Little Bird

[marcytech]

Roger that. Is it the ibp making all the short course trucks I see buck like broncos? Seems like they have too much damping to my untrained eye..


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it could be, but in my opinion its improper spring set up. "durtycam" on ig just finished his and it bucks like a leaf springer. the weird thing is the trucks are bucking BEFORE bottoming out. i also had this exact issue and confirmed the truck wasnt even touching the bumps before creating a bucking scenario. we caulked it up to the crossovers after many many tuning sessions.
i know the "preferred" way to set up a 3.0 is with a huge long main spring and using it to set ride height with the secondary spring slider stops. thats how everyone else is doing it and thats how i tried it at first. As soon as we got rid of the secondaries and set preload/ride height with the top cap and got a slightly heavier top spring to support some weight rather than collapsing all the way at ride height all was good in the world and the rear worked like a dream!
chris did the same in "clifford" with awesome success
both mine and chris truck were similar to yours. shock was 12" forward from axle centerline

 

[partybarge_pilot]

There is no bypass circuit for that valve. Bad design. Without a high speed blow off it will make bucking an issue.

With the short course style you have an almost 1-1 ratio. This results in high shaft speeds. It makes the rear much more sensitive to high speed limitations.

 

[partybarge_pilot]

The hose is trying to flow twice as much fluid as a King. This will mean it's flow limit will be reached at half the shaft speed.

 

[littlebird]

The hose is trying to flow twice as much fluid as a King. This will mean it's flow limit will be reached at half the shaft speed.

The design is admittedly more crude than one would hope, but you get what you pay for.

Seems like my best bet, as usual, is just to get the shock as far forward on the link as possible.


Anything surprising in the shock dyno graphic below? Different colors represent different points in the adjustment of the simple flow valves before the resi.

Excuse me while I put on my expert shock tuner hat. LOL

If I'm not mistaken, the lines with positive and negative slope represent compression and rebound damping respectively.

Thus, the blue line/adjuster position will yield the worst behavior in regard to bucking, due to the more exaggerated relationship (greater slope) between shaft velocity and compression damping?

 

[partybarge_pilot]

35"/sec? LOLZ, they need a real dyno that goes 100"/sec. Then you could see it hit the wall and the pressure spike.

 

[partybarge_pilot]

But yeah, you can all ready start to see the effect of the valve. Its going to ramp almost straight up after that.

 

[partybarge_pilot]

Just asked Khris @ shock seals, their dyno goes to 230IPS.

 

[jonsangel]

damn, I love science

 

[littlebird]

It’s a horrible time of year in NY, 7 degrees out, roads heavily salted, and to be frank, things aren’t looking great for the US of A.

No big updates in regard to labor on the truck but the parts pile grows.

It’s the little things that count though, right?

Had the slugs pictured below made up to land the rear main tubes of the bed cage on. Now that they’re done, it’s time to get serious.


Been sitting on my plans for the rear tube work for a while, but now that I’ve come clean on the rear shock choice and haven’t been booted off DR it’s time to spill the beans.

The slugs will be captured by the factory rear spring hangers. Are they as strong as fabricated versions, no, but they’re prettier in my opinion and strong enough. If you haven’t noticed already from the beams, to rad arms, rear axle, I have a theme going of using as many factory parts as possible but with minor to major changes.

Buying the slickest parts on the market is rad, but for whatever reason repurposing/reimagining factory stuff puts some genuine joy into the whole deal. Clicking “add to cart” online just can’t compare.

Pictured below in yellow is the bed cage, or at least one side of it. In sum it’ll be two simple hoops with a crossover. It will be solid bolted to the frame and the shock will sit in the pocket of the factory wheel arch, and the axle will bump ~10” behind the factory arch.

Where things get weird is with the red tubes. They will be bushing mounted to the frame and cab.

I have a few reasons for doing it this way but most of them have to do with making the truck ride smoother on the street and less chattery over small bumps.

Little bird is shaping up to be more of a late 90’s Raptor than a pure blood prerunner, but at this point in my life, I want something more domesticated.

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[littlebird]

Been searching for a 4l80e out of a motorhome for a while, mainly for the fixed yoke and double roller bearing tail housing, I guess they have straight cut planetary gears too. Of course the unit I find is an early model and also has the wrong output shaft length for the tail housing I need to run for my trans crossmember. As it turns out there are at least two versions of the fixed yoke roller bearing tail housings each with its own output shaft and mount.

Anyway, whats the best way to go about finding the driveline angle? Just slap my angle finder up against the back flat face of the tail housing, or should one really get the angle from measuring off of the output shaft itself?