Tial 38mm V-band EWG (leak?)

[LittleBlueGT]

When I blow on a hose connected to the bottom port of the EWG it doesn't hold pressure. It is like there is a small leak there. it is very small, but definitely there.

 

It works fine though. I just find that if I use a bleed style of boost control set-up a small pill will cause a rise in boost, even at 0% WGDC.

 

Is it normal to have a small amount of air escape the cavity? It seems like it might be. There doesn't appear to be anything wrong with the unit, maybe it is designed to leak a small amount where the valve comes through the body?

 

The reason I want to know for sure is that I am doing a hybrid type boost control (3-port EBCS and MBC) and the smallish ports on the pro-drive unit, combined with the Tees in the system seem to limit overall airflow to the EWG.

 

Here are the set-ups I ran: (all at 0% WGDC, and all with app 1 bar spring)

 

1) small pill bleed style 17 psi tapering 15

2) larger pill bleed style 15 psi solid

3) hybrid boost control 17.5 psi solid (obviously no pill)

 

Thanks

[Boostin1657615274]

When I blow on a hose connected to the bottom port of the EWG it doesn't hold pressure.

It won't. But the top port will. This is normal, it's exactly how my Tial V44 works (on my Rx-7) and my old HKS 40mm and my ebay 50mm.

 

The reason I want to know for sure is that I am doing a hybrid type boost control (3-port EBCS and MBC) and the smallish ports on the pro-drive unit, combined with the Tees in the system seem to limit overall airflow to the EWG.

 

Here are the set-ups I ran: (all at 0% WGDC, and all with app 1 bar spring)

 

1) small pill bleed style 17 psi tapering 15

2) larger pill bleed style 15 psi solid

3) hybrid boost control 17.5 psi solid (obviously no pill)

 

Thanks

I don't get it. Why the complexity? Why don't you hook it up like a normal external wastegate? Side/bottom port gets pressure (either from compressor housing or after the FMIC depending on how much boost you want), top port fed from the normally closed port of a 3 port solenoid? Why are you bleeding pressure from the side port when you should be pushing the top port shut? It defeats the purpose of the dual diaphragm chamber design.

 

http://www.legacygt.com/forums/attachment.php?attachmentid=76663&stc=1&d=1259005196

 

that's a crude drawing, but it illustrates how the dual chamber design works. When the solenoid is at 100% duty, air is applied to the top chamber and the wastegate is held shut. You are not blocking the wastegate signal to the side port as you would on an internal wastegate would. Reducing the signal to the side port still allows the wastegate to open progressively and that hurts spool. The side port of an EBC functions just like an internal wastegate, but you are only hurting yourself by trying to control boost that way. You are giving up the inherent advantage of the 2 chamber design.

 

You can source the pressure for the two ports from multiple places, and each affects the level of duty cycle required for the solenoid:

 

http://www.legacygt.com/forums/attachment.php?attachmentid=76664&stc=1&d=1259005196

 

Here's one way to hook it up with a 3 port solenoid:

 

http://www.legacygt.com/forums/attachment.php?attachmentid=76665&stc=1&d=1259005196

 

The Greddy Profec uses a 3 port solenoid like you have. As the solenoid is switched on, air is fed to the top chamber of the wastegate from the normally closed port. As the solenoid cycles off, pressure is relieved out of the normally open port (the "vent" I'm referring to in the pic). You can also use an OEM 2 port solenoid with an external wastegate. This is basically how I have my Rx-7 plumbed:

 

http://www.legacygt.com/forums/attachment.php?attachmentid=76666&stc=1&d=1259005196

 

It's functionally the same as a 3 port solenoid and saves a little loot by just using some hardware store fittings with an OEM 2 port solenoid. As I said earlier, where you take the pressure from will affect the range of duty cycles needed to achieve a particular level of boost. With that plumbing I run 16psi boost to redline on a 13psi spring with an approximate solenoid duty of 50% once the wastegate opens.

[LittleBlueGT]

Thanks for the reply, but I am going to try the hybrid set-up. Many people like it:

 

Hybrid boost control

 

I didn't buy the Tial EWG for the two port design, I bought it to run an EWG! At least it gives me the opportunity to use it at a later time.

[SubyShop.com]

The hybrid setup has been great. One of my favorite mods.

-Franz

[Boostin1657615274]

I didn't buy the Tial EWG for the two port design, I bought it to run an EWG!

