So do all the usual bodges to get it through sVA and then get on and enjoy it
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.
Do a search..................................
Slight toe out (1-1.5 deg) should help and possibly a little negative camber too.
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.
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.
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.
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.
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.
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
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
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.
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]
quote:
If they think that the car feels vague, they will fail your car
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
)
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
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.
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.
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!
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!
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.
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.
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.
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!
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....
when will people stop bodging their poo geometry and just remake the wishbones to make the car safer and nicer to drive?
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
quote:
Originally posted by procomp
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
Dave/Al - My point is, we have all heard that remaking the wishbones and/or moving the suspension brackets seems to be the way to go. However, as so
many of us are desperately trying to get legal before the IVA, my point was, new 'bones would probably be on the list of post SVA jobs. I'm
not suggesting bodging, then forgetting, far from it, but I bet there were a few shortcuts you both took to ensure an SVA pass....!?
[Edited on 16/3/09 by twybrow]
quote:
Originally posted by twybrow
I bet there were a few shortcuts you both took to ensure an SVA pass....!?
The trouble with the "tone" of the toe out advice is that it tends to give the impression that it is a normal setting. The person who built
the car who is short of time, wants a quick fix, but who wants to turn up to sva and fail?
I tried all of the toe out/pressure fixes and I even considered the springs on the steering rack, but I drove my car and it was scary coming out of
bends, the one place you really need stability.
I simply bit the bullet and got on and remade the top bones. Not only was it a final fix, it transformed the handling.
I may not be telling people what they want to hear, but what they need to hear and should act on.
Giving toe out advice to someone who then goes and stuffs their car the first time they give it some beans would make me feel pretty sick, to be
honest......
[Edited on 17/3/2009 by nitram38]
Hi
what many do not seem to realise is that Castor dose far more than simply help the self centering effect. Now given that these manufacturers claim
they have chassis that have 5 deg of Castor built into them. Why is it that when measured and checked the majority only have 2-4 deg on them. And
given that this results in the finished product not being able to legally pass the SVA / IVA and actualy be legally road worthy. Particularly when a
manufacturer actualy tells there customers how to bodge it through illegally.
It makes you wonder just where the customer stands legally whith the manufacturer. Just thinking about the court case with a certain manufacturer and
his floating cars that did not meet the regulations is was meant too.
Cheers Matt
ok, how out of curiousity will the MK spec R chassis have this issue? If so, what can I do NOW before I start putting it together?
(I have no welding skills so making something is out the window)
Speak to MK and find out... They said the R was a fully CAD designed chassis, so I assume (and you know what they say about assumption) that they could give you the castor angle over the phone....
You need about 22mm offset on the top bone to give the right amount of castor IIRC on a book chassis.
Having said that my GTS self centres beautifully with much less offset than that (about 15mm) and a very small amount of toe out and a fair bit of
camber (essentially the caterham setup)
David
There are other factors alongside castor angle, such as stiffness of steering joints and the steering rack. If the steering mechanism is stiff then
even the correct castor angle will struggle to self-centre. On the other hand, a marginal castor angle will have an easier time if the mechanism
moves freely. So one action would be to ensure that everything runs as free as possible, but without introducing play.
The other thing that may be possible is to use the spacing washers to move the lower wishbones as far forward as possible (1 at the front, and fill up
the remaining space at the back with the remaining ones), and do the opposite at the top to move the top wishbones as far back as possible. This is
assuming that your brackets and wishbone bushes require a stack of washers during assembly! You might gain an extra degree of castor, which might be
enough to get things working.