crochunter

What shocks does everyone use at the rear for drag racing.

falcon coupe

30/70's, i just put some in, they really help the hook up.

XD408

I was just runnin Koni adjustables set to real soft ???? something like the 30/70s gonna work better?? Cause i tried the 90/10s in the front over my koni adjustables set to soft as they could go and the konis definately allowed more front lift

Ziggy

hey guys shocks isn't a forte of mine, but never the less very inportant to get that launch off the line, u guys are talkin about 30/70s and 90/10s wat exactly do the numbers refer to is it a spec of something?? pls expain if u know.
thanks

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Authuorised GM Destroyer

conan

First question - how much do you want to spend, and how serious are you in racing?

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BA GT-P owner and loving it!

tony xa

I think it is the size of the valves.example on the back 90/10. 90 would be the size of the valve for the down motion so it goes down fast 10 would be the size of the up valve so it will go back up slow .This would help with hook up .The front complete oposite .
These are no good for normal road use .
I have gone for koni adjustables set them soft for the strip then back to half way for street.

TruBlu351

90/10's go on the front.

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XE Falcon
393 Tremec TKO 9"

351ClevoCorty

Dampening/Rebound effect. 90/10s on front allow the car to lift easily and transfer weight combined with forward motion to the rear end. There's more to it than this but that's the basic gist. If anyone would like to add to this pls free to do so.

longroof351

The term 90/10 or 70/30 refers to percentage.Percentage of what you ask?
Percentage of dampening force is the answer.

If you combine the bump (compression) and rebound (extension) forces the shock can produce they would total 100 percent. For ease of mathmatics we will say a falcon front shock can produce 100 newtons of force in bump and rebound.
So a 90/10 will have 90% or 90 newtons of bump force (compression).

Therefore the 10 percent left will be rebound(extension) 10 newtons.

This will let the front of the car lift under acceleration but slow the speed in which the front drops back to normal ride height.

Now rear is the same 70/30 = 70%bump force/30% rebound or 50/50 =50%bump and 50% rebound etc etc.

The problem with these numbers is it is only a percentage and does not tell you the actual dampening forces of the shock but just its general characteristic. If you go to the Koni website you will see drag shocks have spa1 as part of the part number. This refers to the valving code.(spa1=drag shock) http://www.koniracing.com/dragstock.html
Also read this too to learn more. http://www.koniracing.com/pdf/spa1.pdf

Back to the original question of what shock to use on rear?
Well in my xd i use a Koni special D (reddy orange ones) straight out of box on minimum (softest adjustment) on the rear. Approx 50/50 shock

The front i have tried Pedders 90/10s and they worked very well for the cost but then i had some Koni fronts valved so i could control the rate in which the front rises. The differance was measured in the hundrenths of a second.


The XD has run a best of 11.29 @ 117mph and 60 foots in the 1.54/55s with no traction aids(eg slapper or cal tracs) but it is on 9inch slicks.

Hope this helps

John

brenx

XD's have built in traction aids which are all the mounting on the topside of the diff or was it the bottom? Can't remember it's been a long time since I've seen under an XD.

A real pain in the butt for XA-XC users as the bars weren't factory on most models. The only mounting is U-bolts and nothing else. Damn Ford!

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XB Fairmont (street car) 11.07@123.02mph.