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Too much boost at low RPMS?

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
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shawneesnaketail
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shawneesnaketail

Too much boost at low RPMS?

Post by shawneesnaketail » Sun May 05, 2019 1:32 pm

Hello all, I have recently done a full overhaul on my MY95 turbo wagon as well as removing my catalytic converter. My car is boosting great up to 12psi and holds pressure throughout WOT. My concern is lower RPM boost. It seems as though sometimes (not all the time) depending on engine load or if going up a hill I will get up to 6psi of boost at 2500-to 3000 rpms. I don't like the idea of destroying my engine, but after the cat removal there seems to be much less turbo lag as boost is appearing much quicker. What is the danger zone on these cars? At what RPM should I be getting boost?

Thanks!



Sommerfeldt
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Sommerfeldt

Re: Too much boost at low RPMS?

Post by Sommerfeldt » Mon May 06, 2019 6:03 am

The automagic cars protect themselves pretty well from too much boost at low RPM. What you should do, is check that your wastegate is set at the right pressure, which will ensure that the engine doesn't see too much boost low down.

My '96 starts building boost pretty quickly from 2300 or so - I don't think your numbers are either worrying or abnormal. :) Boost below 1500-2000 would be a worry, but even then, you would have to have some pressure to be in the danger zone.

Also, put in a cat. What're you doing.

- S


'96 855 T5, R bumper and spoiler, Koni Yellows & blue H&R springs all 'round.

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Clemens
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Clemens

Re: Too much boost at low RPMS?

Post by Clemens » Mon May 06, 2019 7:55 am

shawneesnaketail wrote:
Sun May 05, 2019 1:32 pm
I don't like the idea of destroying my engine ...
I don´t like the idea of you destroying our planet on purpose. Put the cat where it belongs! This reduces unwanted low-rpm-boost as a sideeffect.
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Sommerfeldt


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Re: Too much boost at low RPMS?

Post by RickHaleParker » Mon May 06, 2019 12:17 pm

shawneesnaketail wrote:
Sun May 05, 2019 1:32 pm
as well as removing my catalytic converter.
You are not looking out for the survival of the species, do you really expect others to look out for the survival of your property?
Are you are you Self centered or Sociopathic?
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SommerfeldtClemens


Platform: P80 1998 C70, B5234T3, AW50-42, Bosch Motronic 4.4, Special Edition package, Plant: Uddevalla Sweden.

Platform: X40 (Nedcar) 2003 S40, B4204T3, AW55-50/51SN, Siemens EMS 2000. Plant: Born Netherlands.

Platform P2 2005 XC90 T6 Executive, B6294T, 4T65 AWD, Bosch Motronic 7.0, Plant Torslanda Sweden.
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1997 S90, B6304S, AW30-42, Bosch Motronic 4.4 - Sold

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