phelpsa
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| posted on 2/8/10 at 01:00 PM |
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You'd have twice as much force at the pivot as at the ball joint as the lever as half as long.
That makes sense to me but i'm not too good at teaching 
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phelpsa
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| posted on 2/8/10 at 01:08 PM |
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Have an FBD:
 
The force applied down from the chassis must be twice the force applied up from the pushrod (assuming its in equalibrium at the time!)
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procomp
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| posted on 2/8/10 at 02:32 PM |
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Hi
In basic terms. Yep it will place more load on the chassis how much more will be down to angles of pushrods and dampers. As well as the spring
poundage differences required for the different setup. The Sylvas are not far off a 1-1 ratio but haven't got specific details to hand at the
mo.
You will also suffer pivot problems such as those on the sylva setup.
Cheers Matt
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MikeR
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| posted on 2/8/10 at 02:43 PM |
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What pivot problems?
My cunning dream plan was to use a 1/2 inch rose joint as the pivot, this would be mounted in the box that formed the pivot. As rose joints are used
to taking suspension loads, they are great at having things turn around them and can take up a slight amount of missalignment they seemed ideal.
Later this morning it also occurred to me they have no ability to stop my pivot twisting, so now its two rose joints, one either side of my existing
suspension pick up point and a crush tube where the shock would normally go.
As the weight on the chassis doubles on the existing shock pick up, we've got three choices,
1) replace that section with thicker steel.
2) limit the engines to bec's (if the existing mounts can take P&O anchors and V8's then a bec will give things an easier time
3) drive it till it starts to fatigue and add extra steel at the weak points.
p.s. stupid thoughts stop in 1 hour 
[Edited on 2/8/10 by MikeR]
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bi22le
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| posted on 2/8/10 at 02:55 PM |
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when i went searching for a kit car to buy i looked at the kit car race series. With raw and sylva chassiss seeming very competitive i considered that
the only way to go. The coil overs on my raw are nothing special at all. Shorter throw with different springs and thats it. This is a tried and tested
chassiss that has had years of development and setting up. Buying a a raw buys you that tried and tested setup.
Refering back to op and changing or building an inboard thats where all of the above comments are very relative and i agree to a certain extent. I
think that if you want to build your own inboard setup then give it a go. It sounds like you would enjoy the work and testing. Something else to be
proud of when its finally going around the track.
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
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ali f27
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| posted on 2/8/10 at 03:36 PM |
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Hi scootz will get photo up of mj hoson bula cheers Ali
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procomp
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| posted on 2/8/10 at 03:50 PM |
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Hi
Don't underestimate the loads present. there where a few sylvas modded to use rose balls either side of the pivot. Lasted less than 1000
miles.
bi22le. Now having done a fair bit of work on the RAW strikers with in board suspension with dampers and anti roll bars Etc. Can you tell me which of
them is running a chassis that is as it was when it left Raw unmodified. And running less than 2k worth of dampers upfront.Cause that rules out all of
the cars that have competed in the 750. championships. ?
Cheers Matt
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bi22le
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| posted on 2/8/10 at 09:50 PM |
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Er nope. . . .
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
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Sam_68
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| posted on 14/8/10 at 11:35 PM |
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quote:
Originally posted by procomp ...the Westfield FW400 setup was dropped on the final version after the inboard setup was found to be no
better just added extra weight.
Incorrect. The FW400 was not designed with inboard suspension and the set up was not 'dropped on the final version'. The car as designed
by Martin Ogilvie was always outboard. There was a later conversion of a couple of cars by Pilbeam, which Martin never approved of; to the best of my
knowledge, though, the cars converted (which now live in Japan) are still running the inboard set-up.
A fair proportion of what you've said about Sylvas is pretty much cobblers, too, but I know the size of the axe you've got to grind on
that subject, so I really can't be arsed arguing it all over again with you.
[Edited on 14/8/10 by Sam_68]
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andyps
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| posted on 5/9/10 at 09:01 PM |
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Well, my first post for many months, if not even years on here so if I am out of touch and wrong, apologies in advance!
The obvious answer to the question about a seven with full inboard suspension is the Caterham CSR - at £42900 fully built it is not exactly locost
however, but does show that it can be done, at a price! All reports suggest that it drives very well.
When I get round to working on mine again I will be doing inboard rocker arm suspension, I have made the appropriate parts on the chassis for it, and
will eventually make the wishbones. One thing I haven't decided is the ratio to use on the rockers, but have figured (I think) the mountings and
everything else. I can't remember but am pretty sure I posted some pictures on here when I originally made that part.
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Volvorsport
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| posted on 5/9/10 at 11:02 PM |
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inboard
www.dbsmotorsport.co.uk
getting dirty under a bus
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RK
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| posted on 6/9/10 at 12:16 AM |
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People love reinventing the wheel, don't they? If it makes people happy, why not? However, I don't see the point in trying to turn a
50's era fun car into a modern single seater, which it isn't and never will be. Creativity doesn't have to have a point though.
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scootz
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| posted on 6/9/10 at 11:11 AM |
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quote:
Originally posted by andyps
The obvious answer to the question about a seven with full inboard suspension is the Caterham CSR - at £42900 fully built it is not exactly locost
however, but does show that it can be done, at a price! All reports suggest that it drives very well.
I thought it had a fair number of critics who thought the 'old' set-up was better!?
It's Evolution Baby!
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Neville Jones
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| posted on 6/9/10 at 07:00 PM |
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Most of what Matt says is very correct.
But, the biggest mistakes I see are in the design of the rockers themselves. Inboard with rockers was developed in the open wheelers to cut down drag,
improve polar moments, and packaging.
