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1996 855 T5 - Musings on Wastegate Adjustment

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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abscate
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Re: 1996 855 T5 - Musings on Wastegate Adjustment

Post by abscate » Tue Aug 22, 2017 4:15 pm

Trying to remember this. If I recall boost is applied by the TCV allowing pressure to be sent to the wastegAte, which keeps it closed.

The 3.5 psi measurement is a calibration pressure applied to the wastegAte which is then set to the closed position following the procedure given in VIDA. Shortening -the rod will mean the wastegAte but opens later

Uh oh, what do I have wrong here ?
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Re: 1996 855 T5 - Musings on Wastegate Adjustment

Post by hausmeister » Wed Aug 23, 2017 8:27 am

On the 850s the tcv opens the wastegate by applying pressure.

I recently played with my setup again. Relocated the tcv nearer to the turbo and shortened the hoses a lot. Since then i was able to increase the pretension again and also the boost build up is smoother since the tcv seems to be able to regulate better.
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Re: 1996 855 T5 - Musings on Wastegate Adjustment

Post by abscate » Sun Apr 08, 2018 6:51 am

Reviving old topic

Here is the picture of my discontent
7CD81C68-8752-4D11-B428-AAC95D55E80F.jpeg
7CD81C68-8752-4D11-B428-AAC95D55E80F.jpeg (116.62 KiB) Viewed 1211 times
Yet people report enhanced Or earlier boosting when shortening the wastegate rod.

:?:
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Re: 1996 855 T5 - Musings on Wastegate Adjustment

Post by hausmeister » Mon Apr 09, 2018 7:36 am



that should explain it
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Re: 1996 855 T5 - Musings on Wastegate Adjustment

Post by abscate » Mon Apr 09, 2018 8:29 am

Ha!!

Dumba$$ moment.

Im watching this thinking I know all this already - then realize my mistake - really simple one.

WASTEGATE CLOSED = maximum boost

WASTEGATE OPEN = no boost.

So, as the spring and diaphragm age, the Wastegate Adjuster has less tension to close the waste gate, and it stays open and reduces boost. Shortening the rod compensates for the weakness and closes the waste gate like new.

:oops: :oops: :oops: :oops: :oops: :oops: :oops:
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Re: 1996 855 T5 - Musings on Wastegate Adjustment

Post by abscate » Mon Apr 09, 2018 8:37 am

Awarded this 9 April in the year of our Swede 2018
Screen Shot 2018-04-09 at 10.36.24 AM.png
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Re: 1996 855 T5 - Musings on Wastegate Adjustment

Post by wizechatmgr » Tue Apr 10, 2018 7:40 am

It could have been worse... You could be the broke guy that makes sure everyone on government assistance gets their benefits - on time even. :)
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