Boost

For those of you not faint of heart, who believe the Volvo 480 should have more torque and horsepower, find all you need to know in here.

Moderators: jifflemon, coyote1980, Rachel

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lee-bob
480 Newbie
Posts: 4
Joined: Fri Jun 23, 2017 6:05 am

Boost

Post by lee-bob » Wed Aug 09, 2017 6:02 pm

Hi all,after boost problems I checked solenoid only to find the red pipe had snapped off so I fitted mbc.car only boosts to about halfway on the gauge and on another gauge straight from the inlet it's about 4psi.i wound the mbc all the way out and still the same,any ideas? Or do I need a certain boost controller? Many thanks

jifflemon
480 Is my middle name
Posts: 1090
Joined: Sat Dec 17, 2016 11:03 am

Re: Boost

Post by jifflemon » Thu Aug 10, 2017 4:46 pm

Whats sort of MBC are you using?

I'm fairly certain the Turbo doesn't respond well to MBC's, as they use a similar system to the Saab APC.

Essentially, boost is controlled by the ECU, which opens a solenoid to bleed off boost.

Irolllowvo
480 Newbie
Posts: 11
Joined: Tue Jul 26, 2016 9:25 am

Re: Boost

Post by Irolllowvo » Mon Oct 29, 2018 9:27 pm

Jeff is right, the ignition ecu (small black unit in the centre console) also controls boost.

I stole this segment which may be of use;

"The b18ft has a wastegate, which is connected to the turbo housing by a little silicone line. On it, you will also find a little electromagnetic valve. This valve is used by ECU to control the boost.
One of the major problems with the b18ft is that the ignition controler also has an overboost switch you can not tamper with. The result is that with this ECU it is not possible to go above 0.9-1 bar"

My vehicle is fitted with a bleed valve, there is no vacuum pipe to the ecu the port on tgevecu is blanked. I have to say I'm not overly excited about this as it carries it's risks.
However it may be helpful to you in the interim.

Previous car I had was fitted with a cheap mbc, I uprated the recirculating dump valves to vw/Audi parts as found on the tt Turbo

I used 2, one was fitted after the icv and the other into the pipe that fed the turbo. The car was idling erratically before hand as the diagphram had failed in the standard recirc valve. I believe the use of the mbc had killed it.

Hopefully this information is helpful

Ed

WhiteWolf
Knows an Aerodeck isn't a 480
Posts: 231
Joined: Sat Dec 20, 2014 1:50 pm

Re: Boost

Post by WhiteWolf » Thu Jan 31, 2019 6:31 am

If I remember correctly the failsafe level of boost is 4psi, say for example the solenoid was unplugged it would register only 4psi...
There are resistance parameters to be met for the boost solenoid but I can't remember them, maybe 30ohms??
I would get rid of the boost controller and try and get a modified ecu done by board member Robou...
Good luck...
91 480 Turbo white
with Roboumod..
91 480 Es silver

fireblade
480 Newbie
Posts: 6
Joined: Mon Oct 14, 2019 9:10 am

Re: Boost

Post by fireblade » Sat Dec 07, 2019 8:32 pm

Regarding the boost valve, I would like to know how it works.
The valve has three hoses connected, one goes to the wastegate actuator, but I don't know where the other two hoses goes to. The valve also has an electrical plug that I think it connects to the ECU.

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