eddbaz
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| posted on 15/11/08 at 12:40 PM |
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self centering an indy type r
I need to set up my front end for the self centering for the sva.
Can ayone who has but an indy r thfough sva tell me what they did.
Searching through previous posts it seems that people put a degree of negative camber and toe out a couple of degrees,there is also mention of fitting
valve springs to the rack to aid self centering and running high tyre presures.
I'm not interested in revisiting design flaws in the wishbones and castor angles .I just need help in getting mine through the self centering
check.
Thanks in advance for your help.
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graememk
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| posted on 15/11/08 at 12:42 PM |
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OK FOR MY INDY (CEC)
1deg tow out 25psi, no springs, passed at nottingham sva ok not probs.
the test was that they turned the wheel all to the right and drove around in a circle, as long as the car attempted self center (the circle got
bigger) it passed.
[Edited on 15/11/08 by graememk]
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nitram38
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| posted on 15/11/08 at 02:54 PM |
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"I'm not interested in revisiting design flaws in the wishbones and castor angles .I just need help in getting mine through the self
centering check."
No but you might suddenly become INTERESTED when you end up in a hedge. Plus sva testers are getting wise to the bodges you mention.
Just remake your top bones, it will be quicker and safer than messing around with rack springs and visits to casulty......
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graememk
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| posted on 15/11/08 at 03:42 PM |
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i really dont have a problem with my SC at all.
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Mark Allanson
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| posted on 15/11/08 at 04:06 PM |
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quote:
Originally posted by graememk
i really dont have a problem with my SC at all.
Its probably because you have a proper engine fitted, these whizzy girly bike engines are not heavy enough to let the castor do its job - could try
ballasting the front end just for the SVA
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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graememk
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| posted on 15/11/08 at 04:20 PM |
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thats why i put (cec) on my post... i've always wondered if it was to do with weight myself.
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britishtrident
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| posted on 15/11/08 at 05:07 PM |
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Toe-out is potentially lethal on this type of car
Start with the simple things check the top wishbones are fitted the right way up ie top ball joint should be aft of the lower ball joint.
You can use up to 1.5 degrees of negative camber --- this also increases the KPI which is what will give you more self-centering.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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tootall
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| posted on 15/11/08 at 11:15 PM |
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thought the indy (spec R) had been sorted out as front and rear suspention components are different to the standard external shocker indy ??
some people dream of sucsess, others just get on and do it !!
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Hellfire
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| posted on 16/11/08 at 09:44 AM |
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Like Mark says, it's the lack of weight over the front wheels. You'll need a combination of high pressure, negative camber and plenty of
toe out at SVA. Just don't drive far with toe out. We arrived early for our SVA and adjusted it before and after.
Phil
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nitram38
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| posted on 16/11/08 at 11:28 AM |
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quote:
Originally posted by Mark Allanson
quote:
Originally posted by graememk
i really dont have a problem with my SC at all.
Its probably because you have a proper engine fitted, these whizzy girly bike engines are not heavy enough to let the castor do its job - could try
ballasting the front end just for the SVA
This theory is a bit flawed especially when my F1-2 is rear engined. There is even less weight over my front wheels.
I have driven the F1-2 without castor and it wasn't very good. Your car will feel vague through the steering as centring helps when un-winding
the wheel out of bends.
It took me 2 hrs to re-make my top bones with 7 degrees of camber.
The F1-2 was a totally different car afterwards.
You should trying driving a "castored" car before you decide as we all think things feel ok, but sometimes you need to experience the
difference to believe what people are telling you.
I learned alot about this one experience and now allow for it in my designs. I was learning from scratch built cars. It is a pity that cars are still
being built with this flaw, especially since the 7 is no spring chicken! 
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Hellfire
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| posted on 16/11/08 at 02:05 PM |
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Our top bones were modified so we could correct and adjust the castor as we so wished. First we ran with five degrees of castor and then tried seven.
Seven degrees made the steering feel quite heavy and numb, so we went back to five degrees (which is what the Indy top bones have built in). The self
centring with seven degrees was slightly improved but the feel was awful and not a very good trade off IMO
It could also be a number of things other than the wishbones, including the steering rack being too tight but ultimately if all you want at this stage
is to pass SVA then plenty of toe out is what you need.