Besides the obvious increase in flow, the two port design is the main advantage of an EWG. I'm kind of stunned that Subaru owners use such a crude setup when they have such a sophisticated boost controller built into their reflashable computer. How often do you see Supras running MBC's on their external wastegate? I had one on an EWG for a little while and wasn't happy with it at all.

 

Using an MBC in conjunction with an EBC doesn't change the reality that MBC's can't adjust to the weather (just like a carburetor) and that there is always going to be pressure trying to push the wastegate open. As far as the latter point goes, on an internal wastegate you just have to live with that. On an external wastegate with 2 port plumbing you get much finer control over the way the wastegate opens.

 

a) cockpit adjustability of max boost via a knob.

this is one aspect that i can't stress enough. it is by far the best way to account for atmospheric changes in boost levels as well as driving style changes (highway vs. city, wife driving, valet, etc). two seconds in the morning and it's set for the rest of the day.

huh? On my Rx-7 even my stoneage Apex'i EBC can compensate for the weather and maintain boost within half a psi? And the LGT has a much better boost controller than that. Busting out a laptop to change boost is annoying, but that's why you can somewhat quickly switch maps with the AP... and MBC's always fluctuate with the weather, whether you have this hybrid setup or not. A properly configured full EBC setup will fluctuate so little that it requires zero adjustment. And if you run enough spring pressure, you will naturally have less boost in lower gears because the engine just isn't loaded down as much.

 

b) throttle dependant boost levels.

c) rpm dependant boost levels.

Part throttle Spiking and overboost issues are most common with internally wastegated turbos running 2 or 3 times the spring pressure. Properly sized external wastegates hooked using a 2 port configuration don't have those problems nearly as often. Install a 1 bar spring and boost control gets a lot easier.

 

d) rock solid boost response. e) very quick boost increase.

The 2 port design is superior for both of these. It's simply a matter of physics. Instead of changing the rate that the wastegate opens (single port "feed" style config) you can keep the wastegate completely closed and open it as fast you want depending on the duty curve. Exhaust backpressure is not really an issue unless you have a pretty low boost spring. I used to run an MBC on my external wastegate, vented to atmosphere. I'd always hear the wastegate cracking open way early to achieve the target boost level. Really high flowing wastegates can be snapped open at the last second when using a two port configuration, so that maximum exhaust energy is applied to the turbine wheel for as long as possible.

[LittleBlueGT]

I guess we will see.

 

I get -40 to +100, I have heard a MCB only fluctuates about .5 to 1.0 psi in those conditions.

 

I have found that IWG (no EBCS, no nothing) spikes upon transient throttle applications.

 

My EWG does not spike at all, I absolutely love it. I am now trying a MBC on it. Everything I have seen from MBC is they spool as best as any electronic one, and hold boost very steady.

 

It is obvious you don't think so, but many would disagree.

 

The advantage of EBCS and OEM boost control system is being able to control boost at less then WOT, and being able to drop boost to WG spring value in the event that IAM drops low enough........ Hence the hybrid set-up!

[NSFW]

From the standpoint of tuning, I found the MBC very useful for covering lots of the timing and fueling tables with a series of pulls. I didn't go for the remote control option but it was still really quick to do a couple pulls, pull over, give the knob a twist, and repeat, going from 10psi to 22psi. I did have to add the BCS to fix a boost taper problem when I got to around 20psi or so, but even that only took a couple tries to get dialed in.

 

I will be trying to get the same boost curve using an interrupt-style BCS over the winter though, mostly just out of curiosity. I've been really happy with the way the car drives with the MBC.

[Boostin1657615274]

I have found that IWG (no EBCS, no nothing) spikes upon transient throttle applications.

 

that's why the stock boost control system on a completely stock car is designed the way it is.

 

My EWG does not spike at all, I absolutely love it.

Good to hear. I agree that internal wastegates are more prone to spiking once you modify the car enough. I had all sorts of spiking and annoying boost curves on my Rx-7's stock turbo.

 

I am now trying a MBC on it. Everything I have seen from MBC is they spool as best as any electronic one, and hold boost very steady.

good MBC setup beats a mediocre EBC setup every time

 

It is obvious you don't think so, but many would disagree.

My argument is twofold: 1) an MBC cannot automatically adjust for changing ambient conditions

 

and 2) by using an MBC on an EWG, you are losing the advantage of being able to push the wastegate shut and open it as quickly or as slowly as you like. The opening of the poppet valve is determined by the pressure difference between the upper and lower diaphragm chambers. With an MBC setting, you can only reduce the amount of air pushing the wastegate open.

