I could really use some help. I have just installed an atp gtx3076r turbo since my stock viii turbo went out and now no matter how much I adjust my mbc I can't boost over 22-23 psi. thought the wastegate actuator might need to be adjusted if so do I go tighter with the rod? any help or advice would be hugely appreciated thanks

 

First step do a boost leak test, then go from there. Turning up the mbc will not solve the issue, plus what kind of spring do you have on your mbc? Some mbc have different spring rates. Close mbc all the way down/shut and see what happens, you should get just waste gate boost.

 

I wil check for boost leaks. the mbc was on my car before I installed the new turbo and I was running 25-26psi on the stock turbo. I'm not sure what spring is in the mbc its just a hallman es.

 

He will want to back the MBC's adjustment knob out counterclockwise as far as possible to full soft(-), that is adjust it to the lowest boost setting. Then take the car out for a WOT run in 3rd or 4th gear noting the max boost level indicated on his boost gauge. This reading is his actual spring pressure. By actual spring pressure I mean base spring pressure + preload.

 

no boost leaks. I will turn the mbc all the way closed friday. does anyone know about where I should be with it closed? thanks for all the help guys

 

You should see roughly 12-14 psi just on wastegate pressure.

 

Yeah, you will want to adjust the WGA tighter. Ultimately, how much boost do yo wanna run? Ballpark, I would do three complete 360* clockwise rotations of the turnbuckle just to start. After that, road test it and you may want to tighten it a bit more. But, after the 1st three turns you will want to finalize dialing it in by only 1/2 turn increments(180*) at a time.

Note: Before tightening(adjusting) the WGA back the adjustment knob on the MBC out counterclockwise to full soft(-) which is the lowest possible boost level doable with your MBC. Roadtest it that way before adusting the actuator to establish baseline spring pressure, which should be about what ronaldo9 suggests...13#. But, check it 1st at full soft(-) so as to establish a baseline level.

 

So I turned the mbc all the way counterclockwise and got basically just under 13psi. I would ultimately like the boost to be around where it was before I installed the bigger turbo somewhere at or a little below 30psi. I had it tuned at 30 psi before but I also understand that different turbos are going to change the afrs and require a different tune. but if I could just get it ballpark and safe for the summer I would be happy. Also should I leave the mbc all the way counterclockwise while I'm adjusting the wastegate.

 

Why are you not getting the car tuned?

 

It will get retuned but I really don't want to until I put the O2 dump and turbo manifold on it. I also would like to get it tuned for speed density but not sure how all of that will affect deq since it needs new tags in September.

 

Yes. That is correct. Absolutely, you must leave your MBC adjusted to the lowest possible boost setting while we dial in the WGA adjustment for your turbo.

MBC devices, in general, have a limited range of adjustability ABOVE spring pressure. They cannot adjust boost downwards BELOW spring pressure. They can only adjust boost upwards, above spring pressure.

The upwards range of adjustability on MBC's in general is 10 PSI above spring pressure. We have established that your spring pressure is 13#. Thus, everything else remaining equal, :if the upward range of adjustability with your MBC is 10# then the max boost possible is 23#.

 

Thanks sparky that makes total sense now. I appreciate all of your help

 

How much adjustability(how many exposed threads) are visible behind the turnbuckle and backup nut on the end of the actuator rod?

I am googling for an image of the wastegate setup on your ATP turbo so as I can visualize what we are working with since it is different from the stock frame actuator setup on MHI turbos.

Got a pic by any chance?: Does the actuator rod have an almost severe right angle bend to skirt around the turbine housing? By contrast, the Evo X ATP 3076 actuator rod setup is almost a straight shot affair axially.

 

I really just need to know how many threads are visible on the actuator rod.

 

there is only adjustment on the actuator side of the rod and there is probably 7-8 threads showing. the way the rod has a bend in it I will only be able to turn it full 360