Manual Boost Controller


Building a boost controller is a “slippery slope” sort of mod. Once you complete this you’re just going to want/need to modify something else in the system. A turbo-charger improves the performance of an engine by cramming as much air and fuel into the engine as possible. The engine exhaust drives an impeller in the turbo which drives the compress wheel in the intake path. Engines can’t handle extreme pressures so once the intake pressure reaches a factory set point a “waste-gate” opens to let the exhaust gas bypass the drive impeller so the turbo won’t produce any more boost. Factory boost settings a usually very conservative (otherwise, they’d be doing a lot of repairs) so there is a lot of potential for improvement.

A manual boost controller is placed in the path of the waste-gate’s sensor. The controller bleeds off some of the pressure in the line so that the pressure measured at the waste gate is lower than actual. This tricks the waste gate into staying closed longer than usual so a higher level of boost is reached. They’re really cheap to build, but the most important expense in this project is to getting accurate boost gauge. A little bit of bleed goes a long way and there is no way to tell where you are at without a proper gauge. DSMtuners has quite a few articles on how to build these devices and should work on almost all turbo cars.

29 thoughts on “Manual Boost Controller

  1. what is wrong with a car hack? ohhh wait, you think you are better than the people that post hacks on this site. Ok, well the go start your own damn page with your own hacks, then you can exclude whatever you want, and I can come bitch on your page about hacks you have.

  2. In all fairness, this is a rather well known trick. I wouldn’t even call it a hack as anyone doing the proper research to turbocharge, or upgrade their turbocharged vehicle would come across this.

  3. it is not about the turbo maxing out, it is about where the turbocharger is most efficent. They design the turbo from the factory to have the least amount of lag, and still be able to produce the power that they want. What happens is when you want the least amount of lag, you create a small turbo starts to spool at a low RPM to make the consumer happy, but from a performance standpoint, is not a good turbo to use. I could go into more, but it would prolly bore most of you here :) I <3 cars

  4. A “car hack”? Sure, why not!? It seems simple enough, and an easy-enough thing to think up on your own, but I’ve never heard of it (not that I would, I’m not the most up-to-date about cars). I say good show on it. I’m interested enough in seeing hacks that involve more than pure electronics/code.

  5. the 4g63(the engine made by dsm…its used by talon, eclipse, evo, and a few others) can take more boost than 11 psi in stock form. its pretty durable. by the way, the gst also has a turbo, hence the t, gsx is turbo + all wheel drive. with a 4g63 the turbo isnt the weekest link, its cooling. youll have temp problems before you blow your turbo. the point of this hack is the boost controller though, so whatever engine you have, make sure it can take the pressure youre gonna give it. I WANT MORE CAR HACKS! thanks

  6. I too wouldn’t call this a ‘hack’. Hacked boost control is where you use an air valve solenoid to bleed off the boost. Custom controller circuit pulsing the solenoid with a 40Hz PWM. That’s much more hackish

  7. Listen to me.. I dont know a whole lot about hacking, but I do know a lot about cars, and turbos. I used to own a mr2 turbo that I raced for a couple of years.

    If you do this, get a ball and spring valve, that will help eleminate boost creep, which gives you faster boost response. DO NOT BUY A CHEAP VALVE…

    here is my personal experience… I built one like this 5 years ago. So, this isnt really new, or hack or whatever. But, back to the story… I was racing, and I had used a cheap valve from home depot, and under the pressure the valve closed completely. Meaning I had no control over boost. In 4th gear about 110mph I passed my friend in his muffstain GT 5.0, and bam! I hit a boost spike, and oil was all over the place and my engine was smoking like a chimeny. I had melted 2 pistons, and blew the head gasket.

    IMHO… dont be cheap when it comes to boost controllers, invest in something good. Get an electronic boost controller, not only do they work faster by keeping the valve between the turbo and wastegate completely closed untill desired boost is reached, they are more reliable. They are more reliable. Yes, you will spend probably from 200-500$ for a good one. Its well worth it. I saved a few hundred by doing it myself. But, lets say, after 7k$ in work after that incident, my car never worked the same so I sold it.