 

The advantage of EBCS and OEM boost control system is being able to control boost at less then WOT, and being able to drop boost to WG spring value in the event that IAM drops low enough.

A huge advantage and something you cannot find on any aftermarket EBC I've seen. Even the AEM EMS or the Haltechs don't not have the adjustability of the factory Subaru EBC. Their PID systems allow only fixed proportional and integral settings, unlike the Subarus where the PID logic changes depending on the error calculation (turbo dynamics).

 

Hence the hybrid set-up!

I'm not making the connection. Again it strikes me as so utterly bizarre to put an MBC on an external wastegate when the factory LGT system (even using stock solenoid on an EWG with plumbing fittings as I've shown) is, when tuned properly, better than anything I could ever realistically buy for my Rx-7.

 

Why not keep the factory fuel injection and hook up a blow-through carburetor and low pressure fuel system while you're at it? Then you get the ease and simplicity of tuning with a few screws!

[LittleBlueGT]

Do you have experience with this on our cars?

 

I kinda doubt it. I have played around with boost control on our cars in at least 24 different configurations. I have tried almost every kind of set-up using the OEM EBCS and a 3-port EBCS.

 

I didn't go into detail, because (unlike you) I don't take the enormous amount of time to display cool pics of everything I was thinking.

 

Here is my history of EWG:

 

1) 3-port EBCS interrupt style to bottom port = controls boost but you can hear severe WG flutter

2) 3-port EBCS interrupt to top-port = same thing as above, just not as bad

3) I did not try OEM 2 port in a bleed style to top-port

4) I did try OEM 2 port to bottom port in bleed style, boost was very smooth, boost rise was just as steep as 3-port in any of the above configs. I have done this style with at least 4 different sized restrictor pills

5) now with MBC and 3-port in parallel (as OP, not enough airflow to work properly)

 

FWIW on my old TMIC I had the cold side of the TMIC tapped, and I played with using that side to control boost.

 

I am in no way an expert, but I would assume that I have played with more styles and configs of boost control on our car then 96% of self-tuners.

 

My argument is twofold: 1) an MBC cannot automatically adjust for changing ambient conditions

 

and 2) by using an MBC on an EWG, you are losing the advantage of being able to push the wastegate shut and open it as quickly or as slowly as you like. The opening of the poppet valve is determined by the pressure difference between the upper and lower diaphragm chambers. With an MBC setting, you can only reduce the amount of air pushing the wastegate open.

 

1) how bad does a MBC sway from its set boost in changing atm conditions? If you are talking about changing pressure, then I agree with you, If I drive to Denver where atm press is like 12 psi, I will still be targeting the same psi as I am here at 14.2 atm. For me that is really a non-issue, for some it could be. (FWIW, and I will explain below, you can kinda tune for that with a hybrid set-up)

 

2) there is absolutely a theoretical advantage of pushing the top-port closed with an EWG, but in our cars, at anything less then 23 psi there is none (at least that I could see/log/feel) Even with a bleed style to OEM EBCS using bottom port, I could run an extremely high proportional and my boost would climb just as fast as when the top-port was being held close

 

A huge advantage and something you cannot find on any aftermarket EBC I've seen. Even the AEM EMS or the Haltechs don't not have the adjustability of the factory Subaru EBC. Their PID systems allow only fixed proportional and integral settings, unlike the Subarus where the PID logic changes depending on the error calculation (turbo dynamics).

 

It is PI (not D) logic FWIW. I agree, there is a lot you can do with the OEM tables. In my car I do not have IAT comps for integral, like the newer cars do. For me that matter as I control boost in +100 and -40. I also find the OEM system gets confused with IAT. With my intake my IAT will rocket to 140 or so when I stop, this can mess with WGDCs a bit.

 

I'm not making the connection. Again it strikes me as so utterly bizarre to put an MBC on an external wastegate when the factory LGT system (even using stock solenoid on an EWG with plumbing fittings as I've shown) is, when tuned properly, better than anything I could ever realistically buy for my Rx-7.

 

Do you understand the hybrid set-up works? Maybe you should revisit it?

 

WOT = WGDC = 100% and MBC is the only thing that affect boost

<WOT = WGDC will be less then 100%, and EBCS controls boost

 

This can be configured however you like it.

