Pete,
If it means the pivot point of the arm and the tie rod are moving about a
common axis, Yes.
If the tie rods remain in the same position and the arm pivots are moved
upwards, this could make things worse depending on the rate of spring used
and as a result the degrees of arc the arm moves through under bump or
droop.
If you really want to see if you have bump steer. make up some straight
lengths of timber and connect to a heavy object to hold the timber in
position against the wheel, horizontally below the wheel centre line. Run a
string line along the line of the timber to establish the direction the
timber is pointing.
Jack the cross member up 50mm and let it return to rest. Check the pieces
of wood for movement from their original position. If the pieces of wood
have moved from their original line, you have bump steer.
Then get 2 or 3 persons to press down or sit on the guards and bonnet of
the vehicle sufficient to cause the suspension to become lower at rest.
Check the boards again for movement from the original line.
Cheers
Feral Errol
----------
From: Pete & Kath Liebig <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]
Subject: RE: Front suspension for racing
Date: Wednesday, August 23, 2000 8:41
Errol,
But just moving it upwards should do the trick to fix bumpsteer - yes?
Gotta be the cheap and easy way to go for a guy with a die grinder and a
MIG...
'later
PL
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]] On Behalf Of Errol Smith
Sent: Wednesday, 23 August 2000 19:18
To: [EMAIL PROTECTED]
Subject: Re: Front suspension for racing
Chris,
The problem with moving the lower control arm pivot point out is that the
lower control arm and tie rod then end up describing different arcs in bump
or droop conditions. This causes bump steer!
If you check out the current Nismo catalogue, they offer strut spacers for
the following vehicles and have had them on sale for some 15 years.
3/4" Aluminium spacers for 240, 260, 280 & 280ZX Z cars Part No
99996-34SPGR.
For 510, 610, 710, 200SX (S10 & S110) a 1" spacer is sold Part No
99996-10SPGR.
To quote the current Nissan Motorsport catalogue:-
" 1inch Aluminium spacer, Corrects lower control arm angle when ride height
is reduced. Also reduces camber change and bump steer. Fits between lower
control arm and strut."
Cheers
Feral Errol
----------
From: Chris Halpin <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]
Subject: Re: Front suspension for racing
Date: Thursday, August 24, 2000 9:15
Trevor,
Are you driving this car on the road? If not....Have you seen Peter's? He
lives in Melbourne. I just got some springs off him the other night, and
he's a really generous guy - seems willing to share his knowledge too. He
has actually changed the pivot point on the X-Member, thus changing the
control arm angle drematically, and also giving more camber and a wider
track width at the front end. I personally think It's a great idea to
eliminate the need for bump steer spacers, and also the need for longer
control arms. He says it works well.
Chris
>From: "Pooley, Trevor" <[EMAIL PROTECTED]>
>Reply-To: [EMAIL PROTECTED]
>To: "'[EMAIL PROTECTED]'" <[EMAIL PROTECTED]>
>Subject: Front suspension for racing
>Date: Wed, 23 Aug 2000 16:18:40 +0930
>
>Unless you fork out $1600 for a set of 55DCO/SP Webers from DatRats (
>drooooool ). I agree!
>
>Talking about datrats. I've just recieved a set of 30mm bump steer spacers
>from Datrats (one tenth the cost of the 55's). They look real good (nice
>shinny alloy) and will restore some angle to my lower control arms after
>the
>lowering job I did last week before phillip Island. I had some minor bump
>steer there.
>
>This leads to my next question. There was some talk a little while back
>about the location of the pivot point on the engine crossmember.
Apparently
>the early model had these higher up than the latter models. Can anyone
>confirm this? Also after looking at the pics of the busted cross member,
is
>it worth modifying mine or just looking for a good early 1600 crossmember?
>Does the distance between the two pivot points change as well or just the
>height?
>
>Other thing I want to do is make new adjustable lower control arms to
>replace the datrally ones I am currently using. I would like to either go
>for a monoball arrangement (ie How to hotrod your datsun book) or rod ends
>where the lower control arm joins the crossmember. This would allow for
>lots
>of positive castor without stressing the pivot point. Does anyone know of
a
>cheap source for these parts.
>
>I am also looking into making a rear sway bay (ie How to hotrod your
datsun
>book) but that might be asking a little to much too soon.
>
>Thanks
>Trev
>
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