Effect of geometry on handling characteristics
Discussion
I've got an NA 1.8 turbo which I'm making more track focussed and was wondering about geometry settings. I've no idea how the car is set up at the moment as I've never had it checked since I bought it but I quite like the way it handles now so I'm nervous about getting it done in case I ruin it! I only do trackdays, not racing, so fun is more important than outright speed really.
I'm no expert on these things so not sure on all the right terminology but basically as the car is now it has very little understeer and tends to oversteer on initial turn in (roll oversteer?) needing a quick correction before being quite neutral through the apex and then oversteering a tad on the throttle out of the corner. Basically the back nearly always wants to let go before the front, even on a fairly neutral throttle and it only really understeers on tight hairpins.
The MX5 specalists I've seen tend to offer "standard", "fast road/trackday" and "race" settings...so can anyone tell me how an MX5 actually behaves in those different states? The car will remain road legal but will spend 90% of it's time on the track so I'm tempted to go for the same sort of setup as the race cars but is that actually going to be less fun if the car is too stable?
I'm no expert on these things so not sure on all the right terminology but basically as the car is now it has very little understeer and tends to oversteer on initial turn in (roll oversteer?) needing a quick correction before being quite neutral through the apex and then oversteering a tad on the throttle out of the corner. Basically the back nearly always wants to let go before the front, even on a fairly neutral throttle and it only really understeers on tight hairpins.
The MX5 specalists I've seen tend to offer "standard", "fast road/trackday" and "race" settings...so can anyone tell me how an MX5 actually behaves in those different states? The car will remain road legal but will spend 90% of it's time on the track so I'm tempted to go for the same sort of setup as the race cars but is that actually going to be less fun if the car is too stable?
It's difficult to say how your car will behave in comparison to now, without a benchmark to measure against. For what it's worth, I went with Wheels in Motion's fast road setup, which meant an increase in front caster, more toe out on the front and a little more camber. The result for me was a sharper turn in and the end of roll oversteer! Well happy. Have since done Cadwell and Donington. Car felt very planted, predictable and very easy to catch slides.
I suppose what I'm worried about is the fact that you'd quite possibly be quicker round a track with a more understeery setup than I currently have so asking for "race" settings might result in quicker laps but a less entertaining car. Ideally I'd like to get rid of the low speed understeer but keep the car feeling nervous in higher speed corners.
you'll be a lot quicker with a more planted rear, sounds like you might have a little toe out on the rear which makes it a bit nervous.
understeer is easily neutralised with a bit of right foot if you're turbo'd.
fast road etc are fairly generic set-ups that seem to work well - but anyone alignment shop that knows what they are doing will be happy to talk about what you want from teh car and set it up accordingly. however, i doubt you'd end up too far away from a fast-road / nurburgring set-up.
understeer is easily neutralised with a bit of right foot if you're turbo'd.
fast road etc are fairly generic set-ups that seem to work well - but anyone alignment shop that knows what they are doing will be happy to talk about what you want from teh car and set it up accordingly. however, i doubt you'd end up too far away from a fast-road / nurburgring set-up.
Yes I think talking about how I want the car to actually behave with the suspension guy is the best bet, rather than describing the use the car is put to (road/track). I'd rather have slower lap times than a car that let me get the power down early but was boringly stable through a corner.
Interesting what you said about the turbo though...I think it does improve the handling a bit. When you accelerate through a corner the extra power seems to help shift the slip angle balance away from the rear more effectively than in a standard car. Or would you say towards the rear? Either way I mean giving the rears more slip angle so the car is even less inclined to understeer. Obviously you get the same effect with a standard car but it's much stronger with a few extra horses.
Interesting what you said about the turbo though...I think it does improve the handling a bit. When you accelerate through a corner the extra power seems to help shift the slip angle balance away from the rear more effectively than in a standard car. Or would you say towards the rear? Either way I mean giving the rears more slip angle so the car is even less inclined to understeer. Obviously you get the same effect with a standard car but it's much stronger with a few extra horses.
Edited by T0MMY on Thursday 19th September 19:22
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