 

THE BIG REASON I AM DOING MBC!!!

 

-in colder temps and lower rpm (2800) and at 10+ psi I would get a resonant affect with my EBCS and EWG. Almost like the EWG was pulsing at the same frequency as the EBCS. I can't completely explain it, but it was there. (some stand-alone EM can vary the freq of the EBCS)

 

From the standpoint of tuning, I found the MBC very useful for covering lots of the timing and fueling tables with a series of pulls. I didn't go for the remote control option but it was still really quick to do a couple pulls, pull over, give the knob a twist, and repeat, going from 10psi to 22psi. I did have to add the BCS to fix a boost taper problem when I got to around 20psi or so, but even that only took a couple tries to get dialed in.

 

I am going to like this convenience as well.

[Boostin1657615274]

1) 3-port EBCS interrupt style to bottom port = controls boost but you can hear severe WG flutter

I don't have a clue what wastegate flutter is really. I hear the term thrown around sometimes though. Are you talking about compressor stall?

 

2) 3-port EBCS interrupt to top-port = same thing as above, just not as bad

sounds like you hooked it up wrong. You shouldn't really be interrupting anything to the top port, not in the same way that you would on an internal wastegate. You are supposed to use the normally closed port on the EBCS (works just like a 2 port solenoid), not the normally open port. Then more solenoid duty results in more pressure on the top chamber

 

3) I did not try OEM 2 port in a bleed style to top-port

Good, because if you mean teeing off the pressure line (like the LGT does stock) that doesn't make much sense.

 

4) I did try OEM 2 port to bottom port in bleed style, boost was very smooth, boost rise was just as steep as 3-port in any of the above configs. I have done this style with at least 4 different sized restrictor pills

that's fine, but again you are not hooking it up the way it was designed to be hooked up

 

5) now with MBC and 3-port in parallel (as OP, not enough airflow to work properly)

It sounds like you've tried every single configuration except the one that the external wastegate was actually designed for?

 

The normally open port (called "NO" on Denso/Greddy/Apex'i solenoids)--the one that is used in "feed" style internal wastegate configuration and closes when +12v is applied to the solenoid-- vent that to the atmosphere or route it preturbo.

 

The normally closed port (called "NC" on Denso/Greddy/Apex'i solenoids)--the one that only opens when +12V is applied to the solenoid--hook that to the pressure source

 

The port that is always open no matter what (called "COM" on Denso/Greddy/Apex'i solenoids)--hook that to the top port of the wastegate.

 

for the side port, you can tee it off the same pressure source you used for the solenoid, or you can follow that matrix I posted up earlier. Every single solitary aftermarket boost controller or solenoid calls for this routing or at least recommends it... even Perrin

 

Final benefit is that the EBCS can be used with aftermarket external wastegates as shown above but with a twist. Because of the 3 ports, this enables the use of both top and bottom ports on most aftermarket external wastegate actuators. In these setups they can provide even better more reliable boost control! While this is not a typical setup, if you are using an external wastegate and can manipulate the tables in the ECU this can make for a powerful setup.

http://www.perrinperformance.com/shared/images/jeff_pics/boost_control/boostcontrolsystemperrinlelectronicexternal10psiv2.jpg

Shown above is the system at rest controlling boost to 10psi, which is the wastegate spring pressure.

http://www.perrinperformance.com/shared/images/jeff_pics/boost_control/boostcontrolsystemperrinlelectronicexternalboostplusv2.jpg

With the solenoid turned off the boost pressure pushes the wastegate open at the set spring rate. The top port is vented to the outside air. When the solenoid turns on, pressure is diverted to the top of the wastegate holding the wastegate closed longer and better. This method is great and allows the use of a very light wastegate spring, but still the ability to run huge boost levels. The reason why using a lower rate spring is this allows for better modulation of boost in part throttle situations where you don't want too much boost.

 

in this configuration Perrin has the top port being bled off the same pressure source as the side port, but as I said earlier you can try different combinations to see what works. that config is more prone to spiking than if you took the side port from a separate pressure source.

 

[LittleBlueGT]

I don't have a clue what wastegate flutter is really. I hear the term thrown around sometimes though. Are you talking about compressor stall?

 

 

No, I am not. Boost fluctuates even though WGDC is rock solid, seems to happen only around 50% WGDC, so it depends on a lot of things, but it can happen. You can hear it, and the MAF fluctuates as well, not a slow up&down, but very very rapid.

