stu21t

i started with this

and ended up with this


thats the car in full road trim with all fluids, 1/2 a tank of fuel and a load of ballast in the passenger seat represent me. lol
so it weighs 997kgs wet kerb weight without a driver, not too bad really.

any1 got any ideas on how it can be improved? do i want to try and get more weight over the front wheels so its closer to 50/50, or do i want some more on the rear for more grip?

im going to find out what spring rates ive got and adjust them accordingly soon as well.

Joshy

what do you want the car for, if its a road car i would say 60/40 to the rear as it will be more balanced under breaking.

for track it might be better to do otherwise but not sure to what degree

Chip

iTrader: (3)

How did you manage to make as much change as that? Thats pretty impressive!


Is that with you and a passenger sat in the car? if so thats fucking light, its the same weight as my nova with no one in it

If that wasnt with you and a passenger, then surely you need to be getting it done with as thats what you will have on track?

Roosie

iTrader: (8)

my saxo was cornerweight last week made soo much difference my car weighs 910kg with me in it and im 115kg

Oranoco

Got coilovers on the tank and keep thinking about getting it corner weighted.

stu21t

It weighs 997kgs with all fluids but no driver/passenger.
1077 with me in, That's with 80kgs in the drivers seat, which is how I did it when I corner weighted it.
didn't bother with a passenger as 90% of the time the car is used on road with more time just me in it.
Although thinking about it I could have put 40kgs in, then it would be better than nothing.
I'm going to have to do it again once I change the spring rates anyway.

And I did it by just adjusting the coilovers. I might have to raise it all a bit, the rear end is quite low now lol.

As it's mainly a road car is 57% rear and 43% front ok then?
And what about the bite, how do I improve that?
I'm guessing that's how much "bite" the tyres will get on launch?

And as for braking, I've got a bias adjustable pedal box so can adjust that seperately.

the mk1 kid

Confused.com!

Tom

Mike Rainbird

iTrader: (3)

Normally sand filled containers to represent driver, to the weight required, hence why he said "ballast" . He just made a mistake .

Chip

iTrader: (3)

57% rear doesnt sound too bad on a road car, might have a slight tendancy to understeer as a result but at least you will have good traction from the lights.

I would leave that as it is personally, but the only real way to know is to try it on different settings, you need to drive a car to really know what suits it and your driving style best, it cant be done just from paper.

Im amazed you managed to alter it as much as you did on just altering the coilovers, what sort of changes did you have to make to move so much weight?

Bear in mind that under hard acceleration out of corners its ALWAYS going to have a bit of a tendancy to understeer unless you are oversteering from lighting the rear wheels up as you'll have 75% or more of the weight on the back while its accelerating I bet!

Spiky

iTrader: (1)

yeah mike, but above he says, it has no passenger or driver?

Mike Rainbird

iTrader: (3)

Stu,
I would be experimenting with the corner weights to get the handling "feel" that is good for you, rather than getting into the mind-set of achieving a certain figure. Pointless getting 50/50 if it handles like shit as a result (due to the radically different platform heights).

Geometry will also be key to achieving what YOU want from the car, along with the spring rates to achieve either safe understeer or lairy oversteer. Unfortunately everyone's driving style is different, so one man's poison is another's pint of beer .

stu21t

Ballast is a lose term, It can be anything as long as it adds up to the weight that would normally be there. Being as I'm always in the drivers seat and I weigh 80kilos, I added that in the form of 2 car batteries and bricks. Lol


Also how can I check the spring rates?
Can I just add weight to the strut top and see how much weight is needed to compress it by say 10mm?

Spiky

iTrader: (1)

first you put

then

hence my post

Mike Rainbird

iTrader: (3)

To do it with any degree of accuracy, you need to do it in a proper spring compressor.

stu21t

Just to clear up
I added my weight to the drivers seat while doing it.
I did not add the weight of a passenger.
When I fit the new springs I will redo it with the weight of half a passenger so it's sort of done for both.


I will leave the settings as they are for now and just keep trying. Cheers guys.

Chip I spent all night doing it lol. Just going up and down with the platforms.
I don't know how having 2 coilovers per corner on the rear affects it but I had to move them a lot less to change the weight on them. Also my weight is a lot more in the centre of the car than yours to start with.
The engine is literally 1" off the back of my seat.

stu21t

Sorry spiky, doin this on my iPhone it's not too easy lol.
It's 1077 with me but no passenger, 997 with no driver or passenger.
Lol


And mike, this is just so I get it as close as I can until I get it done properly by a pro.
I could take the springs out, they should have the rate stamped on them, but I don't wanna strip em down lol.
I think they are miles out anyway so should be quite easy to tell. Lol

I know what I want, just gotta find out what I've got.

Spiky

iTrader: (1)

lol no worries dude, i'm the same on mine sometimes

as chip said, quite amazing how much you have altered it,

the mk1 kid

I was only pointing out the passenger/driver seat confusion as it happens, but you weren't to know that. Cheers Mike.

Now you've got some nice corner weights i think you want some track time and a tyre thermometer in order to make the first big step to whats as close to 'right' and 'wrong' as possible, before tailoring to overall balance of the car to your driving style/desire.

