Set MBC properly without doing runs?

[gsxofftheline]

Hello,

I researched and found all the same answers to my question. How to set your MBC? Everyone said to hook it up, back it out all the way and do WOT runs in 3rd and redline it and see what psi it has, pull over and turn it down, and keep doing that till you get the psi you wanted. My question is, How to set your MBC to a certain psi without having to do WOT runs in 3rd gear. Not only does it take some time, trial and error, but it wastes fuel and gets frustrating at times. So I having a problem with my JOE P MBC and it was dropping boost from 12 psi to 7 psi. Took it apart and found out that the rubber seal was ripped causing air to blow right past it. Replaced the seal and tested it. Hooked up a accurate bike pump with a gauge. Pressurize it and it would open at where I wanted it to be, at 15 psi. Now my question is...

I have no boost leaks by the way. If I want to run 15 psi on my car, can I just set the MBC to 15 psi on a bike pump and save all the hassle and time? Or am I missing something?

Or do I ajust it this way.--->My WG opens at 7 psi, so if I were to have my boost set to 15 psi, I need to set my MBC to 8 psi correct? Kind of hard to explain, but if I set my MBC to 8 psi it would open to the WG causing the WG to build pressur to 7 MORE psi having a total of 15 psi? Someone correct me if I am wrong. Thanks.

 

[Ceddy]

Hook your MBC up to a air compressor and set the regulator to the boost you want to run.

Then keep loosening the MBC knob until it lets air through.

Your MBC will be set to the air compressors pressure.


With Ball and Spring Controllers you set the MBC to the boost you want.
It won't let air thru until that pressure is reached.
The wastegate spring pressure doesn't have any effect on the MBC.

 

[dsmfa9nutter]

What's the point in modding a car for more power and speed if you're worried about fuel consumption and "wasting time driving it"?

 

[Dert]

What's the point in modding a car for more power and speed if you're worried about fuel consumption and "wasting time driving it"?

good point

 

[gsxofftheline]

What's the point in modding a car for more power and speed if you're worried about fuel consumption and "wasting time driving it"?

Well I would like to adjust psi correctly without doing runs all the time without breaking the speed limit and possibly getting a ticket, and wasting fuel to get the right psi reading, I'd say its not worth the risk. If I put all this time and money into my car and get pulled over I'm screwed. I race legally on a track. From what I researched on tuners forums is to do 3rd gear pulls at redline, see what your boosting, pull over and adjust acordingly, then do the same thing over and over untill you get the desired psi. Which is correct but 3rd gear redline is around 100 mph. Do you know any place that has 100 mph speed limits? I didn't think so.

So I'm asking if I can save that risk of doing five 3rd gear pulls, save fuel, and save the risk of being pulled over, by just simply adjusting it without even driving it? Do you understand now why I made this post?

 

[gsxofftheline]

Hook your MBC up to a air compressor and set the regulator to the boost you want to run.

Then keep loosening the MBC knob until it lets air through.

Your MBC will be set to the air compressors pressure.


With Ball and Spring Controllers you set the MBC to the boost you want.
It won't let air thru until that pressure is reached.
The wastegate spring pressure doesn't have any effect on the MBC.

Ok the reason why I ask is becuase when the mbc opens up, it lets the boost to the wastegate, doesn't the wg need an additional 7 psi to open? If I set the MBC to 15 psi, when it opens, the wg will open automatically with it? Thanks.

 

[dsmfa9nutter]

Third gear redline pulls are for dyno runs, not for setting your mbc. You can get full boost in first gear just fine.

 

[gsxofftheline]

Why is everyone on tons of threads suggesting 3rd gear redline pulls? Thanks

 

[Ceddy]

Ok the reason why I ask is becuase when the mbc opens up, it lets the boost to the wastegate, doesn't the wg need an additional 7 psi to open? If I set the MBC to 15 psi, when it opens, the wg will open automatically with it? Thanks.

No, when your MBC opens 15 psi will be fed to your wastegate.

The MBC is a valve and the wastegate is diaphram actuator.

Just set your MBC to whatever boost you want to run.

 

[Defiant]

Gosh, it's a pity there aren't any thread about adjusting MBCs on this site. They could be really helpful.