PSpirine
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| posted on 1/8/10 at 08:50 PM |
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Inboard suspension locosts?
What sevens have inboard suspension?
I'm actually asking a bit too late as all the suspension design on mine is now finalised, but thought I'd do a sanity check and see what
solutions the others have had!
Pavs
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v8kid
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| posted on 1/8/10 at 09:00 PM |
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most Silva's
You'd be surprised how quickly the sales people at B&Q try and assist you after ignoring you for the past 15 minutes when you try and start a
chainsaw
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irvined
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| posted on 1/8/10 at 09:03 PM |
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I think most MNR's too.
I think my colleagues robin hood has inboard suspension on the front too.
[Edited on 1/8/10 by irvined]
http://irvined.blogspot.com
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Davegtst
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| posted on 1/8/10 at 09:06 PM |
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MK indy R.
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scootz
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| posted on 1/8/10 at 09:10 PM |
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Quantum Extreme...
It's Evolution Baby!
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FFTS
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| posted on 1/8/10 at 09:11 PM |
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Formula 27 (F27)
Chris.
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PSpirine
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| posted on 1/8/10 at 09:19 PM |
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Sorry should've clarified...
What cars have FULL inboard suspension (i.e. Front and rear!)
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procomp
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| posted on 1/8/10 at 09:29 PM |
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Hi
Now ask the question Which manufacturers have developed an inboard setup THAT WORKS. The answer is non. Not even the freestyle Caterham setup worked
any better than the traditional outboard setup. And the Westfield FW400 setup was dropped on the final version after the inboard setup was found to
be no better just added extra weight.
Cheers Matt
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JF
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| posted on 1/8/10 at 09:38 PM |
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Matt,
Well when talking front I'd say looks is a factor aswell. And most do get that atleast.
But would you mind reminding me (us?) what the real gain of inboard suspension would be when done right?
And what kind of things do most of them wrong?
Maybe a bit of a hijack, but what about the CCAR system that Dax supply... Any experience with it? Usefull?
[Edited on 1/8/10 by JF]
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PSpirine
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| posted on 1/8/10 at 09:48 PM |
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My own personal reasons for going to inboard suspension on the haynes roadster:
- The front wishbone shock mount to me looks like it gets loaded somewhat a lot in bending as the shock isn't outboard enough. Now given that
there's loads of locosts with the same setup I imagine the severity of the issue is limited, but it just makes me feel uneasy worrying about
whether the wishbone will bend over a big bump/pothole. Moving the shock bracket further outboard creates a problem in that a standard length damper
can no longer be used, and it increases the shock angle - more regressive spring rate...
- the regressive spring rate. At the angle the front shock is, unless you use some heavily non-linear progressive springs, you'll end up with a
softer suspension with increased travel. Undesirable, as far as I'm concerned (and therefore the only reason I went inboard on the rears)
- Finally, adjustment of corner weights/ride height without preloading the springs on the dampers seems like an advantage.
Wasn't for aesthetic reasons, as I actually think that the standard setup looks really good!
Having said all that, we'll see if it works or not once it's built!
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dinosaurjuice
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| posted on 1/8/10 at 09:56 PM |
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whenever you start introducing more levers and bell cranks into suspension you start multiplying the forces on bits of the chassis. cant really see
the point to be honest. Just my opinion. 
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Liam
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| posted on 1/8/10 at 10:04 PM |
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Did it front and rear on mine for various reasons, including getting shocks out of the way of the front driveshafts, playing around with different
rocker arm ratios (hence 5 different shock attachment points on my rocker arms), and for fun.
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procomp
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| posted on 1/8/10 at 10:05 PM |
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Hi
Even if done right there is no gain what so ever to be had that's useful on a seven car or kit car. All it will mean is that the weight has been
increased and the cost of dampers needed to do the job correctly has significantly increased. Now look at all the problems that are / have been shown.
Chassis need to be increased in strength or you have the extra loads placed on the chassis leading to brackets falling off. Extra loads placed on the
wishbones leading to wishbones bending and push/pull rods failing.
The fact that it needs a minimum of double or triple adjustable with remote canisters to be used to gain proper control. And finally it makes the
cars much more sensitive to setup thus making every car setting individually for the individual drivers requirements and driving style. This of course
not to say it can not be done on an individuals car that is to be used and setup for a particular individual. But if spending that sort of money you
are past messing around with a kitcar and into the realms of something similar to a radical where the car is mainly to be used for track only.
