Avoneer
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| posted on 29/5/06 at 02:58 PM |
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Spring Rate for Live Axle ???
What's a good spring rate to have on the back of my Bitsablade?
Got 175's on the front.
Leaves me with some 275's and 350's or shall I buy some new 175's for the rear?
Thanks,
Pat...
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Peteff
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| posted on 29/5/06 at 03:38 PM |
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Put the 275 on the front and the 175 on the rear, you'll not be far out.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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MikeR
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| posted on 29/5/06 at 04:42 PM |
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i'd have thought the front depends on your engine, crossflow around 220ish (depending on angle etc)
rear 150 - 180 ish.
all down to personal preference, weight, intended use etc.
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Danozeman
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| posted on 29/5/06 at 04:46 PM |
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Im putting 180s on the rear on my live axle zetec. You dont want it too hard or itl b easier spun.
Iv got 200/220's on the front cant remember which i went for.
Dan
Built the purple peril!! Let the modifications begin!!
http://www.eastangliankitcars.co.uk
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Avoneer
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| posted on 29/5/06 at 04:53 PM |
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Engine is a blade.
Guess I'll buy some 200's.
Cheers,
Pat...
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procomp
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| posted on 29/5/06 at 04:58 PM |
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Hi as was said above put the 275lb on the front . For the rear if it is a english axle and not the atlas you will need sub 175lb starting point would
be 140-150lb it will realy depend on whether you are carrying a pasenger or not .140lb if not 150 if you are.And then you will need to select damper
valving ratio to suit as standard AVO GAZ PROTEC will not work with a live axle and low lb springs .
cheers matt
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Avoneer
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| posted on 29/5/06 at 05:23 PM |
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Yep - english axle.
I've already got AVO ali shocks from an ST that use them on all there live axle cars so can't understand why they won't work.
Proteck for the front.
So should I get some 150's for the back?
Pat...
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MikeRJ
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| posted on 29/5/06 at 05:54 PM |
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If the springs are the right lengths I would put the 175's you already have on the rear as a starting point.
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Peteff
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| posted on 29/5/06 at 06:22 PM |
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I was using the ones you have to save you buying any new ones till you need to fine tune it. You should run it to see whether you prefer stiffer
springing with softer damping or another combination not try to get it right before it's on the road or you'll just be buying springs for
the sake of it
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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procomp
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| posted on 29/5/06 at 06:29 PM |
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Hi ok then put the 175lb on the back and bounce all over the place in a light bec car . Seriously tho put 140-150 on the back as that is what you will
end up with at the end . Damper wise what are supplied as standard to all but those that ask for somthing different are valved at 3-1 ratio you need
less speak to dave ainsworth for gaz or rod or kevin for the protec tell them what youve got ie 140-150 on a live axle not a irs and they will supply
new or probably revalve yours . Avo as far as i know havent got any one to talk to about revalving and i would'nt trust what they send you if
they did revalve yours.
cheers matt
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Peteff
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| posted on 29/5/06 at 08:09 PM |
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bounce all over the place in a light bec car
If the avatar is the car I don't think he's doing a lot of bouncing in it 
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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Avoneer
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| posted on 29/5/06 at 08:53 PM |
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Hi,
Think I'm gonna leave the 175's on the front as they are 7" and look good on my protecks.
Gonna buy some 150's for the rear.
Worst thing will be me needing to stiffen the front, leaving me with a choice of 275 or 350 to try.
How does that sound?
Pat...
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procomp
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| posted on 30/5/06 at 06:46 AM |
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Hi that will do to get the car running but if the 275lb are 7" aswell just put them on the front as again that is what you will end up with
eventually or posibbly 250lb. The 175lb on the front will never work on the road once you start to drive it but will do to hold the car up at ride
height till then.
cheers matt
PS you could do some quick research on the wscc forum as this has just been discussed on there also altho not a bec but still relavent to your
situation.
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JoelP
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| posted on 30/5/06 at 04:39 PM |
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matt, do you think that 175lbs springs combined with an antiroll bar would be enough to control the front end? cheers. (race use)
[Edited on 30/5/06 by JoelP]
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NS Dev
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| posted on 31/5/06 at 07:46 AM |
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I'll answer for Procomp on that one, no definitely not!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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JoelP
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| posted on 31/5/06 at 06:21 PM |
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lol, cheers 
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ChrisGamlin
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| posted on 31/5/06 at 08:06 PM |
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Hi Pat
I agree with Matt, I ran 275F/175R on my book blade chassis and it was a bit too firm even for track use, especially at the back. I dropped it to 250F
and 150R which made it good for track use, although Id go softer again if predominently for road use, maybe 225/125.
All this assumes you're running standard book pickup points on the front though, if they are different then all this goes out the window
[Edited on 31/5/06 by ChrisGamlin]
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britishtrident
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| posted on 31/5/06 at 08:23 PM |
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The mounting angle of the springs on the front and he leverage dictate much stiifer springs are required.
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ChrisGamlin
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| posted on 31/5/06 at 08:30 PM |
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Yep, thats the reason you can't even compare with similar cars if they don't use the same pickup points. For example, when I fitted my new
dampers I moved the chassis pickup point from under the chassis rail to the side of the chassis rail (to make the damper sit more upright) and I had
to drop 25lbs to get the same effective spring rate. Also some dampers such as my Nitrons add effective springrate ( ~15lb in the Nitrons case), but I
dont think the likes of Avos / Protechs etc do to a significant degree as they are a different design.
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Avoneer
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| posted on 31/5/06 at 11:19 PM |
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Hi Chris - thanks for that.
My front shock mount under the chassis rail, but the bottom mounting is much neare the ball joint so shall I go for 220's on the front?
Pat...
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ChrisGamlin
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| posted on 1/6/06 at 08:28 PM |
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Hi Pat
If its nearer the balljoint than standard then the shock will be more laid over (so requiring a harder spring), but the leverage ratio will be less
(so requiring a softer spring!) so hard to say really!
The only real way to be sure is to do a bit of maths
These might be of use this set of calculators, I used the penultimate one to work out how much to
reduce my springs when I changed the angles, but you might need to use the IRS calculator too, maybe getting some dimensions and doing comparative
calculations with the book setup.
cheers
Chris
[Edited on 1/6/06 by ChrisGamlin]
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ChrisGamlin
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| posted on 1/6/06 at 08:37 PM |
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By the way, it might be an idea to try and get the damper as perpendicular to the wishbone as possible (ie more steeply angled towards vertical)
because then you get a more linear effective springrate in bump.
The more the damper is canted over towards the horizontal, the more falling rate you ger because as the wishbone goes up, shock lays even further
over, which gives a significant falling spring rate. This means that as you load up the suspension it gets softer the further it compresses, which
isnt ideal. You always get an element of falling rate on outboard shocks like we have (hence why the Fury / Pheonix etc use rockers to eliminate
this), but its much less pronounced if the damper sits more vertical, and it also means you don't need as firm springs.
cheers
Chris
[Edited on 1/6/06 by ChrisGamlin]
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