Info: Casper's Suspension:

SIKDMAX

Highway Burnouts!
Sep 14, 2007
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Central Coast, Cali
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Ive never understood that one Reno.... but thats what they say.

x2 on the not using a shock to limit travel - pretty easy on some of these shocks to over extend and you can actually pull the shaft out of the shock body and, well, :mad:.
 

Nor-Cal Nick

Suspension Guy
May 14, 2008
86
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Bakersfield Ca.
www.NorCalTruck.com
EXAMPLE:
Valve rating 275 / 78


Rebound force is
2750 Newtons at 0.52


Compression force is
780 Newtons at 0.52

.52 meters per second. It is the velocity.

at a lower velocity the valving figures are less and visa-versa.


Higher numbers mean higher (firmer) damping forces. For example,
360/80 has more

control (is firmer) than 275/78, while 170/60 has less control (is softer) than 275/78.
 
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RENODMAX

Dead Wrong
Mar 4, 2008
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I would agree if they are using a shitty valved shock that doesn't have to control the tire and wheel of bouncing;). Again valving will change all of this.


Nor-Cal Nick

Get 02freighttrain to chime in here. Hes had ALOT of experience with this.
 

McRat

Diesel Hotrodder
Aug 2, 2006
11,249
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Norco CA
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OK, some changes:

Trashed the DJM front shocks. Put on KYB 565102 MonoMax shocks, factory length.
Added a Hellwig front antisway #7654.

Threw 1,400 lb of sand in the bed and took it for a ride.

Very, very much improved. ZERO wallowing. I can bottom out the suspension, but I cannot make it take more than 1.5 cycle to dampen it out. Big freeway undulations at 70mph are now completely ignored, even cornering.

KYB's are "bling", they are bright MonkeyButt Red with pleated boots. WAY more dampening than the stockers, as well as a heftier nitrogen charge. Push both shocks down to max, and the KYB takes about twice as long to extend even though it takes way more pressure to compress the KYB to start with.
 

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McRat

Diesel Hotrodder
Aug 2, 2006
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Nice ...

So let me ask this .... Are you wanting the truck to keep as ridged off the line as possible? Don't want a corner lifting?

I respect the pullers on here alot. They are "no-BS" folk.

If they have issues when they limit extension travel, I believe them. So by putting on "high rebound dampening" shocks and a heavy swaybar, it should make it harder for the front to lift, yet not actually restricting it.

Not to mention those DJM's were actually scary on the street.

In the end, Casper has always been (from even before we bought it) primarily a street pickup truck. It is supposed to be a Jack-Of-All-Trades, and those shocks were entirely one-dimensional. All they did was limit travel.
 

Nor-Cal Nick

Suspension Guy
May 14, 2008
86
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Bakersfield Ca.
www.NorCalTruck.com
I'm sorry:eek:, maybe you thought I was testing your statement or mod done to your truck.

I am really asking what is wanted on a drag truck because I don't know what you guys prefer. Trying to learn. I know a drag to a puller would probably want 2 different things but that's what I am after to learn.

What I do know is how you set your truck up to help predict how it acts while coming off the line for drag racing or sled pulling has to matter. I am trying to understand what people want or might be trying to fix because it is something that I don't get to play with here at my shop and expanding what I can understand could and probably will help at a latter date.
 

McRat

Diesel Hotrodder
Aug 2, 2006
11,249
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Norco CA
www.mcratracing.com
I'm sorry:eek:, maybe you thought I was testing your statement or mod done to your truck.

I am really asking what is wanted on a drag truck because I don't know what you guys prefer. Trying to learn. I know a drag to a puller would probably want 2 different things but that's what I am after to learn.

What I do know is how you set your truck up to help predict how it acts while coming off the line for drag racing or sled pulling has to matter. I am trying to understand what people want or might be trying to fix because it is something that I don't get to play with here at my shop and expanding what I can understand could and probably will help at a latter date.

No problemo.

Up until recently, I have not played much with suspension changes on a pickup, so I'm guessing at it.
 

Redbone

but this one goes to 11
May 1, 2008
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Indy, IN
Nick here's my take, and Pat correct me if I'm wrong, I've been away from drag racing for 18 years.

Anyhow, what we want to do in any form of racing, is to maximize the weight transferred to the driven wheels. In conventional drag racing (2WD), at launch we want transfer as much weight as possible to the rear driven wheels, only allowing enough weight remaining on the steer tires to maintain control, thus, we want to minimize rebound dampening.

