Question about pack

[Loheswaran]

I think I understand that you have more pack with smaller less holes vs larger and more holes.

My question is this - I am running the 6 hole standard pistons in my dex210, and noticed that there is a lot of nose dive and suspension movement so to speak.

My questions are these:

1. Does pack affect low speed handling insofar as making the car more responsive on initial turn in - and quick transitions, or is it the reverse
2. what would be the effect of having more pack on several mini jumps - would it make the car bounce around and hop more?

Can anybody help me here. Thanks.

[mattr]

The are a couple of threads from earlier in the year on pack. Think I've commented on both of them.

On my phone now, but if you search pack against my user name you *should* get what you are after.
If not, I'll post again tomorrow!

[Loheswaran]

What i have read on pack appears to answer the question in relation to bumps and jumps, not the low speed handling issues. I'll look again though

[mattr]

Yes, it does refer to that. Sorry.

But as far as pack goes, given the same total hole area (either lots of small holes or few large holes) the low speed performance or the shock (low piston speeds) will be unaffected (given the same oil).

As the piston speed increases, pack will become more noticeable. The threshold at which you go from "no pack" to "some pack" and then "pack" is related to a lot of things, mainly the viscosity of the fluid (related to reynolds number), the speed of the piston and the size of the holes. (massive oversimplification, but it'll do!)

So *generally speaking* low speed handling should be unaffected (as long as the total hole area and oil used is the same) as the piston speeds will probably be too low to start getting into pack territory. Unless its a bumpy track.

Lots of small bumps will probably make the car jump and hop a lot, as the shocks will pack and stop moving. Depending on the size and speed of the jumps (and how fast they make the pistons go)

FWIW, i don't use the stock pistons anymore as they weren't very good for the tracks we have, so i went to a 2/3 hole set up, with similar sized holes and a less viscous oil. (And now to MIP bypass 1 pistons to see if they work!)

Hope that helps, i'm late for a meeting now. ;-)

[Loheswaran]

much appreciated

[Dino_D]

Originally Posted by Loheswaran

I think I understand that you have more pack with smaller less holes vs larger and more holes.

My question is this - I am running the 6 hole standard pistons in my dex210, and noticed that there is a lot of nose dive and suspension movement so to speak.

My questions are these:

1. Does pack affect low speed handling insofar as making the car more responsive on initial turn in - and quick transitions, or is it the reverse
2. what would be the effect of having more pack on several mini jumps - would it make the car bounce around and hop more?

Can anybody help me here. Thanks.

6 hole standard pistons (kit setup) was designed to use heavier wt oils. If you have a lot of movement, it is because your oils are too thin. Too much weight transfer front to rear and side to side. More pack can either stop the car from bottoming out on several successive jumps, or having too much pack and pogoing after landing. There is a balance you need to find in between.