cornerweighting
19 July 2006, 11:43 AM
#2
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briefly you put all 4 wheels onto some scales then using some calculations you adjust the ride height slightly at each corner which redistributes the weight until you get a more balanced car (weight wise)
19 July 2006, 12:36 PM
#4
Done properly this is a good adjustment to have done.
If you intend to race the car on your own then the technicial should ask you for your weight so he can compensate in the corner weights.
Quite a time consuming job to do properly.
Transformed my 911, but havn't bothered on my hill climb Impreza.
David at www.apiengines.com does it in south Warwickshire.
Graham.
If you intend to race the car on your own then the technicial should ask you for your weight so he can compensate in the corner weights.
Quite a time consuming job to do properly.
Transformed my 911, but havn't bothered on my hill climb Impreza.
David at www.apiengines.com does it in south Warwickshire.
Graham.
19 July 2006, 07:54 PM
#7
I feel not really.
The Impreza shell is very accuratly made as are all modern cars. My old 911 is very very inaccurate in comparison.
I think you can set a decent set of struts to the same height on the bench and fit them to the car and align the whole chassis and the car will be pretty good.
This is what PowerStation did to mine and the way the car corners/accellerates and brakes is 'symetrical', ie a left turn feels like a right turn. It is this even feeling that cornerweighting gives you.
Cornerweighting will not dial-in a twisted chassis!
Just my opinion over 14 years of competing!
Graham
The Impreza shell is very accuratly made as are all modern cars. My old 911 is very very inaccurate in comparison.
I think you can set a decent set of struts to the same height on the bench and fit them to the car and align the whole chassis and the car will be pretty good.
This is what PowerStation did to mine and the way the car corners/accellerates and brakes is 'symetrical', ie a left turn feels like a right turn. It is this even feeling that cornerweighting gives you.
Cornerweighting will not dial-in a twisted chassis!
Just my opinion over 14 years of competing!
Graham
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19 July 2006, 08:55 PM
#8
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that makes perfect sense actually graham, thanks for your input on this one.
I think what i may do is set the right side front 2 or 3 mm higher than the left front and the rear right 1 or 2mm higher than the left....not overly scientific....but i guess it will be more balanced that having all 4 set at the same height with a 100kg mass on the right hand side of the car.
I think what i may do is set the right side front 2 or 3 mm higher than the left front and the rear right 1 or 2mm higher than the left....not overly scientific....but i guess it will be more balanced that having all 4 set at the same height with a 100kg mass on the right hand side of the car.
21 July 2006, 10:20 AM
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Hiya,
A related issue is the difficulty in setting height accurately enough. On my D2 coilovers at least it takes more than a couple of bounces to find a consistent level. Not sure why this is. After a brief run, and thereafter, it's consistent. So, it takes a few iterations to get the height accurate to 1mm or thereabouts.
I suppose it's a stiction effect, but I would have thought a bounce or two would sort that?
Also, with 50/40 springs, my ability to bounce the car is a bit limited!
Andy
A related issue is the difficulty in setting height accurately enough. On my D2 coilovers at least it takes more than a couple of bounces to find a consistent level. Not sure why this is. After a brief run, and thereafter, it's consistent. So, it takes a few iterations to get the height accurate to 1mm or thereabouts.
I suppose it's a stiction effect, but I would have thought a bounce or two would sort that?
Also, with 50/40 springs, my ability to bounce the car is a bit limited!
Andy
21 July 2006, 01:44 PM
#11
Yes, that is all dead right Andy.
I'm not sure if hunting-down to the last 1 mm is worth it and where do you measure from?
The front wing arch on the left is possibly in a different position to the right one (manufacturing tolerances) so you need to find a spot that is true on the chassis.
This is why it is the weight on each corner that is used as body feature positions are irrellavant using weight.
The truth of the floor/scale height is also critical.
In the lte 1970 I actually designed a set of digital corner weghing platforms that were portable for McLaren!! (my only claim to 'fame')
For sure the changes it made to my 1973 911 were dramatic but those shells are everywhere which is why there are so many adjustment points on an early 911!
Graham
I'm not sure if hunting-down to the last 1 mm is worth it and where do you measure from?
The front wing arch on the left is possibly in a different position to the right one (manufacturing tolerances) so you need to find a spot that is true on the chassis.
This is why it is the weight on each corner that is used as body feature positions are irrellavant using weight.
The truth of the floor/scale height is also critical.
In the lte 1970 I actually designed a set of digital corner weghing platforms that were portable for McLaren!! (my only claim to 'fame')
For sure the changes it made to my 1973 911 were dramatic but those shells are everywhere which is why there are so many adjustment points on an early 911!
