Board logo

How do i work out suspension?
speedyxjs - 9/10/08 at 11:19 AM

Im getting dangerously close to needing to buy the suspension (most expensive part of my build )
How do i work out lengths, spring rate and whatever else i need to know?
Also where can i get them from (must be locost as poss)
ETA - I assume i need to weight my car somehow to find out the poundage of the springs? Does this have to accurate or a rough estimate?

[Edited on 9-10-08 by speedyxjs]


maartenromijn - 9/10/08 at 11:27 AM

I think a phone call to Dampertech will clarify a lot. At least for me: Dave advised me well. Gaz shocks seem to be OK. Although I have not road-tested them yet.

Before I contacted Dampertech I was also wandering around checking ebay all the time.


maartenromijn - 9/10/08 at 11:29 AM

btw: I have 4 shocks open length 13", closed 10". Spring rates: front 300 lbs/inch, rear 200 lbs/inch.


Marcus - 9/10/08 at 11:38 AM

quote:

btw: I have 4 shocks open length 13", closed 10". Spring rates: front 300 lbs/inch, rear 200 lbs/inch.



I appreciate Dave advised you here, but i think you're over sprung!!
My car, book chassis with crossflow is currently running 225 front, 150 rear and it seems just right with dampers set 3 clicks from Minimum..
Only used for road, so track use may differ. All IMO of course


speedyxjs - 9/10/08 at 11:40 AM

Remember im using a jag engine. Would maartenromijn's type be ok? Im working on my car weighing under 1000Kg

[Edited on 9-10-08 by speedyxjs]


Mr Whippy - 9/10/08 at 11:50 AM

quote:
Originally posted by speedyxjs
Remember im using a jag engine. Would maartenromijn's be ok? Im working on my car weighing under 1000Kg


In your case I'd recommend something like this...





speedyxjs - 9/10/08 at 11:52 AM

not enough room


Paul TigerB6 - 9/10/08 at 12:00 PM

quote:
Originally posted by speedyxjs
not enough room



And those springs look WAY too light for a V12 Jag engined car!!!

[Edited on 9/10/08 by Paul TigerB6]


maartenromijn - 9/10/08 at 02:18 PM

quote:

I appreciate Dave advised you here, but i think you're over sprung!!
My car, book chassis with crossflow is currently running 225 front, 150 rear and it seems just right with dampers set 3 clicks from Minimum..



As I mentioned, I have not road-tested yet. I hope I have not been screwed...


mr henderson - 9/10/08 at 04:52 PM

My suggestion would be to install the suspension but with lengths of tube instead of shocks/springs. Obviously you need to cut lengths so that the suspension is at the ride height you require.

When the car is up to its full weight, get some analogue bathroom scales from Argos (2 will be enough) put a board across them, make up some spacers of the same height for the other 3 wheels to rest on, then weigh each corner by adding the two readings together.

When you've got the weight of each corner you will be able to use Mike Capon's spreadsheet to calculate the spring rates (AND LENGTHS!) you will need.

There's a link to it halfway down this thread
http://www.locostbuilders.co.uk/viewthread.php?tid=96908

John

[Edited on 9/10/08 by mr henderson]


speedyxjs - 10/10/08 at 06:56 AM

Cheers mr H