1966 Barracuda X's 2
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Hats off to you sir........as from reading your post it's like a foreign language. I take it you can see light at the end of the tunnel regards getting it setup?
Dave Tildesley.....MMA-081
72 Dodge Dart
73 Plymouth Duster - SOLD
I wanna go so FAST i think i'm going to DIE!..........Then i'll shift into second!
"My Car is a work in progress, Probably never gonna get finished, never gonna have the money to Bananarama!!"
72 Dodge Dart
73 Plymouth Duster - SOLD
I wanna go so FAST i think i'm going to DIE!..........Then i'll shift into second!
"My Car is a work in progress, Probably never gonna get finished, never gonna have the money to Bananarama!!"
probably didn't matter with crossply tyres and sloppy steering at the time but to sharpen the handling it needs to be changed.
been reading up on dropping the K frame down a little. this'll gain a little more rack clearance and I should be able to re-raise and centralise the engine as it is biased to the right to clear the huge power steering box.
from what I read doing this mod is what the factory did to get clearance for the big block in the later A body. also been reported it can help to reduce bump steer.
I shall drop the K frame half an inch and re measure bump steer to see what that does.
been reading up on dropping the K frame down a little. this'll gain a little more rack clearance and I should be able to re-raise and centralise the engine as it is biased to the right to clear the huge power steering box.
from what I read doing this mod is what the factory did to get clearance for the big block in the later A body. also been reported it can help to reduce bump steer.
I shall drop the K frame half an inch and re measure bump steer to see what that does.
so i put the steering back to stock and dropped the K frame by 0.575 inch.
and the result is YES it does drop bump steer to just a few thou. virtually eliminated completely at one inch either side from ride height. Camber and Caster gain are unaffected.
with the shorter track rod to simulate the rack i'll be fitting it is still excellent apart from the last inch of bump and droop where it jumps a fair bit but still within the original measurements. so it has four inches of travel with very little bump steer.
and the result is YES it does drop bump steer to just a few thou. virtually eliminated completely at one inch either side from ride height. Camber and Caster gain are unaffected.
with the shorter track rod to simulate the rack i'll be fitting it is still excellent apart from the last inch of bump and droop where it jumps a fair bit but still within the original measurements. so it has four inches of travel with very little bump steer.
this should show the differences easier than just numbers.
Green is the standard factory set up
Pink represents just fitting the rack
Orange line, which is the best at present, is just a K frame drop on the standard steering.
Blue is the rack and a K frame drop
so looking at the graph my best option is a very slight K frame drop for the rack conversion but there is no more point experimenting until I have a rack in place to fine tune as the suspension arms will need setting into the best position for Caster etc before hand.
Green is the standard factory set up
Pink represents just fitting the rack
Orange line, which is the best at present, is just a K frame drop on the standard steering.
Blue is the rack and a K frame drop
so looking at the graph my best option is a very slight K frame drop for the rack conversion but there is no more point experimenting until I have a rack in place to fine tune as the suspension arms will need setting into the best position for Caster etc before hand.
back onto the job in hand. got the dash out so I can modify it to RHD. dash should be easy as I can hide most of the weld behind the crash pad.
no holes found, just a little surface corrosion to the air intake box which will just need treating and painting.
all looks very straight forward at this point.
- paolo_mangusta
- Posts: 588
- Joined: Tue Aug 10, 04 1:34 pm
- Location: Paul, London
that K frame drop is a very interesting tweak! Unless I'm misunderstanding, as the steering is bolted to the K frame, the effect is coming from the change in the relationship between the lower and upper suspension points, and how the line between them relates to the pivot points of the track rods - is that right?
I've seen people move the box and idler to correct bump steer on A-bodies, but never heard of the K-frame drop before. Is the effect on the camber curve good,bad or negligable?!
I've seen people move the box and idler to correct bump steer on A-bodies, but never heard of the K-frame drop before. Is the effect on the camber curve good,bad or negligable?!
'64 Barracuda
i guess raising the upper arm mounts would have the same effect.
from experience with various vehicles just a few millimetres of change in the steering pivot point (raising or lowering a rack) makes a huge difference in bump steer. more than you would think.
another problem with the Barracuda steering is the pitman and idler arms are angled so on a lock it is lowering the inner joint pivot height which drastically effects the bump steer. with the lowered K frame straight ahead is very good but even a slight lock bump steer is terrible again. with a rack moving in a linear motion this shouldn't be an issue.
Camber change is slightly reduced.
from experience with various vehicles just a few millimetres of change in the steering pivot point (raising or lowering a rack) makes a huge difference in bump steer. more than you would think.
another problem with the Barracuda steering is the pitman and idler arms are angled so on a lock it is lowering the inner joint pivot height which drastically effects the bump steer. with the lowered K frame straight ahead is very good but even a slight lock bump steer is terrible again. with a rack moving in a linear motion this shouldn't be an issue.
Camber change is slightly reduced.