Graham
Last edited by 911; 21 July 2006 at 01:47 PM.
21 July 2006, 04:21 PM
#12
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i geuss the best course of action is simply to fit them (all the saem ride height...) drive it around for a few miles to make them settle, then find the flattest bit of road possible and wind out the drivers side a little....
Im sure ill see a massive improvement when they are all the same tbh!!
Im sure ill see a massive improvement when they are all the same tbh!!
21 July 2006, 09:25 PM
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Originally Posted by Neilo
i geuss the best course of action is simply to fit them (all the saem ride height...) drive it around for a few miles to make them settle, then find the flattest bit of road possible and wind out the drivers side a little....
Im sure ill see a massive improvement when they are all the same tbh!!
Im sure ill see a massive improvement when they are all the same tbh!!
Allthough impossible to guess the settings, I would expect the n/s/f to need to come up initially. Then fiddle around for ages on the scales to get it really right.
Better to set to correct ride height and forget about the scales unless you are looking for the last few tenths on a circuit or stage.
I own a set of Longacres and they only tend to come out for serious competition cars. The amount of time it takes to do it properly makes no sense for a road/semi-competition car. Especially as budget suspension (less than a grand a corner) has a lot of stiction that clouds any readings and by the time you have hit a few bumps/potholes/kerbstones, all the weights will be out again anyway.
Just my opinion............
21 July 2006, 10:00 PM
#15
Agree!
Graham.
Last thing on your mind is cornerweights:
http://www.dropshots.com/daymainfram...0030101&cimg=0
http://www.dropshots.com/daymainfram...0030101&cimg=2
Graham.
Last thing on your mind is cornerweights:
http://www.dropshots.com/daymainfram...0030101&cimg=0
http://www.dropshots.com/daymainfram...0030101&cimg=2
Last edited by 911; 21 July 2006 at 10:04 PM.
21 July 2006, 10:06 PM
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that stays so flat, thats awesome 
thats what i need. I think for now i will just get the car riding level and see what the guys at Mocom say when i take it for the tracking and alignment on friday.
thats what i need. I think for now i will just get the car riding level and see what the guys at Mocom say when i take it for the tracking and alignment on friday.
21 July 2006, 10:19 PM
#17
It's all in the Whiteline stuff complimenting the AST's and the Powerstation alignment.
The sum of all the parts ......(masks a crap driver too)
Bet Job is laughing at those vids!
It really is a great chassis/car just so easy to thrash!
Graham
The sum of all the parts ......(masks a crap driver too)
Bet Job is laughing at those vids!
It really is a great chassis/car just so easy to thrash!
Graham
22 July 2006, 08:07 AM
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Looking good Graham.
Nice to see that you can alter the line after committing, without the car trying to send you in the scenery.
The second vid does show that it might need for some extra rebound at the front, maybe some extra low speed bump at the back, or slightly stiffer springs at the back (2 or 3 N/mm or so extra).
Cheers
Nice to see that you can alter the line after committing, without the car trying to send you in the scenery.
The second vid does show that it might need for some extra rebound at the front, maybe some extra low speed bump at the back, or slightly stiffer springs at the back (2 or 3 N/mm or so extra).
Cheers
22 July 2006, 01:09 PM
#19
I'll give that a try Job, yhpm too!
Graham
Should also say sorry to the thread originator, Neilo for screwing the thread a bit, but i hope the chat is relavant...
Graham
Should also say sorry to the thread originator, Neilo for screwing the thread a bit, but i hope the chat is relavant...
Last edited by 911; 22 July 2006 at 01:55 PM.
22 July 2006, 02:21 PM
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it is dont worry,...
ive just finished fitting my D2s, havent put the strut bars back on yet though as its just started to rain.
May post a few pictures later so that you can help me do a very quick set up as im not overly sure what im looking at in truth.
ive just finished fitting my D2s, havent put the strut bars back on yet though as its just started to rain.
May post a few pictures later so that you can help me do a very quick set up as im not overly sure what im looking at in truth.
22 July 2006, 02:37 PM
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Yes, sorry Neilo, for hijacking your thread. Can't seem to help myself :-)
In your case, set the car to your desired ride height, run the car for a week or so, to let the dampers wear in and the springs to settle. Then get a professional geometry set up done to get the wheels pointing in the right direction.
Good luck
In your case, set the car to your desired ride height, run the car for a week or so, to let the dampers wear in and the springs to settle. Then get a professional geometry set up done to get the wheels pointing in the right direction.
Good luck
22 July 2006, 02:48 PM
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thankfully thats exactly whats happening, so im glad im doing the right thing. Its getting the geometry and alignment done this coming friday, so it will have had at least 100 miles of varied roads by then.
