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Front crossmember stress bar
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> The crossmember you are trying to reinforce is MUCH stiffer than the =
"reinforcement"
i have to agree with larry on this one. the stock beam is a 4" =
triangular box, that when un-cracked, can support jacking a scirocco up =
from that front mount bracket, with 0 flexing to boot.
> The crossmember you are trying to reinforce is MUCH stiffer than the =
"reinforcement",
> consequently the stock crossmember is still going to absorb 99% of the =
stress.
i agree with this as well, provided that the original cross member is =
uncracked. this is only because the factory beam is easily more rigid =
than a 4 ft span of 1" box steel. when a force is applied, the 1" beam =
will flex, so most of the load will then be taken by the factory =
x-member.
while erics bar makes more sense than some i have seen in the past, =
it still does rely on the front cross member. actually, erics bar forms =
a 'v'. compared with a beam that sits horizontal, it will make a stiffer =
support, but it will also add tensile forces to the piece that we are =
worried about splitting. the front mount moving upwards will act on that =
'v', and given how shallow of a 'v' it is, this will result in a rather =
large force trying to push the 2 bumper mounts apart from eachother. if =
you already have splits in your core support, a shalow 'v' may end up =
causing more damage in the end. dont get me wrong, erics bar will =
definitely reinforce the cross member, im just concerned about how the =
forces are being redirected by that bar.
i believe the best solution would be a tubular steel boxed 'v'. =
boxed with the same tubes forming the 'v', as opposed to relying on the =
body of the car. this piece could be made of lighter material, as there =
would be no bending stresses on any of the sections, only tensile and =
compressive. minimum diameter would be only limited by buckling under =
compressive load.
picture a 2d version of this: =
http://www.scirocco.org/photos/misc/cross.jpg . if you had a flat, =
vertical boxed 'v' it would be very strong under the up/down loading =
from the engine. it will still be subject to twisting loads, but this =
can be easily compensated for by having the bracket bolt in from behind, =
resulting in the mount cup being in the same plane as the 'v', which =
would kill off the twisting and should make a pretty rigid mount.
...and once you do that, now you have to worry about something else =
cracking :)
Al
----- Original Message -----=20
From: L F=20
To: scirocco81@vwmail.net ; scirocco-l@scirocco.org=20
Sent: Saturday, March 08, 2003 7:47 PM
Subject: Re: Front crossmember stress bar
I have to say something now about this bar; It ain't gonna' do a whole =
hell of a lot. It's way too long for it's diameter...too much flex. =
The crossmember you are trying to reinforce is MUCH stiffer than the =
"reinforcement", consequently the stock crossmember is still going to =
absorb 99% of the stress. If you want to stock the cracking, weld a =
large, thick, form-fitted steel plate to the crossmember. This will =
spread out those stresses. The trick reinforcing bar is way too =
flexible to transmit the vertical stresses to the sides.
That's all...
Larry
sandiego16v
----- Original Message -----=20
From: Eric S=20
To: scirocco-l@scirocco.org=20
Sent: Saturday, March 08, 2003 4:03 PM
Subject: Front crossmember stress bar
Hello all!
Alot of people have been working on this I know...and one bolt =
together bar is in testing.
However, I now have a prototype of a fully welded bar...more =
tweeking continues. It will be FULLY bolt in.
Work continues this week, should have a ready to bolt in bar to test =
on ALL of my A1 chassis vehicles (see my sig...only A1 chassis I am =
missing is a Mk1 Jetta).
Price *should* be $100 plus shipping, fully welded, 3/16s steel (box =
and plate steel used..the box steel has 3/16s walls and is inch square =
outer diameter (IE, strong as hell). However, the plate steel will =
allow for side flex to not load the front motor mount with cornering =
forces...this bar is designed to control upward movement ONLY). Bar =
will come bare or primed based on request. Powder coating, and other =
options will be available for higher cost.
