myke pocock
|
| posted on 14/3/09 at 09:39 PM |
|
|
Self centering
Took the car for a shakedown run. It doesnt quite self centre, slightly worse on LH lock than RH. I have the front tyres up to 30 PSI with neutral
camber and neutral toe in/toe out. What should I do to improve it for SVA. Can always tweek further after the test.
|
|
|
|
|
nitram38
|
| posted on 14/3/09 at 09:41 PM |
|
|
Do a search..................................
|
|
|
nick205
|
| posted on 14/3/09 at 10:00 PM |
|
|
Slight toe out (1-1.5 deg) should help and possibly a little negative camber too.
|
|
|
mistergrumpy
|
| posted on 14/3/09 at 10:05 PM |
|
|
Toe out, 30-35 PSI and check the rack's not too tight. Loosen the slipper on it or whip it off and clean and oil the lot then put it back
together but not too tight.
|
|
|
nitram38
|
| posted on 14/3/09 at 10:40 PM |
|
|
Do you want to live?
Then do a search and fix the problem......more castor is the only safe way to have a good car.
|
|
|
mistergrumpy
|
| posted on 14/3/09 at 10:45 PM |
|
|
He only wants it to pass SVA. It's a home made car at the end of the day, built in a garage.
Besides there's a few on here who don't have enough caster but have no problems.
|
|
|
twybrow
|
| posted on 14/3/09 at 11:21 PM |
|
|
quote:
Originally posted by mistergrumpy
He only wants it to pass SVA. It's a home made car at the end of the day, built in a garage.
Besides there's a few on here who don't have enough caster but have no problems.
Nicely put. If you have SVA in the next few weeks, remaking wishbones/mountings would be pushing it!
When you say loosen the slipper, what do you mean? Is this a case of taking off the little plate on the rack, and tinkering around inside? Mine is a
new quick rack, and I am concerned it is quite tight....
|
|
|
mistergrumpy
|
| posted on 14/3/09 at 11:31 PM |
|
|
For me it was too tight. There's a little plate just to the side of the column attachment. I undid it and it was a bit clagged up so I cleaned
it all and found a servicing guide on someones site. I added some oil then made a gasket out of card to just stand the plate very slightly higher than
it should be and it helped a lot. Any excess oil was spat out. Now I can move the wheels freely by hand whereas I couldn't before.
|
|
|
BenB
|
| posted on 15/3/09 at 01:08 AM |
|
|
Personally I don't see the whole need for self-centering. My car doesn't really self-center. It passed SVA on a fluke. But it's
fine. In all the drives I've done, all the track day slaloms etc I've never once thought "if only I had more
self-centering".
So do all the usual bodges to get it through sVA and then get on and enjoy it 
|
|
|
mangogrooveworkshop
|
| posted on 15/3/09 at 01:59 AM |
|
|
My rust2 rome pug had better self centering than the Indy till i sorted the bones.
It was a very tough drive with out the feedback as you had to do the driving both ways.
As the man says make sure the racks free and the steering column alignment is straight and free running
|
|
|
nitram38
|
| posted on 15/3/09 at 06:35 AM |
|
|
It took me 2 hours to re-make my top 2 bones and it transformed the car from one that felt vague to one where I had feedback through the steering.
Also there are lots of sva testers who read this forum and are aware of the toe out "bodge".
Not only do the testers check for centering, they drive the cars.
If they think that the car feels vague, they will fail your car.
The problem with bad setups is that people will still drive the car and "compensate" for any poor handling.
It is not until you drive a good setup, you realise how bad yours actually is.
It is up to you, but personally would make an attempt to re-make the bones and if I ran out of time, then try the toe out rather than just fudge
it.
At least you will be part way to having them ready and can change them after sva.
|
|
|
whitestu
|
| posted on 15/3/09 at 09:24 AM |
|
|
Wouldn't it be sensible to accurately measue the actual amount of castor the car actually has before remaking wishbones?
Mine doesn't self centre that much, but has plenty of steering feel and isn't vague. In fact it is anything but vague.
