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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 »

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 »

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.
s70 '98 2L na manual Image || 850 T5-R '95 auto Image
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Re: 1996 855 T5 - Musings on Wastegate Adjustment

Post by abscate »

Reviving old topic

Here is the picture of my discontent
7CD81C68-8752-4D11-B428-AAC95D55E80F.jpeg
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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 »



that should explain it
s70 '98 2L na manual Image || 850 T5-R '95 auto Image
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Re: 1996 855 T5 - Musings on Wastegate Adjustment

Post by abscate »

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 »

Awarded this 9 April in the year of our Swede 2018
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Re: 1996 855 T5 - Musings on Wastegate Adjustment

Post by wizechatmgr »

It could have been worse... You could be the broke guy that makes sure everyone on government assistance gets their benefits - on time even. :)
Wisdom requires knowledge as a prerequisite, but knowledge can be developed due to a lack of wisdom.
In order to learn how to fix something, you must first learn how to break it.
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