ClubCalibra | Guide to Reducing Understeer
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Offline 9564thoro

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Re: Guide to Reducing Understeer
« Reply #20 on: August 11, 2010, 23:08:19 PM »

I've driven many cars fast and slow on race tracks and roads!!! This car is still the one that shocks me the most on standard suspension. Pottering about it leans alot, going round a corner fast it understeers, push it in a bit harsher and it gives you very controlable oversteer, when you feel the back go and mess your pants!!!....some how...it still stays under control!!!!!! Stunning car :o
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I don't know whether you're talking about track driving or what, but, being fairly new to the car, I can agree with the first two statements, but my question is, once you've established you get understeer, to push harder than that to then find out about oversteer seems like lunacy?? personally, the point where you get massive understeer, is about the limit of how fast you can corner!
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Online DanSE4

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Re: Guide to Reducing Understeer
« Reply #21 on: August 11, 2010, 23:25:25 PM »
Thread started in 2006, last posted on in 2008.

Move on guys! :)
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Offline se5let

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Re: Guide to Reducing Understeer
« Reply #22 on: February 20, 2011, 11:37:28 AM »
Quote from: DanSE4 on August 11, 2010, 23:25:25 PM
Thread started in 2006, last posted on in 2008.

Move on guys! :)

Err no...as long as the car understeers the age of the topic doesn't matter...

FYI the load on the front is greater....so it needs less weight.  The split is something like 59% weight on the front, doesn't take much to work out that is the problem.  The Calibra is like a Porsche in reverse....The engine hangs over the front far too much.  You cant pull it back so the weight needs shifting.  I would (and am going to) put the battery in the back.  I Have already shaved 5KG off from the lightened flywheel.  Next is to poly bush it and stiffen it up.  If the limit at which the car understeers is improved then I'll let you guys know.

Simply taking out the rear tire is not the solution.  Besides it weighs virtually nothing....A battery however, is around 20KG.  Apart from that the only other adjustments I can see being of benefit is upgrading the steering rack...Other than that the LSD is the only other answer to the issue....

So this is still a valid topic as long as there are different and new things to try out on this car to improve the handling. 

S

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Offline nikp

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Re: Guide to Reducing Understeer
« Reply #23 on: February 20, 2011, 11:40:34 AM »
Quote from: se5let on February 20, 2011, 11:37:28 AM
...A battery however, is around 20KG. 

Bloody hell, what sort of battery do you have! That is one HEAVY battery!
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Bovva

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Re: Guide to Reducing Understeer
« Reply #24 on: February 20, 2011, 14:50:25 PM »
Removing weight from the front where the power (engine) is seems daft? Surely you'd see a loss of traction, poorer cornering and generally less grip at the front resulting in excess wheel spin?

Porsches have power at the back, steering at the front so the wheels for steering only have one job, that's not a reverse of a calibra, not unless they have a fork lift setup.
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Offline nikp

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Re: Guide to Reducing Understeer
« Reply #25 on: February 20, 2011, 14:52:41 PM »
In any car you want to remove as much weight as possible. Weight is not the key to handling. It's the one thing you do not want in any fast car.
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Bovva

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Re: Guide to Reducing Understeer
« Reply #26 on: February 20, 2011, 14:53:41 PM »
Quote from: nikp on February 20, 2011, 14:52:41 PM
In any car you want to remove as much weight as possible. Weight is not the key to handling. It's the one thing you do not want in any fast car.

I agree with weight reduction but shifting weight from the front to the back isn't going to have the same effect.
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Offline Gav

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Re: Guide to Reducing Understeer
« Reply #27 on: February 20, 2011, 14:53:53 PM »
My Cally with the stiffer suspension and heavier front end puts the power down a lot easier than my Astra.

The Cally (apart from the Turbo) is FWD and isn't the best chassis. It will always understeer.

Fit good tyres, good suspension, polybushes, strut braces etc and it will help quite a lot.

It will still understeer though.
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Offline nikp

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Re: Guide to Reducing Understeer
« Reply #28 on: February 20, 2011, 14:56:29 PM »
Quote from: Sh!fty on February 20, 2011, 14:53:41 PM
I agree with weight reduction but shifting weight from the front to the back isn't going to have the same effect.

It'll depend upon the weight distribution - don't get me wrong, i'm hardly the worlds expert on handling but the 'perfect' and most desirable weight distribtion is 50/50. Therefore moving weight from the front to the back may help get close to that.
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Re: Guide to Reducing Understeer
« Reply #29 on: February 20, 2011, 15:00:23 PM »
Quote from: Sh!fty on February 20, 2011, 14:50:25 PM
Removing weight from the front where the power (engine) is seems daft? Surely you'd see a loss of traction, poorer cornering and generally less grip at the front resulting in excess wheel spin?

Porsches have power at the back, steering at the front so the wheels for steering only have one job, that's not a reverse of a calibra, not unless they have a fork lift setup.

I agree, removing weight from the front end of a front wheel drive Calibra is going to make the problem worse! Less weight means less grip means you put your foot down mid corner the car will go straight on. Simple science.
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Bovva

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Re: Guide to Reducing Understeer
« Reply #30 on: February 20, 2011, 15:40:51 PM »
I have driven cars with tool boxes in the boot, it didn't feel like a better handling car because of it?

I also don't know much about the handling aspect but for me if the car is lowered, has wide wheels and good tyres, this is generally enough of a handling improvement to avoid shifting engine componants into the boot.