Stu
Stu
[Edited on 15/3/09 by whitestu]
|
|
|
mistergrumpy
|
| posted on 15/3/09 at 09:41 AM |
|
|
quote:
If they think that the car feels vague, they will fail your car
No they won't, come on. As long as the car attempts to self centre they usually pass it. For loads on here that's meant that the steering
wheel twitches only slightly back and it's passed.
quote:
It is up to you, but personally would make an attempt to re-make the bones and if I ran out of time, then try the toe out rather than just fudge it
That's good advice though and what I hope to do something in the form of what Hellfire's done.
(P.S. Just because I'm quoting you Martin I'm not trying to dismiss you or start an arguement, I don't want it to come across like
that  )
|
|
|
NS Dev
|
| posted on 15/3/09 at 02:23 PM |
|
|
quote:
Originally posted by BenB
Personally I don't see the whole need for self-centering. My car doesn't really self-center. It passed SVA on a fluke. But it's
fine. In all the drives I've done, all the track day slaloms etc I've never once thought "if only I had more
self-centering".
So do all the usual bodges to get it through sVA and then get on and enjoy it
Yea but..............yours is a Stuart Taylor Chassis and Wishbones isn't it???
If it is then it has a vast amount more castor than most of the others, he didn't use "book" geometry!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
|
|
|
NS Dev
|
| posted on 15/3/09 at 02:26 PM |
|
|
quote:
Originally posted by nitram38
It took me 2 hours to re-make my top 2 bones and it transformed the car from one that felt vague to one where I had feedback through the steering.
Also there are lots of sva testers who read this forum and are aware of the toe out "bodge".
Not only do the testers check for centering, they drive the cars.
If they think that the car feels vague, they will fail your car.
The problem with bad setups is that people will still drive the car and "compensate" for any poor handling.
It is not until you drive a good setup, you realise how bad yours actually is.
It is up to you, but personally would make an attempt to re-make the bones and if I ran out of time, then try the toe out rather than just fudge
it.
At least you will be part way to having them ready and can change them after sva.
Completely agree.
My SVA tester at nottingham did drive the car, and made his assessment based on his thoughts, not some silly procedure, and quite right he was too.
These guys are not stupid in my experience. They ae mechanics with suitable knowledge!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
|
|
|
MikeR
|
| posted on 15/3/09 at 04:19 PM |
|
|
Just out of curiosity, can anyone remember how much the top wishbone was supposed to be offset by?
I've got in my head it was something like 5 to 7 in the book and it wants to be double. Just can't remember if the book was mm or degrees.
Quick measure and mine are about 10mm off the centre line.
Ie outside edge to outside edge is 220mm, so centre line is 110mm, centre of TRE is about 120mm.
|
|
|
twybrow
|
| posted on 15/3/09 at 07:44 PM |
|
|
quote:
Originally posted by NS Dev
Yea but..............yours is a Stuart Taylor Chassis and Wishbones isn't it???
If it is then it has a vast amount more castor than most of the others, he didn't use "book" geometry!
I have a ST chassis - so I hope this is true....! Mine is going to SVA in 2 weeks, and I have been trying to set a slight amount of toe out today (by
eye!). Hopefully, the geometry should be better than the majority.... Fingers crossed!
|
|
|
whitestu
|
| posted on 15/3/09 at 10:13 PM |
|
|
quote:
Yea but..............yours is a Stuart Taylor Chassis and Wishbones isn't it???
If it is then it has a vast amount more castor than most of the others, he didn't use "book" geometry!
And it still doens't self centre much.
Maybe there is more to getting the car to self centre than just castor?
Stu
|
|
|
myke pocock
|
| posted on 15/3/09 at 10:26 PM |
|
|
Good God, didnt expect all that. Thanks for the helpful comments and no thanks for the sarky ones. As I said its almost right, just wanted to improve
it a bit. Certainly aint going to make up new wishbones.
|
|
|
nitram38
|
| posted on 16/3/09 at 03:54 AM |
|
|
quote:
Originally posted by myke pocock
Good God, didnt expect all that. Thanks for the helpful comments and no thanks for the sarky ones. As I said its almost right, just wanted to improve
it a bit. Certainly aint going to make up new wishbones.