 

sounds like you hooked it up wrong. You shouldn't really be interrupting anything to the top port, not in the same way that you would on an internal wastegate. You are supposed to use the normally closed port on the EBCS (works just like a 2 port solenoid), not the normally open port. Then more solenoid duty results in more pressure on the top chamber

I did it right, just like yours and other drawings.

 

It sounds like you've tried every single configuration except the one that the external wastegate was actually designed for?

 

The normally open port (called "NO" on Denso/Greddy/Apex'i solenoids)--the one that is used in "feed" style internal wastegate configuration and closes when +12v is applied to the solenoid-- vent that to the atmosphere or route it preturbo.

 

The normally closed port (called "NC" on Denso/Greddy/Apex'i solenoids)--the one that only opens when +12V is applied to the solenoid--hook that to the pressure source

 

The port that is always open no matter what (called "COM" on Denso/Greddy/Apex'i solenoids)--hook that to the top port of the wastegate.

 

for the side port, you can tee it off the same pressure source you used for the solenoid, or you can follow that matrix I posted up earlier. Every single solitary aftermarket boost controller or solenoid calls for this routing or at least recommends it... even Perrin

Again I did it right. The boost fluctuations (I think) are a result of possibly too small of fittings on the Pro-drive EBCS, not really sure though. I could have got a nicer 3-port like Grimmspeed, but I thought I would give the MBC hybrid a try.

 

I really don't understand what you have against manual boost controllers. Did you even look into the hybrid set-up. They can work just fine.

[LittleBlueGT]

in this configuration Perrin has the top port being bled off the same pressure source as the side port, but as I said earlier you can try different combinations to see what works. that config is more prone to spiking than if you took the side port from a separate pressure source.

 

 

This table does present some interesting combinations. If I am not happy with my new set-up I will possibly try some of the above.

[Boostin1657615274]

http://www.frightprops.com/FrightProps/Graphics/Solenoid100x100.gif MAC EBC solenoid $26.50 (1/8 NPT thread) http://www.frightprops.com/FrightProps/Props/CategoryW.asp?ID=A-0013-0082

 

http://www.aempower.com/images/products/30-2400.jpg

 

AEM solenoid, $100, exact same shit but more expensive

 

http://www.legacygt.com/forums/attachment.php?attachmentid=76711&stc=1&d=1259123692

 

OEM Rx-7 2 port solenoid hooked to top of external wastegate. custom brass tee is used to prevent "line lock," taking the place of the 3rd port (normally open) on a 3 port solenoid valve

 

On my Rx-7 I have the side port of the EWG sourced from before the intercooler on its own separate stainless steel line so it will never melt or blow off. The pressure source for the top port/EBCS is also sourced before the intercooler, but it is not being bled off the main for the side port (as the Perrin diagram shows). It is a separate line.

 

I really don't understand what you have against manual boost controllers.

I hate popping the hood and adjusting them every time the seasons change (and I won't pay for an in-cabin MBC). I'm completely sick of adjusting anything on an engine with screws besides a lawnmower carb. Did you know an Rx-7 has 5 adjuster screws and 3 solenoids valves that affect idle speed? And that's after you set the base ignition timing with a light, set the throttle and cruise control cable tension, dial in two independent and sequentially firing sets of plugs/timing maps (leading and trailing) etc. Other cars of that era are similar in complexity. And then I hear some car enthusiasts complain about drive-by-wire and talk about how 'simple' cars used to be, and I wonder what they are smoking...

[NSFW]

http://www.perrinperformance.com/shared/images/jeff_pics/boost_control/boostcontrolsystemperrinlelectronicexternalboostplusv2.jpg

 

I don't see how this is different from venting the top and side ports to atmosphere. I mean, there's equal pressure on both side of the diaphragm either way... so what's the difference?

[LittleBlueGT]

I don't see how this is different from venting the top and side ports to atmosphere. I mean, there's equal pressure on both side of the diaphragm either way... so what's the difference?

 

I don't get what you are asking. The diagram you posted is a very common way of running an EWG.

 

I wish someone would answer my question:

 

How much does a MBC fluctuate according to temp?

[NSFW]

I just don't see how equal pressure on top and bottom 'holds the wastegate closed.' Seems to me that would leave you with spring pressure. I thought the point of the top port was to run more pressure there than the side port, to act like a heavier wastegate spring.

