Single Turbo Boost Control Options

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Platinum Vendor
Jan 23, 2017
JB4 is really the way to go. It can do everything a stand alone controller can do, only better, becuase it's fully integrated. And all the extra safety features come in REALLY HANDY with single turbos. We've saved more customers motors than we can count with the JB4's passive safety systems.


10 Sec Club(N54)
Jul 12, 2017
Detroit, MI
I will chime in with some personal experience. On both my car the boostbox was giving inconsistent performance and doing some odd electrical things. Replaced the voltage regulator on the alternator and still saw the same issues. Went to an EBC for the time being, really enjoy the on-the-fly adjustability. Since then, I have now been getting intermittent alternator codes, so it was likely the alternator itself causing the issues with BB, but still works good enough for the time being. When MHD does offer on the fly load target changes I'll try going back
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Oct 18, 2016
I use the boostbox. Have never had any trouble with mine, I hide it in the ecu compartment area.

The one difference with the JB4 is that you can be installing your single kit on Monday and be on the dyno making 750 on tuesday. That is simply not the case with an etune. More like Tuesday of the next year. Pay someone to dyno tune your car and most of that gripe goes away.


Jun 2, 2019
I would recommend keeping the DME in control of WGDC whenever possible. There's quite a few current and future things you EBC users are going to miss out on, like a separate tuneable wgdc setpoint during anti-lag / NLS / 2-step, as well as on the fly load/boost target switching.
Any updates on these features? Is there any rough timeline for release?


Jul 23, 2017
I have had my ST tuned with JB4 but it needed fettling every time I got in the car. It was not consistent enough for me.
BoostBox has been fussy to tune correctly but well worth the effort and the trouble shooting required.
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Mar 29, 2019
I am using the Greddy Profec Boostcontroller on my N54 Speedtech ST. Works fine so far. Pretty simple to handle. You can switch from springpressure to a low and a high boost setting and change parameters on the Controller while driving.
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Nov 6, 2018
I am glad to report that a real EBC resolved my boosting issues. The boostbox gave me nothing but problems even with a few reputable tuners giving it a shot. After I installed my Gforce 3, the very first run it made boost above spring pressure and is consistent every single pull. Was able to hit 19psi with a gtx3076r on 93. More dialing in is needed but it sure is feeling good now!


Jun 4, 2018
I'm seeing something very strange and would like some input from you guys. During tuning I'm seeing that after a PID timeout the boost pressure going below spring pressure while staying WOT, and we can't figure out why.

This is with the speed tech twin scroll bottom mount kit with a GTX3582R gen II (at a mile of altitude and no spool increases yet), with a turbosmart hypergate Gen V. Boostbox with the proper 3 port mac valve. Boost signal is coming from the throttle body, 1/4 inch silicone tubing used for boost signal with a T to the bottom of the waste gate and the right side port of the MAC valve (when facing it's front) and the left side of the mac valve goes to the top of the waste gate. Aka it's properly plumbed.

If we run a WGDC disabled tune it shows that it runs spring pressure all the way to redline like it should. Spring is a 1 bar spring (which is about 12 psi at this altitude)

But if the PID times out mid run then it drops to below spring pressure, and we are not sure how that is possible. There are no exhaust leaks, no boost leaks, I've pressure tested the waste gate and silicone lines. If you run a no WGDC tune immediately after a PID timeout run you get perfect spring pressure. I"ve pulled the waste gate multiple times to inspect with no change to the results.

So everything to me points to something up with the MAC valve or boost box. New boost box PCB is on the way and I'll also replace the MAC valve while I'm at it.

Note that the ground for the boost box is shared with my AIC6 and a 1/2 amp 5v 20khz open collector pwm output (it's the ground for the open collector). So I'm wondering if maybe the ground might be having some effect here, but even then, how is it possible to go below spring pressure?



Sep 15, 2017
That's a weird issue - sounds like the MAC valve is somehow creating a vacuum at the top of the gate, which is pulling it open. Actually I remember a while ago Cleetus McFarland had a similar issue on one of his cars, here's a timestamped link to when he starts seeing the issue. Swapping out the valve fixed it for him, but his situation was somewhat different; for one, he was running CO2 (don't know how much of a difference it makes in this case), but mainly, no matter what he did, the valve always seemed to pull vacuum while it was being pulsed, whereas on your car it seems to work fine prior to the PID timeout.

Where is your boost reference on the throttle body? Is it upstream or downstream of the throttle blade itself? Typically you want it upstream of the throttle blade, in case you don't already have it that way. Also, it looks like your boost target is dropping suddenly after 5600 RPM prior to PID timeout (or is that the start of PID timeout? I'm a little rusty with stock ECU boost control stuff, it's been a while since I've used it haha). Do you know why it's dropping all of a sudden? My mind went to traction control/other torque limiter, but looks like the throttle is staying open and timing isn't being retarded, so that's doubtful.

Maybe try a map where you 0 out all the PID tables and set a flat WGDC target, and see what that does?


Jun 4, 2018
The PID timeout causes the drop in boost target.

I have a map like you're talking about with the PID logic disabled, I flashed it immediately after the above log and it runs 11.8 PSI flat all the away across. That's what is so strange about it.

Boost signal is from the charge pipe. It's the VRSF charge pipe and I used one of the 1/8 inch NPT plugs on it. So the boost signal is between the FMIC and the throttle body, thus when the throttle closes the boost signal will go up in pressure until the diverter valves open and then it will drop.

I do have a new MAC valve to try, so I'll be replacing that next. I'm also going to put an analog boost gauge on the line to the waste gate so I can see what's really going on there.


Sep 15, 2017
Got it on the PID timeout. How does it behave if you do a pull directly after one where it has timed out? Will it still be below spring pressure?

For your map with PID disabled, it sounds like WGDC is also zeroed? I'd be curious to see what would happen with PID disabled, but WGDC still applied to the solenoid.

Definitely interested to hear what the boost gauge says as well.


Jun 4, 2018
I replaced the MAC valve but it's still doing the same thing.

If I do a pull after the event the results are the same. Similar WGDC to reach target boost, still below spring pressure after PID timeout.

I tend to do a really good job of sealing things and making sure everything is setup "just so." I suspect I may have done too good of a job, and that when the PID cuts out suddenly that it's pulling a vacuum on the top half of the waste gate because there's a "vinturi" effect when it lets the pressure off and then shuts off to cause there to be a vacuum and I made too good of a seal so it holds.

Boost gauge indeed shows that I have close to the reported pressure of the TMAP.

I've ordered the parts needed to put a check valve on the top of the waste gate. This will have a 0.5 PSI crack pressure with a spring loaded ball that seals. This will allow air to enter the top if a greater than 0.5 PSI vacuum is created such that there can never be greater than a 0.5 PSI vacuum, but it will hold pressure up to 150 psi, and the spring will give it quick response time.

So I'll try that out once the parts get here.

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