Finally hooked up my Turbosmart E-Boost Street boost controller. I plumbed the MAC valve exactly how my manual boost controller, so expected my "low boost" to continue to be 6-7psi, like it was.

1st test drive today, with boost controller basically disabled (zeroed out), was 8 psi, but log showed it steady climbed to 11+ through 1st, 2nd, 3rd gears.

My "High Boost" was a rock steady 16psi. No creep or slope.

I am using a dual.port, single solenoid, single turbo configuration. Turbosmart calls it "Method 1"

Would it be better for me, since I run fairly low boost, to simply use a single port configuration where the solenoid only allows pressure to lower port of wastegate?

I attached pics of the 3 choices it gives me.

 

You didn't experience boost creep until swapping to an electronic boost controller?
Nothing else changed in the setup?

If your MAC valve has one of those brass filters on it, try removing that.

 

Correct. Only change was removing the air regulator type boost controller, and swapping on the EBoost Street one. The MAC valve just has the 3 ports, unless the filter is inside? But I dont recall seeing one.

 

Some of them come with a filter for the vent side. Toss the filter lol.

There shouldn't be any reason its boost creeping with a MAC since they typically are able to bleed more air than most MBCs.
Have you tried disconnecting the wiring on the mac valve all together and running it that way?

 

No. Just did this swap after work this afternoon.

 

After doing some more reading about this controller, last night.

It says using either of the two port setups would probably result in higher, than wastegate spring (mine is 6#), boost levels.
It also said that I should have tested low boost, aka: Boost Group 1, with 0.00 Gate Pressure...
damn directions...who needs 'em? lol.

Since, not IF, but WHEN, the dragstrips finally open up, this car will again be unsuccessfully bracket raced, I absolutely NEED the lower boost levels to attempt to stay NHRA legal for my class. In light of that, I'm going to re-configure the boost controller plumbing, for a single port, single solenoid setup, like in the very top picture above. Supposed to rain for like the next 4 or 5 days, so will update what I find, when I actually am able to test it again.

I attached 2 screenshots from my datalog, to show the boost level, from initial hit (7.09#), to just before letting off (11.34#), from a slow roll, 1st through 3rd gears, automatic trans. If space would have allowed me to stay in it, no doubt boost would have continued to climb, as it's upwards slope shows.

 

I don’t get boost creep with my MAC valve with my AEM truboost. I have the 3 port MAC and the front face is the vent.

With it disabled I make gate pressure which bench tested is 12psi but I can make 6psi through a full 3” single exhaust. With no changes I open the electric cutout and I gain 2-2.5psi on just the gate. I just upgraded my down pipe burly cutting out a bad section I wasn’t happy with (2 hard 90 degrees like a Z) and I converted it to 2 45 degree bends and I recirculated my WG which was open to atmosphere. I picked up another 2psi with just the down pipe mod but I feel like recirculating the WG is also increasing boost as clearly the down pipe is a restriction.

But disabling the EBC does not increase gate boost pressure. Sounds like you got a restriction and it’s holding pressure in the gate or not venting properly. The EBC was the only change? The Mac valve is essentially open/free flow (blow on the WG connection port) in the MAC valve and it should blow right through. If it’s not that’s your issue.

 

Thanks for the reply. I rerouted the lines and now have a simple one hose to the lower wastegate port setup, like the 1st poc above. Supposed to be nice tomorrow for a while, so I can finally retest it.

I have quite a bit less boost running through my full exhaust too. I have a cutout right at the end of the downpipe.

 

I run mine like the 2nd pic from the top. Basically single feed line from the compressor housing to a tee, one side goes to the bottom WG port and the other from the tee goes to the inlet on the solenoid. Then the center port on the solenoid is vented with the brass filter and the other side of the solenoid goes to the top hat of the WG. When the solenoid is off boost is supplied to the bottom of the WG but the top of the WG back to the solenoid is vented to atmosphere... basically like hooking up boost line to the bottom of the WG and leaving the top vented to atmosphere. When the solenoid is activated the bottom of the WG is still getting pressure but the solenoid closes off the vent and supplies pressure to the top (pressure on top and bottom of the WG) and it regulates pressure to the top by pulsing (venting) the boost pressure to the top of the gate. So you can achieve higher than spring pressure but if the controller takes a crap the solenoid is inactive and your back on gate pressure. This way allows usually double spring pressure and removing boost to the bottom and only applying to the top will net you higher boost capabilities as you don’t have boost helping open the WG as well as spring pressure. Essentially removing boost from the bottom of the gate and nothing on top either is a sure way to overboost bc it’s gotta push them spring open without the help of boost to help lighten the load.

 

I was able to get a ton of datalogging in this morning, and found a few definitive things about my whole setup...

Most importantly, my initial results were somewhat skewed, because I NEVER tried driving with the cutout CLOSED, with my initial EBC hose routing as yours is, and which is the closest to my old manual setup was.

