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wastegate? ???????

S

srutherford

New member
Joined
Jan 3, 2011
Location
knoxville TN
Hey guys I have a 940 turbo and am new to volvos. I was woundering how I could open the wastgate sooner to get more low end response out of my turbo mu actuator arm doesn't seem to be the adjustable type i
 
How is opening the wg sooner going to help with responce?
 
An Manual Boost Controller is what you want.

And I would recommend some search and reading about turbos and how everything works. Typically you want the WG to open later for quicker spool up, this is what an MBC does in delaying boost signal to the WG until it reaches its set pressure which also can cause a spike.
 
Ok well. How would I improve. That low end responce I have installed a boost guage and have mbc on the way can some one post pics specifically on were and how to install the mbc.
 
Good luck finding some, I bought the last two 18x8.5 5x108 Type FS wheels that Borbet made . . right from the factory.

I have two spare 18x7.5's but those shall be spares for now.
 
hook the vaccume line for the wg directly to your manifold, helps spool up a hair and gives you another 2 or 3 psi....
 
boosted12a said:
hook the vaccume line for the wg directly to your manifold, helps spool up a hair and gives you another 2 or 3 psi....
Click to expand...

He's saying that without an MBC, to get a 2 or 3 psi gain, you can take the rubber hose that connects the wastegate actuator to the compressor housing, and replace it with a longer hose that connects the wastegate actuator to the intake manifold. You would then need to plug the port in the compressor housing since it's no longer being used.

This will delay the wastegate opening because you have lowered the actuator inlet pressure across the board. Let's say the compressor is making 10psi max. There will be some pressure losses between the compressor and the intake manifold (2 or 3 psi), so the actual manifold pressure is lower than what's coming directly out of the compressor housing, say 7 or 8psi. Lower actuator pressure --> actuator doesn't open yet --> turbo spools up to higher boost --> eventually actuator will open when manifold pressure reaches 10psi, meaning compressor outlet pressure is now at 12-13psi --> Yay, more boosts!

This is definitely a simple upgrade if you want to try it. The downside is that most wastegate actuators aren't meant to see vacuum, which will develop in the intake manifold when the throttle is closed and at lower load mid-range engine speeds. The neg. pressure (vacuum) in the actuator can will potentially invert the internal diaphragm and tear it.

Personally I would just install the $15 MBC ... it has the same basic affect. Bleeds pressure off before it gets to the actuator, thereby delaying WG openage and increasing max boost.
 
Yea I have a mbc I am just confused on how to hook it up. I just don't want to screw it up and also I have a sunpro boost gauge will it calibrate its self and when it does how do I know how much boost I have now before the mod. Thanx
 
If your boost gauge shows both vacuum and boost, plumb it into the intake manifold, after the throttle body. If it's just boost (0 - 20psi for example), then T into your wastegate hose between the compressor housing and the wastegate actuator. Do this before you install the MBC. Make some full-throttle pulls in a few gears (2nd, 3rd, 4th) and note the max pressure on the gauge. This is "how much boost" you are running now.

There basic way to route the MBC is shown here: http://www.dsmtuners.com/gallery/files/8/0/8/3/6/MBCpic.bmp

It may even come with instructions. Your boost gage should be T'd in between the compressor housing and MBC, if it's not hooked up to the intake manifold (in which case you don't need to change the gauge hose routing). Now you can adjust the MBC and see the results on your previously-installed boost gauge.
 
Ok it does show vacuum and boost. Can I not hook it up to the factory gauge feed? And then link the mbc in between the wastgate and turbo that vacuum line is what im talking about
 
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