Here are pics (again, this is a very very rough prototype):
http://www.vintagewatercooleds.com/~blklace/BAR/
Please let me know if you are interested...and general feelings of =
its construction. Realize, I am attempting to make a universal bar for =
all A1 chassis, hence some compromises were made in its design. =20
(and damn are there alot of little annoying differences on A1 =
chassis cars throughout the years)
I am fully confident that it will not allow the crossmember to flex =
upward at all however, no matter what A1 chassis it is bolted to.
=20
--
Eric
Northglenn, CO
79 VW Iltis
81 Scirocco S (*TDI* swap and complete restoration in holding =
pattern)
81 Rabbit Truck LX Diesel (Waiting for BAE Turbo Install)
83 Scirocco Wolfsburg
91 Cabriolet (2.0 Crossflow 8v swap and mechanical rebuild in =
progress)
_______________________________________________
Scirocco-l mailing list
Scirocco-l@scirocco.org
http://neubayern.net/mailman/listinfo/scirocco-l
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<DIV><FONT face=3DArial size=3D2>> The crossmember you are trying to =
reinforce is=20
MUCH stiffer than the "reinforcement"</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2> i have to agree =
with larry=20
on this one. the stock beam is a 4" triangular box, that when =
un-cracked, can=20
support jacking a scirocco up from that front mount bracket, with 0 =
flexing to=20
boot.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>> The crossmember you are trying to =
reinforce is=20
MUCH stiffer than the "reinforcement",</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>> consequently the stock crossmember =
is still=20
going to absorb 99% of the stress.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>i agree with this as well, provided =
that the=20
original cross member is uncracked. this is only because the factory =
beam is=20
easily more rigid than a 4 ft span of 1" box steel. when a force is =
applied, the=20
1" beam will flex, so most of the load will then be taken by the factory =
x-member.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2> while erics bar =
makes more sense=20
than some i have seen in the past, it still does rely on the front cross =
member.=20
actually, erics bar forms a 'v'. compared with a beam that sits =
horizontal,=20
it will make a stiffer support, but it will also add tensile forces to =
the piece=20
that we are worried about splitting. the front mount moving upwards =
will=20
act on that 'v', and given how shallow of a 'v' it is, this will result =
in a=20
rather large force trying to push the 2 bumper mounts apart from =
eachother.=20
if you already have splits in your core support, a shalow 'v' may end up =
causing=20
more damage in the end. dont get me wrong, erics bar will definitely =
reinforce=20
the cross member, im just concerned about how the forces are being =
redirected by=20
that bar.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2> i believe the best =
solution=20
would be a tubular steel boxed 'v'. boxed with the same tubes forming =
the 'v',=20
as opposed to relying on the body of the car. this piece could be made =
of=20
lighter material, as there would be no bending stresses on any of the =
sections,=20
only tensile and compressive. minimum diameter would be only limited by =
buckling=20
under compressive load.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2> picture a 2d version =
of this:=20
</FONT><FONT face=3DArial size=3D2><A=20
href=3D"http://www.scirocco.org/photos/misc/cross.jpg";>http://www.scirocc=
o.org/photos/misc/cross.jpg</A> .=20
</FONT><FONT face=3DArial size=3D2>if you had a flat, vertical boxed 'v' =
it would be=20
very strong under the up/down loading from the engine. it will still be =
subject=20
to twisting loads, but this can be easily compensated for by having the =
bracket=20
bolt in from behind, resulting in the mount cup being in the same plane =
as the=20
'v', which would kill off the twisting and should make a pretty rigid=20
mount.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2> ...and once you do =
that, now you=20
have to worry about something else cracking :)</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Al</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV>----- Original Message ----- </DIV>