Just tacking a chassis and cobbling up an inboard setup like all the kit manufacturers have just leads to many problems. Especially when they can not
be bothered to even sort out what spec dampers they need and just supply the same as they run on there out board setups and supply incorrect spring
poundage's.
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.
Cheers Matt
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JF
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| posted on 1/8/10 at 10:20 PM |
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Thanks Matt,
Although you're quite often a bit blunt, it's great that you share your knowledge on here. Well actually you're bluntness is more a
blessing then a shortcoming if you ask me. Nicely short and to the point, if only politicians knew how...
The Dax system always seemed way to good to be true to me. If it really was this great then why don't others give it a try aswell. When only 1
company uses something like this that they claim is as good as Dax does... then others would follow shortly... and clearly they don't in this
case.
Still like the concept of it though... a shame...
And yeah I can really see the problem with the multiple linkages adding stress and possible play with inboards. Which you really don't want.
Personally I'd still want to give it a try really. I really like the clean look of just a pushrod instead of coilovers sticking out.
Couldn't be to bothered to do the rear, execpt if space would be an problem.
But then again I've always been to thick headed to go for the logical and sensible option.
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PSpirine
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| posted on 1/8/10 at 10:22 PM |
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Woah woah woah there Matt, I completely agree you can't just throw it together, but I don't think all your points are valid!
Bending loads on wishbones are all but ELIMINATED with pushrods, as you can put the pushrod right next to your bottom ball joint - wishbone then only
sees push/pull, no bending.
Yep, you need to add extra tubes to the chassis, and you add the weight of a pushrod, but it's not a massive increase, especially if it's
a locost build which is never going to be an ultralight.
And you do not need different dampers, if the suspension is designed to be used with the standard dampers, it'll work very well, and indeed
better as you can build in natural progressive spring rate. As for poundage, yep, mine will need different springs as I'm using a 1:1.2 rocker
ratio.
Just because some have cocked it up, doesn't mean it's not worth doing. As for cost, the only increase to me over standard outboard
shockers is:
- Four tubes (pushrods)
- Eight rod-ends
- Bush for rocker
- Rocker (made out of 3mm steel)
In the grand scheme of things, not massive, and I'd quite like to have the adjustability, particularly as the roads around here are more rally
than race!
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scootz
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| posted on 2/8/10 at 08:55 AM |
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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?
It's Evolution Baby!
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ali f27
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| posted on 2/8/10 at 08:56 AM |
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Mj Hoson bula best set up purdys own works realy well on race car Ali
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MikeR
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| posted on 2/8/10 at 09:07 AM |
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Went to bed thinking about this and ....
What is to stop you from converting an existing locost (with front suspension mounts under the top chassis rail) to inboard via making a simple rocker
arm and shock absorber bracket welded onto some box in the middle of the empty space between the suspension units?
Ok, i appreciate there is some maths to do and this is Matts point that its not just this easy & the shocks are now in warm air flow & the box
is now put into bending with no triangulation.
But it just seems without the maths rather 'easy'. In my dreamy state i was even thinking of using a 1/2" rod end for the rocker
pivot & perhaps poly bushes for the other pivots (cause thats what is on the shock absorber now). If this makes no sense i'll draw something
up, photograph it and post it up.
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scootz
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| posted on 2/8/10 at 09:15 AM |
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quote:
Originally posted by ali f27
Mj Hoson bula best set up purdys own works realy well on race car Ali
What the feck is an "Mj Hoson Bula"???
Is it like a Flux-Capacitor (only more exotic)?
It's Evolution Baby!
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franky
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| posted on 2/8/10 at 09:40 AM |
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Just because one person or company can't make it work or doesn't fully understand it doesn't mean it wont, if every one thought
like that we'd never get any development or advancement in technology
Isn't the fisher fury/syliva cars the most sucessful race cars in the class, they use it so it can't be bad.
In fact i'd look for which chassis has won the most races then start from there.
[Edited on 2/8/10 by franky]
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procomp
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| posted on 2/8/10 at 10:43 AM |
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Hi
No one is saying that it can not be made to work. What i have said is that for the application of a kitcar that will be seeing a bit of track use it
is just not worth it. As i said if you wish to pursue it and make it work well you are moving towards the territory of Radical type cars. If you are
looking at fitting it to a kit type car that will be seeing mostly road use then you are into a huge development with springs and dampers and the
whole front design that will be costing a few £'s. As you'll likely be needing to move towards something like double/ triple adjustable
Olin's / penske's Etc Etc. And if you look at what you are likely to gain as a benefit overall when finished you are on a hiding to
nothing as it's not like your trying to work with slow speed and high speed with huge down forces.
