation to oversteer. Simply lifting off at low medium speeds is not enough to get the tail moving anything like as much as it did in the westfield. Giving it a boot full will cause over-steer if you apply it on the exit of the bend but do it too early and you get under-steer.
Just a thought.
Other options are stiffer rear ARB.
Mismatched tyres front to back.
Roll centre is cocked up by the lowered ride height.
Geo is too tame. PD will in all likelihood have settings erring on the safe side. My advice is go to a garage that preps tarmac cars and ask them to give you a more twitchy set-up.
The reason I ask is that I went from a RWD BEC westy to my Evo and was discussing under-steer with the lad who looks after it. He's an ex works Mitsi rally driver driver and he mentioned that you do need to drive them very differently to a RWD car. They respond to slow in fast out, with either trail braking or big power application, whereas I was used to maintaining a high entry and corner speed and adjusting the yaw via the throttle. This approach didn't work with the Evo.
Mine has coil-overs and an oversteery geo set-up by Arneside and is fitted with a group N ACD ECU and it still takes some provocation to oversteer. Simply lifting off at low medium speeds is not enough to get the tail moving anything like as much as it did in the westfield. Giving it a boot full will cause over-steer if you apply it on the exit of the bend but do it too early and you get under-steer.
Just a thought.
Other options are stiffer rear ARB.
Mismatched tyres front to back.
Roll centre is cocked up by the lowered ride height.
Geo is too tame. PD will in all likelihood have settings erring on the safe side. My advice is go to a garage that preps tarmac cars and ask them to give you a more twitchy set-up.
With what you've had done so far i would get fast road geometry sorted before anything else. Then once that is done you should drive the car under different conditions to see if it still needs tweaking or not. Do a track day and see how that goes before you start blowing cash on stuff you might not need.
If you're still getting too much understeer then you have a couple of options. You can get an anti lift kit (ALK) or have the bump steer modification done, or both, depending on how much understeer you're getting. Personally i would have both ALK and bump steer mod done which would get rid of just about all of the understeer. It does tend to leave the car feeling a tad twitchy under braking but nothing you can't handle.
Equally, If you find the car is rolling around a lot and you want it to corner flatter then then get a thicker anti roll bar with harder bushes. That should help tons with roll. Initially though i would try just harder bushes with your standard ARB.
Do one job at a time. Keeps if affordable and you can also keep a good check on how each of the different mods affects handling.
However, if you have deep pockets do the lot!!
If you're still getting too much understeer then you have a couple of options. You can get an anti lift kit (ALK) or have the bump steer modification done, or both, depending on how much understeer you're getting. Personally i would have both ALK and bump steer mod done which would get rid of just about all of the understeer. It does tend to leave the car feeling a tad twitchy under braking but nothing you can't handle.
Equally, If you find the car is rolling around a lot and you want it to corner flatter then then get a thicker anti roll bar with harder bushes. That should help tons with roll. Initially though i would try just harder bushes with your standard ARB.
Do one job at a time. Keeps if affordable and you can also keep a good check on how each of the different mods affects handling.
However, if you have deep pockets do the lot!!
I have the rear Whiteline 24mm ARB fitted to my WR1 on the medium setting along with uprated drop links but on standard shocks and Prodrive springs. This has made the rear end feel lighter and stiffer but also introduced a degree of movement on initial turn in which was initially unsettling until you get used to it. I am running slightly more camber on the front than is standard which has helped balance the car and eliminate some of the understeer. ARBs will give a sharper turn in and with the adjustments provide a level of flexibility on handling but may decrease overall grip slightly.
Like you I am now contemplating the anti lift kit but have also just sourced a KW v3 coilover kit complete with camber plates on the front and I will get rear camber bolts fitted as well to optimise the geometry (aiming to increase front caster and all round camber).
Though saying all of the above, I am far from an expert and am just enjoying learning the different handling characteristics these mods bring. I would always recommend talking to a specialist who has proven experience setting up Imprezas and see what they advise. Or find an instructor at your next track day and see what they recommend.
Like you I am now contemplating the anti lift kit but have also just sourced a KW v3 coilover kit complete with camber plates on the front and I will get rear camber bolts fitted as well to optimise the geometry (aiming to increase front caster and all round camber).
Though saying all of the above, I am far from an expert and am just enjoying learning the different handling characteristics these mods bring. I would always recommend talking to a specialist who has proven experience setting up Imprezas and see what they advise. Or find an instructor at your next track day and see what they recommend.
paulmoonraker said:
Hi everyone,
I have a 2005 STi with Tein coilovers. How can I reduce understeer? The only thing I have done handling wise is the coilovers, yet I have been meaning to change the roll bars and drop links for ages. The car is a track and weekend toy, so ride comfort is really not a factor...
Thanks...
You say you have fitted coilovers, have you lowered the car too? This will increase a already 'factory set' understeer biased car.I have a 2005 STi with Tein coilovers. How can I reduce understeer? The only thing I have done handling wise is the coilovers, yet I have been meaning to change the roll bars and drop links for ages. The car is a track and weekend toy, so ride comfort is really not a factor...
Thanks...
Yes as others have said increased rear roll resistance from a bigger dia arb will reduce understeer and in general give a more neutral handling characteristic on the limit of handling. This is due to the increase in roll stiffness at the rear, which loads the rear wheels more unevenly and provides slightly less grip at the rear than previous. As the rear resists more roll, the front also does, giving more front balance, and increased front grip.
So, yes a rear will help, but really, an increase in front roll resistance is needed too, to balance the car (spring rates and other kit, inc tyre stickiness aside)
Ride comfort will not be affected by increasing roll bar size
paulmoonraker said:
Porsche Gayman S (the 3.4ltr one). Just fancy a change for a while. Will probably do an Evo FQ360 after that 
I wont lie though - it's going to be really hard letting her go 
Just don't cry when a scooby blows you at the lights I wont lie though - it's going to be really hard letting her go 
Actually, fair play to you. Very nice to have a porsche, even if it is a Gayman with 3.4ltrs.
ScoobieWRX said:
paulmoonraker said:
Porsche Gayman S (the 3.4ltr one). Just fancy a change for a while. Will probably do an Evo FQ360 after that I wont lie though - it's going to be really hard letting her go
Just don't cry when a scooby blows you at the lights I wont lie though - it's going to be really hard letting her go Actually, fair play to you. Very nice to have a porsche, even if it is a Gayman with 3.4ltrs.
yes, there are not many things that will stand up to a mapped STi launched properly, which gets me to the whole performance vs. price problem... Where do you go from the turbonutter cars? The answer is something different enough so you don't attempt direct comparisons.I would probably have gone to an EVO after the scoob just to scratch that itch to make comparisons and decide for everyday use which was the best on the road and easy to live with 4x4 rally rep. After all we don't drive on circuits everyday of the week, unfortunately.
Then i'd have scratched that 2WD itch and gone for the Gayman. I bet you'll find that a Gayman is OK to live with daily. You might love it
Then i'd have scratched that 2WD itch and gone for the Gayman. I bet you'll find that a Gayman is OK to live with daily. You might love it
markCSC said:
£11,240 they say No, I would not bother modifying the arse out of a Cayman... I will wait till I get an Evo for that
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