Forge Recirc DV judders - green, yellow, blue, red springs
#1
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My Forge recirc DV has a blue spring, and juddered horribly even on fairly smooth lift off after the FMIC went on. Since the OEM DV was so much smoother I was all for selling it, and I am getting a yellow and a red spring to try from Forge to try and remedy the problem. Order of strength is as title (red is strongest). Forge reckon that the yellow spring is the one to use, but others tell me the red will sort the problem. When the juddering was happening you could hear the DV venting on and off with the juddering. Any further input appreciated. The OEM one drives nice but at 1.5 bar it may leak a bit even if you can't hear it I gather.
[Edited by john banks - 9/18/2002 3:20:43 PM]
[Edited by john banks - 9/18/2002 3:20:43 PM]
#2
John
You should get a measurement of the actual strength of the spring as opposed to just the colour it has been prepared in
Perhaps Forge will be able to supply you with a range on strengths in original uncoloured form so you can experiment, and establish what best suits your current configuration
You should get a measurement of the actual strength of the spring as opposed to just the colour it has been prepared in
Perhaps Forge will be able to supply you with a range on strengths in original uncoloured form so you can experiment, and establish what best suits your current configuration
#3
try this one. on my wrx01 works beautifully. you can buy it together with a wastegate. the model works on pre my01 with an adaptor.
http://www.bonalume.com/upload/pdf_press/09.pdf
C.
http://www.bonalume.com/upload/pdf_press/09.pdf
C.
#6
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Could it be the compressor going past the surge line ? Or the mixture running weak as the air expands back through the recirc route ? (this is not seen as airflow by the MAF but flow still exists into the engine)
#7
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For the compressor to surge it would require considerable flow through the exhaust housing of the turbo? Low compressor flow, high pressure ratio, high turbine speed could result then leading to surge?
Re the MAF I will log it when I fiddle with different springs and see.
Re the MAF I will log it when I fiddle with different springs and see.
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#8
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Just the inertia left in the rotating assembly can be enough to push past the surge line when the throttle is closed in.
The compressor RPM is still high but the flow is very low until the dump valve opens. Suggest you want a lower pressure spring but that brings you back to standard dump valve pressure during gear shifts. Retention of some charge pressure I presume was the reason for initially fitting it ?
The compressor RPM is still high but the flow is very low until the dump valve opens. Suggest you want a lower pressure spring but that brings you back to standard dump valve pressure during gear shifts. Retention of some charge pressure I presume was the reason for initially fitting it ?
#16
John,
people pay good money and a lot of time to get their BOVs to 'chatter' not 'judder'. Mine does - although it does not seem to upset the car at all.
Tries to maintain charge just that fraction longer for gear shifts and sounds the nadgers
Trout
people pay good money and a lot of time to get their BOVs to 'chatter' not 'judder'. Mine does - although it does not seem to upset the car at all.
Tries to maintain charge just that fraction longer for gear shifts and sounds the nadgers
Trout
#17
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nice one JB !
Trout IIRC you have a link ? I think it is the JECS MAF meter being confused regarding airflow (in, out or roundabout) that causes the 'judders'. Me.... I just love it it's like a like a big bad dog straining to get off the lead
Trout IIRC you have a link ? I think it is the JECS MAF meter being confused regarding airflow (in, out or roundabout) that causes the 'judders'. Me.... I just love it it's like a like a big bad dog straining to get off the lead
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