Re: "Blue" wastegate spring

["Avi Meron" <avi@cosmoslink.net>]

Scott,
Could you Please clarify what is the pressure rating of your springs? does a
1.6 bar means .6 bar above atmosphere?
and 2 bar means 1 bar above atmosphere?

TIA
Avi




Original Message-----
From: Scott Mo. <scottmo@teleport.com>
To: phil@isham-research.demon.co.uk <phil@isham-research.demon.co.uk>
Cc: quattro@coimbra.ans.net <quattro@coimbra.ans.net>
Date: Monday, February 23, 1998 6:09 PM
Subject: Re: "Blue" wastegate spring


>Phil,
>>
>> C'mon, guys - someone _must_ know what blue colour coding means on a
>wastegate spring.
>
>I don't have a match for this spring with a blue paint mark you
>described previously with the length of 75.5mm, OD of 36.5 mm OD, 30.5mm
>ID, 3mm wire. The US ur-Quattro stock WG spring is aproximately 68.6mm
>long, 40.4mm OD, 33.3mm ID. I have never seen the euro ur-Q spring to
>make a comparison....
>
>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. 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.
>
>If the installed WG spring tension is higher than stock then you would
>normally see the behavior mentioned, where the WG solenoid duty cycle is
>shut off (Test LED light stops blinking) as the engine speed climbs at
>WOT.
>
>The ECU senses that enough boost or too much boost is being made so it
>shuts off the WG solenoid. When the WG solenoid is shut off and connects
>the upper WG cap to the intake boot at the turbo intake, the WG upper
>cap will see a slight vacuum at sustained WOT operation. This will
>reduce the boost ~0.1 bar over what the WG spring alone will make with
>the upper cap connected to atmosphere.
>HTH
>--
>Scott Mo.
>1989 200TQ
>http://www.teleport.com/~scottmo
>