No electronic turbo regulation with twin wastegates

Engine:
2.5l B230F + T by RSI
RSI 86mm Billet Stroker Crank
RSI 158mm H-Beam Connecting Rods
RSI Waveguide 8v Turbo Pistons
Cometic MLS Head Gasket
RSI Stage 2+ Cylinder Head Prototype
RSI Race Valvetrain Kit
RSI Stage 3 Turbo Cam Prototype
RSI Square Tooth Adjustable Cam Gear
RSI Twin Scrool SS Turbo Header
RSI Poly Engine Mounts
Twin Tial MVS 38mm External Wastegates
Greddy Type S Blowoff Valve
Holset HX40/Garrett Hybrid Turbo
Isuzu NPR Intercooler
NIW Motoring Intake Manifold
Megasquirt 2 EMS
Mitsubishi Coils
Injector Dynamics 1600cc Fuel Injectors


Issue is I CAN electronically regulate pressure when my exhaust cutout (located shortly after DP) is CLOSED but not when it's open. Using an eboost street 40 with a single solenoid and TWIN tial WGs. Going for ~17psi. Boost levels want to shoot through roof even on lowest boost settings with EBC and the cutout OPEN. Currently running single lower ports on the tials. Going to throw the MBC back on for now... Solenoid tests good in a breadboard.

The solenoid is still wired in/mounted but I am using Hallman MBC for now.
<a data-flickr-embed="true" href="https://www.flickr.com/photos/vividvideo/29250310178/in/dateposted-public/" title="Current Boost control"><img src="https://farm2.staticflickr.com/1821/29250310178_730d5160b1_c.jpg" width="800" height="534" alt="Current Boost control"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
<a data-flickr-embed="true" href="https://www.flickr.com/photos/vividvideo/42403660894/in/dateposted-public/" title="Tial Wastegate"><img src="https://farm1.staticflickr.com/836/42403660894_61b84e7924_c.jpg" width="800" height="534" alt="Tial Wastegate"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
<a data-flickr-embed="true" href="https://www.flickr.com/photos/vividvideo/41328734460/in/dateposted-public/" title="Manifold 2"><img src="https://farm2.staticflickr.com/1769/41328734460_185eb149ef.jpg" width="500" height="375" alt="Manifold 2"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script><a data-flickr-embed="true" href="https://www.flickr.com/photos/vividvideo/42420814144/in/dateposted-public/" title="Manifold 1"><img src="https://farm2.staticflickr.com/1761/42420814144_54de9e9647.jpg" width="500" height="375" alt="Manifold 1"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
<a data-flickr-embed="true" href="https://www.flickr.com/photos/vividvideo/29250308748/in/dateposted-public/" title="Dual Tial Wastegates"><img src="https://farm2.staticflickr.com/1782/29250308748_e3b953789c.jpg" width="333" height="500" alt="Dual Tial Wastegates"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
Ben

Picture of the setup? How many ports on solenoid?

Sure sounds like WGs are not opening enough.

I used to have boost control issues with my 3.5" exhaust using the ported internal WG on my holset (25mm) and when I went to a single 38mm mvs my issues went away . When I had the 3" exhaust I had no boost control issues so with your cutout open the WGs are just not moving enough air.

I know with my single tial and my greddy profec I am running both ports on my MVS.

Let me see if I can find the routing diagram for mine and yours to see what differs.

With a very free-flowing, unrestrictive post turbine exhaust system like your open exhaust cutout, boost creep will become a problem. You are drastically reducing the post-turbine pressure when you open up your cutout, increasing the pressure ratio across the turbine and wastegate. This is a great thing for turbine performance but it means your wastegate flow must increase in order to bypass enough energy to keep turbine speed (hence boost) under control. You need a more freely flowing wastegate to keep up with the system. Twin 38mm may not be enough. You could also try redesigning the wastegate in/out plumbing to encourage flow and reduce restriction through the gates themselves. A pic of the setup would help for sure.

https://goo.gl/images/SEsS3B

This is how it should be hooked up for the mvs with an ebc. I think, very similar to what I have on mine.

Just to be clear, it works OK, with and without cutout, with the MBC but only works without cutout with EBC?

Where is your reference boost/vacuum hose for the EBC connected?

Picture of the custom exhaust manifold and external wastegate?

For my greddy there is a vac line going from the intake manifold right into the controller in the cabin.

For the solenoid in the engine bay one side comes off the compressor housing into the solenoid (that line has a T in it going to the WG) and then the outlet of the solenoid goes to the WG.

The solenoid is a 3 port. I am using intake manifold pressure for the controller reference....do you think tapping the cold compressor is necessary, curious if that may be the issue or if the perpendicular WG placements are a culprit.

The perpendicular WG is not the issue. Mine is like that. Pictures? I would try tapping the vac lines like I showed as that is a very quick and easy test.

Are all the solenoids built/constructed the same? I ask because I read they aren't.
If your unit looks like mine functionally, I'll try that routing out as soon as the engine is back together. Tell me, can your solenoid be ran like mine with just the bottom port connected? If that were so, it would mean they are built in the same direction and I can copy yours for sure.

thelostartof said:

The perpendicular WG is not the issue. Mine is like that. Pictures? I would try tapping the vac lines like I showed as that is a very quick and easy test.

Click to expand...

It has more to do with how the tials need to be connected to function properly.

Is there any reason you want to use the bottom port only? Using top and bottom should give you much better control. Also, what is the ID of your wastegate lines? TIAL specifies 1/4".

It's not the perpendicular orientation of your wastegates. I have a MVS on my RSI manifold and it works great. It's really far away from the collector, but I only had to up the duty cycle a little when I upgraded from a 0.63 AR to 1.05 AR turbine housing. Man I wish I had your twin gate manifold though.

I didn't want bottom ports. I read that they increased minimum boost, but I am unable to regulate at all and it sounds/looks like I had them setup in a way that works fine with an MBC/old exhaust, but no likey the new cutout. Sounds like hose hookup should be the issue.