    Now to reply to some posts…

    John f – The turbo motors in the eclipses is the same motor in the lancer turbos and galant vr4. the motors are very strong and can take up to 20psi on stock internals. (note: stock internals, not stock fuel system or anything else)

    also the mr2 motors, 3sgte… very strong, takes up to 20psi too on stock internals. look at rod millens pikes peak tacoma… it runs a 3sgte and puts out about 1000hp. Its very common in japan to take out the 2jz motor and stick in the 3sgte because its lighter, can make as much horse power and improves weight balance by being shorter.

    priest – they usually run it under effeciency due to the way the boost controllers work… the standard mechanical boost regulation is just a direct hos efrom the turbo to the wastegate actuator. this creates whats called boost creep, where since the actuator sees the pressure at all times, even a little bit will cause the wastegate to open a little bit, allowing the exhaust gasses to bypass the turbo… meaning the boost “creeps” slower to its max. as oppose to a electronic controller or ball and spring valve, it remains closed allowing the max exhaust gass to go through the turbo(spools much faster), then at max boost opens the wastegate. ok, back on topic… the boost creep can tend to allow the the turbo to spool a little higher then “max”, so… just as a safety measure.

  8. listen very carefully and learn this well:


    and for the record, the “car hack” is indeed a hack in the truest sense of the word. that’s a fact, not my opinion.

  9. I’m not going to get into an Internet pissing contest with you gavalt, but this is a “Comment” section, and i am merely “commenting”. To me, a hack would be putting a 3 bar gm map sensor on a honda to hide the fact that it’s seeing positive pressure. or how about chipping the ecu using eeproms with your own fuel and ignition curves… maybe a “how to make a cheap and effective water to air intercooler”. Now that I think about it, who are you to tell anyone they can’t voice an opinion? on the internet of all places! Don’t be so narrow minded man, it’s bad for your health.

  10. toxicbomber. Shut up. I am a huge car nerd and i’m constantly working on my car. and guess what nerds, a few years ago I was all into compiling my whole distrobution of linux from source. so believe me when i say that i know exactly what a “hack” is. upping the boost on a factory turbo’d car is the EXACT same concept as overclocking your processor ~ If you know what you’re doing, you’ll squeeze more power from what you have without really having to pay much for the upgrade. Which is something that car buffs and nerd buffs (is it possible to be buff and nerdy? :P) have in common.

  11. all the retards saying this isnt a hack, stfu, there are plenty of things on this site that arent necessarily ‘hacks’… what about the tornado machine – is that a hack? or not? go to wikipedia and look up hacker and look at number 7 in its jargon file… i think that just about covers anything that gets posted to this site as a hack… so stop the stupid “it is [not] a hack” argument and give it up.

  12. This will not work as well on newer cars unless you take the bleed line and connect it back into the intake line after the MAS (Mass Airflow Sensor). Newer cars use the incoming volume of air to determine the mixture, bleeding air off after it has been counted will cause the car to run progressively more rich and not perform as well.

  13. There is an amazing similarity in the processes and nature of cars and computers.

    I am a programmer (currently using JUnit to test software at an insurance company) from 9-5 outside of that I am an admin at and thouroughly addicted to fiddling with and racing the Wankel rotary engine.

    OOP and cars are so similar. The carburetor takes fuel and air in, mixes them in the appropriate ratios and volumes, then allows it to pass into the engine based on how much the user says should go in (via the gas pedal). I can take any carburetor object from another car, and pretty much bolt it right in to my car. That is no different from modern software design which uses blackbox principles.

    The amatuer car and computer enthusiasts fight the same battles. Car companies generally won’t release API specs, so we gotta get in there with a wrench and a multimeter and figure it out. Just like sending data to an unkown computer widget to figure out how it works when the suits wont tell you.

