Re: "Blue" wastegate spring

[James Marriott <marriott@micron.net>]

Scott Mo. wrote:

...snip...

> It is tough to really compare springs just by their dimensional
> information unless you know the material it is made of or what the
> spring rate is.

All one needs is the ID or OD, number of active coils, wire diameter,
free length, and material (not "alloy," just basic material. ie, steel
(whether 4340 or 1010, modulus is the same) or aluminum (whether 2024-T3
or 5052-O, modulus is the same)). The spring rate can be calculated. Ask
here for the formulae.

> One way to compare different WG springs is to check the
> load it supports at a given compression and calculate the rate.
> 
> I normally measure the WG cap and perch dimensions to figure out the
> installed height of the WG spring. From this information you can then
> test the load of each spring at this compressed height. A electronic
> bathroom scale actually works pretty darn good at estimating this load.
> The US ur-Q has an adjustable WG spring perch which normally is set
> higher (spring is compressed less) than what the 1986-88 5000TQ WG perch
> does.

This and Bob's post summed things up nicely (not to exclude others who
may have posted... :-)

...snip...

Ways to make "your" spring stiffer:
remove coils
increase wire diameter
reduce spring diameter

softer:
add coils
reduce wire diameter
increase spring diameter

hth,
James
'87 4kq
'86 4ks
'64 Falcon
sadly, no springs here . . . :-(