Tom

Chip

iTrader: (3)

Realistically you want it different for different tracks anyway, but he is more interested in road performance by the sounds of it.

when I was out at combe in my mini I used to have it leaning slightly with it lower on the drivers side as its mainly righthand corners and it worked better like that so the weight was more even during cornering, maybe he needs the same technique for the road as its more right handers due to all the roundabouts

FletchCossie

iTrader: (4)

Where did you get it corner weighted Stu?

stu21t

I did it at home steve. But will prob get xsport to do it when I get it done properly.

It is mainly a road car but will see a bit of track, but I'll never be chasing seconds, I'm too scared of gettin it wrong.

I have got a spring rate calculator on my laptop at home, that takes sprung, unsprung weight, sizes of components, lengths of pivot points.... And works out what rate you need depending on what you do with the car. It quotes the (cps? Cms? Can't remember) at 60-80 for a soft road car, 80-100 for a sports road car, 100-150 for a race car I used 100 as my car.
That worked the rate out to 120lbs for the front springs, haven't done the rears yet.
Does this sound right?

Chip

iTrader: (3)

120lbs sounds way to soft to me on the front, but it depends a lot on the amount of leverage in your geometry as actual rate and effective rate can vary a lot (on a mini for example they vary by 500%!)

stu21t

Ok I will double check it, I only did it quickly last night so prob didn't do it right.

RONNIE AMIS

iTrader: (17)

have you got your own corner weight scales then mate?

stu21t

Na m8, I wish. I did it the pikey way with a load of bathroom scales lol.
It's has the same effect tho, and I laser levelled them all through so the platform was the same for all 4 wheels.

That's why I said I got it as close as.
It's pretty accurate tho, I did it a few times to check and the weights didn't change when I didn't adjust anything.
If I did have proper scales I'd happily put your car on them.
But they cost a fortune and I'm no pro lol.

stu21t

Don't shoot me down people
you use the tools you have, don't you lol.

Spiky

iTrader: (1)

what scales are they? to give a reading of 400kgs, seems a cheap way to corner weight a car

my car only ways 800kgs so they sound ideal

Chip

iTrader: (3)

On the contrary, its a cool idea, but even my fatboy edition scales only go upto about 150kg, where the fuck did you get ones that do 400?

stu21t

On the wheels that weigh loads I just used more scales lol.

I took some pics I can upload tonight lol
but quickly,
either get enough to put under all wheels, or do 1 at a time or side-side or front-rear.
The tescos value scales are Ł4ea and go to 120kgs, so 4 on the heaviest an 2 on the lightest.
10 of em read 1200kgs so as the car is only 997 that's Ł40
I did it with 4 last night so took a lot longer, but wanted to try it out 1st.
I will get some more for next time when I change the springs and redo it.

Basically I put a sheet of mdf down under the scales and on top so the weight was fairly even, then packed the wheels without scales up, with bricks and wood.
Then lasered through them all and packed em to suit.

It's not as bad as it sounds, but not far off lol.
Like I said it's only till I get to a pro.

Will upload the pics later.

Chip

iTrader: (3)

LMAO, definately need to see pics of that!

Spiky

iTrader: (1)

pmsl,

bugger i was hoping you had found a "proper" fat boys bathroom scales that i could use.

so easy to make a joke relating to chip here, but i wont

the mk1 kid

Effort = reward fair play!!

Tom

stu21t

If you think that's funny I should find pics from when i built the car.
I couldn't find axle stands that went high enough so I Used some tree logs and breeze blocks to raise the rear of the car about 5 foot lol
I've got pics of that somewhere to.

I've built most of the car using house building tools lol.
Hey. It worked.

If I had 400 kilo scales it would b a piece of piss lol.

sas

Did you disconect the antiroll bars?
And you should be able to adjust the ARB droplinks so when you have finished adjusting the corner weights you can adjust the lengths to connect the ARBs withount placing any load on the ARBs.

Simon.

Markb_s1

Graham Bahr on turbosport does the same on his BM race car.. and he usually does well with that!

LHD220Turbo

iTrader: (4)

that must be a quick little R5 GTT with a cossie lump

what spec & boost is the YB lump you're ruinning? power to weight must be

stu21t

the front i didnt, it has a campus anti roll bar which is 1mm bigger than a std r5, it is fixed/non adjustable. i left that on cos it was late and a trial run. lol
the rear doesnt have an anti roll bar, i guess cos its double wishboned, twin coilovers each side, and tie bars.

if its good enough for a race car, its definately good enough for my shopping trolley. lol


lhd... its running approx 400bhp, with 2bar boost

Chip

iTrader: (3)

If you had a rear ARB you could run softer rear springs which would probably help get it off the line better and improve road comfort, but you will still have enough rear end roll resistance to counter understeer.

I would have though that a correctly weighted rear ARB would be an improvement for what you are using it for.
(certainly improved my nova when I added one, and they are pretty similar)

stu21t

tbh chip, i dont know much about suspension. this is all new to me.
i wouldnt have a clue how/where/what to fit with an arb. plus its not like i can call up and order 1 off the shelf. lol

i need to get the rest of the car sorted before i start going down the route of going to a specialist and doing stuff like that.

sas

Basically the cornerweights you have are not a true representation of the cars stance.
Because you have wound spring cups up and down they have transferred weight into the ARB, this means that the spring rates have changed on each corner.

ie, as you wind the FL spring platform it transfers load into the ARB and moves it across onto the FR so you may now have equal weight on each wheel but the spring rate on the LF is now greater than that of the right, leading to even stranger handing.

S.