Primary Turbo Won't boost over 10 psi...
 

Ok, so I have a weird issue. I just built the car and I can't get the primary turbo to boost over 10 psi. I'm getting the 10-5-5 boost pattern, but I need to sort the primary before moving on to the secondary. I have read a lot and gone through the trouble shooting steps for the primary turbo with no luck...I haven't found too much on people not being able to raise the boost on the primary turbo.

Mods: 1000 miles on everything
Large Streetport
Rebuilt Stock Twins (ceramic coated manifolds)
Power FC (Set at .9 bar = 13.2 psi)
AzKnightz Solenoid Rack (Simplified Twins)
3"exhaust to a turbo muffler (basically zero restriction)
Ported Wastegate
FIC 650/1650 injectors
Twin Power
ETS FMIC
New OEM harness with depinned emissions and relocated turbo control wires

The car is built to push the twins at 1bar until I decide to go single, but I can't get the primary turbo over 10 psi. If anything I would have thought I would of had boost spike issues! I'm have some secondary issues going on too (that I believe are wiring issues from relocating the wires), but the primary needs to be sorted first.

I have checked the following:
- Charge Control closes when you turn the car on and transitions to Turbo Control at 4500. Vacuum and pressure open and close the plate properly.
- Both wastegates open and close under pressure 10 & 15 psi
- Turbo Actuator (bottom of car) moves in and out freely
- The car had Holley 62 (.061") in the primary and secondary lines, and I changed to 58's (.057") jets with no change.

I know most people have a problem with getting no/low boost or boost spikes, but I can't get over 10 psi. Changing to smaller pills should have netted higher boost pressure, so I'm thinking I'm losing boost from either the turbo actuator bleeding off exhaust to the primary turbo or the primary ported wastegate is blowing open early. I checked both the vacuum and pressure tanks to make sure they aren't leaking with air, but I'm going to check them under water.

Has anyone had this issue before?
Any additional areas to look or test procedures?

Thanks in advance.

Sounding a lot like a boost leak.

At only above 10psi? Wouldn't it leak before that too?

I think you are right...I went and rechecked all the vacuum lines on the car again. I found the "E" solenoid had a broken vacuum line right at the solenoid nipple from the vacuum tank.

I replaced that vacuum line. Since it controls the turbo actuator, there is a noticeable difference above 4500 rpm. The secondary turbo kicks in and I'm getting mid 8 psi to redline, but now there is a very noticeable wooshing sound (like a boost leak).

Once it gets cooled off again I will use my homemade pressure test system and hunt down that leak. Sometimes the simplest suggestions trigger checks!

1st gear is really anemic...maybe 5-6psi now. Any thoughts? It pulls strong in other gears...maybe the pressure tank?

Big ass boost leak.

Check the couplers to and from the IC for cracks on the bottom sides.

You might be surprised by how many little boost leaks you have, besides the large leak you have. These cars are getting older.

When I installed my new motor about 1k ago, I put on my old parts that looked well and good, couplers, gaskets etc. The car ran well, just felt sluggish for all the mods it had, I was obviously disappointed.

I decided to do a boost leak test. I made an adapter with an abs cap and compressor fitting and put it on the hot pipe of my ic pipe off of the twins. Have it set decently high on the compressor(60+psi). It won't hurt anything, the extra air excapes out the exhaust

I had my soapy water squirt bottle ready and went to town. I found so many little boost leaks you wouldn't believe it, to the point of needing a retune! My car was over boosting when I was done!

I'm sure my case isn't typical(well I hope), but it's probably more likely than people think. I inspected every part that went back on my car carefully. The biggest leaks I had were the throttle body to him gasket, and the TB to elbow, when I put the soap there, I thought I saw a bubble fly away. The ic couplers- though no tears or flaws, the silicone was hard on the inside from the heat and use and did not seal well at all. Also, little vacuum caps with a zip tie, those things leaked as well. That was probably the biggest pain to fix properly, to drill and tap them and plug them right.

Good luck!

So I found 2 areas leaking. There is a leak at the Greddy elbow to the TB. Pretty sure that is a new gasket, but that is an easy one. The other is the CRV. It won't hold any boost. I'm not sure how exactly that would affect the primary turbo though, definitely after transition.

The PCV I think might have been leaking too, but I'm eliminating that with a catch can set-up any ways.

Any advice on sealing the TB to Greddy elbow area?

Put Hylomar on the o-ring when you install it so it doesn't slip out of place while you are putting the Greddy elbow on.

Mazda uses their silicone gasket stuff, I guess you could do that too.

When you tighten the nuts do them all hand tight and then torque in a cross pattern and no need to over do it.

If you have a leak there, the o-ring may be bad. Check it, and get a new one if it has creases or cuts in it. Install as listed above.