Exhaust holding me back?

[GofaST4life]

Here's the scoop.

With my stock exhaust i was running 15psi very steadily.

Ever since i installed my 3" turbo back i cant build boost past 12-13psi, even though my MBC is set to 15-16psi.

I installed a 3" downpipe (no cat yet), and a 3" cat-back.

Here's were i think my problem is, my downpipe is 3" the outlet is 3", the inlet for my cat-back is 2.5" and the promptly goes to 3" all the way back.


Questions:
1. Is that sudden restriction holding my car back from boost?
2. Is this hurting my car in any way?

 

[habitatguy187]

It shouldn't much of a problem being that far away from the turbo, of course it's not the best thing, but it certainly wouldn't hold your boost back like that. Check for obvious things like boost leaks and every other problem that causes low boost.

 

[daren_p]

Have you tried re-setting the MBC after the exhaust install or did you just leave it at its previous setting, which was 15psi with the stock exhaust & now its 12-13psi with the new system?

 

[pboglio]

My exhaust goes from 2.5" downpipe, to a 2.25" neckdown, then right up to 3" after the 2nd 02 sensor. Not saying its helping me, but I've laid down some impressive power despite it.

What you've described is the polar opposite of what usually happens. Every time I open up my exhaust further the boost just keeps increasing. Your problem is something else.

 

[GofaST4life]

Have you tried re-setting the MBC after the exhaust install or did you just leave it at its previous setting, which was 15psi with the stock exhaust & now its 12-13psi with the new system?

I never actually thought of this. I will read adjust and see what happens.

Thanks for the reassurance, i was feeling guilty about being cheap and was going to spend the money and make it right, but after what you guys have said i feel better about it.

Money is tight anyway.

thanks guys.

 

[GofaST4life]

I adjusted my MBC and there was no change, looks like my MBC isnt working and she is just running off the wastegate which would make sense since once i hit 11psi, she goes no further.

Looks like ill need a new MBC, damn.

 

[Spoolin18]

I adjusted my MBC and there was no change, looks like my MBC isnt working and she is just running off the wastegate which would make sense since once i hit 11psi, she goes no further.

Looks like ill need a new MBC, damn.

I got a new one, Its a sloboy racing with stainless steel internals. PM me if interested.