Hi guys, I'm a newbie to this site...although not newbie to racing, performance. I was thinking of increasing the boost/performance in this car. It's a 2.5t, fwd, nothing fancy. I installed (temporary) a gauge and located it in the glovebox for refrerence....stock, I see 7psi ish...maybe higher on spike. My question involves knowledge of me7 fuel management. I know these cars are difficult to increase boost. My question/thought to all is this, anyone ever thought of manipulating the ecm boost pressure sensor signal to install manual boost controller and "fool" the ecm? I think the maf sensor and closed loop o2 sensor will manage needed fuel enrichment. Any thoughts? just an idea & looking for open minds and/or someone that has done this. I have some testing, minor, and wonder what you guys have done? Ideas? Thanks in advance.

 

MBC and EBC's have been used on the old M4.X cars and the work just fine but the ME7 car's do not play well with the boost controllers. You can do some searching on Volvospeed and sweedspeed. I don't recall the specific reasons but many guys have tried it and there were issues they ran into. The general consensus on the ME7 and ME9 Volvo's is that best and more efficient way to manipulate the boost in these cars is to spend the money on an actual flash tune.

 

volvos are highly tuned, so much so that any little change will cut the engine, its almost as if it can tell some things changed and will go into safe mode
the only real way to create anything more then 1-2Psi higher boost is to get an ECM flash/reprogram
starting at 800 and going into the 3k range

to simply increase HP go ahead and get the R type manifold, a full 3 inch exhaust system, HD Coils, larger fuel injectors and replace all of your intake pipes.

snabb makes a great pre turbo intake and IPD makes all the other pipes (next week they are coming out with a pipe that runs from the IC to the Throttle body for about $148 couple all that with a tune and you could see another 30 hp

add in the ECM upgrade and you could see a grand total of 80HP

 

ok, more information....what if I were to add a air pressure regulator between the charge tube and boost pressure sensor. Lets say, isolate the sensor ....in the past, with a 2000 xc70 se I noticed that once 10 psi was reached, the ecm would cut the etm , essentially killing throttle and boost, performance, etc. So, I "manipulated" the boost signal with a air pressure regulator (like you would use for air compressor, etc. the bleed type does not work) and set it at 8 psi. The ecm will see zero to 8 psi, while the engine got say 15 psi....performed well. I wonder if the maf and o2 sensors were adequate at adding needed fuel...the car ran MUCH better, wolf in sheep's clothing if you will. I did experiment then, that car meant less to me in regards to melting it down if you will. so, laying all my cards out there, what do you guys think? if if performs well, does the ecm enrich enough with only maf signal and o2 signal? I love this car, would love to increase performance like I did with the me7 2000 xc70 car. I just wonder about long term issues. Anyone out there toyed with this? btw, I intially tried fooling ecm electrically by adding resistor to boost press sensor signal....was unable to make this work. thoughts? ideas? experience? thanks again.

 

sounds like the system would run too lean since its thinking it's getting 8psi and really your at 15, the other issue is the CBV will open at 8 psi regardless of with the boost controller is doing, you would have to buy an upgraded spring (about a 10 pound spring) that should get you up to about 17 pounds of boost but still your running lean and probably misfiring left and right.

 

please , i'm trying to understand....I love the input so far. If cbv opens, how did the other car produce boost? I was conservative with mbcv set at ~15 psi. I inspected a turbo from another car like mine (on bench) and noticed the compressor boost pressure pushed on one side (actual pressure inside compressor?) and from intake manifold small vacuum tube carrying boost pressure from intake manifold (and spring pressure in cbv) fighting compressor side of cbv (sealed with rubber gasket). Seemed to balance out & stay closed considering spring and boost pressure pushing on rear side of rubber "diaphram" maybe I'm wrong, dunno. but it worked. I'm telling you I drover this daily for 10k miles with a car that had 147k on original engine....i ran the car hard with daily drive of 50 miles round trip....some city, apprx 18 miles interstate drive. It really ran well, quite well, much more power than stock 5 psi. (trust me, I have experience with 9 second quarter mile domestic n/a stuff) this car ran well and impressed me. My question is does the boost pressure sensor do more than just informing ecm of say, overboost? does this sensor affect air/fuel ratio? I thought maybe the maf and o2 would cover that type of fuel management. thanks again, love the ideas, input.

 

bypass the CBV. then find a way to get the ECM to read the stock PSI. That can be done with a resistor usually.

I have cooked pistons in roundy roundy cars before too much pressure, not enough fuel.

you will have to do something about the lean mixture problem if you go past 12 PSI or so, or risk a meltdown.

 

And the safest way to do that is to get a proper tune.
ARD - Green ME7

 

the CBV only lets off enough to keep the boost pressure at what the ECU wants it to be at, bypassing it would probably be the best thing but then you would need an after market BOV otherwise you would get turbo "flutter" every time you closed the throttle. tune the car properly and you would probably run decently well with this over boost scenario. however after all this work, time and effort and chancing blowing your engine, just go to IPD and buy the $895.00 on the soft loader flash tune

ipd Soft Loader Engine Managment Flash Tune

 

these engines are built insanely well (connecting rods, crank, oil hydraulic system) Keeping everything in balance as you tune is key to not causing damage. Stock long block is good for 350-400 crank before you run into issues on paper of the strength of the components.

There are other proven methods out there that don't involve ECM tuning, though it does help. Running a 100% custom engine control computer is ideal, but very difficult, unless you have the knowledge to build the "maps" yourself.

 

That would be ideal but like you said, difficult not to mention expensive.
Is there a stand alone system out there for the ME7 cars yet? I haven't seen one.
Some of the guys with the built 850/X70 cars have put up some very impressive numbers with turbo tuner or Megasquirt stand alone systems.