In 4x4 drag racing, since the front axle is also driven, and very heavily loaded statically, we want to MINIMIZE weight transfer to the rear axle. In this case we want a front shock to have heavy rebound dampening. This is a little tricky because one size can't fit all, dampening will be somewhat of a function of weight and horsepower (or torque). Too stiff, and it will act like a solid link, raise up, jerk the tires, and bounce the front end. Too light , and we will hit the rebound limit (or other suspension travel limit), meaning damaged shocks, bouncy front end, etc.

Ideally the front shock should be just free enough to not "solid link" the front end. Something valved about like the Bilstein be5-6243-h5 might be interesting to try (4000/1000 @ .52 valving).
 
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Nor-Cal Nick

Suspension Guy
May 14, 2008
86
0
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Bakersfield Ca.
www.NorCalTruck.com
Nick here's my take, and Pat correct me if I'm wrong, I've been away from drag racing for 18 years.

Anyhow, what we want to do in any form of racing, is to maximize the weight transferred to the driven wheels. In conventional drag racing (2WD), at launch we want transfer as much weight as possible to the rear driven wheels, only allowing enough weight remaining on the steer tires to maintain control, thus, we want to minimize rebound dampening.

In 4x4 drag racing, since the front axle is also driven, and very heavily loaded statically, we want to MINIMIZE weight transfer to the rear axle. In this case we want a front shock to have heavy rebound dampening. This is a little tricky because one size can't fit all, dampening will be somewhat of a function of weight and horsepower (or torque). Too stiff, and it will act like a solid link, raise up, jerk the tires, and bounce the front end. Too light , and we will hit the rebound limit (or other suspension travel limit), meaning damaged shocks, bouncy front end, etc.

Ideally the front shock should be just free enough to not "solid link" the front end. Something valved about like the Bilstein be5-6243-h5 might be interesting to try (4000/1000 @ .52 valving).

:D I think I know where you have been surfing.

I am thinking the same. This hole drag and sled truck suspension set ups have me ... well thinking and since I am pretty convertible with the lift scene I was liking the challenge for myself to understand. Iguess in the beginning the hole start of Pat talking about front shocks and what he tried had me thinking that his launch had to be pretty soft and then solid, right away I was thinking it needed a slower rebound.


Seriously guys I am really wanting to try some idea's that I have picked up from what I do that I think may work in what you guys do. Buying a truck and starting a new sport is not going to happen.

Pat I know I missed you the other day but maybe we can chat later in the day when you and myself are not so rapped up. Are you trucking up here for the Nor-Cal Rally?
 

malibu795

misspeelleerr
Apr 28, 2007
7,782
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in the buckeye state
i know they said they are headeding to lancaster this coming saturday for a charity sled pull with several other people from the boards :)


i know several people are coming form sac/san fran area form other boards


should come down :D
 

sweetdiesel

That's better
Aug 6, 2006
10,390
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Thailand
:D I think I know where you have been surfing.

I am thinking the same. This hole drag and sled truck suspension set ups have me ... well thinking and since I am pretty convertible with the lift scene I was liking the challenge for myself to understand. Iguess in the beginning the hole start of Pat talking about front shocks and what he tried had me thinking that his launch had to be pretty soft and then solid, right away I was thinking it needed a slower rebound.


Seriously guys I am really wanting to try some idea's that I have picked up from what I do that I think may work in what you guys do. Buying a truck and starting a new sport is not going to happen.

Pat I know I missed you the other day but maybe we can chat later in the day when you and myself are not so rapped up. Are you trucking up here for the Nor-Cal Rally?

Whatcha got Nick?
 

sweetdiesel

That's better
Aug 6, 2006
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Thailand
Another thing I was wondering about is the wheel alingment

Casper setup to GM spec? Dont places useally setup the vehicles to pull slightly to the right?

what about castor and camber toe in shouldnt these be adjusted different for race trucks?
 

McRat

Diesel Hotrodder
Aug 2, 2006
11,249
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Norco CA
www.mcratracing.com
Casper has zero toe-in, equal camber/caster.

This is so it tracks straight in either lane under power.

Normal spec is about 1/4" toe-in and the caster is unequal so it pulls to the left. This keeps it straight on crowned roads.
 

sweetdiesel

That's better
Aug 6, 2006
10,390
0
0
51
Thailand
Casper has zero toe-in, equal camber/caster.

This is so it tracks straight in either lane under power.

Normal spec is about 1/4" toe-in and the caster is unequal so it pulls to the left. This keeps it straight on crowned roads.


awsome thanks!