Single-seater Hill-cimb car dampers
Discussion
Hi all,
I'm taking part in a project at university to design the front suspension of a hill-climb car. There is just an infinite amount of options on how to go about this and I'm struggling to get my head around it all!
We've chosen to go with a pull-rod system and I'm in charge of finding us some springs and dampers. There is a limited imaginary budget.
Because it's a hill-climb car and will only be used for short sprints, we've decided that we will design a bell-crank that amplifies the wheel travel such that the damper compresses further. (I hope that made sense?) We figured that this will give us more control and reduce the effect of damper 'stickyness'.
It would be greatly appreciated if anyone could give me any advice on spring/damper selection and where you can actually go to buy such components?
Also what factors directly affect spring/damper selection? Sprung mass for example I would assume is a key factor, our target wieght is 320kg (exc. driver)
I'm a complete novice and a google search returned a load of dampers but I don't know which would be suitable for this application.
Any help would be greatly appreciated!
Many thanks!
Adam
I'm taking part in a project at university to design the front suspension of a hill-climb car. There is just an infinite amount of options on how to go about this and I'm struggling to get my head around it all!
We've chosen to go with a pull-rod system and I'm in charge of finding us some springs and dampers. There is a limited imaginary budget.
Because it's a hill-climb car and will only be used for short sprints, we've decided that we will design a bell-crank that amplifies the wheel travel such that the damper compresses further. (I hope that made sense?) We figured that this will give us more control and reduce the effect of damper 'stickyness'.
It would be greatly appreciated if anyone could give me any advice on spring/damper selection and where you can actually go to buy such components?
Also what factors directly affect spring/damper selection? Sprung mass for example I would assume is a key factor, our target wieght is 320kg (exc. driver)
I'm a complete novice and a google search returned a load of dampers but I don't know which would be suitable for this application.
Any help would be greatly appreciated!
Many thanks!
Adam
When I was at uni we used Penske dampers/springs on our formula student car, they weren't cheap but they were very good!
Alternatively, I know a lot of formula student teams use motorbike, quad bike, some even mountain bike dampers. Anything under 500kg and this is your best route if you need to stick to a budget!
Alternatively, I know a lot of formula student teams use motorbike, quad bike, some even mountain bike dampers. Anything under 500kg and this is your best route if you need to stick to a budget!
Dont use expensive stuff, use rear shocks from motorcross bikes, they already have a lot of adjustment possibilities and there is a big assortment of different springs available for them.
They are adjustable for compression and rebound and almost always have high/low speed adjustment.
They are adjustable for compression and rebound and almost always have high/low speed adjustment.
Cheers for the replies, Penske are meant to be one of the best I believe? What university did you go to?
I'm at Oxford Brookes. I'm enjoying this project but I've learnt since being here that a career in motorsport isn't for me.
I'm going to have a closer look at the formula student car tomorrow see what kinda shocks it uses, I just need some dimensions and specs.
I'm at Oxford Brookes. I'm enjoying this project but I've learnt since being here that a career in motorsport isn't for me.
I'm going to have a closer look at the formula student car tomorrow see what kinda shocks it uses, I just need some dimensions and specs.
Penske are excellent, but I agree with others who suggest cheaper solutions.
It's worth downloading their Technical Manual for Adjustable Dampers though, as it's got lots of good information on damper tuning.
You really need to work backwards, though, from what wheel (and hence spring) rates you think you need, then select suitable dampers to suit.
The problem with some of the cheaper solutions (like mountain bike dampers) can then be that if you don't have the range of shims and valves available to tune them to your needs, the tail starts wagging the dog in that you have to start compromising with other aspects of the suspension design and geometry to suit the damper.
Oh, and if you're serious, access to a damper dyno and plenty of testing will be essential.
It's worth downloading their Technical Manual for Adjustable Dampers though, as it's got lots of good information on damper tuning.
You really need to work backwards, though, from what wheel (and hence spring) rates you think you need, then select suitable dampers to suit.
The problem with some of the cheaper solutions (like mountain bike dampers) can then be that if you don't have the range of shims and valves available to tune them to your needs, the tail starts wagging the dog in that you have to start compromising with other aspects of the suspension design and geometry to suit the damper.
Oh, and if you're serious, access to a damper dyno and plenty of testing will be essential.
Seeing as it's imaginary, you're looking at doing the maths rather than trial-and-error. That can be problematic as damping is, in a lot of aspects, as much an art as a science. Specifying something with enough adjustment will be important.
On paper a monoshock system will look good. Google 'GWR Raptor', Graeme has posted a few pictures of the pullrod monoshock system he used on that. It's well proven on the hills, simple and obviously needs one less damper
If you're imaginary budget stretches to £500+ per damper then Ohlins and Konis are the commonly used high end dampers for hillclimb single seaters.
Good luck with the project, sounds like an interesting one!
On paper a monoshock system will look good. Google 'GWR Raptor', Graeme has posted a few pictures of the pullrod monoshock system he used on that. It's well proven on the hills, simple and obviously needs one less damper
If you're imaginary budget stretches to £500+ per damper then Ohlins and Konis are the commonly used high end dampers for hillclimb single seaters.
Good luck with the project, sounds like an interesting one!
These are what the hillclimb cars I worked on used:
http://www.koni.com/213+M54f874a4f99.html
Gives a good list of advantages. Last time I checked they were around £700 each.
http://www.koni.com/213+M54f874a4f99.html
Gives a good list of advantages. Last time I checked they were around £700 each.
Our Formula student have generally used these:
http://ohlinsusa.com/us/index.php?option=com_conte...
For which ohlin also provide force-velocity plots:
http://ohlinsusa.com/us/Automotive/TTX_25%20Dyno_M...
Could make for a good project if you can understand how to apply them!
Edit: They also supply CAD files. Get drawing!
http://ohlinsusa.com/us/index.php?option=com_conte...
For which ohlin also provide force-velocity plots:
http://ohlinsusa.com/us/Automotive/TTX_25%20Dyno_M...
Could make for a good project if you can understand how to apply them!
Edit: They also supply CAD files. Get drawing!
To those considering MTB/Dirtbike dampers, have a read of this: http://deepblue.lib.umich.edu/bitstream/2027.42/49...
They might work but they are not ideal.
They might work but they are not ideal.
Hi Adam,
Go to the library and hunt through the old MSc dissertations. Mine should be in there somewhere http://prism.talis.com/brookes/items?query=edmund+...
It should help you out a bit!
Go to the library and hunt through the old MSc dissertations. Mine should be in there somewhere http://prism.talis.com/brookes/items?query=edmund+...
It should help you out a bit!
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