Several weeks ago, I wrote about this in one post, also presenting a mathematical way how to do this. Yesterday I got accu sphere regassed and it turned out that I was quite close. So I'll describe how to do it, with slightly revisited formula. It's very simple:
1) Warm up the engine to operating temperature, so that it idles at normal idle speed
2) Switch the engine off
3) Decompress the accumulator sphere, loosing the screw on the pressure regulator
4) Wait about a minute, than tighten the screw back
5) Move the height lever to lovest position
6) Switch the engine on and measure the time until STOP extinguish and car start to sink
7) Use the formula
p = (1 - 13.5 * t / 400) ^ 1.35 * 82
This applies to Xantia and XM with anti-sink and 6+2 HP pump, petrol engines. With diesel engine, instead of number 13.5, use 20.
It turned out that, in my car, security valve opens at about 82 bar (according to manufacturer, can be 80-100), hence the number 82 in formula. Formula will give quite accurate results, assuming that pump is in good condition, so that its output is according to specifications.
Before regassing, I measured about 13.5 s, now it's about 5.3 s. According to formula, pressure was 36 bar before regassing (that's what we measured) and now about 63 bar. Sphere wasn't refilled since the car was new (august '98)
It's also interesting that we measured 45 bar in front spheres (multilayer ones - 450 ccm) - pressure dropped only 5 bar during this period !!! These spheres were also genuine and never regassed. I regassed rear spheres 3 months ago, and pressure was only 7-8 bar. What a difference.
DIY - how to measure the pressure in accu sphere
Moderator: RichardW
Hi Norrie - dead simple :
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The image <i><b>must</b></i> reside on a public available server - then submit the <i><b>complete</b></i> URL for the image - between the IMG codes found under the small picture icon above the posting text window here.
(when in submitting mode)
- by the internet nature it won't work submitting the URL to your local harddisc [:)]
For exploiting more advanced features on this Q&A board - try the FAQ button upper right.