oOps, my bad! got my orange and blue mixed up :thumbdown::lol: (I've edited all my previous posts, thanks Chris!)
I'm actually running orange pistons in the rear, not blue.

CD & all,

Thanks for all the help :)


Cris

whats the Pack set up then??

in the back of the S4/B44

orange/27.5wt was used when we needed to land jumps (Stotfold)
blue/30wt was used to ride ripples and ruts

i never under stand pack- but thanks for that will make a note

with big holes and thick oil Vs small holes and thin oil - you (within reason) get a similar 'slow' speed damping.

the differance is at high speed (piston speed, not car speed) (landing a massive jump) the thin oil flows faster through the small holes compared to the thick oil through the big holes and the thin oil flowing fast becomes turbulant and less efficient at getting through the holes, and 'packs' up a bit making the damping a little stiffer.

I think that’s the best that’s ever been written and explained to me


do you have an example of when to use big holes or small holes on uk tracks with the b4 on ae shocks?

Umm,

Chris (D)....I unsderstand the theory that thick oil and big holes is similar to thin oil and small holes at low speed....but if the thin oil 'packs' up at 'speed', where does the difference lie between using big holes and thick oil at 'speed'?

Agree with Millzy though, great explaination! :)

B4 with AE shocks does not really need changing, it was always the case that I just ask Mick Cragg what he was running, I can't drive or setup a 2WD car for toffee :woot:

with regard to the thin/small combo packing up, basically because of the smaller holes, the oil has to flow faster through these holes, the faster the flow of oil the more turbulant and less efficient at 'getting through' the holes the oil becomes.
thats why, at high speed movement of the piston, the small/light combo has more resistance than the 'matching' big/thick combo

Graham North likes this :thumbsup:

is there a psiton oil change thta you make to the front with losi shovks when changing the rear to the pack set up

not normally, typically the front end of cars seems to get through the bumps without too much issue, its just the rear that has issues with bumps

you can go for a black piston with lighter oil if you find the front end double bouncing when landing a jump (batley double springs to mind here)

you dont lose any steering / front end responce when changing from pack to non pack set up

in theory, No, as weight transfer is typically slow piston speed movements, but you might notice something.

with setups, things are rarely perfect to theory

oh god new can of worms - slow piston speed movements??

can i ask is going from 27.5 to 30 enough of a weight increase ?


loving the replys chris, huge help .

i would go thicker personally but thats just me. The assumption is made that if pistons are changed, the viscosity of the oil is also adapted, to give the same static feel. (Same low-speed damping)

I think we used to change about 5wt(maybe 2.5wt) per piston size to get a similar static damping feel.

but it depends on so many things, shock position, springs, ambient temperature and so on...

oh oh oh - tell me more

how would it be effected by shock position and springs

the further out on the wishbone the shock is mounted, the faster the piston speed for the same 'wheel' speed.

springs probably don't make enough differance to care about.

ok that little line lost me??