Sylvas with inboard suspension winning races. Well if you take any of the inboard setup strikers and compare them to a well setup Westfield then you
soon learn it a no no. The majority of true successful Inc the works Sylvas where converted back to outboard setup. Even the current RAW setup is
flawed and truly requires very expensive dampers and many mods to get it to work as well as a traditional out board setup.
All in all if we are talking 5-15K kitcars do you really need to go adding an additional 5-7 K of dampers to make it handel as good as the traditional
outboard setup. However if it's an individual with plenty of time and deep pockets then there's no problem just do it. But i think some
are not understanding just how much development it requires and just how sensitive the car / handling can become As i say fine if your developing a
Radical type motor for track use but for the average Kit that's being used on the road with some track work then the rules are keep it simple
and develop the overall package to be precise well setup with good handling.
Re what was mentioned regarding the Haynes setup. Well your always going to have problems with that type of design because there is no design. Take a
basic look at the tracks and wheelbase and ask does it resemble anything that has proved to work. Nope it just way way to big purely so it can use
standard production parts with no modification. It's a cheap design for a bit of road cruising rather than a setup that's designed to get
round corners quickly.
Cheers Matt
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MikeR
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| posted on 2/8/10 at 10:56 AM |
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quote:
Originally posted by procomp
Re what was mentioned regarding the Haynes setup. Well your always going to have problems with that type of design because there is no design. Take a
basic look at the tracks and wheelbase and ask does it resemble anything that has proved to work. Nope it just way way to big purely so it can use
standard production parts with no modification. It's a cheap design for a bit of road cruising rather than a setup that's designed to get
round corners quickly.
Cheers Matt
This is why i liked my night time thinking - if you take the existing haynes / locost setup as 'good enough'. Then making it inboard means
you'll still have a setup thats (hopefully) 'good enough' but ....
a) keeps me from finishing the car so i can be still building in year 11
b) reduces unsprung weight without costing a fortune on new calipers
c) gives me something to think about whilst unemployed
d) is generally accepted to be 'cool' without knowing why
e) has an incredibly marginal improvement in aerodynamics - as incredibly marginal improvements are great achievements in F1 this means my car is now
WAAAY superior to everyone else's
f) allows me to move my spring pick up out to the ball joint (which i'd really like to do cause i don't like the current solution - its
just wrong to me).
g) did i mention another excuse not to finish the car?
h) hopefully gives me rising rate suspension (or far less falling rate)
Right, i'm off to play with my seating position / steering wheel height again (cause i'm struggling to be able to hit the brake pedal and
steer with its current location).
(nb - in case its not obvious, i'm basically agreeing with Matt here, but i've got a 'fun' road car and therefore am happy as
long as I don't add any additional compromises or worsen the already made in a shed by me suspension.)
[Edited on 2/8/10 by MikeR]
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MikeRJ
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| posted on 2/8/10 at 11:39 AM |
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quote:
Originally posted by procomp
Sylvas with inboard suspension winning races. Well if you take any of the inboard setup strikers and compare them to a well setup Westfield then you
soon learn it a no no.
I'm surprised, the Sylva inboard design is very basic with no rising rate linkages or anything fancy - all it really does is allow the shock to
sit nearly at right angles to the wishbone which has to be a good thing? A problem with the older ones at least is the bearings in the upper wishbone
wearing, but this is really a materials problem.
[Edited on 2/8/10 by MikeRJ]
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procomp
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| posted on 2/8/10 at 12:13 PM |
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Hi
there's just too much loading placed in to the one area of the chassis. Even the ST setup with bearings was useless. Not to mention the chassis
constantly needing to re straightened when the car is subjected to a jarring from road surfaces.
Cheers Matt
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MikeR
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| posted on 2/8/10 at 12:40 PM |
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Ahh .....
I remember here reading ages ago that the forces can be quite huge. Hadn't thought of that.
(ok, i'm now conceptually picking your brain Matt / others whilst waiting to take the doggy to the vets as it appears he's eaten something
he shouldn't and has a blockage - don't ask how i found this out, but cleaning up hasn't been fun).
If i had my lever ratio 1:1 would it still get the huge forces? Say the lever was 20cm long. In the exact middle i had my pivot rose joint. Exactly
8cm from the pivot at either end I had the push rod & damper pivots. If i go over a bump now - would the pivot point and the shock chassis
mounting see any greater force than the shock was mounted directly to the chassis?
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