Installed MBC but still get boost roll off at high RPM. Is my waste gate bad?
#1
Installed MBC but still get boost roll off at high RPM. Is my waste gate bad?
I was changing my vacuum lines and discovered by cycling valve was broken so decided to upgrade to a MBC.
I installed a Lindsey Racing MBC I also did all the vacuum lines at the same time and fixed all my exhaust leaks (stock system) a few weeks ago.
When I went for a test drive to adjust the MBC I noticed the boost drops from just under 15 psi to 10 psi at high RPM in second gear no matter what the MBC is set at.
From what searching turned up the boost roll off would be normal for a stock system with a cycling value but I would expect a MBC setup to hold full boost up to red line.
Is my waste gate bad and just opening when any pressure gets through the MBC?
I installed a Lindsey Racing MBC I also did all the vacuum lines at the same time and fixed all my exhaust leaks (stock system) a few weeks ago.
When I went for a test drive to adjust the MBC I noticed the boost drops from just under 15 psi to 10 psi at high RPM in second gear no matter what the MBC is set at.
From what searching turned up the boost roll off would be normal for a stock system with a cycling value but I would expect a MBC setup to hold full boost up to red line.
Is my waste gate bad and just opening when any pressure gets through the MBC?
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#8
Shoulda got the 62" youlll want one............
Naw.. Get both. Turbo and Wastegate.. But.. then you'll need some management.. Wait then Fuel to keep up, so injectors and pump.. Then you'll need bigger tires.. But then some sort of suspension to handle them... ... It's what we all go through. But... I say wastegate also.
Naw.. Get both. Turbo and Wastegate.. But.. then you'll need some management.. Wait then Fuel to keep up, so injectors and pump.. Then you'll need bigger tires.. But then some sort of suspension to handle them... ... It's what we all go through. But... I say wastegate also.
#13
Methinks your roll off could really be a little bit of both...the 26/6 and a tired wastegate.
My Turbo S with the stock chip, fresh stock 26/8, 3" stainless downpipe/bypass, dual port Tial WG and a Lindsey MBC holds whatever limit I dial into the MBC all the way from 3200 to 6000+ rpm in second and third.
My MBC lives at its lowest setting...staying around 12 psi...and spending the money other guys invest in head gaskets on big TVs and my track toy
My Turbo S with the stock chip, fresh stock 26/8, 3" stainless downpipe/bypass, dual port Tial WG and a Lindsey MBC holds whatever limit I dial into the MBC all the way from 3200 to 6000+ rpm in second and third.
My MBC lives at its lowest setting...staying around 12 psi...and spending the money other guys invest in head gaskets on big TVs and my track toy
#15
I am having the same problem. I have the Lindsey MBC, a 26/8, Russell's chips, a shimmed wastegate, no CV, and all new vacuum lines and my boost still falls off. Also, the MBC does not hold the same boost in different gears. In lower gears my boost goes to 13 -14 then in 4th goes up to 16 -17.