In racecars the inboard setup works well, because the amount of wheel movement is usually kept to near zero in droop, and no more than 40mm or so in
bump. When you get to the movements needed for a road car, the size of the rockers needed is astronomical compared to a racecar. The small rockers
udsed by most amateur builders end up producing all sorts of undesirable effects at their limits and beyond.
As a final note, what's wrong with a properly designed outboard setup, with properly designed wishbones and coilover pickup geometry? Caterham
have been doing it for years.
Cheers,
Nev.
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JF
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| posted on 6/9/10 at 08:16 PM |
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Whats wrong with trying something for yourself instead of simply doing the very same thing over and over again.
If everyone had always done that, we probably wouldn't even exist...
Sure could be that most 'amateur' inboard setups are inferior to 'pro' outboard setups. But most of those
'amateurs' might never even notice the difference... As they're not pro racing drivers. They might never even drive a single mile on
a circuit.
So who gives a f*ck if it's not as good as X. As long as that 'amateur' is happy with the result....
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scootz
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| posted on 6/9/10 at 08:29 PM |
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quote:
Originally posted by JF
But most of those 'amateurs' might never even notice the difference...
I suspect they would! Screw up an outboard set-up and it's nasty... screw up an inboard set-up (very likely if you don't have specialist
assistance) and it will be absolutely rank rotten!
It's Evolution Baby!
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JF
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| posted on 6/9/10 at 09:07 PM |
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Well might have come accross a bit grumpy, but my point is... Live al little and try something. Experiment. Because really... why else would you want
to build your own car when you can just buy a standard tintop...
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ceebmoj
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| posted on 5/4/12 at 10:07 PM |
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quote:
Originally posted by Volvorsport
inboard
Why would an inboard set up be mutch worse than an out board set up? Also can you point out the problems in the above set up? found the thread through
a serch so was suprised my the resurrection.
[Edited on 5/4/12 by ceebmoj]
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phelpsa
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| posted on 6/4/12 at 08:07 AM |
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quote:
Originally posted by ceebmoj
quote:
Originally posted by Volvorsport
inboard
Why would an inboard set up be mutch worse than an out board set up? Also can you point out the problems in the above set up? found the thread through
a serch so was suprised my the resurrection.
[Edited on 5/4/12 by ceebmoj]
It isn't much worse. It can be better in certain circumstances, but in the kit world those circumstances are quite rare.
The problem in that setup is that you have more than twice the corner weight of the car trying to rip the rocker bracket off the car. Its not what you
would call a 'material efficient' design.
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ceebmoj
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| posted on 6/4/12 at 10:18 AM |
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Given that it might not be material effishent, can a rocker set up ever be efisent in that way ? Do the benafirs of
1. Rising rate suspention with the corect
Rocker.
2. Using a lager % of the shock travel
3. Moving the actuater point on the bottom wishbon closer to the balljoint and Moving another thing out of the air stream
and any othere things i dont know about make it worth wile
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phelpsa
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| posted on 6/4/12 at 10:34 AM |
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quote:
Originally posted by ceebmoj
Given that it might not be material effishent, can a rocker set up ever be efisent in that way ? Do the benafirs of
1. Rising rate suspention with the corect
Rocker.
2. Using a lager % of the shock travel
3. Moving the actuater point on the bottom wishbon closer to the balljoint and Moving another thing out of the air stream
and any othere things i dont know about make it worth wile
You're basically trading off different inefficiencies of the two designs.
The problem with most of the inboard setups on spaceframe 7s is that they aren't there for any reason other than to have inboard suspension, and
they have ended up with the inadequacies and inefficiencies of both designs (large bending moments in wishbones, high wheel:damper ratios and reduced
system stiffness).
An outboard system is much much easier to get right, and with some reasonably simple design can be 90% as competent and 50% of the weight of a
properly engineered inboard system on a spaceframe 7.
If you're chasing small drag reductions on a 7 then you're in the wrong business
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rdodger
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| posted on 6/4/12 at 03:25 PM |
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I have always wondered why kit manufacturers use inboard for a much more simple reason.
They all appear to place the shock directly behind the radiator. So what happens as the hot air flowing out of the radiator heats up the oil in the
shocks? Surely the viscosity changes and the damping alters?
I know shock oil is meant to be quite stable but since expensive shocks and small bike shocks have remote reservoirs to prevent this. What happens to
our cheapo Protec or Gaz shocks?
I asked a couple of manufacturers this question at a show last year. I was basically told to bugger off.
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Twin40
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| posted on 10/4/12 at 12:29 PM |
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thought i'd do a little 'internet research' and managed to stumble across this....amazing work
http://www.kirkhammotorsports.com/book_aoe/aoe_12.pdf
certainly not locost!
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mcerd1
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| posted on 10/4/12 at 02:39 PM |
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quote:
Originally posted by scootz
quote:
Originally posted by procomp
The DAX setup has been proved to be a complete waste of time. Both the works cars that ran it have proved that it is far worse than the original
setups. with far quicker lap times on circuit. With much complaining to DAX.
Hi Matt
Is that just their in-board option or the CC&AR thingy that they offer?
^^ I assume he's talking about the inboard ones, dax did make a few cars with inboard shocks, but never really put them into production.
the CC&AR has always caused a bit of debate, its patened though so othe manufacturers can't use it even if they wanted to...
this is the new rush chassis they were showing off at last years open days (BMW E36 / E46 donor)
-
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dream
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| posted on 10/4/12 at 03:54 PM |
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mirach front suspension picture
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