***Blackonorange's STS Turbo Build!! - Done by Speedtech Saskatoon***

AkumaMS

Just a little info to maybe simplify the functionality of the the Forced Induction systems. I am sure this is on the boards, but maybe we can really break it down so troubleshooting the set up becomes easier. I keeping the terminology and concept basic so we can get the fundamentals going.

The turbo consists of 2 wheels...compressor and the turbine enclosed in their respective housings. These wheels are linked via a shaft, however they are sealed from one another. The exhaust gasses from the motor spin the turbine, or Hot Side. This, in turn, spins the compressor(cold side) and produces boost. Now we need to control the boost...

Try and think of the Wastegate as a literal 'boost controller' The Gate has a spring in it applying pressure to the piston, or flapper depending on style of gate. This spring will hold closed based on the mechanical rating of the spring. Once the pressure exceeds the spring rating, exhaust gasses are diverted and boost is limited. So, an 8PSI spring should produce 8PSI of boost. There are many things that can effect the actual boost, but for our purposes this example is OK. We will com back to this concept in a few.

The wastegate is ofter controlled by a secondary solenoid. This is known as a Boost Controller(BC). The BC can be in the form of a solenoid(electronic) or manual valve(ball spring/bleed/etc). So literally, the boost controller is a Wastegate Controller.

So back to our controlling of the actual boost...
The WG(wastegate) can be run with a port from the compressor housing of the turbo (or as close to it as possible) connected to the WG(bottom port or only port on the swing type). This orientation will run only the mechanical rating of the spring in the WG.

With the BC(boost controller) in line between the turbo(cold side) and WG. This will allow us to divert compressed air to the side of the WG valve opposite the exhaust gasses. This basically makes our WG spring behave like a far heavier spring, thus increasing boost. This can be done in a few ways, depending on the BC style. EBC(3 port) designs allow for 2 main styles of routing. Typically, one port comes from the Comp housing, a second comes from the bottom port on the WG, and the third port on the EBC is vented toi atmosphere or plumbed to the intake(does not matter). This is a very simplified explanation of the boost control system. An EBC assumes the ECU has a table to control it...we can go over tuning in another thread if anyone is interested.

The one variant that 95% of all Forced Induction systems has is a BOV(blow off valve). These come in many different flavors and styles. The main purpose of the BOV is to give the compressed air a place to go, after the throttle is closed, thus protecting the turbo. The BOV has a diaphragm or a piston, a spring and one(or more) ports. The idea here is a little different than the WG. The port on the WG should not see vacuum, so it is not an issue(because we are using a pressure only port...ie the comp housing) so you can run an 8 psi spring at sea level without the fear of a leak. We want a spring for the BOV that is stiff enough to stay closed at idle, and no more. A spring that is overly stiff, can lead to poor throttle response and decreased performance. In this example, we see the Tial Q. The spring should be selected based off of your ambient barometric pressure. The closer to sea level, the stiffer spring you will require. You may find the Tial Q requires a shim on the stiffest spring(11psi) to preload the spring a bit, keeping it closed at idle.

On a MAF or metered air based system, it is critical to make sure you have no vacuum leaks. Ideally, you want a BOV that recirculates back to the intake, so the ECU does not need to make dramatic fuel corrections at transient throttle conditions. Basically, the ECU sees X Airflow at the MAF and provides Y amount of fuel. If you dump it to atmosphere you have fuel Y and and not the metered X volume of air resulting in a rich condition. This over fueling can lead to stumbling, misfires, and poor driveability. This same concept applies to boost leaks after the MAF sensor.

Now we run VTA(vent to atmosphere) BOVs all the time, and can tune effectively for it, so I am not saying you have to run one or the other, that is up to you and your tuner.

I hope this breaks down the system in a very easily digested manner. There are a number of boosted Zs' so we should have a good understanding of how to set it up.

I hope this did not hijack the OP, I only intended to add to the discussion. Good luck, and if anyone needs help, feel free to drop me a line anytime.

-John

blackonorange

This is great info but sadly doesn't help with what's happening with my car

hindi1973

Pcv switch and solenoid was full of oil from the blow back that happened , the oil blocked the solenoid which made the air compressed back to the crankcase thus flow oil back to manifold,throttle ,piping,cooler etc etc we cleaned that as well we will run it tomorrow and see wht happens ,if it's all good we are Hana delete the Pcv system and make it directly going to the catch can , let's see

blackonorange

Hmmm interesting was your vacuum low at idle as well?

hindi1973

yes its -9 to -12 , before the problem it was -19 to -20 in that range .

blackonorange

Yea same as me I think I'm just gonna run a catch can

Dzel

Black I'm sorry about are the trouble your having, but I have to be honest this thread is giving me a bad feeling about this kit.

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blackonorange

Kits sweet man just a couple hiccups

blackonorange

Turned out to be a bad blow off valve go figure

tower74

You and me both. Even STS can't seem to get the tune correct on mine. I've had the kit for 8+ months and no one can seem to figure it out. Problem after problems but I've found a good tuner and I'm hoping he can solve what no one else can seem to figure out. Maybe it's time for the new Subbie coupe....hmmmm

blackonorange

The kit is good and has been proven it just has to be installed correctly , we just took the bov apart and reseated the seal and now it's fine

hindi1973

we cleaned the pcv valve, same problem , tried to delete it and for some reason the hose it self flows so much air that you cant close the hose with your finger , it means the boost is going is flowing in routes where it should not go to , such as catch can and every single place it can leak from . compression test is up , maybe just maybe its a bad ring piston .

blackonorange

While you got it open may as well do some internals!!!!

hindi1973

i hope i am wrong being something internal , but lets see wht the compression shows , because all the air is flowing back to the crankcase not going to where it should to , which means this might be a burnt ring piston , but the car idles,fine,drives fine, no smoke , so not sure yet , i just hope its not with 1500miles only on the car , and the owner was on 7 psi only and a week only on 11psi , so no matter how beat on it it should have held it, it had 500 miles when he got it and he broke it in till 1000miles or so , so 500miles boosted miles .

AkumaMS

If you are having some issues with trouble shooting, give me a call at the shop. We are there Tues - Sat. I would be happy to help out.

John
732 326 0090

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John Shafer
Owner/Calibrator
Akuma Motorsports LLC
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