It's obvious that mid engined cars are better for handling but you won't be able to achieve a 50/50 weight ratio on a calibra simply because the engine is at one end of the car and to counter balance that you'd have to weigh the back end down which will likely cause body roll problems and slower acceleration.

4x4 is the only real solution or to a degree an LSD with FWD setup.
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Offline CalibraTurbo666

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Re: Guide to Reducing Understeer
« Reply #31 on: February 20, 2011, 15:55:16 PM »
Putting a lot of weight (200kg or so) in the boot of a calibra turbo in front wheel drive makes them corner better , doing the same to my 1.8 vectra or my merc 180 has the opposite effect ( 200kg in the boot of vectra is virtualy undrivable )
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Offline nikp

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Re: Guide to Reducing Understeer
« Reply #32 on: February 20, 2011, 16:56:41 PM »
Quote from: fitasabutchersdog on February 20, 2011, 15:00:23 PM
I agree, removing weight from the front end of a front wheel drive Calibra is going to make the problem worse! Less weight means less grip means you put your foot down mid corner the car will go straight on. Simple science.

We better tell the F1 teams that they're doing it all wrong then. They need to load their cars with lead in every conceiveable space thenn, so they handle better in corners.
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Re: Guide to Reducing Understeer
« Reply #33 on: February 20, 2011, 17:29:08 PM »
Quote from: nikp on February 20, 2011, 16:56:41 PM
We better tell the F1 teams that they're doing it all wrong then. They need to load their cars with lead in every conceiveable space thenn, so they handle better in corners.

What are you talking about? A formula 1 car is rear engined rear wheel drive meaning the engine weight is over the driving wheels! And yes formula 1 cars are very light meaning they are virtually un drivable at slow speed due no down force pushing the car into the road. Even though a formula 1 car is light it's force against the Tarmac gets bigger the faster it go's due to down force pushing it harder into the road, it almost gets heavier the faster it go's (in a way)

Your taking weight from the front of a front wheel drive car and putting it in the boot? How is this going to help front end grip? Please explain because you've lost me.

And your comment about formula 1 cars is completely irrelevant as we are talking about a front engined, front wheel drive car. 
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Offline nikp

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Re: Guide to Reducing Understeer
« Reply #34 on: February 20, 2011, 18:33:54 PM »
One of the reasons the calibra understeers is DUE to the heavy engine up front. It's also engineered in, but much of it is to do with the heavy engine. It 'pushes' the car in a straight line when trying to turn it if forced to go too quickly. The relative front end grip afforded by the engine weight is little compensation compared to the effect it has at pushing the car in a straight line. I would much rather move the weight from the front to the back, but even better reduce the weight of the car in total than worry about the weight at the front helping to push the front end down because it offers so little benefits compared to reducing the weight.

And an F1 car is very difficult to drive at low speed due to many other factors, but not lack of grip. The aerodynamic forces that give the car grip are where most of the grip comes from in an F1 car, but they also have great mechanical grip due to suspension and car design. Ask an engineer if he would rather have a heavy engine to give him grip or improved suspension geometry for better cornering and grip I think i know what he would answer.

Front end weight is no way to improve understeer.
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Offline Bad Kid

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Re: Guide to Reducing Understeer
« Reply #35 on: February 20, 2011, 21:24:07 PM »
Threads like this are bad.
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Re: Guide to Reducing Understeer
« Reply #36 on: February 20, 2011, 21:26:11 PM »
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Offline Gordo

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Re: Guide to Reducing Understeer
« Reply #37 on: February 24, 2011, 11:17:05 AM »
Quote from: fitasabutchersdog on February 20, 2011, 15:00:23 PM
I agree, removing weight from the front end of a front wheel drive Calibra is going to make the problem worse! Less weight means less grip means you put your foot down mid corner the car will go straight on. Simple science.

Simple, at least!

For best cornering 'grip' you want ALL the tyres to be evenly loaded. Obviously, this is not possible, so you want to reduce load (weight) transfer as having one heavily loaded tyre and one lightl loaded tyre at the same end has less total grip than the evenly loaded tyres.
This is why anti roll bars are used to help the cornering balance - by using a stronger ARB on the rear, the outer tyre is even more heavily loaded and the total grip is further reduced - the ultimate is with the inside wheel just lifting off the surface - any more is detrimental as the body roll increases positive camber on all wheels and reduces total grip.
With front wheel drive cars, there is the complication of power applications reducing grip on that end (traction/grip circle concept) and the desire to have as high a proportion of mass (weight) as possible for maximum power transfer to the ground.

So, a rough suggestion would be a combination of..
LSD if inside wheelspin is a problem, together with throttle control.
Use springs (with dampers) and ARBs to reduce ride height (lowered CoG and reduced body roll), provide suitable bump travel and allow the rear to lift no more than just off the ground (may not need to be that stiff, depending on vehicle).
Play around with tyre pressures, these make a big difference.
If looking at weight saving for a track/play car, I'd look at initially removing any excess parts, like seats, and replacing the glass with plastic as that will remove high weight which will improve CoG height, body roll, performance everywhere and as most of it is towards the back, it should help the balance of the car.
Some may want to play with cambers, caster, toe settings, tyre sizes, etc, which is a whole new ball game.

Forgot, tyres DO make a big difference, check out what the other guys are using, I'd recommend a spare set of rims for the track tyres, so you don't chew them out in general driving.
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