    The Talon/Eclipse (DSM chassis) is jokingly (lovingly?) called a disposable speed machine. They’re inexpensive, and can be ‘hacked’ to be rather quick. Maybe not the fastest car ever, but they’ll get the job done. Essentially the same as the efforts on the CVS One-Time-Use digicam hacks.

    To say that modifying cars does not fall under the realm of hacking is a slippery slope. In the end who cares, some people enjoy case modding, some like building motors, some like writing software, some like making show cars.

  14. Wow i sure made a few people mad now didn’t I?

    Yeah I guess you could call this a “hack” in the most exacting sense by what has been the accepted generalization of what a “true hack” is.

    But IMHO, this doesn’t really constitute a hack, a hack is usually something original, something nobody else has really thought up before. A good hack would have been something along the lines of what turbusa said, this is just an upgrade you can do yourself for a little bit cheaper then if you actually went out and bought it.

    The quality of hacks on this site is starting to slip, and nothing will improve if we don’t voice our opinion on the matter, no matter what that may be. But you can only really complain about that kind of crap if you have tried to do something other then whine about it, which I have.So when you have sent these guys some info on a hack, regardless of whether or not they used it, then you can come back to me and bitch about my opinion.

  15. Hacking has nothing to do with the medium. It has to do with the act. Anytime a product or concept is moved beyond the original intention of the creator, it has been hacked. Be that a cell phone, source code, or even a car.

    Those of you limiting your perceptions to the scope of things that can be hacked are by definition not embracing the true spirit of the hacker. Your not letting yourself see greater potential due to your own constrained understanding.

    Please, move toward enlightenment or piss off.

  16. fasttrak…

    thats inccorrect…

    you are right in what you say, but incorrect in the application.

    thats the bov(blow off valve) which vents the air (usually) back into the intake pipe.

    what happens is the throttle body opens, more air gets sucked in, and more fuel gets dumped in the engine, revving more, and the turbo spools up… well, the turbo spins freely, so when you let off the gas the turbo spools down slower, still pushing a bit of boost, this is a problem when you left off the gas because the throttle body closes… so you have this boost, with no where to go. thats where the bov comes in, its a pressure activated valve like the wastegate that relieves the pressure between the turbo and throttle body.

    now! you do have the option of venting it into the atmosphere, and thats where you get the “whoosh” sound. but the problem is, venting to the atmostphere usually leaves an open hole in the intake, after the airsensor,

    this causes air to be sucked in that isnt being measured by the air sensor, meaning, not enough fuel will get into the engine as well.

    most cars can vent to the atmosphere and run fine if you seal off the whole, but some cant.

  17. I think svecias is nearly right. The problem is not the hole left behind. It is that you’re dumping air that has already passed through the Mass Air Sensor. The computer is calculating fuel based on that amount of air, but that air never arrives so you end up with a really rich mixture. I’m pretty sure if you switch to a Manifold Absolute Pressure sensor dumping the air to atmosphere is not a problem. It has been a while since I’ve looked into this stuff though.

  18. Aah, us turbo Saab drivers have been doing this for long.. We’ve also had knock sensing and immediate boost release technology since 1982 (APC).. Makes it much easier on the engine – it automatically drops the boost pressure once knocking is detected + you don’t have to put in a bleeder valve, you just modify the APC box to allow more boost before it starts moderating it. The boost control is done with a PWM controlled solenoid valve.


  20. john f… 11psi maxed out turbo from the factory… Thats a 14b turbo it should do 18psi or so. I run 14psi with my 12a turbo and I haven’t blown up anything yet lol. So go ahead and put the MBC on your eclipse.

  21. Can someone plz send me a diagram of the waste gate lines and how they are supposed to go. I have a 16g turbo on my 98 eclipse spyder and an manual boost controller. Im not sure on how the lines go. Im using a factory waste gate. Also where can i get a header with external blow off cheap I see them In the 400’s wow thats steep. thanks my e_mail is

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