T66
|
| posted on 9/12/09 at 05:26 PM |
|
|
Fiat 126 Blackbird - Front End
I am shopping for Cortina uprights for my Fiat, I would like new units for a car in the 550kg region.
The rallydesign ones have caught my eye @ £195 a pair.
Wozsher will be supplying wishbones (I hope).
Anywhere else to consider ?
I would prefer to buy everything from the same place in one go , ie brakes,hubs and so on , if possible.
|
|
|
|
|
britishtrident
|
| posted on 9/12/09 at 06:03 PM |
|
|
As you will have next to know weight over the front wheels Cortina geometry won't really suit your car.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
|
|
|
aitch
|
| posted on 9/12/09 at 06:14 PM |
|
|
quote:
Originally posted by britishtrident
As you will have next to know weight over the front wheels Cortina geometry won't really suit your car.
can you elaborate, whats wrong with the geometry? im doing a BEC mid engine and planning on taking the same route, although i will have a little more
weight o the front.
and also if the geometry is not right then what would be a better option ?
aitch
|
|
|
T66
|
| posted on 9/12/09 at 06:33 PM |
|
|
Yes would like to know more on your thoughts Trident ?
T66
|
|
|
britishtrident
|
| posted on 9/12/09 at 07:53 PM |
|
|
Cortina geometry isn't exactly known for good self centering it was design to provide light steering on a heavy car (some Cortinas had very
heavy iron block V6 engines) without PAS.
If you look at the steering geometry used on old small rear engine cars like the Hillman Imp & Davrian you can see how they generated self
centering
What is needed is an upright that is light, easy to dial in a lot of caster and has a larger king pin inclination than the the Cortina. These days
such things are a bit thin on the ground so the only option is to look at what is available from FWD cars or mid-engined sports cars like the MGTF.
The interesting thing is the MGTF uses Metro uprights with a dummy spindle to act as a live stub axle in place of the CV joint. I believe the
uprights are swapped left to right and the steering arms unbolted and changed over.
|
|
|
T66
|
| posted on 9/12/09 at 08:15 PM |
|
|
Ok....
The reason I have looked at the RD uprights is they come with more castor built in ontop of the stock Ford items.
Unless I am wrong of course.
Point noted re the MGTF uprights, I will have a look about.
Anyone else want to join in ??
|
|
|
grassracer
|
| posted on 9/12/09 at 08:55 PM |
|
|
Try www.berrisford.co.uk
or www.drdracing.co.uk
Fabricated uprights/alloy hubs used for racing where mid engined is the norm not the exception, not sure about road use but can't see why not
really
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
|
aitch
|
| posted on 9/12/09 at 08:57 PM |
|
|
i dont understand the whole geometry issue, would be nice to get some advice other than thats not right,
ive looked at diagrams of the uprights "original" and they show the ball joints offset bottom being furthr back than the top with the
steering arm horizontal !! is this how they should be or should they be in line vertically? and what are the differences in handling/ self
centering?
aitch
|
|
|
JEPY
|
| posted on 9/12/09 at 10:19 PM |
|
|
I'd picked up a pair of sierra uprights for a 126 conversion but must admit I hadn't given much thought yet to suspension geometry.
Will have to get me book out and sketch it out I think.
T66 - how far are you into the conversion?
J
|
|
|
redscamp
|
| posted on 10/12/09 at 01:43 AM |
|
|
what about vauxhall viva?
too old school?
|
|
|
britishtrident
|
| posted on 10/12/09 at 07:50 AM |
|
|
A lot of self-centering is generated by king pin inclination rather than caster.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
|
|
|
T66
|
| posted on 10/12/09 at 09:32 AM |
|
|
I am buying up the parts over the next few months, Retropower are doing the big bits/initila build up
And I finish off the car.
The front wishbones are going to come from Wozsher
I will be speaking with MNR & RD about these issues raised here.
The rear arms are coming from Berrisford
cheers
|
|
|
aitch
|
| posted on 10/12/09 at 09:59 AM |
|
|
quote:
Originally posted by britishtrident
A lot of self-centering is generated by king pin inclination rather than caster.
suspension geometry is new to me, can you explain king pin inclination?
is the top ball joint being further forwards than bottom ball joint?
looks about 5degrees in the sierra oprights?
aitch
|
|
|
smart51
|
| posted on 10/12/09 at 11:47 AM |
|
|
quote:
Originally posted by aitch
quote:
Originally posted by britishtrident
A lot of self-centering is generated by king pin inclination rather than caster.
suspension geometry is new to me, can you explain king pin inclination?
is the top ball joint being further forwards than bottom ball joint?
looks about 5degrees in the sierra oprights?
aitch
KPI is the top ball joint being further towards the centre line of the car than the bottom. 10° is a typical figure.