Phil
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eddbaz
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| posted on 16/11/08 at 02:18 PM |
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Phil, how many degrees toe out ( not sure now much plenty is) and after sva do you set it neutral or slightly negative?
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Hellfire
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| posted on 16/11/08 at 02:30 PM |
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For SVA we didn't measure it. We simply toed out as much as the steering arms would allow. It was set straight ahead both before and after SVA,
so we could drive it there and back.
Phil
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nitram38
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| posted on 16/11/08 at 03:00 PM |
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If you have the correct castor, then your front wheels should toe in slightly on rear wheel drive cars.
This allows the front wheels to "straighten up" when the rear wheels are pushing the fronts.
I am running with 0.5 degree toe in on the F1-2.
Toe out not only wears your tyres, it makes the grip that you gained from using it disappear as you turn.......very handy in bends.
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Hellfire
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| posted on 16/11/08 at 03:15 PM |
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I'm not suggesting the car is driven with toe out other than at SVA. Straight ahead is much easier to achieve than 0.5 degrees toe in, both
before and after SVA.
Afterwards, the owner can spend as much or as little time as they need to get it setup properly and handling how they like it.
Phil
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jacko
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| posted on 16/11/08 at 03:27 PM |
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quote:
Originally posted by tootall
thought the indy (spec R) had been sorted out as front and rear suspention components are different to the standard external shocker indy ??
Thats what i thought too
were talking about the NEW type chassis are't we?
not the old Indy ?
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Hellfire
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| posted on 16/11/08 at 03:40 PM |
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quote:
Originally posted by jacko
quote:
Originally posted by tootall
thought the indy (spec R) had been sorted out as front and rear suspention components are different to the standard external shocker indy ??
Thats what i thought too
were talking about the NEW type chassis are't we?
not the old Indy ?
This thread is purely about self centring. If the Indy Spec R uses the same Sierra uprights and has the same five degrees of castor, then it will have
the same self centring traits as any other vehicle using these components.
Phil
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jacko
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| posted on 16/11/08 at 06:09 PM |
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Phil you are probably right but on the first page it says self centering a indy type R
that's why i posted that
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tootall
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| posted on 16/11/08 at 11:53 PM |
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the front bones are compleatly different to old indy front bones
old indy bones can be fitted wrong way round very easly but impossable to do this with the spec r
according to MK sportscars the geomatry is compleatly different and far superior to the old indy ????????????
so it must be different does eany one know the exact spec of new chassie ?
some people dream of sucsess, others just get on and do it !!
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Hellfire
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| posted on 17/11/08 at 12:40 PM |
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I don't think I'm getting across what I'm trying to say, so I'll try and explain a bit better.
First of all, the Spec R chassis and suspension geometry front and rear, are totally different to the Indy (including the shape of the front
top wishbones.)
This thread is about the self centring, which is influenced mainly by the angle of castor. The Spec R front top bones have 25mm setback, which equates
to 5 degrees. This is the same setback that the old Indy front top wishbones have, so although the shape of the wishbones is different, they both have
5 degrees of castor. The Spec R Indy uses the same Sierra uprights as the old Indy IIRC, therefore the old Indy and the Spec R Indy both have 5
degrees of castor. Therefore it doesn't matter which chassis you have, the self centring traits are the same.
The same thing goes for any manufacturers vehicle which use Sierra uprights and whose top bones have 25mm setback.
Phil
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procomp
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| posted on 17/11/08 at 03:00 PM |
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Hi.
If we get back to the OP's original point. You want a MIN of 5 deg Castor for a CEC and a bit more for a BEC. 7 - 8 is good.
The point though is that regardless of what figures are quoted by MK themselves and other MK owners. What is the actual Castor measurement on the car
in question.
Cheers Matt
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paulmw
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| posted on 17/11/08 at 04:34 PM |
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I tried all of the above with no success (Spec r ZX10R)
I put valve springs in the steering rack and it worked fine at SVA.
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