I have a question what vacuum source or line would you put a universal vacuum block in? Is is efficient or would it not be advised? I'm going to hook up a MBC, Blow off valve when I got FMIC, and add a boost gauge. Any info would be great!. Thanks
Universal Vacuum Block
- Thread starter PakmanMP5
- Start date
- :
- Completely Stock P5
Search. Use the brake booster line BEFORE the check valve.
OP: If you have an MS3 as in your sig, be careful. I think you need to do some reading in this forum before proceeding with your plan. Your options for mods do not seem to be well thought out, if I may so suggest.
MS3 has a MAF sensor controlled engine. Blow off valve (vent to air) is bad for this engine. You don't want to be expelling already metered air to atmosphere. The ECU will be sending a signal to the injectors to spray a particular amount of fuel based on its reading of the air mass. Expel some of that already metered and calculated air instead of keeping it in the intake and the engine is likely to run roughly, have poor idle, after-fire or hesitate or both between shifts and run pig rich.
And the stock bypass valve (BPV) is a very sophisticated dual diaphragm design. It has been shown consistently to hold as much as 2 psi higher boost at high rpm, high load conditions than the most popular aftermarket bpv. It is extremely smooth in operation and rarely fails. Most guys that claim it leaks are just looking for an excuse to buy some eye candy bling to put on their engine to show off to their buddies at the expense of smooth and more powerful performance. Only if you can prove that it leaks should you consider replacing it, IMHO. If you insist on spending money on an aftermarket valve, make sure you get one that allows recirculation and has the correct fittings to recirculate the released air back into your intake post MAF.
As to vacuum block on the MS3, probably no need if you are simply running one vacuum device such as a manual boost gauge. All you really need for that is a "T" fitting off of the vacuum/boost line on the stock BPV. Very simple and works well for me.
Finally, I would also question the wisdom of trying to run a MBC on this engine for anything other than the occasional short term use at the drag strip, if we are talking about the MS3. Personally, I think MBC's in combination with the way the ECU controls this engine otherwise and the direct injection fuel system makes it very difficult to safely control this engine in the long term. The DISI engine needs to be able to taper boost under wide open throttle high rpm conditions. There is an ECU load cap that cuts in at around 17.5 psi. It is there for a reason. ECU reflash can change mapping to make the load cap higher and do it safely. But you can only safely raise boost about 2-3 psi on the DISI engine before turning the little K04 turbo into a flame thrower. After about 18-19 psi on pump gas all you get is more heat and not more power, and that is only at lower rpm when first coming up on boost and up to about 5,500 rpm when the throttle plate starts closing, even with an MBC. So pushing more boost through a closing throttle plate makes no sense.
And, on stock tune it makes no more power to maintain high boost out past 5,500 rpm. It does dramatically raise exhaust gas temps and puts the turbo and the engine at risk for failure.
There are threads here on proper connection for a MBC, and it is NOT traditional, because of the presence of a restrictor pill in the boost line coming back off of the turbo compressor. I'm not conversant in that, but if you must try it, read those threads carefully to make sure you have it connected properly.
For short term, (put it on, then remove it), at the dragstrip and limiting boost to 18 psi, it would work. For regular use, MBC's . . . I think not.
Much better solution would be to spend the money you would spend on the MBC, the FMIC (marginal benefits unless you spend a lot of time stuck in traffic and heat soak the stock TMIC) and fancy, expensive BOV on a tuning option such as Hypertech or AP, again if we are talking about MS3.
I am assuming you already have some form of aftermarket intake, either CAI or SRI, because that is where you should begin your modding. You can gain an honest 15-20 whp by that mod alone and improved air flow is the beginning point for all power mods on the DISI engine.
MS3 has a MAF sensor controlled engine. Blow off valve (vent to air) is bad for this engine. You don't want to be expelling already metered air to atmosphere. The ECU will be sending a signal to the injectors to spray a particular amount of fuel based on its reading of the air mass. Expel some of that already metered and calculated air instead of keeping it in the intake and the engine is likely to run roughly, have poor idle, after-fire or hesitate or both between shifts and run pig rich.
And the stock bypass valve (BPV) is a very sophisticated dual diaphragm design. It has been shown consistently to hold as much as 2 psi higher boost at high rpm, high load conditions than the most popular aftermarket bpv. It is extremely smooth in operation and rarely fails. Most guys that claim it leaks are just looking for an excuse to buy some eye candy bling to put on their engine to show off to their buddies at the expense of smooth and more powerful performance. Only if you can prove that it leaks should you consider replacing it, IMHO. If you insist on spending money on an aftermarket valve, make sure you get one that allows recirculation and has the correct fittings to recirculate the released air back into your intake post MAF.
As to vacuum block on the MS3, probably no need if you are simply running one vacuum device such as a manual boost gauge. All you really need for that is a "T" fitting off of the vacuum/boost line on the stock BPV. Very simple and works well for me.
Finally, I would also question the wisdom of trying to run a MBC on this engine for anything other than the occasional short term use at the drag strip, if we are talking about the MS3. Personally, I think MBC's in combination with the way the ECU controls this engine otherwise and the direct injection fuel system makes it very difficult to safely control this engine in the long term. The DISI engine needs to be able to taper boost under wide open throttle high rpm conditions. There is an ECU load cap that cuts in at around 17.5 psi. It is there for a reason. ECU reflash can change mapping to make the load cap higher and do it safely. But you can only safely raise boost about 2-3 psi on the DISI engine before turning the little K04 turbo into a flame thrower. After about 18-19 psi on pump gas all you get is more heat and not more power, and that is only at lower rpm when first coming up on boost and up to about 5,500 rpm when the throttle plate starts closing, even with an MBC. So pushing more boost through a closing throttle plate makes no sense.
And, on stock tune it makes no more power to maintain high boost out past 5,500 rpm. It does dramatically raise exhaust gas temps and puts the turbo and the engine at risk for failure.
There are threads here on proper connection for a MBC, and it is NOT traditional, because of the presence of a restrictor pill in the boost line coming back off of the turbo compressor. I'm not conversant in that, but if you must try it, read those threads carefully to make sure you have it connected properly.
For short term, (put it on, then remove it), at the dragstrip and limiting boost to 18 psi, it would work. For regular use, MBC's . . . I think not.
Much better solution would be to spend the money you would spend on the MBC, the FMIC (marginal benefits unless you spend a lot of time stuck in traffic and heat soak the stock TMIC) and fancy, expensive BOV on a tuning option such as Hypertech or AP, again if we are talking about MS3.
I am assuming you already have some form of aftermarket intake, either CAI or SRI, because that is where you should begin your modding. You can gain an honest 15-20 whp by that mod alone and improved air flow is the beginning point for all power mods on the DISI engine.
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