Castor angle is the top ball joint being closer to the rear of the car than the bottom one.
|
|
|
britishtrident
|
| posted on 10/12/09 at 03:10 PM |
|
|
Not sure what the KPI was on the Cortina but it wasn't much something like a couple of degrees.
One of the side effects of adding negative camber is that it also increases KPI ---- the only exception to this I can think of is the offset mushroom
conversion on a Sierra style strut.
[Edited on 10/12/09 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
|
|
|
aitch
|
| posted on 10/12/09 at 05:47 PM |
|
|
quote:
Originally posted by smart51
quote:
Originally posted by aitch
quote:
Originally posted by britishtrident
A lot of self-centering is generated by king pin inclination rather than caster.
suspension geometry is new to me, can you explain king pin inclination?
is the top ball joint being further forwards than bottom ball joint?
looks about 5degrees in the sierra oprights?
aitch
KPI is the top ball joint being further towards the centre line of the car than the bottom. 10° is a typical figure.
Castor angle is the top ball joint being closer to the rear of the car than the bottom one.
Hi Smart51
can i just confirm, you say top ball joing closer to the rear of the car although all the drawings i see of the sierra uprights have the top ball
joint closer to the front of the car, steering arm forwards, brake caliper rear??
thanks
aitch
|
|
|
smart51
|
| posted on 10/12/09 at 06:50 PM |
|
|
quote:
Originally posted by aitch
Hi Smart51
can i just confirm, you say top ball joing closer to the rear of the car although all the drawings i see of the sierra uprights have the top ball
joint closer to the front of the car, steering arm forwards, brake caliper rear??
thanks
aitch
Look
here for a pic and description
of castor angle. top ball joint should be further back than the bottom so that the line that intersects the two falls on the floor in front of the
tyre.
|
|
|
mad-butcher
|
| posted on 10/12/09 at 07:06 PM |
|
|
recommended reading
competition car suspension by allan staniforth
tony
|
|
|
britishtrident
|
| posted on 10/12/09 at 09:56 PM |
|
|
Stainforth's orignal book "High Speed, Low Cost" shows how to use Mini parts for a midi single seater.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
|
|
|
MikeRJ
|
| posted on 10/12/09 at 10:01 PM |
|
|
quote:
Originally posted by aitch
can i just confirm, you say top ball joing closer to the rear of the car although all the drawings i see of the sierra uprights have the top ball
joint closer to the front of the car, steering arm forwards, brake caliper rear??
That definitely doesn't sound right, have you got a link to a pic that shows this?
The object of castor is to build in the same effect that castors have on shopping trolleys etc. To do this the point at which the steering axis
intercepts the ground has to fall in front of the centre of the tyre contact patch. The only way you can achieve this to any noticeable degree is to
have the top balljoint behind the bottom one (i.e. further to the rear).
|
|
|
aitch
|
| posted on 11/12/09 at 08:56 AM |
|
|
quote:
Originally posted by smart51
quote:
Originally posted by aitch
Hi Smart51
can i just confirm, you say top ball joing closer to the rear of the car although all the drawings i see of the sierra uprights have the top ball
joint closer to the front of the car, steering arm forwards, brake caliper rear??
thanks
aitch
Look
here for a pic and description
of castor angle. top ball joint should be further back than the bottom so that the line that intersects the two falls on the floor in front of the
tyre.
yes that sounds right after some reading, i had made the wrong assumption tht the steering arb was horizontal.
was out for a ride on my bike yesterday and realised its like the steering rake "andgle of th forks" i get it it now
aitch
|
|
|
T66
|
| posted on 11/12/09 at 10:47 AM |
|
|
Same as your bike then, so you did know...
|
|
|
NS Dev
|
| posted on 27/11/10 at 10:53 AM |
|
|
quote:
Originally posted by britishtrident
Not sure what the KPI was on the Cortina but it wasn't much something like a couple of degrees.
One of the side effects of adding negative camber is that it also increases KPI ---- the only exception to this I can think of is the offset mushroom
conversion on a Sierra style strut.
[Edited on 10/12/09 by britishtrident]
Digging up an old thread here, but stmbled across it looking for something else!
Have to say, regardless of KPI, I never had ANY issue with self centering or feedback on my old grasstrack car, and I ran cortina uprights on that,
and you could pick the front end up by hand easily!!!
I have built the front end of the fiat with plenty of castor adjustment potential, and I'm quite sure it will be fine.
its looking pretty smart, think Ivan (T66) will prob post some updates on here sometime soon!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
|
|
|
scootz
|
| posted on 27/11/10 at 11:04 AM |
|
|
I think he's keeping (some of) us in suspenders!
I've had a sneak preview and it looks fabby-do!
It's Evolution Baby!
|
|
|
MikeR
|
| posted on 27/11/10 at 10:03 PM |
|
|
I saw it a couple of weeks ago when i popped into Retro power .... I liked it, but not as much as the 'beetle' they've got in
[Edited on 27/11/10 by MikeR]
|
|
|
