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Discussion Starter · #1 · (Edited)
XXXXX:mad:XXXXX
 

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Technically, it is a electronically controlled wastegate lol. the ECU does it just like you said!

I have bypassed these guys before. Until we can get an ECU tuner that we can tune boost the way we want, the next best thing is our own aftermarket elec or manual boost controller.

I heard you have boost issues, but my logs consistently show initial spike of 6-17 psi, then slowly tapering off to about 11-12 psi before i shift to the next gear.
If we could hold consistent 16-18 psi of boost until redline, the car would make a lot more power.

I pulled this from KGIS:

Wastegate solenoid.jpg

The only possible side effect is a CEL. Then I would also be cautious of A/F ratio where boost has changed, and you most certainly have the ability to see that.

I would start by installing a controller, and setting it to the lowest possible setting and see the PSI that results. Then slowly go up from there, taking logs and making sure the boost stays consistent as intended. If you hook that up the first time and it stays at one boost level the whole time, then awesome!
 

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I'm curious to know about this as well. I feel the lurching quite a bit.
 

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I don't mind buying parts that are usable in other projects like this controller or the boost gauge I'm not going to use now if the Greddy works, but buying car specific things that are by chance it might fit I will shy away from. The rotors for instance I don't mind buying those, I already went to the parts store bought a stock rotor put it on then returned it so I now know the drilled will fit. The Greddy if by chance it doesn't work, I go to the track for test and tune once a month with the owner of that Camaro I posted, so finding a home for that will be easy too. Just for future reference the down pipe for the VT doesn't fit, I tried a stock DP when I was putting factory exhaust back on and it had a different angle coming off of the turbo. My custom exhaust broke after hitting a Goodyear Gator on I4 at 80 mph. Broke 3 welds and 2 mounts luckily that was it other than a few black scuff marks underneath.
Thank for letting me know about the downpipe. It looks like a pain to remove. I hope to start working on that in the next couple months.
 

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So I hooked a vacuum and boost gauge (not a in dash gauge its more for diagnostics and more accurate) to the vacuum port for the BOV just to find out that little chamber never gets boost pressure (kind of like the vacuum pods gm cars used for ac vents in older models). As I was driving normal head out the window panting I could hear what sounded like the BOV open losing all the boost so I stop and put the gauge on the other side of the ecu controlled valve to see that it was in fact dumping boost and under medium throttle was also releasing boost so even with a separate boost controller you will still need to fix this BOV issue. I'm not an expert on ecu controlled boost but does this sound right?
If the ECU uses the solenoid for the BOV to help regulate boost pressure WITH the wastegate, that is something I've never seen before.

I could be mis-reading this info, but the KGIS says the ECU activates the solenoid when the throttle is closed. I'm assuming this happens when throttle position is reduced.
I have noticed how fast the valve reacts to throttle position changes. I can fluctuate my foot on the pedal between 25% and 75% throttle and every time i back off the valve immediately opens.

As for leaking, I won't know that for sure until boost control is actually doable.

Good research though!
 

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What would happen if after we get the adapter under the map sensor in place we use one of those ports to feed the solenoid instead of the constant vacuum it is using now? That would disable the ecu from being able to release the pressure while boost is present and throttle is open once closed it should automatically pull vacuum and dump the boost that is still present opposite the throttle plate it would sort of be like bypassing it without setting a CEL. Just for kicks I'll give it a try tomorrow.
I did check one more thing, I have 2 map sensors I took and read the data for those under normal driving. Intake pressure which is measured at the top of the intercooler and boost/vacuum which is what is measured on the actual intake manifold. So while I am driving the boost data shows a vacuum and intake pressure will be 2-4 lb (intake pressure never goes into a vacuum reading). Guess my question now is even with a manual BOV would it still blow off under the lower boost pressures if there is a vacuum present in the intake?
That's interesting, but makes sense.

We have a "boost pressure sensor" installed at the top of the intercooler, and that measures strictly boost pressure (amount of pressure above 14.7 psi (or 1 atm, or 29.95 inHg).
The MAP sensor is the one attached to the intake manifold, and that one measures total air pressure (14.7 psi + boost) along with air temp in the manifold.

So the map reads full signal, as far down as -29.95 inHg and as high as 41.19 psi. Subract atmospheric pressure and we theoretically know what boost pressure our MAP sensor can functional normally at, and that is 26.5 psi of positive boost.

I hope I'm wrong and the spec sheet actually means 41.19 psi of positive boost. That means we would never have to replace the sensor for the guys who wanna go beast mode on a larger turbo.
 

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Next test, I want to see what the ECU does if you maintain a constant 16 psi while leaving the factory EBC connected allowing it to increase the boost to 18-19 psi. My idea if it works will benefit the cars mid range power more by preventing the drop of boost pressure between 3500 and 4500 rpm.
This is what I ordered with the tuning kit to adjust pressure more precise.
Forge Motorsport | Alloy Fabrication

Let me know what you think, am I wasting my time or is this a good idea?
according to all the logs ive taken, i get full 16-17 psi of boot from full throttle @ 3000=3500 rpm and then when 4000-4500 comes it just dies all the way down to 10 psi by redline.

If you were just to run the car using strictly the wastegate spring and no sort of control, you would be able to find out the psi spring in there. If there is not other controlling factor, the system is mechanically limited to the pressure allowed by the spring. If you have seen we have an adjustable one, then this would be at the shortest waste gate rod length.

If it were me i'd try the easy manual boost control way (MBC).

- Remove any OEM boost control parts
- install MBC in between pressure source and wastegate
- test run with MBC turned to lowest setting, this should match factory spring pressure, or just be slightly higher
- slowly turn the MBC up click-by-click until you reach desired boost pressure

What we don't know is how the ECU will work with the increased pressure and a absent boost control system. Personally, i wouldn't worry about it until maybe 2-3psi higher than stock in the rpms above 5000. I would keep a close eye on things like a/f ratio and fuel pressure with data logs.
 

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If you are looking for a DIY way to control boost this actually works nice.
 
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