I need a Mechanic!!Someone who knows Volvos

cpozzer · Post by **cpozzer** » 28 Jul 2004, 10:30

Ok!Today a went to a guy to install this valve that lets out the air that remains in the tubes!(we call it popoff)Im from italy and i dont know the technical words for all this.
After he installed the valve we found out that volvo turbos dont have much pressure (aprox 0.4bar).
Does somebody know how to get more pressure out of that turbo?is it difficult?will this create problems to the engine?How much pressure can i get out of it(must be safe).
Thanks

I have an 1995 Volvo 850 T5R,2000cc(not2300).210hp

Post by **matthew1** » 28 Jul 2004, 10:40

You need what is called a manual boost controller. It's a very inexpensive small mechanical device that overrides the computer's boost pressure setting. This is from my Tips page (found in a scrolling window on my Main page):

Manual Boost Control...
Rich S

If you're using the stock ecu programming then I wouldn't go anymore than 13 psi. There are some good tuners that have spent many hours tuning the fuel and ignition maps to allow more boost, like 18psi. In doing this they can maintain reasonable peak cylinder pressures and still allow more boost. If you just turn up the boost without optimizing the fuel and ignition maps then bad things will happen. I have run 18-19 psi in mine for over 10k miles with no problems.

Do a Google search for 'manual boost controller volvo 850' and you'll see some results. Be careful, you can blow your engine with these. I'd recommend a performance chip from TME (Sweden).

SweedSpeed · Post by **SweedSpeed** » 08 Apr 2012, 21:01

Hey Fellas

Regarding the MBC Matt mentioned above, I'm having trouble wrapping my brain around how to use this in conjunction with the turbo control valve. I have the IPD HD TCV and want to continue using it. Would I splice the positive pressure line to the turbo, attaching to the MBC and run the line from the MBC's waste port directly to the waste gate/ bypass valve? Would I just leave the HD TCV port for the bypass valve without tubing? Would I need to plug it? I appreciate your feedback!

D_V_ENT850R · Post by **D_V_ENT850R** » 09 Apr 2012, 11:56

The MBC goes inline with the line from the TCV to the wastegate. That is all you need to do. Leave all other hoses alone. Should be fine.

SweedSpeed · Post by **SweedSpeed** » 10 Apr 2012, 21:34

Thanks D_V. Just wasn't thinking the ECU/ TCV would allow it to be that easy.

SweedSpeed · Post by **SweedSpeed** » 20 Apr 2012, 00:23

So I installed the MBC inline to the wastegate. It does indeed work well, holding at 10 lbs as it was set, but it does not allow the TCV to regulate boost pressure in the low gears. So rather than 5lbs in 1st and 2nd, where I set the actuator arm, it builds 10lbs in ALL gears and I'm really not tryin to buy a new cam shaft. Any ideas on how use the MBC so that the TCV will control boost in the low gears but allows more pressure to 3-5? This was what I was getting at in the original post.