 

I haven't noticed much difference in boost with my MBC yet but temps haven't dropped much since I got it.

[Boostin1657615274]

I just don't see how equal pressure on top and bottom 'holds the wastegate closed.' Seems to me that would leave you with spring pressure. I thought the point of the top port was to run more pressure there than the side port, to act like a heavier wastegate spring.

the design of the diaphragm chamber and spring are such that there is more mechanical advantage in the top chamber. It might have to do with the fact that the lower chamber slowly bleeds pressure out (as the OP has noted) but the top port will hold pressure (as I have noted). If you run straight pressure to both the top and side port (no solenoid at all, no MBC or pill), the wastegate will probably not open at all. There are all sorts of warnings in the instructions of some aftermarket EBC's about this.

 

That's why at near 100% solenoid duty the wastegate is completely shut, and then as duty drops more the poppet valve opens slowly. The third port of the EBCS keeps the top port/chamber of the wastegate from holding pressure and sticking shut.

 

How much does a MBC fluctuate according to temp?

 

What I noticed is that, while the peak boost does fluctuate more than with a properly set EBC (hard to quantify, but maybe an extra +/- .5 or 1 psi), the boost curve seemed to change every time. And MBC's do taper off boost up top more. I guess on Subarus boost taper is expected, so that doesn't bother people that much.

[NSFW]

This is what I plan to do when I go EWG next summer:

 

http://forums.nasioc.com/forums/showpost.php?p=18201836&postcount=202

 

http://freon.shackspace.com/car/ecu%20and%20tuning/gmbcs/4portsolenoid-hookup.jpg

[SubyShop.com]

I don't get what you are asking. The diagram you posted is a very common way of running an EWG.

 

I wish someone would answer my question:

 

How much does a MBC fluctuate according to temp?

 

No freezing temperature here yet since I switched to the MBC, but I have not had to adjust my MBC with 40* F ambient temps. During the summer months it was in the 90's and I was hitting 1.3 bar instead of 1.4, which is ok. I don't think I've touched the remote adjustment since tuning last summer. The fluctuation is very minor for pressures around 20 PSI. My boost gauge has a warn feature for overboost btw and I watch it carefully in the upper gears. No issues with that to date.

-Franz

[LittleBlueGT]

No freezing temperature here yet since I switched to the MBC, but I have not had to adjust my MBC with 40* F ambient temps. During the summer months it was in the 90's and I was hitting 1.3 bar instead of 1.4, which is ok. I don't think I've touched the remote adjustment since tuning last summer. The fluctuation is very minor for pressures around 20 PSI. My boost gauge has a warn feature for overboost btw and I watch it carefully in the upper gears. No issues with that to date.

-Franz

 

 

I will let you know how much mine changes as temp changes.

 

IMO a MBC will spin the turbo to X speed, at warmer temps that will be less boost, in colder temps it will be more. I kinda like that. If I run the turbo to 95% of its capacity it will be doing that in any temp (if boost rises a bit as it gets colder).

[Boostin1657615274]

This is what I plan to do when I go EWG next summer:

 

http://forums.nasioc.com/forums/showpost.php?p=18201836&postcount=202

 

http://freon.shackspace.com/car/ecu%20and%20tuning/gmbcs/4portsolenoid-hookup.jpg

 

I think choosing the plumbing setup has a lot to do with what your wastegate spring is and what your target boost pressure is.

[LittleBlueGT]

Well Boostin, I think you are right.

 

In 40 (F) degrees spread I am seeing a 1.5 degree change in boost.

 

That would give me over 5 psi swing in the temps I drive in! So back to EWG and playing with my 3-port!

 

FWIW boost was very solid with MBC, and easy to play with.

[LittleBlueGT]

I know my MBC is not working properly for me. My Tial EWG leaks a small amount of air (this is normal I hear) through the bottom port, anything that restricts airflow makes the boost rise. That likely explains why the MBC on its lowest setting raised boost from 14.5 to 17.5 psi.

[Boostin1657615274]

Good luck, I hope you find a setup that works for you. If you are concerned about spiking, I've had good luck running separate pressure sources to the side port and top port. That's as opposed to the Perrin diagram, where the top port is bled off the pressure source for the side port.

[LittleBlueGT]

I have had to reshape my whole turbo dynamics tables.

 

So fare my WGDC is at 13.5%, but I am not at target boost quite yet.