Boosting SR

[SlowTK]

Alright, first of all, I want to say that I feel really stupid even having to ask this question but I have read many topics and still cannot find a definate answer.

Installing a S13 SR here is the next week or so, factory T25. In order to up the boost with a MBC, what is all needed to be done? Understood that you have to hook the darn thing up, but as far as the wastegate with the turbo?

From my understanding, it is an internal wastegate on the T25. So, how does one go about closing it off?

Thanks in advance for helping with this lame question

[9240sx]

If your going to up the boost,You will need the supporting mods to do it.Fuel pump,Intercooler,exhaust....And the only way to close off the wastegate on a factory sr turbo is to weld the wastegate flap closed..

[SlowTK]

Supporting mods will be installed with the SR (Thanks for the advice though). Another question though, because the turbo housing is cast, won't the welding on it be a bad thing?Because of the nature of cast metal, only one part of it would get hot with the rest of it being relatively cool, won't it crack? Or, am I putting too much thought into this...

Thanks for the response

-TK

[green91]

You can use a mbc with your internal wastegate. the MBC goes inline between your boost reference source and the wastegate actuator.

[Blown240sx]

WOOOOO do not weld ANYTHING!!

Your internal wastegate is there for a reason. You weld that flap shut your gonna blow that turbo or motor.

Little info for ya. The boost is regulated by exhaust flow. Hince the Wastegate. When you get to the boost level the wastegate is set for it opens a flap and allows exauhst to bypass the turbine. If this is welded closed the turbo will spool till something blows which will either be the turbo or motor.The MBC is kind of tricking the wastegate. It allows pressure to be realeased into the air so that the wastegate doesnt reach the pressure signal it needs to open (till later). Thus making more boost.

MBC is to be plugged into the vac line running from the Wastegate to a pressure point. Like intake manifold or cold pipe.

Little diagram

Wastegate---------- Manual Boost controller---------- Pressure Signal (Adjust the opening of the MBC will raise or lower the boost)

Tips: Close the MBC all the way then open it a few turns. Then run the car to full boost see what you get. And adjust a turn or so each time till you get close to the boost you want. If the car begins to boost higher than you want let off and turn it down.

[Nismo_Freak]

Alright, first of all, I want to say that I feel really stupid even having to ask this question but I have read many topics and still cannot find a definate answer.

Installing a S13 SR here is the next week or so, factory T25. In order to up the boost with a MBC, what is all needed to be done? Understood that you have to hook the darn thing up, but as far as the wastegate with the turbo?

From my understanding, it is an internal wastegate on the T25. So, how does one go about closing it off?

Thanks in advance for helping with this lame question

A turbocharger spools using exhaust gas energy. The compressor will spool and begin to flow more air than the engine can consume. This creates a back-up of airflow in the intake system and the pressure will rise (boost pressure).

What prevents a turbocharger from overpressurizing the system is the wastegate. It vents exhaust gas away from the turbine when it opens, which regulates the speed of the compressor wheel.

You have two types of wastegates. Internal and external. External look like this:



and internal wastegates look like this:



Notice the flapper door on the left, it's opened by an actuator.

The SR T25 has an internal wastegate, so all wastegate operation is determined by the wastegate actuator, seen below.



#2 is the actuator, you can see the mechanical connection to the wastegate flapper.

Now, the actuator opens when it sees 7 PSI (from a vacuum line that runs to it). What a boost controller does is restrict the line to mask the real boost pressure the engine is running. The wastegate will see 7 PSI and open, but the engine will actually be running at 14 PSI.

[SlowTK]

Ah ha, I see the light now. Thank you very much for all your information and especially Nismo_Freak for the pics, since I am more of a graphic with my understanding.

One last question. With the purchase of a MBC (brand name, not a Home Depot jerry-rig), I would assume that if it is made for a S13 SR, it would come with all the necessary equipment.

Correct me if I am wrong, but is it close to a 'plug-and-play' application or is it more in depth to the point to I would need to have the engine out of the car in order to install the MBC?

Once again, thanks for the info and taking the time to answer.

-TK

[boost_creep]

its a simple matter of cutting the vacuum line and put the mbc inline.installation takes two minutes.but then you gotta set at the desired psi.

[drifter_for_life06]

MBC i think are universal? since all you do is tap into a vac line

im personally going to make my own and pay like $15 rather than liek 60 for the same thing with a name on it

[Nismo_Freak]

Ah ha, I see the light now. Thank you very much for all your information and especially Nismo_Freak for the pics, since I am more of a graphic with my understanding.

One last question. With the purchase of a MBC (brand name, not a Home Depot jerry-rig), I would assume that if it is made for a S13 SR, it would come with all the necessary equipment.

Correct me if I am wrong, but is it close to a 'plug-and-play' application or is it more in depth to the point to I would need to have the engine out of the car in order to install the MBC?

Once again, thanks for the info and taking the time to answer.

-TK

It's universal, it installs in the vacuum line that you run to the wastegate actuator.

[SlowTK]

Thanks again for all the input! Hopefully in the future, I'll be giving out knowledge rather than asking for it

BTW, happy Mother's Day to all our mommies out there!

-TK