I have an ON3 kit, which is flipped stock truck manifolds, 2.25" crossover to a T-4 flange, 1.5" wastegate exhaust (may be slightly larger, but that's my guess), VS Racing 78/75 T-4 cast turbo, 3" downpipe, back to a stock style catback. I have 3" cutout basically right next to the starter.

Using a Turbosmart EBoost STREET controller...and running 65% ethanol content, 17* timing
With Set Point 1, zeroed out, and Set Point 1 Gate Pressure zeroed out, it should be as if I have direct hose from boost source, to lower wastegate port...44mm wastegate came with a 6# spring.
CUTOUT CLOSED:
Several shorter (1 or 2 gear) WOT hits, from various MPH and RPM's, resulted in 3.5-4.5# boost
CUTOUT OPEN:
Several hits, many different loads (same as above), RPM, and MPH start points, resulted in anywhere from 5 to 8.5# of boost

Then...With Set Point 2, set at 65% solenoid duty cycle, and Gate Pressure set at 10.0 psi
CUTOUT CLOSED:
Same scenarios as above, 11-13, low and high points, fairly steady at 12+# of boost
CUTOUT OPEN:
Again, same as above, rock steady 15+# of boost

Stopped and viewed the logs, and decided to make a change to the controller...
Changed "low boost" to 10% duty cycle, with 4# of gate pressure
OPEN CUTOUT made 8#, and CLOSED CUTOUT made 6#, which is the spring rating.
Changed "high boost" to 50% solenoid duty cycle (15% lower than before), with 12# of gate pressure (2# higher than before)
OPEN CUTOUT made 13.5# and CLOSED CUTOUT made 12#

Now, at that point I figure I'm good...lol
Of course not...
OPEN CUTOUT, set on "low boost", but this time a WOT from a slow roll (6 MPH), through 3 gears (4L80E automatic, btw) up to 98 MPH, boost "flashed" with converter, to 6#, then ended up at 12#....

So...in the end, the EBC plumbing change probably made zero actual "change"...
With cutout open, on "low" or "high" boost, it makes anywhere from 4-6# more boost than running through the complete exhaust.

To limit and somewhat accurately control boost, I'll have to keep exhaust closed at the track...

Unless of course you or anyone else has any suggestions, advice, or tips to share.

I thought I may have had a too small of a wastegate, issue, because at 12-13# and higher it does not creep at all...

Opinions?

 

Why are you setting the gate pressure higher than the actual boost recorded. I read that you set it at 10psi gate when you only made 5-8.5lbs. If I remember correctly the gate setting has to be set correctly to the actual gate spring psi or slightly under it otherwise the gate starts to open before the controller starts and you get surges or spikes etc. which is why they want it dead on or slightly lower.

Your results should be repeatable if they aren’t then your messing something up. I would only set gate pressure either cutout open or closed and then realize when it’s open your going to go up X amount of boost, that part should be repeatable.

 

Gate pressure is set at 10# for the "high" boost setting, aka Boost Group 2, which I want at 13 or so, for now. My gate pressure for Boost Group 1, is at 3#

 

Yes but that isn’t your actual gate pressure. I don’t understand the boost group labels as I don’t have the EBC that you have.

I look at it like you set the boost EBC gate setting accurately so the EBC knows what the gate is doing and how to control it. If your getting 5psi and you set the EBC gate at 3psi that’s 2psi that the EBC doesn’t understand or know about. Setting the gate pressure lower is better than higher but I don’t see the point in being that far off. I don’t have the ability to have multiple gate settings so I can only set it once and I can have 2 boost programs and a scramble mode.

maybe the feature works for you but I would set the gate pressures accurately and maybe that will help with your results. Maybe keep the gate settings the same have you tried that and what were the results?

 

I understand (and appreciate) that you are trying to help, but you're saying I am doing something wrong, or setting wrong, a boost controller that you admittedly do not understand it's functionality?

The Gate Pressures are set how Turbosmart, (who makes the Boost Controller), says to set them.


Two things I have not tried...
One, is lowering the Gate Pressures, so that the wastegate starts opening sooner. Kind of a moot point now, because I am resigned to the fact, that the car simply makes faster, higher boost with cutout open, yet works exactly as set, with it closed.

and Two, re-installing the manual, air regulator boost controller and re-testing it. The more I think about it, the more I believe that I've never had the cutout closed (except for just idling through the neighborhood), since swapping turbos.

I know it (the MBC) controlled boost with the smaller turbo, cutout open or closed, which is why this whole deal has me puzzled.

Here's how they suggest to start dialing in the boost levels...which, again, is a moot point, since mine varies greatly depending on whether cutout is open or closed....


If you or anyone else sees something that I am just flat out missing, or misinterpreting, by all means, PLEASE let me know...

https://www.turbosmart.com/wp-conten...psi-JUL-12.pdf

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GP MUST be set lower than your actual desired boost, by at least 2-3psi. Until this pressure is reached...the controller is effectively blocking the signal to the gate in an attempt to prevent it cracking open early.
But it is trial and error, and too high will cause erratic control.

And there is no question altering the plumbing has made a difference. It would be impossible for it not to make a difference.

 

Very interesting, great information, thanks.