<BLOCKQUOTE dir=3Dltr=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A title=3Drocco16v@netzero.net href=3D"mailto:rocco16v@netzero.net";>L =
F</A>=20
</DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3Dscirocco81@vwmail.net=20
href=3D"mailto:scirocco81@vwmail.net";>scirocco81@vwmail.net</A> ; <A=20
title=3Dscirocco-l@scirocco.org=20
href=3D"mailto:scirocco-l@scirocco.org";>scirocco-l@scirocco.org</A> =
</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Saturday, March 08, 2003 =
7:47=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: Front crossmember =
stress=20
bar</DIV>
<DIV><BR></DIV>
<DIV><FONT face=3DArial size=3D2>I have to say something now about =
this bar; It=20
ain't gonna' do a whole hell of a lot. It's way too long for =
it's=20
diameter...too much flex. The crossmember you are trying to =
reinforce is=20
MUCH stiffer than the "reinforcement", consequently the stock =
crossmember is=20
still going to absorb 99% of the stress. If you want to stock the =
cracking, weld a large, thick, form-fitted steel plate to the=20
crossmember. This will spread out those stresses. The =
trick=20
reinforcing bar is way too flexible to transmit the vertical stresses =
to the=20
sides.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>That's all...</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>Larry</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>sandiego16v</FONT></DIV>
<BLOCKQUOTE=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A title=3Dscirocco81@vwmail.net =
href=3D"mailto:scirocco81@vwmail.net";>Eric=20
S</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3Dscirocco-l@scirocco.org=20
href=3D"mailto:scirocco-l@scirocco.org";>scirocco-l@scirocco.org</A> =
</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Saturday, March 08, =
2003 4:03=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Front crossmember =
stress=20
bar</DIV>
<DIV><BR></DIV>Hello all!<BR><BR>Alot of people have been working on =
this I=20
know...and one bolt together bar is in testing.<BR><BR>However, I =
now have a=20
prototype of a fully welded bar...more tweeking continues. It =
will be=20
FULLY bolt in.<BR><BR>Work continues this week, should have a ready =
to bolt=20
in bar to test on ALL of my A1 chassis vehicles (see my sig...only =
A1=20
chassis I am missing is a Mk1 Jetta).<BR><BR>Price *should* be $100 =
plus=20
shipping, fully welded, 3/16s steel (box and plate steel used..the =
box steel=20
has 3/16s walls and is inch square outer diameter (IE, strong as=20
hell). However, the plate steel will allow for side flex to =
not load=20
the front motor mount with cornering forces...this bar is designed =
to=20
control upward movement ONLY). Bar will come bare or primed =
based on=20
request. Powder coating, and other options will be available =
for=20
higher cost.<BR><BR>Here are pics (again, this is a very very rough=20
prototype):<BR><BR><A=20
=
href=3D"http://www.vintagewatercooleds.com/~blklace/BAR/";>http://www.vint=
agewatercooleds.com/~blklace/BAR/</A><BR><BR>Please=20
let me know if you are interested...and general feelings of its=20
construction. Realize, I am attempting to make a universal bar =
for all=20
A1 chassis, hence some compromises were made in its design. =20
<BR><BR>(and damn are there alot of little annoying differences on =
A1=20
chassis cars throughout the years)<BR><BR>I am fully confident that =
it will=20
not allow the crossmember to flex upward at all however, no matter =
what A1=20
chassis it is bolted to.<BR> <BR>--<BR>Eric<BR>Northglenn, =
CO<BR><BR>79=20
VW Iltis<BR>81 Scirocco S (*TDI* swap and complete restoration in =
holding=20
pattern)<BR>81 Rabbit Truck LX Diesel (Waiting for BAE Turbo =
Install)<BR>83=20
Scirocco Wolfsburg<BR>91 Cabriolet (2.0 Crossflow 8v swap and =
mechanical=20
rebuild in=20
=
progress)<BR><BR>_______________________________________________<BR>Sciro=
cco-l=20
mailing list<BR><A=20
=
href=3D"mailto:Scirocco-l@scirocco.org";>Scirocco-l@scirocco.org</A><BR><A=
=20
=
href=3D"http://neubayern.net/mailman/listinfo/scirocco-l";>http://neubayer=
n.net/mailman/listinfo/scirocco-l</A><BR></BLOCKQUOTE></BLOCKQUOTE></BODY=
></HTML>
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