Critique on my suspension

Muddi44

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OK guys, I have seen others have posted videos on their setups, youtube link to a short vid of my truck (it is not my video therefore a couple of other trucks are at the start, I am on the last minute, car 52)
Current setup is 188lb/inch parabolics on the rear, 270lb/inch front. Fox 2" resis front & rear, front shimmed 50:50, rear 40:40.
I am pleased with the set up & will be fitting 4" air bumps, hopefully in time for the next race. I am a complete novice at setting up suspension,so over to you, does it look OK. What I am aiming for with the air bumps is to have a gently rising rate for the 1st 2" or so & then a steep rising rate for the last 2", this is so that I can have a softer spring rate for when the air bumps are not in play. Some of the courses we race on are rally stages & I need compliance in the suspension for these. We do not have the big whoops you desert racers have so overall travel is pegged at 11"
For information I race in a leafsprung only class, any thing else goes, I probably have the smallest engine competing this season. At this race I was 27th out of 51. Courses are relatively short (6 miles or so) often through trees etc. Wheel track cannot be too wide or the tracks will be too narrow, W/base is currently 101"


[ame="http://www.youtube.com/watch?v=MtzP_9HR5v8"]YouTube - AWDC Round 3 Radnor,Cars 106 101 & 52. 24th May 2009[/ame]

Tim
 

FastEddy760

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Hi Tim,

Interesting racing you got going on over there.

My 2¢ based on the current value of the dollar...

Consider bypasses. It seems you might have the spring rate at or near where it needs to be.
The bump stops will help when you bottom, however I do not see the need to 'catch' the truck based on the portion of the course in the video. I think this might be a waste of money.

What you do need to do is stop the oscillating bounce from fast compression and fast rebounding.

The (leaf?) springs will hold the truck up. The Fox shocks could use some valving adjustments. However bypasses will allow you to tune on the spot, make a pass, and tune some more.

Start there.

P.S. That girl talks funny ;-)
 

Muddi44

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Hi Tim,

Interesting racing you got going on over there.

Courses are short compared to yours, each lap is about 6 miles, 8 laps per race
My 2¢ based on the current value of the dollar...

Consider bypasses. It seems you might have the spring rate at or near where it needs to be.
The bump stops will help when you bottom, however I do not see the need to 'catch' the truck based on the portion of the course in the video. I think this might be a waste of money.

What do you mean catch the truck?

What you do need to do is stop the oscillating bounce from fast compression and fast rebounding.

The (leaf?) springs will hold the truck up.
The springs are leaf, they taper in thickness from the middle to the eyes, each leaf is separated by PTFE blocks so interleaf friction is minmised.

The Fox shocks could use some valving adjustments.
Any clues which way to go

However bypasses will allow you to tune on the spot, make a pass, and tune some more.
Bypasses are out of my current price range (factor in that they are almost twice the cost in the UK as in the US & all my racing is out of my own pocket) plus I already have the air bumps

Start there.

P.S. That girl talks funny ;-) I bet she would say the same about you:)
I am struggling a bit with this, I made several major changes over the winter & the improvement is so significant (10 seconds plus per mile) I cannot see the wood from the trees. I am trying to re-learn how to drive the truck & to tune the suspension at the same time

Thanks for taking the time to help

Tim
 
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