Manual Boost Control opinions wanted

[SweedSpeed]

Installed mine this morning, in my S40 T4, and have set it to 1.2BAR, about 17.40456 PSI.

I have read quit a bite about this and without ECM/ECU remapping its as high has I should go.

According to my math the engine gained about 31bhp. I made mine. It costed me 10,80€. Very cheap way to gain horsepower.

My car is running on LPG, and because of the extra boost pressure I will have to adjust the LPG pressure as well, otherwise it keeps reverting to gas.

So far the engine runs very well and without a glitch.

Here is a photo of mine:

Hey dtm - wondering if you can give me some pointers on how you installed the MBC? The current configuration I'm using allows the TCV to calculate/ regulate boost and keeps it below 6 lbs (where I have the actuator arm set) so as not to damage valves/ cam shaft in 1st and 2nd gears, but won't allow the pressure to get any higher. The original suggestion suggested installing the MBC inline from the TCV to the waste gate, but that allowed way too much pressure to build (whatever the MBC was set at) in low gears. I;m out of the danger zone but cannot utilize the MBC!! Please help if you can. Thanks!

[dtm]

Hi,

Not sure I understand your issue. Way shouldn't the car hold has much boost with low gears has it does with higher ones? Valves and cam shaft rotate at the speed in every gear. The TCV (is it some king of boost control solenoid?) if it works like BCS, is regulated by the ECU/ECM and regulates boost according to the parameters set by the ECU/ECM. If you hook a MBC in line with the BCS, before or after, the boost should be the one set by the controller with the higher settings. With an MBC you cannot regulat different boosts according to the gears. You set a boost of 17psi or what ever and that is what it should do through every gear. If the actuator arm of the wastegate is set to a very low boost you could andup with a wastegate not strong enough to hold the flap closed (it is happening to me). The turbulence coming from the exhaust gases is strong enough to open the wastegate flap and release boost pressure before the intended value. I'm about to install a helper spring to hold the boost set by the MBC. The best way to do it is to get a new wastegate with a stronger spring.
The only way to do what you intend is with a remap, where you can choose the max amount of boost in every .

Good luck

[SweedSpeed]

dtm,

Thanks for taking the time to answer. To speak to your first question, I am told by persons far more qualified than I (to include some of the folks at IPD) that too much pressure in the low gears will bend rods and possibly even the cam shaft. They have recommended not exceeding 4.5 lbs in first and second gear though I see a lot of guys pushing 6 lbs. It is also recommended that one should not exceed 12-13 lbs total unless you're talking about the R series engine.

As for the TCV, yes, it is a boost control solenoid. This one comes from IPD and they call it the Turbo Control Valve. It is regulated by the ECU. The wastegate, or compressor bypass valve, was upgraded with a heavy duty spring good for up to around 15 lbs, so I;ve got that covered. I see what your sayin about the boost pressure defaulting to the one with the higher setting. Perhaps the only answer is a proper tune.

Thanks again

[dtm]

Hi SweedSpeed,

Good luck with that.

Cheers,

Daniel

[deadmerelda]

I have no idea how best to safely boost my V70 yet. This looks like good reading here. The Conquest/Starion guys I run with like the Greddy Profec-B. Real nice and adjustable with a few presets. Obviously not like an $18 mbc though.

[SweedSpeed]

Wish I had an answer for you. I've been after this one for quite some time. pkplok posted this link: http://forums.vwvortex.com/showthread.p ... Controller , on another thread i started on the same subject. The forum is applicable to VW but the process described would seem to work, in theory. The meat of it is the below diagram on how to allow the ECU/solenoid to regulate boost in lower gears while utilizing the manual boost controller in the higher gears. I've reconfigured to match the diagram and it seems to work but have now realized a leak somewhere that won't let me build more than 10 # of boost so I cannot recommend just yet. I'll post again after I have located the leak and replaced the part.

Regards
Geoffrey

mbc_parallel.jpg (55.08 KiB) Viewed 4745 times

[dtm]

Hi SweedSpeed,

The diagram is much different then hooking an MBC in line with the BCS, but still, it will work fine regulating the low end boost, but I think, unless the n75 valve cuts out at a certain rpm you might never be able to achieve the top boost you're looking for, this is, if the n75 valve is always bowling of boost, and you have set the MBC for say 17psi, it will be difficult to get to those 17psi because you are always losing part of it through the n75 valve. Of course I don not know how the n75 works, and what parameters it is following, but it is indeed very interesting. My s40 is currently doing 1.1bar with stock BCS. Just yesterday it was spiking above 1.5 bar (my boost gauge only goes to 1.5bar), so this morning I toned it down, but still I'm going to set the MBC to 1.3bar and hook instead of the BCS.

Regards,

Daniel

[SweedSpeed]

Hey dtm,

Yea i found the above after I posed the question to you, asking about the inline configuration; this one is totally different. The n75 is either a VW part or something aftermarket that that fella was using. I just borrowed the theory. Good point thought, about there always being some bleed-off present with the t-fitting to the CBV. Though the fella that posted the link to the diagram seemed to be able to achieve much higher boost levels. It is encouraging to think I may not have a leak after all. Weekend is booked but when I get a moment, I'll plug the line to the CBV, just to see if I can actually get more than 9lbs of boost.

BTW...Is your S40 a R design? Just wondering if you heard anything about the risk of pushing too much boost, in the lower gears, if it is not.

Take care,
Geoffrey

[97_boostedgLt]

MBC+Properly Tuned ECU= LOTS OF FUN! of course stage zero and other little mods. Its all in the tune of the ecu! my ecu is tuned to only allow 3lbs in 1st and so forth, or once im passed 3000 rpm all hell breaks lose! Have my 850 gLT with the 13g turbo pushing 12 lbs of boost at 242 hp all day long and not a single problem! LOTS OF FUN!

[bouldergeek]

I had one of the flEaBay cheapo boost controllers on my old 244ti.

I put it between the positive pressure line off the turbo housing and the wastegate actuator.

I upgraded the in-dash boot/vacuum guage to a calibrated one. I ran the MBC at 12lbs max. More than that and I would detonate on 93 octane at 5300 feet of elevation.

Worked OK for a bit. Blew off the throttle body intake hose a few times.

When my car started throwing codes and behaving badly, I took it to my shop for diagnosis. I also had an IPD adjustable cam pulley, which I experimented with in advancing and retarding timing.

On picking up the car, I was handed back the MBC and informed that it was ghetto and they wouldn't work on diagnosing the car with it installed. Also, they reset the cam timing to 0.

I was a little irritated at this. After the car returned to being a dependable driver (though not as fun), I forgot about the MBC and just drove.

I have to say that these shop mechanics are probably the best Volvo people in Colorado and I respect their experience and opinions greatly. I have come to them with many problems, and like good doctors, they politely ignore my self diagnoses and fix that's wrong. So, I haven't run an MBC since. YMMV.