Why do they ask for a car to cenre on your sva test?
Simple, it is a safety requirement.
Yes, while you drive your car in the first few days it will feel great and the car will all be new to you.
The main reason for the centering is coming out of bends your steering will unwind by it's self and make driving easier on your arms. Apart
from it being a smoother drive, it is more stable.
There have been a couple of threads in the last few days where people are driving cars with toe out and are complaining of the car wandering and
being out of control.
This will be you once you start driving your car properly.
Your choice and your accident.
|
|
|
twybrow
|
| posted on 16/3/09 at 01:08 PM |
|
|
quote:
Originally posted by nitram38
Why do they ask for a car to cenre on your sva test?
Simple, it is a safety requirement.
Yes, while you drive your car in the first few days it will feel great and the car will all be new to you.
The main reason for the centering is coming out of bends your steering will unwind by it's self and make driving easier on your arms. Apart
from it being a smoother drive, it is more stable.
There have been a couple of threads in the last few days where people are driving cars with toe out and are complaining of the car wandering and
being out of control.
This will be you once you start driving your car properly.
Your choice and your accident.
Nitram - not exactly a helpful response there. We all know there are sections of the SVA test that we have to adhere to, that have no long term
relavance to our cars (or are you going to keep all of your additional silencers, cats, emissions mapping, nut covers etc etc on your car?). I agree,
a car that won't self centre would feel odd, but we don't need the amateur dramatics to prove the point. Just as you are doing, we all
make modifications for the test, that get replaced/tweaked/fall off after the test. Maybe this is the scenario myke is in....? Just a thought....
|
|
|
NS Dev
|
| posted on 16/3/09 at 01:14 PM |
|
|
quote:
Originally posted by twybrow
quote:
Originally posted by NS Dev
Yea but..............yours is a Stuart Taylor Chassis and Wishbones isn't it???
If it is then it has a vast amount more castor than most of the others, he didn't use "book" geometry!
I have a ST chassis - so I hope this is true....! Mine is going to SVA in 2 weeks, and I have been trying to set a slight amount of toe out today (by
eye!). Hopefully, the geometry should be better than the majority.... Fingers crossed!
Shouls be ok, mine was with no tweaking and toe in, not out.
make a simple toe gauge, i just use what is most easily described as a giant g clamp made from bits and bobs of steel, that can reach right round
the front wheels, with m6 screws to adjust till it touches the wheel rims. Do it at the front, than at the back, of the front wheel rims, campare the
turns of adjustment on the screws (1 turn = 1mm ) and use a bit of simple trigonometry to get the degrees of toe in, or just set it to about 3mm
smaller at the front of the rim compared to the back this will be about right.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
|
|
|
David Jenkins
|
| posted on 16/3/09 at 01:19 PM |
|
|
quote:
Originally posted by twybrow
Nitram - not exactly a helpful response there. We all know there are sections of the SVA test that we have to adhere to, that have no long term
relavance to our cars (or are you going to keep all of your additional silencers, cats, emissions mapping, nut covers etc etc on your car?). I agree,
a car that won't self centre would feel odd, but we don't need the amateur dramatics to prove the point. Just as you are doing, we all
make modifications for the test, that get replaced/tweaked/fall off after the test. Maybe this is the scenario myke is in....? Just a thought....
I wouldn't say that self-centering is in the 'bits of stuff that comes off after SVA' category! Having driven cars with poor
self-centering, my personal opinion it's fundamental to safe driving on the public roads.
|
|
|
alistairolsen
|
| posted on 16/3/09 at 01:32 PM |
|
|
when will people stop bodging their poo geometry and just remake the wishbones to make the car safer and nicer to drive?
|
|
|
procomp
|
| posted on 16/3/09 at 03:33 PM |
|
|
Hi
When will the KIT manufacturers actualy sort the problems out rather than leaving customers who have spent a large amount of money with them. With a
car that will not legally pass the SVA / IVA test without being bodged.
It really is appalling.
Cheers Matt
|
|
|
