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What Do You Know About Boost Control? | [TECH NUGGET]

October 9, 2019

– When it comes to controlling boost
electronically with an external wastegate, the three port solenoid is probably
the most common option you’re going to see. And in most applications that’s gonna be
absolutely fine. What we do find though is that there
is a limit to the range of control you can get or achieve with the three port
solenoid. This is because with the way the three
port solenoid is normally plumbed, we’re always going to have boost pressure
making its way to the underside of the wastegate. This boost pressure helps try and push
the wastegate open. What this means is that if for example
we had a wastegate spring fitted that gave us a 10 psi base or minimum boost
pressure, we may find that with the three port
solenoid maxed out at maximum duty cycle, we may only be able to raise
the boost up to perhaps 20 or maybe 25 psi. And again, that’s probably fine for most
applications. In a situation however where we want to
get a really wide range of boost control, this may not be adequate. If we wanted to be able to achieve
a minimum boost pressure of 20 psi, but perhaps a maximum boost pressure
of 35 to 40 psi, we simply wouldn’t be able get there
because we’ve still got that boost reaching the bottom of the wastegate,
trying to force it open. Of course when the engine’s at high
RPM and high boost, we’ve also got exhaust back pressure
trying to force the wastegate open too. The option here is to swap out a three
port solenoid for a four port solenoid. The way this solenoid works is that it can
completely remove boost pressure from the underside of the wastegate
and instead just supply it to the top of the wastegate. In this situation we’ve still got that
exhaust manifold back pressure trying to force the wastegate open,
however now we’ve got boost pressure trying to force the wastegate closed,
this gives us that wider range of boost control. This is really important in some
situations such as high power drag cars where we need to be able to leave
the line with relatively low boost to achieve low power and make sure
we’ve got traction, however the deep end of the drag
strip, when we do have more traction available, we can then wind the boost
up to make a lot more power. If you want to learn more about
electronic boost control, and external wastegates, you can
check out our boost control tuning course at


  • Reply Josh Lewis September 26, 2018 at 9:25 pm

    Boost per gear, boost per speed, and boost-per-gear-per-speed are good ways to do it.

  • Reply kel kel Blackman September 26, 2018 at 11:02 pm

    There are so much to learn about boost control. And the HP academy has awsome content about wide rages off these. Once more you have done it again HP academy đź‘Ťđź‘Ťđź‘Ť

  • Reply Anton Pepkolaj September 26, 2018 at 11:31 pm

    Man you have the best voice and one of the best people that explains things in extremely detailed way. Thumbs up đź‘Ť

  • Reply Fidel U. Cortez September 27, 2018 at 5:13 am

    HP Academy is the only place to learn about engine tuning. They break it down to where you can understand without getting too technical. They are the best at what they do!

  • Reply Maikal _ September 27, 2018 at 10:34 am

    Not to be a troll (love everything about this chan)
    Im not in the know anymore, but watching this vid in 2018 makes me think why the hell are ppl controlling something so vital like motor pressure with solenoid and laggy liquid lines pre and post. Surely a fit for purpose geared stepper motor closed loop system is the way to do this? We all were scared of fly by wire throttles a while back; they're accepted now yah?
    Basement neckbearded trolls asside, im interested why this hasnt been done yet. Im interested why ppl are making money off $3 PWM solenoids and a basic SW alg and why im even commenting on this vid lol.
    PS; think of me when someone does this and makes a decent fund

  • Reply Buff Superbike September 27, 2018 at 1:05 pm

    Can you do a video on how a CO2 boost controller works?

  • Reply GordoWG1 WG1 September 28, 2018 at 1:53 pm

    Good points.
    I'd say torque, rather than power, and more engine torque being useable further down the strip as less multiplication is done in the higher gears.

  • Reply s j September 29, 2018 at 6:54 pm

    Great đź‘Ť

  • Reply Tbone Touch Hadebe October 5, 2018 at 4:38 pm

    I love this channel

  • Reply SovL:Remedy October 8, 2018 at 11:05 am

    Does a 4 port differ in sensitivity (Adjustment sensitivity/gain)

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